Tue, 17 Oct 2017 12:58:25 +0800
merge
1 /*
2 * Copyright (c) 1999, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
25 // no precompiled headers
26 #include "classfile/classLoader.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "classfile/vmSymbols.hpp"
29 #include "code/icBuffer.hpp"
30 #include "code/vtableStubs.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "compiler/disassembler.hpp"
33 #include "interpreter/interpreter.hpp"
34 #include "jvm_linux.h"
35 #include "memory/allocation.inline.hpp"
36 #include "memory/filemap.hpp"
37 #include "mutex_linux.inline.hpp"
38 #include "oops/oop.inline.hpp"
39 #include "os_share_linux.hpp"
40 #include "prims/jniFastGetField.hpp"
41 #include "prims/jvm.h"
42 #include "prims/jvm_misc.hpp"
43 #include "runtime/arguments.hpp"
44 #include "runtime/extendedPC.hpp"
45 #include "runtime/globals.hpp"
46 #include "runtime/interfaceSupport.hpp"
47 #include "runtime/init.hpp"
48 #include "runtime/java.hpp"
49 #include "runtime/javaCalls.hpp"
50 #include "runtime/mutexLocker.hpp"
51 #include "runtime/objectMonitor.hpp"
52 #include "runtime/orderAccess.inline.hpp"
53 #include "runtime/osThread.hpp"
54 #include "runtime/perfMemory.hpp"
55 #include "runtime/sharedRuntime.hpp"
56 #include "runtime/statSampler.hpp"
57 #include "runtime/stubRoutines.hpp"
58 #include "runtime/thread.inline.hpp"
59 #include "runtime/threadCritical.hpp"
60 #include "runtime/timer.hpp"
61 #include "services/attachListener.hpp"
62 #include "services/memTracker.hpp"
63 #include "services/runtimeService.hpp"
64 #include "utilities/decoder.hpp"
65 #include "utilities/defaultStream.hpp"
66 #include "utilities/events.hpp"
67 #include "utilities/elfFile.hpp"
68 #include "utilities/growableArray.hpp"
69 #include "utilities/vmError.hpp"
71 // put OS-includes here
72 # include <sys/types.h>
73 # include <sys/mman.h>
74 # include <sys/stat.h>
75 # include <sys/select.h>
76 # include <pthread.h>
77 # include <signal.h>
78 # include <errno.h>
79 # include <dlfcn.h>
80 # include <stdio.h>
81 # include <unistd.h>
82 # include <sys/resource.h>
83 # include <pthread.h>
84 # include <sys/stat.h>
85 # include <sys/time.h>
86 # include <sys/times.h>
87 # include <sys/utsname.h>
88 # include <sys/socket.h>
89 # include <sys/wait.h>
90 # include <pwd.h>
91 # include <poll.h>
92 # include <semaphore.h>
93 # include <fcntl.h>
94 # include <string.h>
95 # include <syscall.h>
96 # include <sys/sysinfo.h>
97 # include <gnu/libc-version.h>
98 # include <sys/ipc.h>
99 # include <sys/shm.h>
100 # include <link.h>
101 # include <stdint.h>
102 # include <inttypes.h>
103 # include <sys/ioctl.h>
105 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
107 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling
108 // getrusage() is prepared to handle the associated failure.
109 #ifndef RUSAGE_THREAD
110 #define RUSAGE_THREAD (1) /* only the calling thread */
111 #endif
113 #define MAX_PATH (2 * K)
115 #define MAX_SECS 100000000
117 // for timer info max values which include all bits
118 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
120 #define LARGEPAGES_BIT (1 << 6)
121 ////////////////////////////////////////////////////////////////////////////////
122 // global variables
123 julong os::Linux::_physical_memory = 0;
125 address os::Linux::_initial_thread_stack_bottom = NULL;
126 uintptr_t os::Linux::_initial_thread_stack_size = 0;
128 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
129 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
130 Mutex* os::Linux::_createThread_lock = NULL;
131 pthread_t os::Linux::_main_thread;
132 int os::Linux::_page_size = -1;
133 const int os::Linux::_vm_default_page_size = (8 * K);
134 bool os::Linux::_is_floating_stack = false;
135 bool os::Linux::_is_NPTL = false;
136 bool os::Linux::_supports_fast_thread_cpu_time = false;
137 const char * os::Linux::_glibc_version = NULL;
138 const char * os::Linux::_libpthread_version = NULL;
139 pthread_condattr_t os::Linux::_condattr[1];
141 static jlong initial_time_count=0;
143 static int clock_tics_per_sec = 100;
145 // For diagnostics to print a message once. see run_periodic_checks
146 static sigset_t check_signal_done;
147 static bool check_signals = true;
149 static pid_t _initial_pid = 0;
151 /* Signal number used to suspend/resume a thread */
153 /* do not use any signal number less than SIGSEGV, see 4355769 */
154 static int SR_signum = SIGUSR2;
155 sigset_t SR_sigset;
157 /* Used to protect dlsym() calls */
158 static pthread_mutex_t dl_mutex;
160 // Declarations
161 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time);
163 // utility functions
165 static int SR_initialize();
167 julong os::available_memory() {
168 return Linux::available_memory();
169 }
171 julong os::Linux::available_memory() {
172 // values in struct sysinfo are "unsigned long"
173 struct sysinfo si;
174 sysinfo(&si);
176 return (julong)si.freeram * si.mem_unit;
177 }
179 julong os::physical_memory() {
180 return Linux::physical_memory();
181 }
183 ////////////////////////////////////////////////////////////////////////////////
184 // environment support
186 bool os::getenv(const char* name, char* buf, int len) {
187 const char* val = ::getenv(name);
188 if (val != NULL && strlen(val) < (size_t)len) {
189 strcpy(buf, val);
190 return true;
191 }
192 if (len > 0) buf[0] = 0; // return a null string
193 return false;
194 }
197 // Return true if user is running as root.
199 bool os::have_special_privileges() {
200 static bool init = false;
201 static bool privileges = false;
202 if (!init) {
203 privileges = (getuid() != geteuid()) || (getgid() != getegid());
204 init = true;
205 }
206 return privileges;
207 }
210 #ifndef SYS_gettid
211 // i386: 224, ia64: 1105, amd64: 186, sparc 143
212 #ifdef __ia64__
213 #define SYS_gettid 1105
214 #else
215 #ifdef __i386__
216 #define SYS_gettid 224
217 #else
218 #ifdef __amd64__
219 #define SYS_gettid 186
220 #else
221 #ifdef __sparc__
222 #define SYS_gettid 143
223 #else
224 #error define gettid for the arch
225 #endif
226 #endif
227 #endif
228 #endif
229 #endif
231 // Cpu architecture string
232 static char cpu_arch[] = HOTSPOT_LIB_ARCH;
234 // pid_t gettid()
235 //
236 // Returns the kernel thread id of the currently running thread. Kernel
237 // thread id is used to access /proc.
238 //
239 // (Note that getpid() on LinuxThreads returns kernel thread id too; but
240 // on NPTL, it returns the same pid for all threads, as required by POSIX.)
241 //
242 pid_t os::Linux::gettid() {
243 int rslt = syscall(SYS_gettid);
244 if (rslt == -1) {
245 // old kernel, no NPTL support
246 return getpid();
247 } else {
248 return (pid_t)rslt;
249 }
250 }
252 // Most versions of linux have a bug where the number of processors are
253 // determined by looking at the /proc file system. In a chroot environment,
254 // the system call returns 1. This causes the VM to act as if it is
255 // a single processor and elide locking (see is_MP() call).
256 static bool unsafe_chroot_detected = false;
257 static const char *unstable_chroot_error = "/proc file system not found.\n"
258 "Java may be unstable running multithreaded in a chroot "
259 "environment on Linux when /proc filesystem is not mounted.";
261 void os::Linux::initialize_system_info() {
262 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
263 if (processor_count() == 1) {
264 pid_t pid = os::Linux::gettid();
265 char fname[32];
266 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
267 FILE *fp = fopen(fname, "r");
268 if (fp == NULL) {
269 unsafe_chroot_detected = true;
270 } else {
271 fclose(fp);
272 }
273 }
274 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
275 assert(processor_count() > 0, "linux error");
276 }
278 void os::init_system_properties_values() {
279 // The next steps are taken in the product version:
280 //
281 // Obtain the JAVA_HOME value from the location of libjvm.so.
282 // This library should be located at:
283 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so.
284 //
285 // If "/jre/lib/" appears at the right place in the path, then we
286 // assume libjvm.so is installed in a JDK and we use this path.
287 //
288 // Otherwise exit with message: "Could not create the Java virtual machine."
289 //
290 // The following extra steps are taken in the debugging version:
291 //
292 // If "/jre/lib/" does NOT appear at the right place in the path
293 // instead of exit check for $JAVA_HOME environment variable.
294 //
295 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
296 // then we append a fake suffix "hotspot/libjvm.so" to this path so
297 // it looks like libjvm.so is installed there
298 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
299 //
300 // Otherwise exit.
301 //
302 // Important note: if the location of libjvm.so changes this
303 // code needs to be changed accordingly.
305 // See ld(1):
306 // The linker uses the following search paths to locate required
307 // shared libraries:
308 // 1: ...
309 // ...
310 // 7: The default directories, normally /lib and /usr/lib.
311 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390))
312 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
313 #else
314 #define DEFAULT_LIBPATH "/lib:/usr/lib"
315 #endif
317 // Base path of extensions installed on the system.
318 #define SYS_EXT_DIR "/usr/java/packages"
319 #define EXTENSIONS_DIR "/lib/ext"
320 #define ENDORSED_DIR "/lib/endorsed"
322 // Buffer that fits several sprintfs.
323 // Note that the space for the colon and the trailing null are provided
324 // by the nulls included by the sizeof operator.
325 const size_t bufsize =
326 MAX3((size_t)MAXPATHLEN, // For dll_dir & friends.
327 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR), // extensions dir
328 (size_t)MAXPATHLEN + sizeof(ENDORSED_DIR)); // endorsed dir
329 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
331 // sysclasspath, java_home, dll_dir
332 {
333 char *pslash;
334 os::jvm_path(buf, bufsize);
336 // Found the full path to libjvm.so.
337 // Now cut the path to <java_home>/jre if we can.
338 *(strrchr(buf, '/')) = '\0'; // Get rid of /libjvm.so.
339 pslash = strrchr(buf, '/');
340 if (pslash != NULL) {
341 *pslash = '\0'; // Get rid of /{client|server|hotspot}.
342 }
343 Arguments::set_dll_dir(buf);
345 if (pslash != NULL) {
346 pslash = strrchr(buf, '/');
347 if (pslash != NULL) {
348 *pslash = '\0'; // Get rid of /<arch>.
349 pslash = strrchr(buf, '/');
350 if (pslash != NULL) {
351 *pslash = '\0'; // Get rid of /lib.
352 }
353 }
354 }
355 Arguments::set_java_home(buf);
356 set_boot_path('/', ':');
357 }
359 // Where to look for native libraries.
360 //
361 // Note: Due to a legacy implementation, most of the library path
362 // is set in the launcher. This was to accomodate linking restrictions
363 // on legacy Linux implementations (which are no longer supported).
364 // Eventually, all the library path setting will be done here.
365 //
366 // However, to prevent the proliferation of improperly built native
367 // libraries, the new path component /usr/java/packages is added here.
368 // Eventually, all the library path setting will be done here.
369 {
370 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
371 // should always exist (until the legacy problem cited above is
372 // addressed).
373 const char *v = ::getenv("LD_LIBRARY_PATH");
374 const char *v_colon = ":";
375 if (v == NULL) { v = ""; v_colon = ""; }
376 // That's +1 for the colon and +1 for the trailing '\0'.
377 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char,
378 strlen(v) + 1 +
379 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH) + 1,
380 mtInternal);
381 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib/%s:" DEFAULT_LIBPATH, v, v_colon, cpu_arch);
382 Arguments::set_library_path(ld_library_path);
383 FREE_C_HEAP_ARRAY(char, ld_library_path, mtInternal);
384 }
386 // Extensions directories.
387 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home());
388 Arguments::set_ext_dirs(buf);
390 // Endorsed standards default directory.
391 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
392 Arguments::set_endorsed_dirs(buf);
394 FREE_C_HEAP_ARRAY(char, buf, mtInternal);
396 #undef DEFAULT_LIBPATH
397 #undef SYS_EXT_DIR
398 #undef EXTENSIONS_DIR
399 #undef ENDORSED_DIR
400 }
402 ////////////////////////////////////////////////////////////////////////////////
403 // breakpoint support
405 void os::breakpoint() {
406 BREAKPOINT;
407 }
409 extern "C" void breakpoint() {
410 // use debugger to set breakpoint here
411 }
413 ////////////////////////////////////////////////////////////////////////////////
414 // signal support
416 debug_only(static bool signal_sets_initialized = false);
417 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
419 bool os::Linux::is_sig_ignored(int sig) {
420 struct sigaction oact;
421 sigaction(sig, (struct sigaction*)NULL, &oact);
422 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
423 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
424 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))
425 return true;
426 else
427 return false;
428 }
430 void os::Linux::signal_sets_init() {
431 // Should also have an assertion stating we are still single-threaded.
432 assert(!signal_sets_initialized, "Already initialized");
433 // Fill in signals that are necessarily unblocked for all threads in
434 // the VM. Currently, we unblock the following signals:
435 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
436 // by -Xrs (=ReduceSignalUsage));
437 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
438 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
439 // the dispositions or masks wrt these signals.
440 // Programs embedding the VM that want to use the above signals for their
441 // own purposes must, at this time, use the "-Xrs" option to prevent
442 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
443 // (See bug 4345157, and other related bugs).
444 // In reality, though, unblocking these signals is really a nop, since
445 // these signals are not blocked by default.
446 sigemptyset(&unblocked_sigs);
447 sigemptyset(&allowdebug_blocked_sigs);
448 sigaddset(&unblocked_sigs, SIGILL);
449 sigaddset(&unblocked_sigs, SIGSEGV);
450 sigaddset(&unblocked_sigs, SIGBUS);
451 sigaddset(&unblocked_sigs, SIGFPE);
452 #if defined(PPC64)
453 sigaddset(&unblocked_sigs, SIGTRAP);
454 #endif
455 sigaddset(&unblocked_sigs, SR_signum);
457 if (!ReduceSignalUsage) {
458 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
459 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
460 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
461 }
462 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
463 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
464 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
465 }
466 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
467 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
468 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
469 }
470 }
471 // Fill in signals that are blocked by all but the VM thread.
472 sigemptyset(&vm_sigs);
473 if (!ReduceSignalUsage)
474 sigaddset(&vm_sigs, BREAK_SIGNAL);
475 debug_only(signal_sets_initialized = true);
477 }
479 // These are signals that are unblocked while a thread is running Java.
480 // (For some reason, they get blocked by default.)
481 sigset_t* os::Linux::unblocked_signals() {
482 assert(signal_sets_initialized, "Not initialized");
483 return &unblocked_sigs;
484 }
486 // These are the signals that are blocked while a (non-VM) thread is
487 // running Java. Only the VM thread handles these signals.
488 sigset_t* os::Linux::vm_signals() {
489 assert(signal_sets_initialized, "Not initialized");
490 return &vm_sigs;
491 }
493 // These are signals that are blocked during cond_wait to allow debugger in
494 sigset_t* os::Linux::allowdebug_blocked_signals() {
495 assert(signal_sets_initialized, "Not initialized");
496 return &allowdebug_blocked_sigs;
497 }
499 void os::Linux::hotspot_sigmask(Thread* thread) {
501 //Save caller's signal mask before setting VM signal mask
502 sigset_t caller_sigmask;
503 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
505 OSThread* osthread = thread->osthread();
506 osthread->set_caller_sigmask(caller_sigmask);
508 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
510 if (!ReduceSignalUsage) {
511 if (thread->is_VM_thread()) {
512 // Only the VM thread handles BREAK_SIGNAL ...
513 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
514 } else {
515 // ... all other threads block BREAK_SIGNAL
516 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
517 }
518 }
519 }
521 //////////////////////////////////////////////////////////////////////////////
522 // detecting pthread library
524 void os::Linux::libpthread_init() {
525 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION
526 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a
527 // generic name for earlier versions.
528 // Define macros here so we can build HotSpot on old systems.
529 # ifndef _CS_GNU_LIBC_VERSION
530 # define _CS_GNU_LIBC_VERSION 2
531 # endif
532 # ifndef _CS_GNU_LIBPTHREAD_VERSION
533 # define _CS_GNU_LIBPTHREAD_VERSION 3
534 # endif
536 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
537 if (n > 0) {
538 char *str = (char *)malloc(n, mtInternal);
539 confstr(_CS_GNU_LIBC_VERSION, str, n);
540 os::Linux::set_glibc_version(str);
541 } else {
542 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version()
543 static char _gnu_libc_version[32];
544 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version),
545 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release());
546 os::Linux::set_glibc_version(_gnu_libc_version);
547 }
549 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
550 if (n > 0) {
551 char *str = (char *)malloc(n, mtInternal);
552 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
553 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells
554 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this
555 // is the case. LinuxThreads has a hard limit on max number of threads.
556 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value.
557 // On the other hand, NPTL does not have such a limit, sysconf()
558 // will return -1 and errno is not changed. Check if it is really NPTL.
559 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 &&
560 strstr(str, "NPTL") &&
561 sysconf(_SC_THREAD_THREADS_MAX) > 0) {
562 free(str);
563 os::Linux::set_libpthread_version("linuxthreads");
564 } else {
565 os::Linux::set_libpthread_version(str);
566 }
567 } else {
568 // glibc before 2.3.2 only has LinuxThreads.
569 os::Linux::set_libpthread_version("linuxthreads");
570 }
572 if (strstr(libpthread_version(), "NPTL")) {
573 os::Linux::set_is_NPTL();
574 } else {
575 os::Linux::set_is_LinuxThreads();
576 }
578 // LinuxThreads have two flavors: floating-stack mode, which allows variable
579 // stack size; and fixed-stack mode. NPTL is always floating-stack.
580 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) {
581 os::Linux::set_is_floating_stack();
582 }
583 }
585 /////////////////////////////////////////////////////////////////////////////
586 // thread stack
588 // Force Linux kernel to expand current thread stack. If "bottom" is close
589 // to the stack guard, caller should block all signals.
590 //
591 // MAP_GROWSDOWN:
592 // A special mmap() flag that is used to implement thread stacks. It tells
593 // kernel that the memory region should extend downwards when needed. This
594 // allows early versions of LinuxThreads to only mmap the first few pages
595 // when creating a new thread. Linux kernel will automatically expand thread
596 // stack as needed (on page faults).
597 //
598 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
599 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
600 // region, it's hard to tell if the fault is due to a legitimate stack
601 // access or because of reading/writing non-exist memory (e.g. buffer
602 // overrun). As a rule, if the fault happens below current stack pointer,
603 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
604 // application (see Linux kernel fault.c).
605 //
606 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
607 // stack overflow detection.
608 //
609 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
610 // not use this flag. However, the stack of initial thread is not created
611 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though
612 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack
613 // and then attach the thread to JVM.
614 //
615 // To get around the problem and allow stack banging on Linux, we need to
616 // manually expand thread stack after receiving the SIGSEGV.
617 //
618 // There are two ways to expand thread stack to address "bottom", we used
619 // both of them in JVM before 1.5:
620 // 1. adjust stack pointer first so that it is below "bottom", and then
621 // touch "bottom"
622 // 2. mmap() the page in question
623 //
624 // Now alternate signal stack is gone, it's harder to use 2. For instance,
625 // if current sp is already near the lower end of page 101, and we need to
626 // call mmap() to map page 100, it is possible that part of the mmap() frame
627 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
628 // That will destroy the mmap() frame and cause VM to crash.
629 //
630 // The following code works by adjusting sp first, then accessing the "bottom"
631 // page to force a page fault. Linux kernel will then automatically expand the
632 // stack mapping.
633 //
634 // _expand_stack_to() assumes its frame size is less than page size, which
635 // should always be true if the function is not inlined.
637 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute
638 #define NOINLINE
639 #else
640 #define NOINLINE __attribute__ ((noinline))
641 #endif
643 static void _expand_stack_to(address bottom) NOINLINE;
645 static void _expand_stack_to(address bottom) {
646 address sp;
647 size_t size;
648 volatile char *p;
650 // Adjust bottom to point to the largest address within the same page, it
651 // gives us a one-page buffer if alloca() allocates slightly more memory.
652 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
653 bottom += os::Linux::page_size() - 1;
655 // sp might be slightly above current stack pointer; if that's the case, we
656 // will alloca() a little more space than necessary, which is OK. Don't use
657 // os::current_stack_pointer(), as its result can be slightly below current
658 // stack pointer, causing us to not alloca enough to reach "bottom".
659 sp = (address)&sp;
661 if (sp > bottom) {
662 size = sp - bottom;
663 p = (volatile char *)alloca(size);
664 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
665 p[0] = '\0';
666 }
667 }
669 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
670 assert(t!=NULL, "just checking");
671 assert(t->osthread()->expanding_stack(), "expand should be set");
672 assert(t->stack_base() != NULL, "stack_base was not initialized");
674 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) {
675 sigset_t mask_all, old_sigset;
676 sigfillset(&mask_all);
677 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
678 _expand_stack_to(addr);
679 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
680 return true;
681 }
682 return false;
683 }
685 //////////////////////////////////////////////////////////////////////////////
686 // create new thread
688 static address highest_vm_reserved_address();
690 // check if it's safe to start a new thread
691 static bool _thread_safety_check(Thread* thread) {
692 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) {
693 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat)
694 // Heap is mmap'ed at lower end of memory space. Thread stacks are
695 // allocated (MAP_FIXED) from high address space. Every thread stack
696 // occupies a fixed size slot (usually 2Mbytes, but user can change
697 // it to other values if they rebuild LinuxThreads).
698 //
699 // Problem with MAP_FIXED is that mmap() can still succeed even part of
700 // the memory region has already been mmap'ed. That means if we have too
701 // many threads and/or very large heap, eventually thread stack will
702 // collide with heap.
703 //
704 // Here we try to prevent heap/stack collision by comparing current
705 // stack bottom with the highest address that has been mmap'ed by JVM
706 // plus a safety margin for memory maps created by native code.
707 //
708 // This feature can be disabled by setting ThreadSafetyMargin to 0
709 //
710 if (ThreadSafetyMargin > 0) {
711 address stack_bottom = os::current_stack_base() - os::current_stack_size();
713 // not safe if our stack extends below the safety margin
714 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address();
715 } else {
716 return true;
717 }
718 } else {
719 // Floating stack LinuxThreads or NPTL:
720 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When
721 // there's not enough space left, pthread_create() will fail. If we come
722 // here, that means enough space has been reserved for stack.
723 return true;
724 }
725 }
727 // Thread start routine for all newly created threads
728 static void *java_start(Thread *thread) {
729 // Try to randomize the cache line index of hot stack frames.
730 // This helps when threads of the same stack traces evict each other's
731 // cache lines. The threads can be either from the same JVM instance, or
732 // from different JVM instances. The benefit is especially true for
733 // processors with hyperthreading technology.
734 static int counter = 0;
735 int pid = os::current_process_id();
736 alloca(((pid ^ counter++) & 7) * 128);
738 ThreadLocalStorage::set_thread(thread);
740 OSThread* osthread = thread->osthread();
741 Monitor* sync = osthread->startThread_lock();
743 // non floating stack LinuxThreads needs extra check, see above
744 if (!_thread_safety_check(thread)) {
745 // notify parent thread
746 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
747 osthread->set_state(ZOMBIE);
748 sync->notify_all();
749 return NULL;
750 }
752 // thread_id is kernel thread id (similar to Solaris LWP id)
753 osthread->set_thread_id(os::Linux::gettid());
755 if (UseNUMA) {
756 int lgrp_id = os::numa_get_group_id();
757 if (lgrp_id != -1) {
758 thread->set_lgrp_id(lgrp_id);
759 }
760 }
761 // initialize signal mask for this thread
762 os::Linux::hotspot_sigmask(thread);
764 // initialize floating point control register
765 os::Linux::init_thread_fpu_state();
767 // handshaking with parent thread
768 {
769 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
771 // notify parent thread
772 osthread->set_state(INITIALIZED);
773 sync->notify_all();
775 // wait until os::start_thread()
776 while (osthread->get_state() == INITIALIZED) {
777 sync->wait(Mutex::_no_safepoint_check_flag);
778 }
779 }
781 // call one more level start routine
782 thread->run();
784 return 0;
785 }
787 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
788 assert(thread->osthread() == NULL, "caller responsible");
790 // Allocate the OSThread object
791 OSThread* osthread = new OSThread(NULL, NULL);
792 if (osthread == NULL) {
793 return false;
794 }
796 // set the correct thread state
797 osthread->set_thread_type(thr_type);
799 // Initial state is ALLOCATED but not INITIALIZED
800 osthread->set_state(ALLOCATED);
802 thread->set_osthread(osthread);
804 // init thread attributes
805 pthread_attr_t attr;
806 pthread_attr_init(&attr);
807 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
809 // stack size
810 if (os::Linux::supports_variable_stack_size()) {
811 // calculate stack size if it's not specified by caller
812 if (stack_size == 0) {
813 stack_size = os::Linux::default_stack_size(thr_type);
815 switch (thr_type) {
816 case os::java_thread:
817 // Java threads use ThreadStackSize which default value can be
818 // changed with the flag -Xss
819 assert (JavaThread::stack_size_at_create() > 0, "this should be set");
820 stack_size = JavaThread::stack_size_at_create();
821 break;
822 case os::compiler_thread:
823 if (CompilerThreadStackSize > 0) {
824 stack_size = (size_t)(CompilerThreadStackSize * K);
825 break;
826 } // else fall through:
827 // use VMThreadStackSize if CompilerThreadStackSize is not defined
828 case os::vm_thread:
829 case os::pgc_thread:
830 case os::cgc_thread:
831 case os::watcher_thread:
832 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
833 break;
834 }
835 }
837 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
838 pthread_attr_setstacksize(&attr, stack_size);
839 } else {
840 // let pthread_create() pick the default value.
841 }
843 // glibc guard page
844 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
846 ThreadState state;
848 {
849 // Serialize thread creation if we are running with fixed stack LinuxThreads
850 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack();
851 if (lock) {
852 os::Linux::createThread_lock()->lock_without_safepoint_check();
853 }
855 pthread_t tid;
856 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
858 pthread_attr_destroy(&attr);
860 if (ret != 0) {
861 if (PrintMiscellaneous && (Verbose || WizardMode)) {
862 perror("pthread_create()");
863 }
864 // Need to clean up stuff we've allocated so far
865 thread->set_osthread(NULL);
866 delete osthread;
867 if (lock) os::Linux::createThread_lock()->unlock();
868 return false;
869 }
871 // Store pthread info into the OSThread
872 osthread->set_pthread_id(tid);
874 // Wait until child thread is either initialized or aborted
875 {
876 Monitor* sync_with_child = osthread->startThread_lock();
877 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
878 while ((state = osthread->get_state()) == ALLOCATED) {
879 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
880 }
881 }
883 if (lock) {
884 os::Linux::createThread_lock()->unlock();
885 }
886 }
888 // Aborted due to thread limit being reached
889 if (state == ZOMBIE) {
890 thread->set_osthread(NULL);
891 delete osthread;
892 return false;
893 }
895 // The thread is returned suspended (in state INITIALIZED),
896 // and is started higher up in the call chain
897 assert(state == INITIALIZED, "race condition");
898 return true;
899 }
901 /////////////////////////////////////////////////////////////////////////////
902 // attach existing thread
904 // bootstrap the main thread
905 bool os::create_main_thread(JavaThread* thread) {
906 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
907 return create_attached_thread(thread);
908 }
910 bool os::create_attached_thread(JavaThread* thread) {
911 #ifdef ASSERT
912 thread->verify_not_published();
913 #endif
915 // Allocate the OSThread object
916 OSThread* osthread = new OSThread(NULL, NULL);
918 if (osthread == NULL) {
919 return false;
920 }
922 // Store pthread info into the OSThread
923 osthread->set_thread_id(os::Linux::gettid());
924 osthread->set_pthread_id(::pthread_self());
926 // initialize floating point control register
927 os::Linux::init_thread_fpu_state();
929 // Initial thread state is RUNNABLE
930 osthread->set_state(RUNNABLE);
932 thread->set_osthread(osthread);
934 if (UseNUMA) {
935 int lgrp_id = os::numa_get_group_id();
936 if (lgrp_id != -1) {
937 thread->set_lgrp_id(lgrp_id);
938 }
939 }
941 if (os::Linux::is_initial_thread()) {
942 // If current thread is initial thread, its stack is mapped on demand,
943 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
944 // the entire stack region to avoid SEGV in stack banging.
945 // It is also useful to get around the heap-stack-gap problem on SuSE
946 // kernel (see 4821821 for details). We first expand stack to the top
947 // of yellow zone, then enable stack yellow zone (order is significant,
948 // enabling yellow zone first will crash JVM on SuSE Linux), so there
949 // is no gap between the last two virtual memory regions.
951 JavaThread *jt = (JavaThread *)thread;
952 address addr = jt->stack_yellow_zone_base();
953 assert(addr != NULL, "initialization problem?");
954 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
956 osthread->set_expanding_stack();
957 os::Linux::manually_expand_stack(jt, addr);
958 osthread->clear_expanding_stack();
959 }
961 // initialize signal mask for this thread
962 // and save the caller's signal mask
963 os::Linux::hotspot_sigmask(thread);
965 return true;
966 }
968 void os::pd_start_thread(Thread* thread) {
969 OSThread * osthread = thread->osthread();
970 assert(osthread->get_state() != INITIALIZED, "just checking");
971 Monitor* sync_with_child = osthread->startThread_lock();
972 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
973 sync_with_child->notify();
975 #ifdef MIPS64
976 /* 2013/11/5 Jin: To be accessed in NativeGeneralJump::patch_verified_entry() */
977 if (thread->is_Java_thread())
978 {
979 ((JavaThread*)thread)->set_handle_wrong_method_stub(SharedRuntime::get_handle_wrong_method_stub());
980 }
981 #endif
982 }
984 // Free Linux resources related to the OSThread
985 void os::free_thread(OSThread* osthread) {
986 assert(osthread != NULL, "osthread not set");
988 if (Thread::current()->osthread() == osthread) {
989 // Restore caller's signal mask
990 sigset_t sigmask = osthread->caller_sigmask();
991 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
992 }
994 delete osthread;
995 }
997 //////////////////////////////////////////////////////////////////////////////
998 // thread local storage
1000 // Restore the thread pointer if the destructor is called. This is in case
1001 // someone from JNI code sets up a destructor with pthread_key_create to run
1002 // detachCurrentThread on thread death. Unless we restore the thread pointer we
1003 // will hang or crash. When detachCurrentThread is called the key will be set
1004 // to null and we will not be called again. If detachCurrentThread is never
1005 // called we could loop forever depending on the pthread implementation.
1006 static void restore_thread_pointer(void* p) {
1007 Thread* thread = (Thread*) p;
1008 os::thread_local_storage_at_put(ThreadLocalStorage::thread_index(), thread);
1009 }
1011 int os::allocate_thread_local_storage() {
1012 pthread_key_t key;
1013 int rslt = pthread_key_create(&key, restore_thread_pointer);
1014 assert(rslt == 0, "cannot allocate thread local storage");
1015 return (int)key;
1016 }
1018 // Note: This is currently not used by VM, as we don't destroy TLS key
1019 // on VM exit.
1020 void os::free_thread_local_storage(int index) {
1021 int rslt = pthread_key_delete((pthread_key_t)index);
1022 assert(rslt == 0, "invalid index");
1023 }
1025 void os::thread_local_storage_at_put(int index, void* value) {
1026 int rslt = pthread_setspecific((pthread_key_t)index, value);
1027 assert(rslt == 0, "pthread_setspecific failed");
1028 }
1030 extern "C" Thread* get_thread() {
1031 return ThreadLocalStorage::thread();
1032 }
1034 //////////////////////////////////////////////////////////////////////////////
1035 // initial thread
1037 // Check if current thread is the initial thread, similar to Solaris thr_main.
1038 bool os::Linux::is_initial_thread(void) {
1039 char dummy;
1040 // If called before init complete, thread stack bottom will be null.
1041 // Can be called if fatal error occurs before initialization.
1042 if (initial_thread_stack_bottom() == NULL) return false;
1043 assert(initial_thread_stack_bottom() != NULL &&
1044 initial_thread_stack_size() != 0,
1045 "os::init did not locate initial thread's stack region");
1046 if ((address)&dummy >= initial_thread_stack_bottom() &&
1047 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size())
1048 return true;
1049 else return false;
1050 }
1052 // Find the virtual memory area that contains addr
1053 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1054 FILE *fp = fopen("/proc/self/maps", "r");
1055 if (fp) {
1056 address low, high;
1057 while (!feof(fp)) {
1058 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1059 if (low <= addr && addr < high) {
1060 if (vma_low) *vma_low = low;
1061 if (vma_high) *vma_high = high;
1062 fclose (fp);
1063 return true;
1064 }
1065 }
1066 for (;;) {
1067 int ch = fgetc(fp);
1068 if (ch == EOF || ch == (int)'\n') break;
1069 }
1070 }
1071 fclose(fp);
1072 }
1073 return false;
1074 }
1076 // Locate initial thread stack. This special handling of initial thread stack
1077 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1078 // bogus value for initial thread.
1079 void os::Linux::capture_initial_stack(size_t max_size) {
1080 // stack size is the easy part, get it from RLIMIT_STACK
1081 size_t stack_size;
1082 struct rlimit rlim;
1083 getrlimit(RLIMIT_STACK, &rlim);
1084 stack_size = rlim.rlim_cur;
1086 // 6308388: a bug in ld.so will relocate its own .data section to the
1087 // lower end of primordial stack; reduce ulimit -s value a little bit
1088 // so we won't install guard page on ld.so's data section.
1089 stack_size -= 2 * page_size();
1091 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
1092 // 7.1, in both cases we will get 2G in return value.
1093 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
1094 // SuSE 7.2, Debian) can not handle alternate signal stack correctly
1095 // for initial thread if its stack size exceeds 6M. Cap it at 2M,
1096 // in case other parts in glibc still assumes 2M max stack size.
1097 // FIXME: alt signal stack is gone, maybe we can relax this constraint?
1098 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
1099 if (stack_size > 2 * K * K IA64_ONLY(*2))
1100 stack_size = 2 * K * K IA64_ONLY(*2);
1101 // Try to figure out where the stack base (top) is. This is harder.
1102 //
1103 // When an application is started, glibc saves the initial stack pointer in
1104 // a global variable "__libc_stack_end", which is then used by system
1105 // libraries. __libc_stack_end should be pretty close to stack top. The
1106 // variable is available since the very early days. However, because it is
1107 // a private interface, it could disappear in the future.
1108 //
1109 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1110 // to __libc_stack_end, it is very close to stack top, but isn't the real
1111 // stack top. Note that /proc may not exist if VM is running as a chroot
1112 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1113 // /proc/<pid>/stat could change in the future (though unlikely).
1114 //
1115 // We try __libc_stack_end first. If that doesn't work, look for
1116 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1117 // as a hint, which should work well in most cases.
1119 uintptr_t stack_start;
1121 // try __libc_stack_end first
1122 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1123 if (p && *p) {
1124 stack_start = *p;
1125 } else {
1126 // see if we can get the start_stack field from /proc/self/stat
1127 FILE *fp;
1128 int pid;
1129 char state;
1130 int ppid;
1131 int pgrp;
1132 int session;
1133 int nr;
1134 int tpgrp;
1135 unsigned long flags;
1136 unsigned long minflt;
1137 unsigned long cminflt;
1138 unsigned long majflt;
1139 unsigned long cmajflt;
1140 unsigned long utime;
1141 unsigned long stime;
1142 long cutime;
1143 long cstime;
1144 long prio;
1145 long nice;
1146 long junk;
1147 long it_real;
1148 uintptr_t start;
1149 uintptr_t vsize;
1150 intptr_t rss;
1151 uintptr_t rsslim;
1152 uintptr_t scodes;
1153 uintptr_t ecode;
1154 int i;
1156 // Figure what the primordial thread stack base is. Code is inspired
1157 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1158 // followed by command name surrounded by parentheses, state, etc.
1159 char stat[2048];
1160 int statlen;
1162 fp = fopen("/proc/self/stat", "r");
1163 if (fp) {
1164 statlen = fread(stat, 1, 2047, fp);
1165 stat[statlen] = '\0';
1166 fclose(fp);
1168 // Skip pid and the command string. Note that we could be dealing with
1169 // weird command names, e.g. user could decide to rename java launcher
1170 // to "java 1.4.2 :)", then the stat file would look like
1171 // 1234 (java 1.4.2 :)) R ... ...
1172 // We don't really need to know the command string, just find the last
1173 // occurrence of ")" and then start parsing from there. See bug 4726580.
1174 char * s = strrchr(stat, ')');
1176 i = 0;
1177 if (s) {
1178 // Skip blank chars
1179 do s++; while (isspace(*s));
1181 #define _UFM UINTX_FORMAT
1182 #define _DFM INTX_FORMAT
1184 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */
1185 /* 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 */
1186 i = sscanf(s, "%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld " _UFM _UFM _DFM _UFM _UFM _UFM _UFM,
1187 &state, /* 3 %c */
1188 &ppid, /* 4 %d */
1189 &pgrp, /* 5 %d */
1190 &session, /* 6 %d */
1191 &nr, /* 7 %d */
1192 &tpgrp, /* 8 %d */
1193 &flags, /* 9 %lu */
1194 &minflt, /* 10 %lu */
1195 &cminflt, /* 11 %lu */
1196 &majflt, /* 12 %lu */
1197 &cmajflt, /* 13 %lu */
1198 &utime, /* 14 %lu */
1199 &stime, /* 15 %lu */
1200 &cutime, /* 16 %ld */
1201 &cstime, /* 17 %ld */
1202 &prio, /* 18 %ld */
1203 &nice, /* 19 %ld */
1204 &junk, /* 20 %ld */
1205 &it_real, /* 21 %ld */
1206 &start, /* 22 UINTX_FORMAT */
1207 &vsize, /* 23 UINTX_FORMAT */
1208 &rss, /* 24 INTX_FORMAT */
1209 &rsslim, /* 25 UINTX_FORMAT */
1210 &scodes, /* 26 UINTX_FORMAT */
1211 &ecode, /* 27 UINTX_FORMAT */
1212 &stack_start); /* 28 UINTX_FORMAT */
1213 }
1215 #undef _UFM
1216 #undef _DFM
1218 if (i != 28 - 2) {
1219 assert(false, "Bad conversion from /proc/self/stat");
1220 // product mode - assume we are the initial thread, good luck in the
1221 // embedded case.
1222 warning("Can't detect initial thread stack location - bad conversion");
1223 stack_start = (uintptr_t) &rlim;
1224 }
1225 } else {
1226 // For some reason we can't open /proc/self/stat (for example, running on
1227 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1228 // most cases, so don't abort:
1229 warning("Can't detect initial thread stack location - no /proc/self/stat");
1230 stack_start = (uintptr_t) &rlim;
1231 }
1232 }
1234 // Now we have a pointer (stack_start) very close to the stack top, the
1235 // next thing to do is to figure out the exact location of stack top. We
1236 // can find out the virtual memory area that contains stack_start by
1237 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1238 // and its upper limit is the real stack top. (again, this would fail if
1239 // running inside chroot, because /proc may not exist.)
1241 uintptr_t stack_top;
1242 address low, high;
1243 if (find_vma((address)stack_start, &low, &high)) {
1244 // success, "high" is the true stack top. (ignore "low", because initial
1245 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1246 stack_top = (uintptr_t)high;
1247 } else {
1248 // failed, likely because /proc/self/maps does not exist
1249 warning("Can't detect initial thread stack location - find_vma failed");
1250 // best effort: stack_start is normally within a few pages below the real
1251 // stack top, use it as stack top, and reduce stack size so we won't put
1252 // guard page outside stack.
1253 stack_top = stack_start;
1254 stack_size -= 16 * page_size();
1255 }
1257 // stack_top could be partially down the page so align it
1258 stack_top = align_size_up(stack_top, page_size());
1260 if (max_size && stack_size > max_size) {
1261 _initial_thread_stack_size = max_size;
1262 } else {
1263 _initial_thread_stack_size = stack_size;
1264 }
1266 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1267 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1268 }
1270 ////////////////////////////////////////////////////////////////////////////////
1271 // time support
1273 // Time since start-up in seconds to a fine granularity.
1274 // Used by VMSelfDestructTimer and the MemProfiler.
1275 double os::elapsedTime() {
1277 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution
1278 }
1280 jlong os::elapsed_counter() {
1281 return javaTimeNanos() - initial_time_count;
1282 }
1284 jlong os::elapsed_frequency() {
1285 return NANOSECS_PER_SEC; // nanosecond resolution
1286 }
1288 bool os::supports_vtime() { return true; }
1289 bool os::enable_vtime() { return false; }
1290 bool os::vtime_enabled() { return false; }
1292 double os::elapsedVTime() {
1293 struct rusage usage;
1294 int retval = getrusage(RUSAGE_THREAD, &usage);
1295 if (retval == 0) {
1296 return (double) (usage.ru_utime.tv_sec + usage.ru_stime.tv_sec) + (double) (usage.ru_utime.tv_usec + usage.ru_stime.tv_usec) / (1000 * 1000);
1297 } else {
1298 // better than nothing, but not much
1299 return elapsedTime();
1300 }
1301 }
1303 jlong os::javaTimeMillis() {
1304 timeval time;
1305 int status = gettimeofday(&time, NULL);
1306 assert(status != -1, "linux error");
1307 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1308 }
1310 #ifndef CLOCK_MONOTONIC
1311 #define CLOCK_MONOTONIC (1)
1312 #endif
1314 void os::Linux::clock_init() {
1315 // we do dlopen's in this particular order due to bug in linux
1316 // dynamical loader (see 6348968) leading to crash on exit
1317 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1318 if (handle == NULL) {
1319 handle = dlopen("librt.so", RTLD_LAZY);
1320 }
1322 if (handle) {
1323 int (*clock_getres_func)(clockid_t, struct timespec*) =
1324 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1325 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1326 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1327 if (clock_getres_func && clock_gettime_func) {
1328 // See if monotonic clock is supported by the kernel. Note that some
1329 // early implementations simply return kernel jiffies (updated every
1330 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1331 // for nano time (though the monotonic property is still nice to have).
1332 // It's fixed in newer kernels, however clock_getres() still returns
1333 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1334 // resolution for now. Hopefully as people move to new kernels, this
1335 // won't be a problem.
1336 struct timespec res;
1337 struct timespec tp;
1338 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1339 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1340 // yes, monotonic clock is supported
1341 _clock_gettime = clock_gettime_func;
1342 return;
1343 } else {
1344 // close librt if there is no monotonic clock
1345 dlclose(handle);
1346 }
1347 }
1348 }
1349 warning("No monotonic clock was available - timed services may " \
1350 "be adversely affected if the time-of-day clock changes");
1351 }
1353 #ifndef SYS_clock_getres
1355 #if defined(IA32) || defined(AMD64)
1356 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229)
1357 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1358 #else
1359 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1360 #define sys_clock_getres(x,y) -1
1361 #endif
1363 #else
1364 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1365 #endif
1367 void os::Linux::fast_thread_clock_init() {
1368 if (!UseLinuxPosixThreadCPUClocks) {
1369 return;
1370 }
1371 clockid_t clockid;
1372 struct timespec tp;
1373 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1374 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1376 // Switch to using fast clocks for thread cpu time if
1377 // the sys_clock_getres() returns 0 error code.
1378 // Note, that some kernels may support the current thread
1379 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1380 // returned by the pthread_getcpuclockid().
1381 // If the fast Posix clocks are supported then the sys_clock_getres()
1382 // must return at least tp.tv_sec == 0 which means a resolution
1383 // better than 1 sec. This is extra check for reliability.
1385 if(pthread_getcpuclockid_func &&
1386 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1387 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1389 _supports_fast_thread_cpu_time = true;
1390 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1391 }
1392 }
1394 jlong os::javaTimeNanos() {
1395 if (Linux::supports_monotonic_clock()) {
1396 struct timespec tp;
1397 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1398 assert(status == 0, "gettime error");
1399 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1400 return result;
1401 } else {
1402 timeval time;
1403 int status = gettimeofday(&time, NULL);
1404 assert(status != -1, "linux error");
1405 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1406 return 1000 * usecs;
1407 }
1408 }
1410 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1411 if (Linux::supports_monotonic_clock()) {
1412 info_ptr->max_value = ALL_64_BITS;
1414 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1415 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1416 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1417 } else {
1418 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1419 info_ptr->max_value = ALL_64_BITS;
1421 // gettimeofday is a real time clock so it skips
1422 info_ptr->may_skip_backward = true;
1423 info_ptr->may_skip_forward = true;
1424 }
1426 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1427 }
1429 // Return the real, user, and system times in seconds from an
1430 // arbitrary fixed point in the past.
1431 bool os::getTimesSecs(double* process_real_time,
1432 double* process_user_time,
1433 double* process_system_time) {
1434 struct tms ticks;
1435 clock_t real_ticks = times(&ticks);
1437 if (real_ticks == (clock_t) (-1)) {
1438 return false;
1439 } else {
1440 double ticks_per_second = (double) clock_tics_per_sec;
1441 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1442 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1443 *process_real_time = ((double) real_ticks) / ticks_per_second;
1445 return true;
1446 }
1447 }
1450 char * os::local_time_string(char *buf, size_t buflen) {
1451 struct tm t;
1452 time_t long_time;
1453 time(&long_time);
1454 localtime_r(&long_time, &t);
1455 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1456 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1457 t.tm_hour, t.tm_min, t.tm_sec);
1458 return buf;
1459 }
1461 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1462 return localtime_r(clock, res);
1463 }
1465 ////////////////////////////////////////////////////////////////////////////////
1466 // runtime exit support
1468 // Note: os::shutdown() might be called very early during initialization, or
1469 // called from signal handler. Before adding something to os::shutdown(), make
1470 // sure it is async-safe and can handle partially initialized VM.
1471 void os::shutdown() {
1473 // allow PerfMemory to attempt cleanup of any persistent resources
1474 perfMemory_exit();
1476 // needs to remove object in file system
1477 AttachListener::abort();
1479 // flush buffered output, finish log files
1480 ostream_abort();
1482 // Check for abort hook
1483 abort_hook_t abort_hook = Arguments::abort_hook();
1484 if (abort_hook != NULL) {
1485 abort_hook();
1486 }
1488 }
1490 // Note: os::abort() might be called very early during initialization, or
1491 // called from signal handler. Before adding something to os::abort(), make
1492 // sure it is async-safe and can handle partially initialized VM.
1493 void os::abort(bool dump_core) {
1494 os::shutdown();
1495 if (dump_core) {
1496 #ifndef PRODUCT
1497 fdStream out(defaultStream::output_fd());
1498 out.print_raw("Current thread is ");
1499 char buf[16];
1500 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1501 out.print_raw_cr(buf);
1502 out.print_raw_cr("Dumping core ...");
1503 #endif
1504 ::abort(); // dump core
1505 }
1507 ::exit(1);
1508 }
1510 // Die immediately, no exit hook, no abort hook, no cleanup.
1511 void os::die() {
1512 // _exit() on LinuxThreads only kills current thread
1513 ::abort();
1514 }
1517 // This method is a copy of JDK's sysGetLastErrorString
1518 // from src/solaris/hpi/src/system_md.c
1520 size_t os::lasterror(char *buf, size_t len) {
1522 if (errno == 0) return 0;
1524 const char *s = ::strerror(errno);
1525 size_t n = ::strlen(s);
1526 if (n >= len) {
1527 n = len - 1;
1528 }
1529 ::strncpy(buf, s, n);
1530 buf[n] = '\0';
1531 return n;
1532 }
1534 intx os::current_thread_id() { return (intx)pthread_self(); }
1535 int os::current_process_id() {
1537 // Under the old linux thread library, linux gives each thread
1538 // its own process id. Because of this each thread will return
1539 // a different pid if this method were to return the result
1540 // of getpid(2). Linux provides no api that returns the pid
1541 // of the launcher thread for the vm. This implementation
1542 // returns a unique pid, the pid of the launcher thread
1543 // that starts the vm 'process'.
1545 // Under the NPTL, getpid() returns the same pid as the
1546 // launcher thread rather than a unique pid per thread.
1547 // Use gettid() if you want the old pre NPTL behaviour.
1549 // if you are looking for the result of a call to getpid() that
1550 // returns a unique pid for the calling thread, then look at the
1551 // OSThread::thread_id() method in osThread_linux.hpp file
1553 return (int)(_initial_pid ? _initial_pid : getpid());
1554 }
1556 // DLL functions
1558 const char* os::dll_file_extension() { return ".so"; }
1560 // This must be hard coded because it's the system's temporary
1561 // directory not the java application's temp directory, ala java.io.tmpdir.
1562 const char* os::get_temp_directory() { return "/tmp"; }
1564 static bool file_exists(const char* filename) {
1565 struct stat statbuf;
1566 if (filename == NULL || strlen(filename) == 0) {
1567 return false;
1568 }
1569 return os::stat(filename, &statbuf) == 0;
1570 }
1572 bool os::dll_build_name(char* buffer, size_t buflen,
1573 const char* pname, const char* fname) {
1574 bool retval = false;
1575 // Copied from libhpi
1576 const size_t pnamelen = pname ? strlen(pname) : 0;
1578 // Return error on buffer overflow.
1579 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1580 return retval;
1581 }
1583 if (pnamelen == 0) {
1584 snprintf(buffer, buflen, "lib%s.so", fname);
1585 retval = true;
1586 } else if (strchr(pname, *os::path_separator()) != NULL) {
1587 int n;
1588 char** pelements = split_path(pname, &n);
1589 if (pelements == NULL) {
1590 return false;
1591 }
1592 for (int i = 0 ; i < n ; i++) {
1593 // Really shouldn't be NULL, but check can't hurt
1594 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1595 continue; // skip the empty path values
1596 }
1597 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1598 if (file_exists(buffer)) {
1599 retval = true;
1600 break;
1601 }
1602 }
1603 // release the storage
1604 for (int i = 0 ; i < n ; i++) {
1605 if (pelements[i] != NULL) {
1606 FREE_C_HEAP_ARRAY(char, pelements[i], mtInternal);
1607 }
1608 }
1609 if (pelements != NULL) {
1610 FREE_C_HEAP_ARRAY(char*, pelements, mtInternal);
1611 }
1612 } else {
1613 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1614 retval = true;
1615 }
1616 return retval;
1617 }
1619 // check if addr is inside libjvm.so
1620 bool os::address_is_in_vm(address addr) {
1621 static address libjvm_base_addr;
1622 Dl_info dlinfo;
1624 if (libjvm_base_addr == NULL) {
1625 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1626 libjvm_base_addr = (address)dlinfo.dli_fbase;
1627 }
1628 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1629 }
1631 if (dladdr((void *)addr, &dlinfo) != 0) {
1632 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1633 }
1635 return false;
1636 }
1638 bool os::dll_address_to_function_name(address addr, char *buf,
1639 int buflen, int *offset) {
1640 // buf is not optional, but offset is optional
1641 assert(buf != NULL, "sanity check");
1643 Dl_info dlinfo;
1645 if (dladdr((void*)addr, &dlinfo) != 0) {
1646 // see if we have a matching symbol
1647 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1648 if (!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) {
1649 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1650 }
1651 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1652 return true;
1653 }
1654 // no matching symbol so try for just file info
1655 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1656 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1657 buf, buflen, offset, dlinfo.dli_fname)) {
1658 return true;
1659 }
1660 }
1661 }
1663 buf[0] = '\0';
1664 if (offset != NULL) *offset = -1;
1665 return false;
1666 }
1668 struct _address_to_library_name {
1669 address addr; // input : memory address
1670 size_t buflen; // size of fname
1671 char* fname; // output: library name
1672 address base; // library base addr
1673 };
1675 static int address_to_library_name_callback(struct dl_phdr_info *info,
1676 size_t size, void *data) {
1677 int i;
1678 bool found = false;
1679 address libbase = NULL;
1680 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1682 // iterate through all loadable segments
1683 for (i = 0; i < info->dlpi_phnum; i++) {
1684 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1685 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1686 // base address of a library is the lowest address of its loaded
1687 // segments.
1688 if (libbase == NULL || libbase > segbase) {
1689 libbase = segbase;
1690 }
1691 // see if 'addr' is within current segment
1692 if (segbase <= d->addr &&
1693 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1694 found = true;
1695 }
1696 }
1697 }
1699 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1700 // so dll_address_to_library_name() can fall through to use dladdr() which
1701 // can figure out executable name from argv[0].
1702 if (found && info->dlpi_name && info->dlpi_name[0]) {
1703 d->base = libbase;
1704 if (d->fname) {
1705 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1706 }
1707 return 1;
1708 }
1709 return 0;
1710 }
1712 bool os::dll_address_to_library_name(address addr, char* buf,
1713 int buflen, int* offset) {
1714 // buf is not optional, but offset is optional
1715 assert(buf != NULL, "sanity check");
1717 Dl_info dlinfo;
1718 struct _address_to_library_name data;
1720 // There is a bug in old glibc dladdr() implementation that it could resolve
1721 // to wrong library name if the .so file has a base address != NULL. Here
1722 // we iterate through the program headers of all loaded libraries to find
1723 // out which library 'addr' really belongs to. This workaround can be
1724 // removed once the minimum requirement for glibc is moved to 2.3.x.
1725 data.addr = addr;
1726 data.fname = buf;
1727 data.buflen = buflen;
1728 data.base = NULL;
1729 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1731 if (rslt) {
1732 // buf already contains library name
1733 if (offset) *offset = addr - data.base;
1734 return true;
1735 }
1736 if (dladdr((void*)addr, &dlinfo) != 0) {
1737 if (dlinfo.dli_fname != NULL) {
1738 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1739 }
1740 if (dlinfo.dli_fbase != NULL && offset != NULL) {
1741 *offset = addr - (address)dlinfo.dli_fbase;
1742 }
1743 return true;
1744 }
1746 buf[0] = '\0';
1747 if (offset) *offset = -1;
1748 return false;
1749 }
1751 // Loads .dll/.so and
1752 // in case of error it checks if .dll/.so was built for the
1753 // same architecture as Hotspot is running on
1756 // Remember the stack's state. The Linux dynamic linker will change
1757 // the stack to 'executable' at most once, so we must safepoint only once.
1758 bool os::Linux::_stack_is_executable = false;
1760 // VM operation that loads a library. This is necessary if stack protection
1761 // of the Java stacks can be lost during loading the library. If we
1762 // do not stop the Java threads, they can stack overflow before the stacks
1763 // are protected again.
1764 class VM_LinuxDllLoad: public VM_Operation {
1765 private:
1766 const char *_filename;
1767 char *_ebuf;
1768 int _ebuflen;
1769 void *_lib;
1770 public:
1771 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
1772 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
1773 VMOp_Type type() const { return VMOp_LinuxDllLoad; }
1774 void doit() {
1775 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
1776 os::Linux::_stack_is_executable = true;
1777 }
1778 void* loaded_library() { return _lib; }
1779 };
1781 void * os::dll_load(const char *filename, char *ebuf, int ebuflen)
1782 {
1783 void * result = NULL;
1784 bool load_attempted = false;
1786 // Check whether the library to load might change execution rights
1787 // of the stack. If they are changed, the protection of the stack
1788 // guard pages will be lost. We need a safepoint to fix this.
1789 //
1790 // See Linux man page execstack(8) for more info.
1791 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
1792 ElfFile ef(filename);
1793 if (!ef.specifies_noexecstack()) {
1794 if (!is_init_completed()) {
1795 os::Linux::_stack_is_executable = true;
1796 // This is OK - No Java threads have been created yet, and hence no
1797 // stack guard pages to fix.
1798 //
1799 // This should happen only when you are building JDK7 using a very
1800 // old version of JDK6 (e.g., with JPRT) and running test_gamma.
1801 //
1802 // Dynamic loader will make all stacks executable after
1803 // this function returns, and will not do that again.
1804 assert(Threads::first() == NULL, "no Java threads should exist yet.");
1805 } else {
1806 warning("You have loaded library %s which might have disabled stack guard. "
1807 "The VM will try to fix the stack guard now.\n"
1808 "It's highly recommended that you fix the library with "
1809 "'execstack -c <libfile>', or link it with '-z noexecstack'.",
1810 filename);
1812 assert(Thread::current()->is_Java_thread(), "must be Java thread");
1813 JavaThread *jt = JavaThread::current();
1814 if (jt->thread_state() != _thread_in_native) {
1815 // This happens when a compiler thread tries to load a hsdis-<arch>.so file
1816 // that requires ExecStack. Cannot enter safe point. Let's give up.
1817 warning("Unable to fix stack guard. Giving up.");
1818 } else {
1819 if (!LoadExecStackDllInVMThread) {
1820 // This is for the case where the DLL has an static
1821 // constructor function that executes JNI code. We cannot
1822 // load such DLLs in the VMThread.
1823 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1824 }
1826 ThreadInVMfromNative tiv(jt);
1827 debug_only(VMNativeEntryWrapper vew;)
1829 VM_LinuxDllLoad op(filename, ebuf, ebuflen);
1830 VMThread::execute(&op);
1831 if (LoadExecStackDllInVMThread) {
1832 result = op.loaded_library();
1833 }
1834 load_attempted = true;
1835 }
1836 }
1837 }
1838 }
1840 if (!load_attempted) {
1841 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1842 }
1844 if (result != NULL) {
1845 // Successful loading
1846 return result;
1847 }
1849 Elf32_Ehdr elf_head;
1850 int diag_msg_max_length=ebuflen-strlen(ebuf);
1851 char* diag_msg_buf=ebuf+strlen(ebuf);
1853 if (diag_msg_max_length==0) {
1854 // No more space in ebuf for additional diagnostics message
1855 return NULL;
1856 }
1859 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1861 if (file_descriptor < 0) {
1862 // Can't open library, report dlerror() message
1863 return NULL;
1864 }
1866 bool failed_to_read_elf_head=
1867 (sizeof(elf_head)!=
1868 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ;
1870 ::close(file_descriptor);
1871 if (failed_to_read_elf_head) {
1872 // file i/o error - report dlerror() msg
1873 return NULL;
1874 }
1876 typedef struct {
1877 Elf32_Half code; // Actual value as defined in elf.h
1878 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1879 char elf_class; // 32 or 64 bit
1880 char endianess; // MSB or LSB
1881 char* name; // String representation
1882 } arch_t;
1884 #ifndef EM_486
1885 #define EM_486 6 /* Intel 80486 */
1886 #endif
1888 static const arch_t arch_array[]={
1889 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1890 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1891 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1892 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1893 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1894 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1895 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1896 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1897 #if defined(VM_LITTLE_ENDIAN)
1898 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64"},
1899 #else
1900 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1901 #endif
1902 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1903 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1904 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1905 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1906 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1907 {EM_MIPS, EM_MIPS, ELFCLASS64, ELFDATA2LSB, (char*)"MIPS64 LE"},
1908 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1909 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}
1910 };
1912 #if (defined IA32)
1913 static Elf32_Half running_arch_code=EM_386;
1914 #elif (defined AMD64)
1915 static Elf32_Half running_arch_code=EM_X86_64;
1916 #elif (defined IA64)
1917 static Elf32_Half running_arch_code=EM_IA_64;
1918 #elif (defined __sparc) && (defined _LP64)
1919 static Elf32_Half running_arch_code=EM_SPARCV9;
1920 #elif (defined __sparc) && (!defined _LP64)
1921 static Elf32_Half running_arch_code=EM_SPARC;
1922 #elif (defined MIPS64)
1923 static Elf32_Half running_arch_code=EM_MIPS;
1924 #elif (defined __powerpc64__)
1925 static Elf32_Half running_arch_code=EM_PPC64;
1926 #elif (defined __powerpc__)
1927 static Elf32_Half running_arch_code=EM_PPC;
1928 #elif (defined ARM)
1929 static Elf32_Half running_arch_code=EM_ARM;
1930 #elif (defined S390)
1931 static Elf32_Half running_arch_code=EM_S390;
1932 #elif (defined ALPHA)
1933 static Elf32_Half running_arch_code=EM_ALPHA;
1934 #elif (defined MIPSEL)
1935 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1936 #elif (defined PARISC)
1937 static Elf32_Half running_arch_code=EM_PARISC;
1938 #elif (defined MIPS)
1939 static Elf32_Half running_arch_code=EM_MIPS;
1940 #elif (defined M68K)
1941 static Elf32_Half running_arch_code=EM_68K;
1942 #else
1943 #error Method os::dll_load requires that one of following is defined:\
1944 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, __mips64, PARISC, M68K
1945 #endif
1947 // Identify compatability class for VM's architecture and library's architecture
1948 // Obtain string descriptions for architectures
1950 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1951 int running_arch_index=-1;
1953 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) {
1954 if (running_arch_code == arch_array[i].code) {
1955 running_arch_index = i;
1956 }
1957 if (lib_arch.code == arch_array[i].code) {
1958 lib_arch.compat_class = arch_array[i].compat_class;
1959 lib_arch.name = arch_array[i].name;
1960 }
1961 }
1963 assert(running_arch_index != -1,
1964 "Didn't find running architecture code (running_arch_code) in arch_array");
1965 if (running_arch_index == -1) {
1966 // Even though running architecture detection failed
1967 // we may still continue with reporting dlerror() message
1968 return NULL;
1969 }
1971 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1972 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1973 return NULL;
1974 }
1976 #ifndef S390
1977 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1978 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1979 return NULL;
1980 }
1981 #endif // !S390
1983 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1984 if ( lib_arch.name!=NULL ) {
1985 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1986 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1987 lib_arch.name, arch_array[running_arch_index].name);
1988 } else {
1989 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1990 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1991 lib_arch.code,
1992 arch_array[running_arch_index].name);
1993 }
1994 }
1996 return NULL;
1997 }
1999 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, int ebuflen) {
2000 void * result = ::dlopen(filename, RTLD_LAZY);
2001 if (result == NULL) {
2002 ::strncpy(ebuf, ::dlerror(), ebuflen - 1);
2003 ebuf[ebuflen-1] = '\0';
2004 }
2005 return result;
2006 }
2008 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, int ebuflen) {
2009 void * result = NULL;
2010 if (LoadExecStackDllInVMThread) {
2011 result = dlopen_helper(filename, ebuf, ebuflen);
2012 }
2014 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
2015 // library that requires an executable stack, or which does not have this
2016 // stack attribute set, dlopen changes the stack attribute to executable. The
2017 // read protection of the guard pages gets lost.
2018 //
2019 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
2020 // may have been queued at the same time.
2022 if (!_stack_is_executable) {
2023 JavaThread *jt = Threads::first();
2025 while (jt) {
2026 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized
2027 jt->stack_yellow_zone_enabled()) { // No pending stack overflow exceptions
2028 if (!os::guard_memory((char *) jt->stack_red_zone_base() - jt->stack_red_zone_size(),
2029 jt->stack_yellow_zone_size() + jt->stack_red_zone_size())) {
2030 warning("Attempt to reguard stack yellow zone failed.");
2031 }
2032 }
2033 jt = jt->next();
2034 }
2035 }
2037 return result;
2038 }
2040 /*
2041 * glibc-2.0 libdl is not MT safe. If you are building with any glibc,
2042 * chances are you might want to run the generated bits against glibc-2.0
2043 * libdl.so, so always use locking for any version of glibc.
2044 */
2045 void* os::dll_lookup(void* handle, const char* name) {
2046 pthread_mutex_lock(&dl_mutex);
2047 void* res = dlsym(handle, name);
2048 pthread_mutex_unlock(&dl_mutex);
2049 return res;
2050 }
2052 void* os::get_default_process_handle() {
2053 return (void*)::dlopen(NULL, RTLD_LAZY);
2054 }
2056 static bool _print_ascii_file(const char* filename, outputStream* st) {
2057 int fd = ::open(filename, O_RDONLY);
2058 if (fd == -1) {
2059 return false;
2060 }
2062 char buf[32];
2063 int bytes;
2064 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) {
2065 st->print_raw(buf, bytes);
2066 }
2068 ::close(fd);
2070 return true;
2071 }
2073 void os::print_dll_info(outputStream *st) {
2074 st->print_cr("Dynamic libraries:");
2076 char fname[32];
2077 pid_t pid = os::Linux::gettid();
2079 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
2081 if (!_print_ascii_file(fname, st)) {
2082 st->print("Can not get library information for pid = %d\n", pid);
2083 }
2084 }
2086 void os::print_os_info_brief(outputStream* st) {
2087 os::Linux::print_distro_info(st);
2089 os::Posix::print_uname_info(st);
2091 os::Linux::print_libversion_info(st);
2093 }
2095 void os::print_os_info(outputStream* st) {
2096 st->print("OS:");
2098 os::Linux::print_distro_info(st);
2100 os::Posix::print_uname_info(st);
2102 // Print warning if unsafe chroot environment detected
2103 if (unsafe_chroot_detected) {
2104 st->print("WARNING!! ");
2105 st->print_cr("%s", unstable_chroot_error);
2106 }
2108 os::Linux::print_libversion_info(st);
2110 os::Posix::print_rlimit_info(st);
2112 os::Posix::print_load_average(st);
2114 os::Linux::print_full_memory_info(st);
2115 }
2117 // Try to identify popular distros.
2118 // Most Linux distributions have a /etc/XXX-release file, which contains
2119 // the OS version string. Newer Linux distributions have a /etc/lsb-release
2120 // file that also contains the OS version string. Some have more than one
2121 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and
2122 // /etc/redhat-release.), so the order is important.
2123 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have
2124 // their own specific XXX-release file as well as a redhat-release file.
2125 // Because of this the XXX-release file needs to be searched for before the
2126 // redhat-release file.
2127 // Since Red Hat has a lsb-release file that is not very descriptive the
2128 // search for redhat-release needs to be before lsb-release.
2129 // Since the lsb-release file is the new standard it needs to be searched
2130 // before the older style release files.
2131 // Searching system-release (Red Hat) and os-release (other Linuxes) are a
2132 // next to last resort. The os-release file is a new standard that contains
2133 // distribution information and the system-release file seems to be an old
2134 // standard that has been replaced by the lsb-release and os-release files.
2135 // Searching for the debian_version file is the last resort. It contains
2136 // an informative string like "6.0.6" or "wheezy/sid". Because of this
2137 // "Debian " is printed before the contents of the debian_version file.
2138 void os::Linux::print_distro_info(outputStream* st) {
2139 if (!_print_ascii_file("/etc/oracle-release", st) &&
2140 !_print_ascii_file("/etc/mandriva-release", st) &&
2141 !_print_ascii_file("/etc/mandrake-release", st) &&
2142 !_print_ascii_file("/etc/sun-release", st) &&
2143 !_print_ascii_file("/etc/redhat-release", st) &&
2144 !_print_ascii_file("/etc/lsb-release", st) &&
2145 !_print_ascii_file("/etc/SuSE-release", st) &&
2146 !_print_ascii_file("/etc/turbolinux-release", st) &&
2147 !_print_ascii_file("/etc/gentoo-release", st) &&
2148 !_print_ascii_file("/etc/ltib-release", st) &&
2149 !_print_ascii_file("/etc/angstrom-version", st) &&
2150 !_print_ascii_file("/etc/system-release", st) &&
2151 !_print_ascii_file("/etc/os-release", st)) {
2153 if (file_exists("/etc/debian_version")) {
2154 st->print("Debian ");
2155 _print_ascii_file("/etc/debian_version", st);
2156 } else {
2157 st->print("Linux");
2158 }
2159 }
2160 st->cr();
2161 }
2163 void os::Linux::print_libversion_info(outputStream* st) {
2164 // libc, pthread
2165 st->print("libc:");
2166 st->print("%s ", os::Linux::glibc_version());
2167 st->print("%s ", os::Linux::libpthread_version());
2168 if (os::Linux::is_LinuxThreads()) {
2169 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed");
2170 }
2171 st->cr();
2172 }
2174 void os::Linux::print_full_memory_info(outputStream* st) {
2175 st->print("\n/proc/meminfo:\n");
2176 _print_ascii_file("/proc/meminfo", st);
2177 st->cr();
2178 }
2180 void os::print_memory_info(outputStream* st) {
2182 st->print("Memory:");
2183 st->print(" %dk page", os::vm_page_size()>>10);
2185 // values in struct sysinfo are "unsigned long"
2186 struct sysinfo si;
2187 sysinfo(&si);
2189 st->print(", physical " UINT64_FORMAT "k",
2190 os::physical_memory() >> 10);
2191 st->print("(" UINT64_FORMAT "k free)",
2192 os::available_memory() >> 10);
2193 st->print(", swap " UINT64_FORMAT "k",
2194 ((jlong)si.totalswap * si.mem_unit) >> 10);
2195 st->print("(" UINT64_FORMAT "k free)",
2196 ((jlong)si.freeswap * si.mem_unit) >> 10);
2197 st->cr();
2198 }
2200 void os::pd_print_cpu_info(outputStream* st) {
2201 st->print("\n/proc/cpuinfo:\n");
2202 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2203 st->print(" <Not Available>");
2204 }
2205 st->cr();
2206 }
2208 void os::print_siginfo(outputStream* st, void* siginfo) {
2209 const siginfo_t* si = (const siginfo_t*)siginfo;
2211 os::Posix::print_siginfo_brief(st, si);
2212 #if INCLUDE_CDS
2213 if (si && (si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
2214 UseSharedSpaces) {
2215 FileMapInfo* mapinfo = FileMapInfo::current_info();
2216 if (mapinfo->is_in_shared_space(si->si_addr)) {
2217 st->print("\n\nError accessing class data sharing archive." \
2218 " Mapped file inaccessible during execution, " \
2219 " possible disk/network problem.");
2220 }
2221 }
2222 #endif
2223 st->cr();
2224 }
2227 static void print_signal_handler(outputStream* st, int sig,
2228 char* buf, size_t buflen);
2230 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2231 st->print_cr("Signal Handlers:");
2232 print_signal_handler(st, SIGSEGV, buf, buflen);
2233 print_signal_handler(st, SIGBUS , buf, buflen);
2234 print_signal_handler(st, SIGFPE , buf, buflen);
2235 print_signal_handler(st, SIGPIPE, buf, buflen);
2236 print_signal_handler(st, SIGXFSZ, buf, buflen);
2237 print_signal_handler(st, SIGILL , buf, buflen);
2238 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
2239 print_signal_handler(st, SR_signum, buf, buflen);
2240 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2241 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2242 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2243 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2244 #if defined(PPC64)
2245 print_signal_handler(st, SIGTRAP, buf, buflen);
2246 #endif
2247 }
2249 static char saved_jvm_path[MAXPATHLEN] = {0};
2251 // Find the full path to the current module, libjvm.so
2252 void os::jvm_path(char *buf, jint buflen) {
2253 // Error checking.
2254 if (buflen < MAXPATHLEN) {
2255 assert(false, "must use a large-enough buffer");
2256 buf[0] = '\0';
2257 return;
2258 }
2259 // Lazy resolve the path to current module.
2260 if (saved_jvm_path[0] != 0) {
2261 strcpy(buf, saved_jvm_path);
2262 return;
2263 }
2265 char dli_fname[MAXPATHLEN];
2266 bool ret = dll_address_to_library_name(
2267 CAST_FROM_FN_PTR(address, os::jvm_path),
2268 dli_fname, sizeof(dli_fname), NULL);
2269 assert(ret, "cannot locate libjvm");
2270 char *rp = NULL;
2271 if (ret && dli_fname[0] != '\0') {
2272 rp = realpath(dli_fname, buf);
2273 }
2274 if (rp == NULL)
2275 return;
2277 if (Arguments::created_by_gamma_launcher()) {
2278 // Support for the gamma launcher. Typical value for buf is
2279 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at
2280 // the right place in the string, then assume we are installed in a JDK and
2281 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix
2282 // up the path so it looks like libjvm.so is installed there (append a
2283 // fake suffix hotspot/libjvm.so).
2284 const char *p = buf + strlen(buf) - 1;
2285 for (int count = 0; p > buf && count < 5; ++count) {
2286 for (--p; p > buf && *p != '/'; --p)
2287 /* empty */ ;
2288 }
2290 if (strncmp(p, "/jre/lib/", 9) != 0) {
2291 // Look for JAVA_HOME in the environment.
2292 char* java_home_var = ::getenv("JAVA_HOME");
2293 if (java_home_var != NULL && java_home_var[0] != 0) {
2294 char* jrelib_p;
2295 int len;
2297 // Check the current module name "libjvm.so".
2298 p = strrchr(buf, '/');
2299 assert(strstr(p, "/libjvm") == p, "invalid library name");
2301 rp = realpath(java_home_var, buf);
2302 if (rp == NULL)
2303 return;
2305 // determine if this is a legacy image or modules image
2306 // modules image doesn't have "jre" subdirectory
2307 len = strlen(buf);
2308 assert(len < buflen, "Ran out of buffer room");
2309 jrelib_p = buf + len;
2310 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch);
2311 if (0 != access(buf, F_OK)) {
2312 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch);
2313 }
2315 if (0 == access(buf, F_OK)) {
2316 // Use current module name "libjvm.so"
2317 len = strlen(buf);
2318 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
2319 } else {
2320 // Go back to path of .so
2321 rp = realpath(dli_fname, buf);
2322 if (rp == NULL)
2323 return;
2324 }
2325 }
2326 }
2327 }
2329 strncpy(saved_jvm_path, buf, MAXPATHLEN);
2330 }
2332 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2333 // no prefix required, not even "_"
2334 }
2336 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2337 // no suffix required
2338 }
2340 ////////////////////////////////////////////////////////////////////////////////
2341 // sun.misc.Signal support
2343 static volatile jint sigint_count = 0;
2345 static void
2346 UserHandler(int sig, void *siginfo, void *context) {
2347 // 4511530 - sem_post is serialized and handled by the manager thread. When
2348 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2349 // don't want to flood the manager thread with sem_post requests.
2350 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
2351 return;
2353 // Ctrl-C is pressed during error reporting, likely because the error
2354 // handler fails to abort. Let VM die immediately.
2355 if (sig == SIGINT && is_error_reported()) {
2356 os::die();
2357 }
2359 os::signal_notify(sig);
2360 }
2362 void* os::user_handler() {
2363 return CAST_FROM_FN_PTR(void*, UserHandler);
2364 }
2366 class Semaphore : public StackObj {
2367 public:
2368 Semaphore();
2369 ~Semaphore();
2370 void signal();
2371 void wait();
2372 bool trywait();
2373 bool timedwait(unsigned int sec, int nsec);
2374 private:
2375 sem_t _semaphore;
2376 };
2378 Semaphore::Semaphore() {
2379 sem_init(&_semaphore, 0, 0);
2380 }
2382 Semaphore::~Semaphore() {
2383 sem_destroy(&_semaphore);
2384 }
2386 void Semaphore::signal() {
2387 sem_post(&_semaphore);
2388 }
2390 void Semaphore::wait() {
2391 sem_wait(&_semaphore);
2392 }
2394 bool Semaphore::trywait() {
2395 return sem_trywait(&_semaphore) == 0;
2396 }
2398 bool Semaphore::timedwait(unsigned int sec, int nsec) {
2400 struct timespec ts;
2401 // Semaphore's are always associated with CLOCK_REALTIME
2402 os::Linux::clock_gettime(CLOCK_REALTIME, &ts);
2403 // see unpackTime for discussion on overflow checking
2404 if (sec >= MAX_SECS) {
2405 ts.tv_sec += MAX_SECS;
2406 ts.tv_nsec = 0;
2407 } else {
2408 ts.tv_sec += sec;
2409 ts.tv_nsec += nsec;
2410 if (ts.tv_nsec >= NANOSECS_PER_SEC) {
2411 ts.tv_nsec -= NANOSECS_PER_SEC;
2412 ++ts.tv_sec; // note: this must be <= max_secs
2413 }
2414 }
2416 while (1) {
2417 int result = sem_timedwait(&_semaphore, &ts);
2418 if (result == 0) {
2419 return true;
2420 } else if (errno == EINTR) {
2421 continue;
2422 } else if (errno == ETIMEDOUT) {
2423 return false;
2424 } else {
2425 return false;
2426 }
2427 }
2428 }
2430 extern "C" {
2431 typedef void (*sa_handler_t)(int);
2432 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2433 }
2435 void* os::signal(int signal_number, void* handler) {
2436 struct sigaction sigAct, oldSigAct;
2438 sigfillset(&(sigAct.sa_mask));
2439 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2440 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2442 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2443 // -1 means registration failed
2444 return (void *)-1;
2445 }
2447 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2448 }
2450 void os::signal_raise(int signal_number) {
2451 ::raise(signal_number);
2452 }
2454 /*
2455 * The following code is moved from os.cpp for making this
2456 * code platform specific, which it is by its very nature.
2457 */
2459 // Will be modified when max signal is changed to be dynamic
2460 int os::sigexitnum_pd() {
2461 return NSIG;
2462 }
2464 // a counter for each possible signal value
2465 static volatile jint pending_signals[NSIG+1] = { 0 };
2467 // Linux(POSIX) specific hand shaking semaphore.
2468 static sem_t sig_sem;
2469 static Semaphore sr_semaphore;
2471 void os::signal_init_pd() {
2472 // Initialize signal structures
2473 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2475 // Initialize signal semaphore
2476 ::sem_init(&sig_sem, 0, 0);
2477 }
2479 void os::signal_notify(int sig) {
2480 Atomic::inc(&pending_signals[sig]);
2481 ::sem_post(&sig_sem);
2482 }
2484 static int check_pending_signals(bool wait) {
2485 Atomic::store(0, &sigint_count);
2486 for (;;) {
2487 for (int i = 0; i < NSIG + 1; i++) {
2488 jint n = pending_signals[i];
2489 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2490 return i;
2491 }
2492 }
2493 if (!wait) {
2494 return -1;
2495 }
2496 JavaThread *thread = JavaThread::current();
2497 ThreadBlockInVM tbivm(thread);
2499 bool threadIsSuspended;
2500 do {
2501 thread->set_suspend_equivalent();
2502 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2503 ::sem_wait(&sig_sem);
2505 // were we externally suspended while we were waiting?
2506 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2507 if (threadIsSuspended) {
2508 //
2509 // The semaphore has been incremented, but while we were waiting
2510 // another thread suspended us. We don't want to continue running
2511 // while suspended because that would surprise the thread that
2512 // suspended us.
2513 //
2514 ::sem_post(&sig_sem);
2516 thread->java_suspend_self();
2517 }
2518 } while (threadIsSuspended);
2519 }
2520 }
2522 int os::signal_lookup() {
2523 return check_pending_signals(false);
2524 }
2526 int os::signal_wait() {
2527 return check_pending_signals(true);
2528 }
2530 ////////////////////////////////////////////////////////////////////////////////
2531 // Virtual Memory
2533 int os::vm_page_size() {
2534 // Seems redundant as all get out
2535 assert(os::Linux::page_size() != -1, "must call os::init");
2536 return os::Linux::page_size();
2537 }
2539 // Solaris allocates memory by pages.
2540 int os::vm_allocation_granularity() {
2541 assert(os::Linux::page_size() != -1, "must call os::init");
2542 return os::Linux::page_size();
2543 }
2545 // Rationale behind this function:
2546 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2547 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2548 // samples for JITted code. Here we create private executable mapping over the code cache
2549 // and then we can use standard (well, almost, as mapping can change) way to provide
2550 // info for the reporting script by storing timestamp and location of symbol
2551 void linux_wrap_code(char* base, size_t size) {
2552 static volatile jint cnt = 0;
2554 if (!UseOprofile) {
2555 return;
2556 }
2558 char buf[PATH_MAX+1];
2559 int num = Atomic::add(1, &cnt);
2561 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2562 os::get_temp_directory(), os::current_process_id(), num);
2563 unlink(buf);
2565 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2567 if (fd != -1) {
2568 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2569 if (rv != (off_t)-1) {
2570 if (::write(fd, "", 1) == 1) {
2571 mmap(base, size,
2572 PROT_READ|PROT_WRITE|PROT_EXEC,
2573 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2574 }
2575 }
2576 ::close(fd);
2577 unlink(buf);
2578 }
2579 }
2581 static bool recoverable_mmap_error(int err) {
2582 // See if the error is one we can let the caller handle. This
2583 // list of errno values comes from JBS-6843484. I can't find a
2584 // Linux man page that documents this specific set of errno
2585 // values so while this list currently matches Solaris, it may
2586 // change as we gain experience with this failure mode.
2587 switch (err) {
2588 case EBADF:
2589 case EINVAL:
2590 case ENOTSUP:
2591 // let the caller deal with these errors
2592 return true;
2594 default:
2595 // Any remaining errors on this OS can cause our reserved mapping
2596 // to be lost. That can cause confusion where different data
2597 // structures think they have the same memory mapped. The worst
2598 // scenario is if both the VM and a library think they have the
2599 // same memory mapped.
2600 return false;
2601 }
2602 }
2604 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2605 int err) {
2606 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2607 ", %d) failed; error='%s' (errno=%d)", addr, size, exec,
2608 strerror(err), err);
2609 }
2611 static void warn_fail_commit_memory(char* addr, size_t size,
2612 size_t alignment_hint, bool exec,
2613 int err) {
2614 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2615 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", addr, size,
2616 alignment_hint, exec, strerror(err), err);
2617 }
2619 // NOTE: Linux kernel does not really reserve the pages for us.
2620 // All it does is to check if there are enough free pages
2621 // left at the time of mmap(). This could be a potential
2622 // problem.
2623 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) {
2624 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2625 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2626 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2627 if (res != (uintptr_t) MAP_FAILED) {
2628 if (UseNUMAInterleaving) {
2629 numa_make_global(addr, size);
2630 }
2631 return 0;
2632 }
2634 int err = errno; // save errno from mmap() call above
2636 if (!recoverable_mmap_error(err)) {
2637 warn_fail_commit_memory(addr, size, exec, err);
2638 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory.");
2639 }
2641 return err;
2642 }
2644 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2645 return os::Linux::commit_memory_impl(addr, size, exec) == 0;
2646 }
2648 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2649 const char* mesg) {
2650 assert(mesg != NULL, "mesg must be specified");
2651 int err = os::Linux::commit_memory_impl(addr, size, exec);
2652 if (err != 0) {
2653 // the caller wants all commit errors to exit with the specified mesg:
2654 warn_fail_commit_memory(addr, size, exec, err);
2655 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, mesg);
2656 }
2657 }
2659 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2660 #ifndef MAP_HUGETLB
2661 #define MAP_HUGETLB 0x40000
2662 #endif
2664 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2665 #ifndef MADV_HUGEPAGE
2666 #define MADV_HUGEPAGE 14
2667 #endif
2669 int os::Linux::commit_memory_impl(char* addr, size_t size,
2670 size_t alignment_hint, bool exec) {
2671 int err = os::Linux::commit_memory_impl(addr, size, exec);
2672 if (err == 0) {
2673 realign_memory(addr, size, alignment_hint);
2674 }
2675 return err;
2676 }
2678 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2679 bool exec) {
2680 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0;
2681 }
2683 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2684 size_t alignment_hint, bool exec,
2685 const char* mesg) {
2686 assert(mesg != NULL, "mesg must be specified");
2687 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec);
2688 if (err != 0) {
2689 // the caller wants all commit errors to exit with the specified mesg:
2690 warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
2691 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, mesg);
2692 }
2693 }
2695 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2696 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
2697 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2698 // be supported or the memory may already be backed by huge pages.
2699 ::madvise(addr, bytes, MADV_HUGEPAGE);
2700 }
2701 }
2703 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2704 // This method works by doing an mmap over an existing mmaping and effectively discarding
2705 // the existing pages. However it won't work for SHM-based large pages that cannot be
2706 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
2707 // small pages on top of the SHM segment. This method always works for small pages, so we
2708 // allow that in any case.
2709 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
2710 commit_memory(addr, bytes, alignment_hint, !ExecMem);
2711 }
2712 }
2714 void os::numa_make_global(char *addr, size_t bytes) {
2715 Linux::numa_interleave_memory(addr, bytes);
2716 }
2718 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the
2719 // bind policy to MPOL_PREFERRED for the current thread.
2720 #define USE_MPOL_PREFERRED 0
2722 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2723 // To make NUMA and large pages more robust when both enabled, we need to ease
2724 // the requirements on where the memory should be allocated. MPOL_BIND is the
2725 // default policy and it will force memory to be allocated on the specified
2726 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on
2727 // the specified node, but will not force it. Using this policy will prevent
2728 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no
2729 // free large pages.
2730 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED);
2731 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2732 }
2734 bool os::numa_topology_changed() { return false; }
2736 size_t os::numa_get_groups_num() {
2737 int max_node = Linux::numa_max_node();
2738 return max_node > 0 ? max_node + 1 : 1;
2739 }
2741 int os::numa_get_group_id() {
2742 int cpu_id = Linux::sched_getcpu();
2743 if (cpu_id != -1) {
2744 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2745 if (lgrp_id != -1) {
2746 return lgrp_id;
2747 }
2748 }
2749 return 0;
2750 }
2752 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2753 for (size_t i = 0; i < size; i++) {
2754 ids[i] = i;
2755 }
2756 return size;
2757 }
2759 bool os::get_page_info(char *start, page_info* info) {
2760 return false;
2761 }
2763 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2764 return end;
2765 }
2768 int os::Linux::sched_getcpu_syscall(void) {
2769 unsigned int cpu;
2770 int retval = -1;
2772 #if defined(IA32)
2773 # ifndef SYS_getcpu
2774 # define SYS_getcpu 318
2775 # endif
2776 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2777 #elif defined(AMD64)
2778 // Unfortunately we have to bring all these macros here from vsyscall.h
2779 // to be able to compile on old linuxes.
2780 # define __NR_vgetcpu 2
2781 # define VSYSCALL_START (-10UL << 20)
2782 # define VSYSCALL_SIZE 1024
2783 # define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2784 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2785 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2786 retval = vgetcpu(&cpu, NULL, NULL);
2787 #endif
2789 return (retval == -1) ? retval : cpu;
2790 }
2792 // Something to do with the numa-aware allocator needs these symbols
2793 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2794 extern "C" JNIEXPORT void numa_error(char *where) { }
2795 extern "C" JNIEXPORT int fork1() { return fork(); }
2798 // If we are running with libnuma version > 2, then we should
2799 // be trying to use symbols with versions 1.1
2800 // If we are running with earlier version, which did not have symbol versions,
2801 // we should use the base version.
2802 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2803 void *f = dlvsym(handle, name, "libnuma_1.1");
2804 if (f == NULL) {
2805 f = dlsym(handle, name);
2806 }
2807 return f;
2808 }
2810 bool os::Linux::libnuma_init() {
2811 // sched_getcpu() should be in libc.
2812 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2813 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2815 // If it's not, try a direct syscall.
2816 if (sched_getcpu() == -1)
2817 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, (void*)&sched_getcpu_syscall));
2819 if (sched_getcpu() != -1) { // Does it work?
2820 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2821 if (handle != NULL) {
2822 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2823 libnuma_dlsym(handle, "numa_node_to_cpus")));
2824 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2825 libnuma_dlsym(handle, "numa_max_node")));
2826 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2827 libnuma_dlsym(handle, "numa_available")));
2828 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2829 libnuma_dlsym(handle, "numa_tonode_memory")));
2830 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2831 libnuma_dlsym(handle, "numa_interleave_memory")));
2832 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t,
2833 libnuma_dlsym(handle, "numa_set_bind_policy")));
2836 if (numa_available() != -1) {
2837 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2838 // Create a cpu -> node mapping
2839 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
2840 rebuild_cpu_to_node_map();
2841 return true;
2842 }
2843 }
2844 }
2845 return false;
2846 }
2848 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2849 // The table is later used in get_node_by_cpu().
2850 void os::Linux::rebuild_cpu_to_node_map() {
2851 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2852 // in libnuma (possible values are starting from 16,
2853 // and continuing up with every other power of 2, but less
2854 // than the maximum number of CPUs supported by kernel), and
2855 // is a subject to change (in libnuma version 2 the requirements
2856 // are more reasonable) we'll just hardcode the number they use
2857 // in the library.
2858 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2860 size_t cpu_num = os::active_processor_count();
2861 size_t cpu_map_size = NCPUS / BitsPerCLong;
2862 size_t cpu_map_valid_size =
2863 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2865 cpu_to_node()->clear();
2866 cpu_to_node()->at_grow(cpu_num - 1);
2867 size_t node_num = numa_get_groups_num();
2869 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
2870 for (size_t i = 0; i < node_num; i++) {
2871 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2872 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2873 if (cpu_map[j] != 0) {
2874 for (size_t k = 0; k < BitsPerCLong; k++) {
2875 if (cpu_map[j] & (1UL << k)) {
2876 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
2877 }
2878 }
2879 }
2880 }
2881 }
2882 }
2883 FREE_C_HEAP_ARRAY(unsigned long, cpu_map, mtInternal);
2884 }
2886 int os::Linux::get_node_by_cpu(int cpu_id) {
2887 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2888 return cpu_to_node()->at(cpu_id);
2889 }
2890 return -1;
2891 }
2893 GrowableArray<int>* os::Linux::_cpu_to_node;
2894 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2895 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2896 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2897 os::Linux::numa_available_func_t os::Linux::_numa_available;
2898 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2899 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2900 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy;
2901 unsigned long* os::Linux::_numa_all_nodes;
2903 bool os::pd_uncommit_memory(char* addr, size_t size) {
2904 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2905 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2906 return res != (uintptr_t) MAP_FAILED;
2907 }
2909 static
2910 address get_stack_commited_bottom(address bottom, size_t size) {
2911 address nbot = bottom;
2912 address ntop = bottom + size;
2914 size_t page_sz = os::vm_page_size();
2915 unsigned pages = size / page_sz;
2917 unsigned char vec[1];
2918 unsigned imin = 1, imax = pages + 1, imid;
2919 int mincore_return_value = 0;
2921 assert(imin <= imax, "Unexpected page size");
2923 while (imin < imax) {
2924 imid = (imax + imin) / 2;
2925 nbot = ntop - (imid * page_sz);
2927 // Use a trick with mincore to check whether the page is mapped or not.
2928 // mincore sets vec to 1 if page resides in memory and to 0 if page
2929 // is swapped output but if page we are asking for is unmapped
2930 // it returns -1,ENOMEM
2931 mincore_return_value = mincore(nbot, page_sz, vec);
2933 if (mincore_return_value == -1) {
2934 // Page is not mapped go up
2935 // to find first mapped page
2936 if (errno != EAGAIN) {
2937 assert(errno == ENOMEM, "Unexpected mincore errno");
2938 imax = imid;
2939 }
2940 } else {
2941 // Page is mapped go down
2942 // to find first not mapped page
2943 imin = imid + 1;
2944 }
2945 }
2947 nbot = nbot + page_sz;
2949 // Adjust stack bottom one page up if last checked page is not mapped
2950 if (mincore_return_value == -1) {
2951 nbot = nbot + page_sz;
2952 }
2954 return nbot;
2955 }
2958 // Linux uses a growable mapping for the stack, and if the mapping for
2959 // the stack guard pages is not removed when we detach a thread the
2960 // stack cannot grow beyond the pages where the stack guard was
2961 // mapped. If at some point later in the process the stack expands to
2962 // that point, the Linux kernel cannot expand the stack any further
2963 // because the guard pages are in the way, and a segfault occurs.
2964 //
2965 // However, it's essential not to split the stack region by unmapping
2966 // a region (leaving a hole) that's already part of the stack mapping,
2967 // so if the stack mapping has already grown beyond the guard pages at
2968 // the time we create them, we have to truncate the stack mapping.
2969 // So, we need to know the extent of the stack mapping when
2970 // create_stack_guard_pages() is called.
2972 // We only need this for stacks that are growable: at the time of
2973 // writing thread stacks don't use growable mappings (i.e. those
2974 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
2975 // only applies to the main thread.
2977 // If the (growable) stack mapping already extends beyond the point
2978 // where we're going to put our guard pages, truncate the mapping at
2979 // that point by munmap()ping it. This ensures that when we later
2980 // munmap() the guard pages we don't leave a hole in the stack
2981 // mapping. This only affects the main/initial thread
2983 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
2985 if (os::Linux::is_initial_thread()) {
2986 // As we manually grow stack up to bottom inside create_attached_thread(),
2987 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and
2988 // we don't need to do anything special.
2989 // Check it first, before calling heavy function.
2990 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom();
2991 unsigned char vec[1];
2993 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) {
2994 // Fallback to slow path on all errors, including EAGAIN
2995 stack_extent = (uintptr_t) get_stack_commited_bottom(
2996 os::Linux::initial_thread_stack_bottom(),
2997 (size_t)addr - stack_extent);
2998 }
3000 if (stack_extent < (uintptr_t)addr) {
3001 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent));
3002 }
3003 }
3005 return os::commit_memory(addr, size, !ExecMem);
3006 }
3008 // If this is a growable mapping, remove the guard pages entirely by
3009 // munmap()ping them. If not, just call uncommit_memory(). This only
3010 // affects the main/initial thread, but guard against future OS changes
3011 // It's safe to always unmap guard pages for initial thread because we
3012 // always place it right after end of the mapped region
3014 bool os::remove_stack_guard_pages(char* addr, size_t size) {
3015 uintptr_t stack_extent, stack_base;
3017 if (os::Linux::is_initial_thread()) {
3018 return ::munmap(addr, size) == 0;
3019 }
3021 return os::uncommit_memory(addr, size);
3022 }
3024 static address _highest_vm_reserved_address = NULL;
3026 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
3027 // at 'requested_addr'. If there are existing memory mappings at the same
3028 // location, however, they will be overwritten. If 'fixed' is false,
3029 // 'requested_addr' is only treated as a hint, the return value may or
3030 // may not start from the requested address. Unlike Linux mmap(), this
3031 // function returns NULL to indicate failure.
3032 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
3033 char * addr;
3034 int flags;
3036 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
3037 if (fixed) {
3038 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
3039 flags |= MAP_FIXED;
3040 }
3042 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
3043 // touch an uncommitted page. Otherwise, the read/write might
3044 // succeed if we have enough swap space to back the physical page.
3045 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
3046 flags, -1, 0);
3048 if (addr != MAP_FAILED) {
3049 // anon_mmap() should only get called during VM initialization,
3050 // don't need lock (actually we can skip locking even it can be called
3051 // from multiple threads, because _highest_vm_reserved_address is just a
3052 // hint about the upper limit of non-stack memory regions.)
3053 if ((address)addr + bytes > _highest_vm_reserved_address) {
3054 _highest_vm_reserved_address = (address)addr + bytes;
3055 }
3056 }
3058 return addr == MAP_FAILED ? NULL : addr;
3059 }
3061 // Don't update _highest_vm_reserved_address, because there might be memory
3062 // regions above addr + size. If so, releasing a memory region only creates
3063 // a hole in the address space, it doesn't help prevent heap-stack collision.
3064 //
3065 static int anon_munmap(char * addr, size_t size) {
3066 return ::munmap(addr, size) == 0;
3067 }
3069 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
3070 size_t alignment_hint) {
3071 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
3072 }
3074 bool os::pd_release_memory(char* addr, size_t size) {
3075 return anon_munmap(addr, size);
3076 }
3078 static address highest_vm_reserved_address() {
3079 return _highest_vm_reserved_address;
3080 }
3082 static bool linux_mprotect(char* addr, size_t size, int prot) {
3083 // Linux wants the mprotect address argument to be page aligned.
3084 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
3086 // According to SUSv3, mprotect() should only be used with mappings
3087 // established by mmap(), and mmap() always maps whole pages. Unaligned
3088 // 'addr' likely indicates problem in the VM (e.g. trying to change
3089 // protection of malloc'ed or statically allocated memory). Check the
3090 // caller if you hit this assert.
3091 assert(addr == bottom, "sanity check");
3093 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
3094 return ::mprotect(bottom, size, prot) == 0;
3095 }
3097 // Set protections specified
3098 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
3099 bool is_committed) {
3100 unsigned int p = 0;
3101 switch (prot) {
3102 case MEM_PROT_NONE: p = PROT_NONE; break;
3103 case MEM_PROT_READ: p = PROT_READ; break;
3104 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
3105 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
3106 default:
3107 ShouldNotReachHere();
3108 }
3109 // is_committed is unused.
3110 return linux_mprotect(addr, bytes, p);
3111 }
3113 bool os::guard_memory(char* addr, size_t size) {
3114 return linux_mprotect(addr, size, PROT_NONE);
3115 }
3117 bool os::unguard_memory(char* addr, size_t size) {
3118 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
3119 }
3121 bool os::Linux::transparent_huge_pages_sanity_check(bool warn, size_t page_size) {
3122 bool result = false;
3123 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
3124 MAP_ANONYMOUS|MAP_PRIVATE,
3125 -1, 0);
3126 if (p != MAP_FAILED) {
3127 void *aligned_p = align_ptr_up(p, page_size);
3129 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
3131 munmap(p, page_size * 2);
3132 }
3134 if (warn && !result) {
3135 warning("TransparentHugePages is not supported by the operating system.");
3136 }
3138 return result;
3139 }
3141 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
3142 bool result = false;
3143 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
3144 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
3145 -1, 0);
3147 if (p != MAP_FAILED) {
3148 // We don't know if this really is a huge page or not.
3149 FILE *fp = fopen("/proc/self/maps", "r");
3150 if (fp) {
3151 while (!feof(fp)) {
3152 char chars[257];
3153 long x = 0;
3154 if (fgets(chars, sizeof(chars), fp)) {
3155 if (sscanf(chars, "%lx-%*x", &x) == 1
3156 && x == (long)p) {
3157 if (strstr (chars, "hugepage")) {
3158 result = true;
3159 break;
3160 }
3161 }
3162 }
3163 }
3164 fclose(fp);
3165 }
3166 munmap(p, page_size);
3167 }
3169 if (warn && !result) {
3170 warning("HugeTLBFS is not supported by the operating system.");
3171 }
3173 return result;
3174 }
3176 /*
3177 * Set the coredump_filter bits to include largepages in core dump (bit 6)
3178 *
3179 * From the coredump_filter documentation:
3180 *
3181 * - (bit 0) anonymous private memory
3182 * - (bit 1) anonymous shared memory
3183 * - (bit 2) file-backed private memory
3184 * - (bit 3) file-backed shared memory
3185 * - (bit 4) ELF header pages in file-backed private memory areas (it is
3186 * effective only if the bit 2 is cleared)
3187 * - (bit 5) hugetlb private memory
3188 * - (bit 6) hugetlb shared memory
3189 */
3190 static void set_coredump_filter(void) {
3191 FILE *f;
3192 long cdm;
3194 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
3195 return;
3196 }
3198 if (fscanf(f, "%lx", &cdm) != 1) {
3199 fclose(f);
3200 return;
3201 }
3203 rewind(f);
3205 if ((cdm & LARGEPAGES_BIT) == 0) {
3206 cdm |= LARGEPAGES_BIT;
3207 fprintf(f, "%#lx", cdm);
3208 }
3210 fclose(f);
3211 }
3213 // Large page support
3215 static size_t _large_page_size = 0;
3217 size_t os::Linux::find_large_page_size() {
3218 size_t large_page_size = 0;
3220 // large_page_size on Linux is used to round up heap size. x86 uses either
3221 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3222 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3223 // page as large as 256M.
3224 //
3225 // Here we try to figure out page size by parsing /proc/meminfo and looking
3226 // for a line with the following format:
3227 // Hugepagesize: 2048 kB
3228 //
3229 // If we can't determine the value (e.g. /proc is not mounted, or the text
3230 // format has been changed), we'll use the largest page size supported by
3231 // the processor.
3233 #ifndef ZERO
3234 large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M)
3235 ARM_ONLY(2 * M) PPC_ONLY(4 * M) MIPS64_ONLY(4 * M); //In MIPS _large_page_size is seted 4*M.
3236 #endif // ZERO
3238 FILE *fp = fopen("/proc/meminfo", "r");
3239 if (fp) {
3240 while (!feof(fp)) {
3241 int x = 0;
3242 char buf[16];
3243 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3244 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3245 large_page_size = x * K;
3246 break;
3247 }
3248 } else {
3249 // skip to next line
3250 for (;;) {
3251 int ch = fgetc(fp);
3252 if (ch == EOF || ch == (int)'\n') break;
3253 }
3254 }
3255 }
3256 fclose(fp);
3257 }
3259 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) {
3260 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is "
3261 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size),
3262 proper_unit_for_byte_size(large_page_size));
3263 }
3265 return large_page_size;
3266 }
3268 size_t os::Linux::setup_large_page_size() {
3269 _large_page_size = Linux::find_large_page_size();
3270 const size_t default_page_size = (size_t)Linux::page_size();
3271 if (_large_page_size > default_page_size) {
3272 _page_sizes[0] = _large_page_size;
3273 _page_sizes[1] = default_page_size;
3274 _page_sizes[2] = 0;
3275 }
3277 return _large_page_size;
3278 }
3280 bool os::Linux::setup_large_page_type(size_t page_size) {
3281 if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
3282 FLAG_IS_DEFAULT(UseSHM) &&
3283 FLAG_IS_DEFAULT(UseTransparentHugePages)) {
3285 // The type of large pages has not been specified by the user.
3287 // Try UseHugeTLBFS and then UseSHM.
3288 UseHugeTLBFS = UseSHM = true;
3290 // Don't try UseTransparentHugePages since there are known
3291 // performance issues with it turned on. This might change in the future.
3292 UseTransparentHugePages = false;
3293 }
3295 if (UseTransparentHugePages) {
3296 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
3297 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
3298 UseHugeTLBFS = false;
3299 UseSHM = false;
3300 return true;
3301 }
3302 UseTransparentHugePages = false;
3303 }
3305 if (UseHugeTLBFS) {
3306 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3307 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3308 UseSHM = false;
3309 return true;
3310 }
3311 UseHugeTLBFS = false;
3312 }
3314 return UseSHM;
3315 }
3317 void os::large_page_init() {
3318 if (!UseLargePages &&
3319 !UseTransparentHugePages &&
3320 !UseHugeTLBFS &&
3321 !UseSHM) {
3322 // Not using large pages.
3323 return;
3324 }
3326 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
3327 // The user explicitly turned off large pages.
3328 // Ignore the rest of the large pages flags.
3329 UseTransparentHugePages = false;
3330 UseHugeTLBFS = false;
3331 UseSHM = false;
3332 return;
3333 }
3335 size_t large_page_size = Linux::setup_large_page_size();
3336 UseLargePages = Linux::setup_large_page_type(large_page_size);
3338 set_coredump_filter();
3339 }
3341 #ifndef SHM_HUGETLB
3342 #define SHM_HUGETLB 04000
3343 #endif
3345 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3346 // "exec" is passed in but not used. Creating the shared image for
3347 // the code cache doesn't have an SHM_X executable permission to check.
3348 assert(UseLargePages && UseSHM, "only for SHM large pages");
3349 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3351 if (!is_size_aligned(bytes, os::large_page_size()) || alignment > os::large_page_size()) {
3352 return NULL; // Fallback to small pages.
3353 }
3355 key_t key = IPC_PRIVATE;
3356 char *addr;
3358 bool warn_on_failure = UseLargePages &&
3359 (!FLAG_IS_DEFAULT(UseLargePages) ||
3360 !FLAG_IS_DEFAULT(UseSHM) ||
3361 !FLAG_IS_DEFAULT(LargePageSizeInBytes)
3362 );
3363 char msg[128];
3365 // Create a large shared memory region to attach to based on size.
3366 // Currently, size is the total size of the heap
3367 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3368 if (shmid == -1) {
3369 // Possible reasons for shmget failure:
3370 // 1. shmmax is too small for Java heap.
3371 // > check shmmax value: cat /proc/sys/kernel/shmmax
3372 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3373 // 2. not enough large page memory.
3374 // > check available large pages: cat /proc/meminfo
3375 // > increase amount of large pages:
3376 // echo new_value > /proc/sys/vm/nr_hugepages
3377 // Note 1: different Linux may use different name for this property,
3378 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3379 // Note 2: it's possible there's enough physical memory available but
3380 // they are so fragmented after a long run that they can't
3381 // coalesce into large pages. Try to reserve large pages when
3382 // the system is still "fresh".
3383 if (warn_on_failure) {
3384 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno);
3385 warning("%s", msg);
3386 }
3387 return NULL;
3388 }
3390 // attach to the region
3391 addr = (char*)shmat(shmid, req_addr, 0);
3392 int err = errno;
3394 // Remove shmid. If shmat() is successful, the actual shared memory segment
3395 // will be deleted when it's detached by shmdt() or when the process
3396 // terminates. If shmat() is not successful this will remove the shared
3397 // segment immediately.
3398 shmctl(shmid, IPC_RMID, NULL);
3400 if ((intptr_t)addr == -1) {
3401 if (warn_on_failure) {
3402 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err);
3403 warning("%s", msg);
3404 }
3405 return NULL;
3406 }
3408 return addr;
3409 }
3411 static void warn_on_large_pages_failure(char* req_addr, size_t bytes, int error) {
3412 assert(error == ENOMEM, "Only expect to fail if no memory is available");
3414 bool warn_on_failure = UseLargePages &&
3415 (!FLAG_IS_DEFAULT(UseLargePages) ||
3416 !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
3417 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
3419 if (warn_on_failure) {
3420 char msg[128];
3421 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
3422 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
3423 warning("%s", msg);
3424 }
3425 }
3427 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, char* req_addr, bool exec) {
3428 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3429 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size");
3430 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3432 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3433 char* addr = (char*)::mmap(req_addr, bytes, prot,
3434 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB,
3435 -1, 0);
3437 if (addr == MAP_FAILED) {
3438 warn_on_large_pages_failure(req_addr, bytes, errno);
3439 return NULL;
3440 }
3442 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be");
3444 return addr;
3445 }
3447 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3448 size_t large_page_size = os::large_page_size();
3450 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
3452 // Allocate small pages.
3454 char* start;
3455 if (req_addr != NULL) {
3456 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3457 assert(is_size_aligned(bytes, alignment), "Must be");
3458 start = os::reserve_memory(bytes, req_addr);
3459 assert(start == NULL || start == req_addr, "Must be");
3460 } else {
3461 start = os::reserve_memory_aligned(bytes, alignment);
3462 }
3464 if (start == NULL) {
3465 return NULL;
3466 }
3468 assert(is_ptr_aligned(start, alignment), "Must be");
3470 if (MemTracker::tracking_level() > NMT_minimal) {
3471 // os::reserve_memory_special will record this memory area.
3472 // Need to release it here to prevent overlapping reservations.
3473 Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
3474 tkr.record((address)start, bytes);
3475 }
3477 char* end = start + bytes;
3479 // Find the regions of the allocated chunk that can be promoted to large pages.
3480 char* lp_start = (char*)align_ptr_up(start, large_page_size);
3481 char* lp_end = (char*)align_ptr_down(end, large_page_size);
3483 size_t lp_bytes = lp_end - lp_start;
3485 assert(is_size_aligned(lp_bytes, large_page_size), "Must be");
3487 if (lp_bytes == 0) {
3488 // The mapped region doesn't even span the start and the end of a large page.
3489 // Fall back to allocate a non-special area.
3490 ::munmap(start, end - start);
3491 return NULL;
3492 }
3494 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3497 void* result;
3499 if (start != lp_start) {
3500 result = ::mmap(start, lp_start - start, prot,
3501 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3502 -1, 0);
3503 if (result == MAP_FAILED) {
3504 ::munmap(lp_start, end - lp_start);
3505 return NULL;
3506 }
3507 }
3509 result = ::mmap(lp_start, lp_bytes, prot,
3510 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB,
3511 -1, 0);
3512 if (result == MAP_FAILED) {
3513 warn_on_large_pages_failure(req_addr, bytes, errno);
3514 // If the mmap above fails, the large pages region will be unmapped and we
3515 // have regions before and after with small pages. Release these regions.
3516 //
3517 // | mapped | unmapped | mapped |
3518 // ^ ^ ^ ^
3519 // start lp_start lp_end end
3520 //
3521 ::munmap(start, lp_start - start);
3522 ::munmap(lp_end, end - lp_end);
3523 return NULL;
3524 }
3526 if (lp_end != end) {
3527 result = ::mmap(lp_end, end - lp_end, prot,
3528 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3529 -1, 0);
3530 if (result == MAP_FAILED) {
3531 ::munmap(start, lp_end - start);
3532 return NULL;
3533 }
3534 }
3536 return start;
3537 }
3539 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3540 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3541 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3542 assert(is_power_of_2(alignment), "Must be");
3543 assert(is_power_of_2(os::large_page_size()), "Must be");
3544 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
3546 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
3547 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
3548 } else {
3549 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
3550 }
3551 }
3553 char* os::reserve_memory_special(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3554 assert(UseLargePages, "only for large pages");
3556 char* addr;
3557 if (UseSHM) {
3558 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
3559 } else {
3560 assert(UseHugeTLBFS, "must be");
3561 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
3562 }
3564 if (addr != NULL) {
3565 if (UseNUMAInterleaving) {
3566 numa_make_global(addr, bytes);
3567 }
3569 // The memory is committed
3570 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC);
3571 }
3573 return addr;
3574 }
3576 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
3577 // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
3578 return shmdt(base) == 0;
3579 }
3581 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
3582 return pd_release_memory(base, bytes);
3583 }
3585 bool os::release_memory_special(char* base, size_t bytes) {
3586 bool res;
3587 if (MemTracker::tracking_level() > NMT_minimal) {
3588 Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
3589 res = os::Linux::release_memory_special_impl(base, bytes);
3590 if (res) {
3591 tkr.record((address)base, bytes);
3592 }
3594 } else {
3595 res = os::Linux::release_memory_special_impl(base, bytes);
3596 }
3597 return res;
3598 }
3600 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) {
3601 assert(UseLargePages, "only for large pages");
3602 bool res;
3604 if (UseSHM) {
3605 res = os::Linux::release_memory_special_shm(base, bytes);
3606 } else {
3607 assert(UseHugeTLBFS, "must be");
3608 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
3609 }
3610 return res;
3611 }
3613 size_t os::large_page_size() {
3614 return _large_page_size;
3615 }
3617 // With SysV SHM the entire memory region must be allocated as shared
3618 // memory.
3619 // HugeTLBFS allows application to commit large page memory on demand.
3620 // However, when committing memory with HugeTLBFS fails, the region
3621 // that was supposed to be committed will lose the old reservation
3622 // and allow other threads to steal that memory region. Because of this
3623 // behavior we can't commit HugeTLBFS memory.
3624 bool os::can_commit_large_page_memory() {
3625 return UseTransparentHugePages;
3626 }
3628 bool os::can_execute_large_page_memory() {
3629 return UseTransparentHugePages || UseHugeTLBFS;
3630 }
3632 // Reserve memory at an arbitrary address, only if that area is
3633 // available (and not reserved for something else).
3635 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3636 const int max_tries = 10;
3637 char* base[max_tries];
3638 size_t size[max_tries];
3639 const size_t gap = 0x000000;
3641 // Assert only that the size is a multiple of the page size, since
3642 // that's all that mmap requires, and since that's all we really know
3643 // about at this low abstraction level. If we need higher alignment,
3644 // we can either pass an alignment to this method or verify alignment
3645 // in one of the methods further up the call chain. See bug 5044738.
3646 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3648 // Repeatedly allocate blocks until the block is allocated at the
3649 // right spot. Give up after max_tries. Note that reserve_memory() will
3650 // automatically update _highest_vm_reserved_address if the call is
3651 // successful. The variable tracks the highest memory address every reserved
3652 // by JVM. It is used to detect heap-stack collision if running with
3653 // fixed-stack LinuxThreads. Because here we may attempt to reserve more
3654 // space than needed, it could confuse the collision detecting code. To
3655 // solve the problem, save current _highest_vm_reserved_address and
3656 // calculate the correct value before return.
3657 address old_highest = _highest_vm_reserved_address;
3659 // Linux mmap allows caller to pass an address as hint; give it a try first,
3660 // if kernel honors the hint then we can return immediately.
3661 char * addr = anon_mmap(requested_addr, bytes, false);
3662 if (addr == requested_addr) {
3663 return requested_addr;
3664 }
3666 if (addr != NULL) {
3667 // mmap() is successful but it fails to reserve at the requested address
3668 anon_munmap(addr, bytes);
3669 }
3671 int i;
3672 for (i = 0; i < max_tries; ++i) {
3673 base[i] = reserve_memory(bytes);
3675 if (base[i] != NULL) {
3676 // Is this the block we wanted?
3677 if (base[i] == requested_addr) {
3678 size[i] = bytes;
3679 break;
3680 }
3682 // Does this overlap the block we wanted? Give back the overlapped
3683 // parts and try again.
3685 size_t top_overlap = requested_addr + (bytes + gap) - base[i];
3686 if (top_overlap >= 0 && top_overlap < bytes) {
3687 unmap_memory(base[i], top_overlap);
3688 base[i] += top_overlap;
3689 size[i] = bytes - top_overlap;
3690 } else {
3691 size_t bottom_overlap = base[i] + bytes - requested_addr;
3692 if (bottom_overlap >= 0 && bottom_overlap < bytes) {
3693 unmap_memory(requested_addr, bottom_overlap);
3694 size[i] = bytes - bottom_overlap;
3695 } else {
3696 size[i] = bytes;
3697 }
3698 }
3699 }
3700 }
3702 // Give back the unused reserved pieces.
3704 for (int j = 0; j < i; ++j) {
3705 if (base[j] != NULL) {
3706 unmap_memory(base[j], size[j]);
3707 }
3708 }
3710 if (i < max_tries) {
3711 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes);
3712 return requested_addr;
3713 } else {
3714 _highest_vm_reserved_address = old_highest;
3715 return NULL;
3716 }
3717 }
3719 size_t os::read(int fd, void *buf, unsigned int nBytes) {
3720 return ::read(fd, buf, nBytes);
3721 }
3723 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation.
3724 // Solaris uses poll(), linux uses park().
3725 // Poll() is likely a better choice, assuming that Thread.interrupt()
3726 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with
3727 // SIGSEGV, see 4355769.
3729 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
3730 assert(thread == Thread::current(), "thread consistency check");
3732 ParkEvent * const slp = thread->_SleepEvent ;
3733 slp->reset() ;
3734 OrderAccess::fence() ;
3736 if (interruptible) {
3737 jlong prevtime = javaTimeNanos();
3739 for (;;) {
3740 if (os::is_interrupted(thread, true)) {
3741 return OS_INTRPT;
3742 }
3744 jlong newtime = javaTimeNanos();
3746 if (newtime - prevtime < 0) {
3747 // time moving backwards, should only happen if no monotonic clock
3748 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3749 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3750 } else {
3751 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
3752 }
3754 if(millis <= 0) {
3755 return OS_OK;
3756 }
3758 prevtime = newtime;
3760 {
3761 assert(thread->is_Java_thread(), "sanity check");
3762 JavaThread *jt = (JavaThread *) thread;
3763 ThreadBlockInVM tbivm(jt);
3764 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
3766 jt->set_suspend_equivalent();
3767 // cleared by handle_special_suspend_equivalent_condition() or
3768 // java_suspend_self() via check_and_wait_while_suspended()
3770 slp->park(millis);
3772 // were we externally suspended while we were waiting?
3773 jt->check_and_wait_while_suspended();
3774 }
3775 }
3776 } else {
3777 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
3778 jlong prevtime = javaTimeNanos();
3780 for (;;) {
3781 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
3782 // the 1st iteration ...
3783 jlong newtime = javaTimeNanos();
3785 if (newtime - prevtime < 0) {
3786 // time moving backwards, should only happen if no monotonic clock
3787 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3788 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3789 } else {
3790 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
3791 }
3793 if(millis <= 0) break ;
3795 prevtime = newtime;
3796 slp->park(millis);
3797 }
3798 return OS_OK ;
3799 }
3800 }
3802 //
3803 // Short sleep, direct OS call.
3804 //
3805 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee
3806 // sched_yield(2) will actually give up the CPU:
3807 //
3808 // * Alone on this pariticular CPU, keeps running.
3809 // * Before the introduction of "skip_buddy" with "compat_yield" disabled
3810 // (pre 2.6.39).
3811 //
3812 // So calling this with 0 is an alternative.
3813 //
3814 void os::naked_short_sleep(jlong ms) {
3815 struct timespec req;
3817 assert(ms < 1000, "Un-interruptable sleep, short time use only");
3818 req.tv_sec = 0;
3819 if (ms > 0) {
3820 req.tv_nsec = (ms % 1000) * 1000000;
3821 }
3822 else {
3823 req.tv_nsec = 1;
3824 }
3826 nanosleep(&req, NULL);
3828 return;
3829 }
3831 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3832 void os::infinite_sleep() {
3833 while (true) { // sleep forever ...
3834 ::sleep(100); // ... 100 seconds at a time
3835 }
3836 }
3838 // Used to convert frequent JVM_Yield() to nops
3839 bool os::dont_yield() {
3840 return DontYieldALot;
3841 }
3843 void os::yield() {
3844 sched_yield();
3845 }
3847 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;}
3849 void os::yield_all(int attempts) {
3850 // Yields to all threads, including threads with lower priorities
3851 // Threads on Linux are all with same priority. The Solaris style
3852 // os::yield_all() with nanosleep(1ms) is not necessary.
3853 sched_yield();
3854 }
3856 // Called from the tight loops to possibly influence time-sharing heuristics
3857 void os::loop_breaker(int attempts) {
3858 os::yield_all(attempts);
3859 }
3861 ////////////////////////////////////////////////////////////////////////////////
3862 // thread priority support
3864 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
3865 // only supports dynamic priority, static priority must be zero. For real-time
3866 // applications, Linux supports SCHED_RR which allows static priority (1-99).
3867 // However, for large multi-threaded applications, SCHED_RR is not only slower
3868 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
3869 // of 5 runs - Sep 2005).
3870 //
3871 // The following code actually changes the niceness of kernel-thread/LWP. It
3872 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
3873 // not the entire user process, and user level threads are 1:1 mapped to kernel
3874 // threads. It has always been the case, but could change in the future. For
3875 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
3876 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
3878 int os::java_to_os_priority[CriticalPriority + 1] = {
3879 19, // 0 Entry should never be used
3881 4, // 1 MinPriority
3882 3, // 2
3883 2, // 3
3885 1, // 4
3886 0, // 5 NormPriority
3887 -1, // 6
3889 -2, // 7
3890 -3, // 8
3891 -4, // 9 NearMaxPriority
3893 -5, // 10 MaxPriority
3895 -5 // 11 CriticalPriority
3896 };
3898 static int prio_init() {
3899 if (ThreadPriorityPolicy == 1) {
3900 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
3901 // if effective uid is not root. Perhaps, a more elegant way of doing
3902 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
3903 if (geteuid() != 0) {
3904 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
3905 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
3906 }
3907 ThreadPriorityPolicy = 0;
3908 }
3909 }
3910 if (UseCriticalJavaThreadPriority) {
3911 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
3912 }
3913 return 0;
3914 }
3916 OSReturn os::set_native_priority(Thread* thread, int newpri) {
3917 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK;
3919 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
3920 return (ret == 0) ? OS_OK : OS_ERR;
3921 }
3923 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
3924 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) {
3925 *priority_ptr = java_to_os_priority[NormPriority];
3926 return OS_OK;
3927 }
3929 errno = 0;
3930 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
3931 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
3932 }
3934 // Hint to the underlying OS that a task switch would not be good.
3935 // Void return because it's a hint and can fail.
3936 void os::hint_no_preempt() {}
3938 ////////////////////////////////////////////////////////////////////////////////
3939 // suspend/resume support
3941 // the low-level signal-based suspend/resume support is a remnant from the
3942 // old VM-suspension that used to be for java-suspension, safepoints etc,
3943 // within hotspot. Now there is a single use-case for this:
3944 // - calling get_thread_pc() on the VMThread by the flat-profiler task
3945 // that runs in the watcher thread.
3946 // The remaining code is greatly simplified from the more general suspension
3947 // code that used to be used.
3948 //
3949 // The protocol is quite simple:
3950 // - suspend:
3951 // - sends a signal to the target thread
3952 // - polls the suspend state of the osthread using a yield loop
3953 // - target thread signal handler (SR_handler) sets suspend state
3954 // and blocks in sigsuspend until continued
3955 // - resume:
3956 // - sets target osthread state to continue
3957 // - sends signal to end the sigsuspend loop in the SR_handler
3958 //
3959 // Note that the SR_lock plays no role in this suspend/resume protocol.
3960 //
3962 static void resume_clear_context(OSThread *osthread) {
3963 osthread->set_ucontext(NULL);
3964 osthread->set_siginfo(NULL);
3965 }
3967 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
3968 osthread->set_ucontext(context);
3969 osthread->set_siginfo(siginfo);
3970 }
3972 //
3973 // Handler function invoked when a thread's execution is suspended or
3974 // resumed. We have to be careful that only async-safe functions are
3975 // called here (Note: most pthread functions are not async safe and
3976 // should be avoided.)
3977 //
3978 // Note: sigwait() is a more natural fit than sigsuspend() from an
3979 // interface point of view, but sigwait() prevents the signal hander
3980 // from being run. libpthread would get very confused by not having
3981 // its signal handlers run and prevents sigwait()'s use with the
3982 // mutex granting granting signal.
3983 //
3984 // Currently only ever called on the VMThread and JavaThreads (PC sampling)
3985 //
3986 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
3987 // Save and restore errno to avoid confusing native code with EINTR
3988 // after sigsuspend.
3989 int old_errno = errno;
3991 Thread* thread = Thread::current();
3992 OSThread* osthread = thread->osthread();
3993 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
3995 os::SuspendResume::State current = osthread->sr.state();
3996 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
3997 suspend_save_context(osthread, siginfo, context);
3999 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
4000 os::SuspendResume::State state = osthread->sr.suspended();
4001 if (state == os::SuspendResume::SR_SUSPENDED) {
4002 sigset_t suspend_set; // signals for sigsuspend()
4004 // get current set of blocked signals and unblock resume signal
4005 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
4006 sigdelset(&suspend_set, SR_signum);
4008 sr_semaphore.signal();
4009 // wait here until we are resumed
4010 while (1) {
4011 sigsuspend(&suspend_set);
4013 os::SuspendResume::State result = osthread->sr.running();
4014 if (result == os::SuspendResume::SR_RUNNING) {
4015 sr_semaphore.signal();
4016 break;
4017 }
4018 }
4020 } else if (state == os::SuspendResume::SR_RUNNING) {
4021 // request was cancelled, continue
4022 } else {
4023 ShouldNotReachHere();
4024 }
4026 resume_clear_context(osthread);
4027 } else if (current == os::SuspendResume::SR_RUNNING) {
4028 // request was cancelled, continue
4029 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
4030 // ignore
4031 } else {
4032 // ignore
4033 }
4035 errno = old_errno;
4036 }
4039 static int SR_initialize() {
4040 struct sigaction act;
4041 char *s;
4042 /* Get signal number to use for suspend/resume */
4043 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
4044 int sig = ::strtol(s, 0, 10);
4045 if (sig > 0 || sig < _NSIG) {
4046 SR_signum = sig;
4047 }
4048 }
4050 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
4051 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
4053 sigemptyset(&SR_sigset);
4054 sigaddset(&SR_sigset, SR_signum);
4056 /* Set up signal handler for suspend/resume */
4057 act.sa_flags = SA_RESTART|SA_SIGINFO;
4058 act.sa_handler = (void (*)(int)) SR_handler;
4060 // SR_signum is blocked by default.
4061 // 4528190 - We also need to block pthread restart signal (32 on all
4062 // supported Linux platforms). Note that LinuxThreads need to block
4063 // this signal for all threads to work properly. So we don't have
4064 // to use hard-coded signal number when setting up the mask.
4065 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
4067 if (sigaction(SR_signum, &act, 0) == -1) {
4068 return -1;
4069 }
4071 // Save signal flag
4072 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
4073 return 0;
4074 }
4076 static int sr_notify(OSThread* osthread) {
4077 int status = pthread_kill(osthread->pthread_id(), SR_signum);
4078 assert_status(status == 0, status, "pthread_kill");
4079 return status;
4080 }
4082 // "Randomly" selected value for how long we want to spin
4083 // before bailing out on suspending a thread, also how often
4084 // we send a signal to a thread we want to resume
4085 static const int RANDOMLY_LARGE_INTEGER = 1000000;
4086 static const int RANDOMLY_LARGE_INTEGER2 = 100;
4088 // returns true on success and false on error - really an error is fatal
4089 // but this seems the normal response to library errors
4090 static bool do_suspend(OSThread* osthread) {
4091 assert(osthread->sr.is_running(), "thread should be running");
4092 assert(!sr_semaphore.trywait(), "semaphore has invalid state");
4094 // mark as suspended and send signal
4095 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
4096 // failed to switch, state wasn't running?
4097 ShouldNotReachHere();
4098 return false;
4099 }
4101 if (sr_notify(osthread) != 0) {
4102 ShouldNotReachHere();
4103 }
4105 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
4106 while (true) {
4107 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4108 break;
4109 } else {
4110 // timeout
4111 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
4112 if (cancelled == os::SuspendResume::SR_RUNNING) {
4113 return false;
4114 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
4115 // make sure that we consume the signal on the semaphore as well
4116 sr_semaphore.wait();
4117 break;
4118 } else {
4119 ShouldNotReachHere();
4120 return false;
4121 }
4122 }
4123 }
4125 guarantee(osthread->sr.is_suspended(), "Must be suspended");
4126 return true;
4127 }
4129 static void do_resume(OSThread* osthread) {
4130 assert(osthread->sr.is_suspended(), "thread should be suspended");
4131 assert(!sr_semaphore.trywait(), "invalid semaphore state");
4133 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
4134 // failed to switch to WAKEUP_REQUEST
4135 ShouldNotReachHere();
4136 return;
4137 }
4139 while (true) {
4140 if (sr_notify(osthread) == 0) {
4141 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4142 if (osthread->sr.is_running()) {
4143 return;
4144 }
4145 }
4146 } else {
4147 ShouldNotReachHere();
4148 }
4149 }
4151 guarantee(osthread->sr.is_running(), "Must be running!");
4152 }
4154 ////////////////////////////////////////////////////////////////////////////////
4155 // interrupt support
4157 void os::interrupt(Thread* thread) {
4158 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
4159 "possibility of dangling Thread pointer");
4161 OSThread* osthread = thread->osthread();
4163 if (!osthread->interrupted()) {
4164 osthread->set_interrupted(true);
4165 // More than one thread can get here with the same value of osthread,
4166 // resulting in multiple notifications. We do, however, want the store
4167 // to interrupted() to be visible to other threads before we execute unpark().
4168 OrderAccess::fence();
4169 ParkEvent * const slp = thread->_SleepEvent ;
4170 if (slp != NULL) slp->unpark() ;
4171 }
4173 // For JSR166. Unpark even if interrupt status already was set
4174 if (thread->is_Java_thread())
4175 ((JavaThread*)thread)->parker()->unpark();
4177 ParkEvent * ev = thread->_ParkEvent ;
4178 if (ev != NULL) ev->unpark() ;
4180 }
4182 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
4183 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
4184 "possibility of dangling Thread pointer");
4186 OSThread* osthread = thread->osthread();
4188 bool interrupted = osthread->interrupted();
4190 if (interrupted && clear_interrupted) {
4191 osthread->set_interrupted(false);
4192 // consider thread->_SleepEvent->reset() ... optional optimization
4193 }
4195 return interrupted;
4196 }
4198 ///////////////////////////////////////////////////////////////////////////////////
4199 // signal handling (except suspend/resume)
4201 // This routine may be used by user applications as a "hook" to catch signals.
4202 // The user-defined signal handler must pass unrecognized signals to this
4203 // routine, and if it returns true (non-zero), then the signal handler must
4204 // return immediately. If the flag "abort_if_unrecognized" is true, then this
4205 // routine will never retun false (zero), but instead will execute a VM panic
4206 // routine kill the process.
4207 //
4208 // If this routine returns false, it is OK to call it again. This allows
4209 // the user-defined signal handler to perform checks either before or after
4210 // the VM performs its own checks. Naturally, the user code would be making
4211 // a serious error if it tried to handle an exception (such as a null check
4212 // or breakpoint) that the VM was generating for its own correct operation.
4213 //
4214 // This routine may recognize any of the following kinds of signals:
4215 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
4216 // It should be consulted by handlers for any of those signals.
4217 //
4218 // The caller of this routine must pass in the three arguments supplied
4219 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
4220 // field of the structure passed to sigaction(). This routine assumes that
4221 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
4222 //
4223 // Note that the VM will print warnings if it detects conflicting signal
4224 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
4225 //
4226 extern "C" JNIEXPORT int
4227 JVM_handle_linux_signal(int signo, siginfo_t* siginfo,
4228 void* ucontext, int abort_if_unrecognized);
4230 void signalHandler(int sig, siginfo_t* info, void* uc) {
4231 assert(info != NULL && uc != NULL, "it must be old kernel");
4232 int orig_errno = errno; // Preserve errno value over signal handler.
4233 JVM_handle_linux_signal(sig, info, uc, true);
4234 errno = orig_errno;
4235 }
4238 // This boolean allows users to forward their own non-matching signals
4239 // to JVM_handle_linux_signal, harmlessly.
4240 bool os::Linux::signal_handlers_are_installed = false;
4242 // For signal-chaining
4243 struct sigaction os::Linux::sigact[MAXSIGNUM];
4244 unsigned int os::Linux::sigs = 0;
4245 bool os::Linux::libjsig_is_loaded = false;
4246 typedef struct sigaction *(*get_signal_t)(int);
4247 get_signal_t os::Linux::get_signal_action = NULL;
4249 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
4250 struct sigaction *actp = NULL;
4252 if (libjsig_is_loaded) {
4253 // Retrieve the old signal handler from libjsig
4254 actp = (*get_signal_action)(sig);
4255 }
4256 if (actp == NULL) {
4257 // Retrieve the preinstalled signal handler from jvm
4258 actp = get_preinstalled_handler(sig);
4259 }
4261 return actp;
4262 }
4264 static bool call_chained_handler(struct sigaction *actp, int sig,
4265 siginfo_t *siginfo, void *context) {
4266 // Call the old signal handler
4267 if (actp->sa_handler == SIG_DFL) {
4268 // It's more reasonable to let jvm treat it as an unexpected exception
4269 // instead of taking the default action.
4270 return false;
4271 } else if (actp->sa_handler != SIG_IGN) {
4272 if ((actp->sa_flags & SA_NODEFER) == 0) {
4273 // automaticlly block the signal
4274 sigaddset(&(actp->sa_mask), sig);
4275 }
4277 sa_handler_t hand;
4278 sa_sigaction_t sa;
4279 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
4280 // retrieve the chained handler
4281 if (siginfo_flag_set) {
4282 sa = actp->sa_sigaction;
4283 } else {
4284 hand = actp->sa_handler;
4285 }
4287 if ((actp->sa_flags & SA_RESETHAND) != 0) {
4288 actp->sa_handler = SIG_DFL;
4289 }
4291 // try to honor the signal mask
4292 sigset_t oset;
4293 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
4295 // call into the chained handler
4296 if (siginfo_flag_set) {
4297 (*sa)(sig, siginfo, context);
4298 } else {
4299 (*hand)(sig);
4300 }
4302 // restore the signal mask
4303 pthread_sigmask(SIG_SETMASK, &oset, 0);
4304 }
4305 // Tell jvm's signal handler the signal is taken care of.
4306 return true;
4307 }
4309 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
4310 bool chained = false;
4311 // signal-chaining
4312 if (UseSignalChaining) {
4313 struct sigaction *actp = get_chained_signal_action(sig);
4314 if (actp != NULL) {
4315 chained = call_chained_handler(actp, sig, siginfo, context);
4316 }
4317 }
4318 return chained;
4319 }
4321 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
4322 if ((( (unsigned int)1 << sig ) & sigs) != 0) {
4323 return &sigact[sig];
4324 }
4325 return NULL;
4326 }
4328 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
4329 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4330 sigact[sig] = oldAct;
4331 sigs |= (unsigned int)1 << sig;
4332 }
4334 // for diagnostic
4335 int os::Linux::sigflags[MAXSIGNUM];
4337 int os::Linux::get_our_sigflags(int sig) {
4338 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4339 return sigflags[sig];
4340 }
4342 void os::Linux::set_our_sigflags(int sig, int flags) {
4343 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4344 sigflags[sig] = flags;
4345 }
4347 void os::Linux::set_signal_handler(int sig, bool set_installed) {
4348 // Check for overwrite.
4349 struct sigaction oldAct;
4350 sigaction(sig, (struct sigaction*)NULL, &oldAct);
4352 void* oldhand = oldAct.sa_sigaction
4353 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4354 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4355 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
4356 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
4357 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
4358 if (AllowUserSignalHandlers || !set_installed) {
4359 // Do not overwrite; user takes responsibility to forward to us.
4360 return;
4361 } else if (UseSignalChaining) {
4362 // save the old handler in jvm
4363 save_preinstalled_handler(sig, oldAct);
4364 // libjsig also interposes the sigaction() call below and saves the
4365 // old sigaction on it own.
4366 } else {
4367 fatal(err_msg("Encountered unexpected pre-existing sigaction handler "
4368 "%#lx for signal %d.", (long)oldhand, sig));
4369 }
4370 }
4372 struct sigaction sigAct;
4373 sigfillset(&(sigAct.sa_mask));
4374 sigAct.sa_handler = SIG_DFL;
4375 if (!set_installed) {
4376 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4377 } else {
4378 sigAct.sa_sigaction = signalHandler;
4379 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4380 }
4381 // Save flags, which are set by ours
4382 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4383 sigflags[sig] = sigAct.sa_flags;
4385 int ret = sigaction(sig, &sigAct, &oldAct);
4386 assert(ret == 0, "check");
4388 void* oldhand2 = oldAct.sa_sigaction
4389 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4390 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4391 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
4392 }
4394 // install signal handlers for signals that HotSpot needs to
4395 // handle in order to support Java-level exception handling.
4397 void os::Linux::install_signal_handlers() {
4398 if (!signal_handlers_are_installed) {
4399 signal_handlers_are_installed = true;
4401 // signal-chaining
4402 typedef void (*signal_setting_t)();
4403 signal_setting_t begin_signal_setting = NULL;
4404 signal_setting_t end_signal_setting = NULL;
4405 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4406 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
4407 if (begin_signal_setting != NULL) {
4408 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4409 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
4410 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
4411 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
4412 libjsig_is_loaded = true;
4413 assert(UseSignalChaining, "should enable signal-chaining");
4414 }
4415 if (libjsig_is_loaded) {
4416 // Tell libjsig jvm is setting signal handlers
4417 (*begin_signal_setting)();
4418 }
4420 set_signal_handler(SIGSEGV, true);
4421 set_signal_handler(SIGPIPE, true);
4422 set_signal_handler(SIGBUS, true);
4423 set_signal_handler(SIGILL, true);
4424 set_signal_handler(SIGFPE, true);
4425 #if defined(PPC64)
4426 set_signal_handler(SIGTRAP, true);
4427 #endif
4428 set_signal_handler(SIGXFSZ, true);
4430 if (libjsig_is_loaded) {
4431 // Tell libjsig jvm finishes setting signal handlers
4432 (*end_signal_setting)();
4433 }
4435 // We don't activate signal checker if libjsig is in place, we trust ourselves
4436 // and if UserSignalHandler is installed all bets are off.
4437 // Log that signal checking is off only if -verbose:jni is specified.
4438 if (CheckJNICalls) {
4439 if (libjsig_is_loaded) {
4440 if (PrintJNIResolving) {
4441 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
4442 }
4443 check_signals = false;
4444 }
4445 if (AllowUserSignalHandlers) {
4446 if (PrintJNIResolving) {
4447 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
4448 }
4449 check_signals = false;
4450 }
4451 }
4452 }
4453 }
4455 // This is the fastest way to get thread cpu time on Linux.
4456 // Returns cpu time (user+sys) for any thread, not only for current.
4457 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
4458 // It might work on 2.6.10+ with a special kernel/glibc patch.
4459 // For reference, please, see IEEE Std 1003.1-2004:
4460 // http://www.unix.org/single_unix_specification
4462 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
4463 struct timespec tp;
4464 int rc = os::Linux::clock_gettime(clockid, &tp);
4465 assert(rc == 0, "clock_gettime is expected to return 0 code");
4467 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
4468 }
4470 /////
4471 // glibc on Linux platform uses non-documented flag
4472 // to indicate, that some special sort of signal
4473 // trampoline is used.
4474 // We will never set this flag, and we should
4475 // ignore this flag in our diagnostic
4476 #ifdef SIGNIFICANT_SIGNAL_MASK
4477 #undef SIGNIFICANT_SIGNAL_MASK
4478 #endif
4479 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
4481 static const char* get_signal_handler_name(address handler,
4482 char* buf, int buflen) {
4483 int offset;
4484 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
4485 if (found) {
4486 // skip directory names
4487 const char *p1, *p2;
4488 p1 = buf;
4489 size_t len = strlen(os::file_separator());
4490 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
4491 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
4492 } else {
4493 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
4494 }
4495 return buf;
4496 }
4498 static void print_signal_handler(outputStream* st, int sig,
4499 char* buf, size_t buflen) {
4500 struct sigaction sa;
4502 sigaction(sig, NULL, &sa);
4504 // See comment for SIGNIFICANT_SIGNAL_MASK define
4505 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4507 st->print("%s: ", os::exception_name(sig, buf, buflen));
4509 address handler = (sa.sa_flags & SA_SIGINFO)
4510 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
4511 : CAST_FROM_FN_PTR(address, sa.sa_handler);
4513 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
4514 st->print("SIG_DFL");
4515 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
4516 st->print("SIG_IGN");
4517 } else {
4518 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
4519 }
4521 st->print(", sa_mask[0]=");
4522 os::Posix::print_signal_set_short(st, &sa.sa_mask);
4524 address rh = VMError::get_resetted_sighandler(sig);
4525 // May be, handler was resetted by VMError?
4526 if(rh != NULL) {
4527 handler = rh;
4528 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
4529 }
4531 st->print(", sa_flags=");
4532 os::Posix::print_sa_flags(st, sa.sa_flags);
4534 // Check: is it our handler?
4535 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
4536 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
4537 // It is our signal handler
4538 // check for flags, reset system-used one!
4539 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
4540 st->print(
4541 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
4542 os::Linux::get_our_sigflags(sig));
4543 }
4544 }
4545 st->cr();
4546 }
4549 #define DO_SIGNAL_CHECK(sig) \
4550 if (!sigismember(&check_signal_done, sig)) \
4551 os::Linux::check_signal_handler(sig)
4553 // This method is a periodic task to check for misbehaving JNI applications
4554 // under CheckJNI, we can add any periodic checks here
4556 void os::run_periodic_checks() {
4558 if (check_signals == false) return;
4560 // SEGV and BUS if overridden could potentially prevent
4561 // generation of hs*.log in the event of a crash, debugging
4562 // such a case can be very challenging, so we absolutely
4563 // check the following for a good measure:
4564 DO_SIGNAL_CHECK(SIGSEGV);
4565 DO_SIGNAL_CHECK(SIGILL);
4566 DO_SIGNAL_CHECK(SIGFPE);
4567 DO_SIGNAL_CHECK(SIGBUS);
4568 DO_SIGNAL_CHECK(SIGPIPE);
4569 DO_SIGNAL_CHECK(SIGXFSZ);
4570 #if defined(PPC64)
4571 DO_SIGNAL_CHECK(SIGTRAP);
4572 #endif
4574 // ReduceSignalUsage allows the user to override these handlers
4575 // see comments at the very top and jvm_solaris.h
4576 if (!ReduceSignalUsage) {
4577 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4578 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4579 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4580 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4581 }
4583 DO_SIGNAL_CHECK(SR_signum);
4584 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
4585 }
4587 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4589 static os_sigaction_t os_sigaction = NULL;
4591 void os::Linux::check_signal_handler(int sig) {
4592 char buf[O_BUFLEN];
4593 address jvmHandler = NULL;
4596 struct sigaction act;
4597 if (os_sigaction == NULL) {
4598 // only trust the default sigaction, in case it has been interposed
4599 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4600 if (os_sigaction == NULL) return;
4601 }
4603 os_sigaction(sig, (struct sigaction*)NULL, &act);
4606 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4608 address thisHandler = (act.sa_flags & SA_SIGINFO)
4609 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4610 : CAST_FROM_FN_PTR(address, act.sa_handler) ;
4613 switch(sig) {
4614 case SIGSEGV:
4615 case SIGBUS:
4616 case SIGFPE:
4617 case SIGPIPE:
4618 case SIGILL:
4619 case SIGXFSZ:
4620 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4621 break;
4623 case SHUTDOWN1_SIGNAL:
4624 case SHUTDOWN2_SIGNAL:
4625 case SHUTDOWN3_SIGNAL:
4626 case BREAK_SIGNAL:
4627 jvmHandler = (address)user_handler();
4628 break;
4630 case INTERRUPT_SIGNAL:
4631 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
4632 break;
4634 default:
4635 if (sig == SR_signum) {
4636 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4637 } else {
4638 return;
4639 }
4640 break;
4641 }
4643 if (thisHandler != jvmHandler) {
4644 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4645 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4646 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4647 // No need to check this sig any longer
4648 sigaddset(&check_signal_done, sig);
4649 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
4650 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
4651 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
4652 exception_name(sig, buf, O_BUFLEN));
4653 }
4654 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4655 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4656 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig));
4657 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags);
4658 // No need to check this sig any longer
4659 sigaddset(&check_signal_done, sig);
4660 }
4662 // Dump all the signal
4663 if (sigismember(&check_signal_done, sig)) {
4664 print_signal_handlers(tty, buf, O_BUFLEN);
4665 }
4666 }
4668 extern void report_error(char* file_name, int line_no, char* title, char* format, ...);
4670 extern bool signal_name(int signo, char* buf, size_t len);
4672 const char* os::exception_name(int exception_code, char* buf, size_t size) {
4673 if (0 < exception_code && exception_code <= SIGRTMAX) {
4674 // signal
4675 if (!signal_name(exception_code, buf, size)) {
4676 jio_snprintf(buf, size, "SIG%d", exception_code);
4677 }
4678 return buf;
4679 } else {
4680 return NULL;
4681 }
4682 }
4684 // this is called _before_ the most of global arguments have been parsed
4685 void os::init(void) {
4686 char dummy; /* used to get a guess on initial stack address */
4687 // first_hrtime = gethrtime();
4689 // With LinuxThreads the JavaMain thread pid (primordial thread)
4690 // is different than the pid of the java launcher thread.
4691 // So, on Linux, the launcher thread pid is passed to the VM
4692 // via the sun.java.launcher.pid property.
4693 // Use this property instead of getpid() if it was correctly passed.
4694 // See bug 6351349.
4695 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
4697 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
4699 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4701 init_random(1234567);
4703 ThreadCritical::initialize();
4705 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4706 if (Linux::page_size() == -1) {
4707 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)",
4708 strerror(errno)));
4709 }
4710 init_page_sizes((size_t) Linux::page_size());
4712 Linux::initialize_system_info();
4714 // main_thread points to the aboriginal thread
4715 Linux::_main_thread = pthread_self();
4717 Linux::clock_init();
4718 initial_time_count = javaTimeNanos();
4720 // pthread_condattr initialization for monotonic clock
4721 int status;
4722 pthread_condattr_t* _condattr = os::Linux::condAttr();
4723 if ((status = pthread_condattr_init(_condattr)) != 0) {
4724 fatal(err_msg("pthread_condattr_init: %s", strerror(status)));
4725 }
4726 // Only set the clock if CLOCK_MONOTONIC is available
4727 if (Linux::supports_monotonic_clock()) {
4728 if ((status = pthread_condattr_setclock(_condattr, CLOCK_MONOTONIC)) != 0) {
4729 if (status == EINVAL) {
4730 warning("Unable to use monotonic clock with relative timed-waits" \
4731 " - changes to the time-of-day clock may have adverse affects");
4732 } else {
4733 fatal(err_msg("pthread_condattr_setclock: %s", strerror(status)));
4734 }
4735 }
4736 }
4737 // else it defaults to CLOCK_REALTIME
4739 pthread_mutex_init(&dl_mutex, NULL);
4741 // If the pagesize of the VM is greater than 8K determine the appropriate
4742 // number of initial guard pages. The user can change this with the
4743 // command line arguments, if needed.
4744 if (vm_page_size() > (int)Linux::vm_default_page_size()) {
4745 StackYellowPages = 1;
4746 StackRedPages = 1;
4747 StackShadowPages = round_to((StackShadowPages*Linux::vm_default_page_size()), vm_page_size()) / vm_page_size();
4748 }
4749 }
4751 // To install functions for atexit system call
4752 extern "C" {
4753 static void perfMemory_exit_helper() {
4754 perfMemory_exit();
4755 }
4756 }
4758 // this is called _after_ the global arguments have been parsed
4759 jint os::init_2(void)
4760 {
4761 Linux::fast_thread_clock_init();
4763 // Allocate a single page and mark it as readable for safepoint polling
4764 #ifdef OPT_SAFEPOINT
4765 void * p = (void *)(0x10000);
4766 address polling_page = (address) ::mmap(p, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4767 #else
4768 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4769 #endif
4770 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" );
4772 os::set_polling_page( polling_page );
4774 #ifndef PRODUCT
4775 if(Verbose && PrintMiscellaneous)
4776 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
4777 #endif
4779 if (!UseMembar) {
4780 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4781 guarantee( mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page");
4782 os::set_memory_serialize_page( mem_serialize_page );
4784 #ifndef PRODUCT
4785 if(Verbose && PrintMiscellaneous)
4786 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
4787 #endif
4788 }
4790 // initialize suspend/resume support - must do this before signal_sets_init()
4791 if (SR_initialize() != 0) {
4792 perror("SR_initialize failed");
4793 return JNI_ERR;
4794 }
4796 Linux::signal_sets_init();
4797 Linux::install_signal_handlers();
4799 // Check minimum allowable stack size for thread creation and to initialize
4800 // the java system classes, including StackOverflowError - depends on page
4801 // size. Add a page for compiler2 recursion in main thread.
4802 // Add in 2*BytesPerWord times page size to account for VM stack during
4803 // class initialization depending on 32 or 64 bit VM.
4805 /* 2014/1/2 Liao: JDK8 requires larger -Xss option.
4806 * TongWeb cannot run with -Xss192K.
4807 * We are not sure whether this causes errors, so simply print a warning. */
4808 size_t min_stack_allowed_jdk6 = os::Linux::min_stack_allowed;
4809 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed,
4810 (size_t)(StackYellowPages+StackRedPages+StackShadowPages) * Linux::page_size() +
4811 (2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::vm_default_page_size());
4813 size_t threadStackSizeInBytes = ThreadStackSize * K;
4814 if (threadStackSizeInBytes != 0 &&
4815 threadStackSizeInBytes < min_stack_allowed_jdk6) {
4816 tty->print_cr("\nThe stack size specified is too small, "
4817 "Specify at least %dk",
4818 os::Linux::min_stack_allowed/ K);
4819 return JNI_ERR;
4820 }
4822 // Make the stack size a multiple of the page size so that
4823 // the yellow/red zones can be guarded.
4824 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
4825 vm_page_size()));
4827 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4829 #if defined(IA32)
4830 workaround_expand_exec_shield_cs_limit();
4831 #endif
4833 Linux::libpthread_init();
4834 if (PrintMiscellaneous && (Verbose || WizardMode)) {
4835 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n",
4836 Linux::glibc_version(), Linux::libpthread_version(),
4837 Linux::is_floating_stack() ? "floating stack" : "fixed stack");
4838 }
4840 if (UseNUMA) {
4841 if (!Linux::libnuma_init()) {
4842 UseNUMA = false;
4843 } else {
4844 if ((Linux::numa_max_node() < 1)) {
4845 // There's only one node(they start from 0), disable NUMA.
4846 UseNUMA = false;
4847 }
4848 }
4849 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
4850 // we can make the adaptive lgrp chunk resizing work. If the user specified
4851 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and
4852 // disable adaptive resizing.
4853 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
4854 if (FLAG_IS_DEFAULT(UseNUMA)) {
4855 UseNUMA = false;
4856 } else {
4857 if (FLAG_IS_DEFAULT(UseLargePages) &&
4858 FLAG_IS_DEFAULT(UseSHM) &&
4859 FLAG_IS_DEFAULT(UseHugeTLBFS)) {
4860 UseLargePages = false;
4861 } else {
4862 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing");
4863 UseAdaptiveSizePolicy = false;
4864 UseAdaptiveNUMAChunkSizing = false;
4865 }
4866 }
4867 }
4868 if (!UseNUMA && ForceNUMA) {
4869 UseNUMA = true;
4870 }
4871 }
4873 if (MaxFDLimit) {
4874 // set the number of file descriptors to max. print out error
4875 // if getrlimit/setrlimit fails but continue regardless.
4876 struct rlimit nbr_files;
4877 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
4878 if (status != 0) {
4879 if (PrintMiscellaneous && (Verbose || WizardMode))
4880 perror("os::init_2 getrlimit failed");
4881 } else {
4882 nbr_files.rlim_cur = nbr_files.rlim_max;
4883 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
4884 if (status != 0) {
4885 if (PrintMiscellaneous && (Verbose || WizardMode))
4886 perror("os::init_2 setrlimit failed");
4887 }
4888 }
4889 }
4891 // Initialize lock used to serialize thread creation (see os::create_thread)
4892 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
4894 // at-exit methods are called in the reverse order of their registration.
4895 // atexit functions are called on return from main or as a result of a
4896 // call to exit(3C). There can be only 32 of these functions registered
4897 // and atexit() does not set errno.
4899 if (PerfAllowAtExitRegistration) {
4900 // only register atexit functions if PerfAllowAtExitRegistration is set.
4901 // atexit functions can be delayed until process exit time, which
4902 // can be problematic for embedded VM situations. Embedded VMs should
4903 // call DestroyJavaVM() to assure that VM resources are released.
4905 // note: perfMemory_exit_helper atexit function may be removed in
4906 // the future if the appropriate cleanup code can be added to the
4907 // VM_Exit VMOperation's doit method.
4908 if (atexit(perfMemory_exit_helper) != 0) {
4909 warning("os::init_2 atexit(perfMemory_exit_helper) failed");
4910 }
4911 }
4913 // initialize thread priority policy
4914 prio_init();
4916 return JNI_OK;
4917 }
4919 // Mark the polling page as unreadable
4920 void os::make_polling_page_unreadable(void) {
4921 if( !guard_memory((char*)_polling_page, Linux::page_size()) )
4922 fatal("Could not disable polling page");
4923 };
4925 // Mark the polling page as readable
4926 void os::make_polling_page_readable(void) {
4927 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
4928 fatal("Could not enable polling page");
4929 }
4930 };
4932 #ifdef MIPS64
4933 /* 2016/9/18 Jin
4934 * Refer to: libnuma_init() */
4935 int get_available_cpus() {
4936 typedef int (*numa_num_task_cpus_t)(void);
4937 static numa_num_task_cpus_t _numa_num_task_cpus;
4939 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
4941 if (handle == NULL)
4942 return sysconf(_SC_NPROCESSORS_ONLN);
4944 _numa_num_task_cpus = CAST_FROM_FN_PTR(numa_num_task_cpus_t, dlsym(handle, "numa_num_task_cpus"));
4946 if (_numa_num_task_cpus == NULL) {
4947 dlclose(handle);
4948 return sysconf(_SC_NPROCESSORS_ONLN);
4949 }
4951 int ret = _numa_num_task_cpus();
4952 dlclose(handle);
4953 return ret;
4954 }
4955 #endif
4957 int os::active_processor_count() {
4958 // Linux doesn't yet have a (official) notion of processor sets,
4959 // so just return the number of online processors.
4960 #ifdef MIPS64
4961 int online_cpus = get_available_cpus();
4962 #else
4963 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
4964 #endif
4965 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
4966 return online_cpus;
4967 }
4969 void os::set_native_thread_name(const char *name) {
4970 // Not yet implemented.
4971 return;
4972 }
4974 bool os::distribute_processes(uint length, uint* distribution) {
4975 // Not yet implemented.
4976 return false;
4977 }
4979 bool os::bind_to_processor(uint processor_id) {
4980 // Not yet implemented.
4981 return false;
4982 }
4984 ///
4986 void os::SuspendedThreadTask::internal_do_task() {
4987 if (do_suspend(_thread->osthread())) {
4988 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
4989 do_task(context);
4990 do_resume(_thread->osthread());
4991 }
4992 }
4994 class PcFetcher : public os::SuspendedThreadTask {
4995 public:
4996 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {}
4997 ExtendedPC result();
4998 protected:
4999 void do_task(const os::SuspendedThreadTaskContext& context);
5000 private:
5001 ExtendedPC _epc;
5002 };
5004 ExtendedPC PcFetcher::result() {
5005 guarantee(is_done(), "task is not done yet.");
5006 return _epc;
5007 }
5009 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) {
5010 Thread* thread = context.thread();
5011 OSThread* osthread = thread->osthread();
5012 if (osthread->ucontext() != NULL) {
5013 _epc = os::Linux::ucontext_get_pc((ucontext_t *) context.ucontext());
5014 } else {
5015 // NULL context is unexpected, double-check this is the VMThread
5016 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
5017 }
5018 }
5020 // Suspends the target using the signal mechanism and then grabs the PC before
5021 // resuming the target. Used by the flat-profiler only
5022 ExtendedPC os::get_thread_pc(Thread* thread) {
5023 // Make sure that it is called by the watcher for the VMThread
5024 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
5025 assert(thread->is_VM_thread(), "Can only be called for VMThread");
5027 PcFetcher fetcher(thread);
5028 fetcher.run();
5029 return fetcher.result();
5030 }
5032 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime)
5033 {
5034 if (is_NPTL()) {
5035 return pthread_cond_timedwait(_cond, _mutex, _abstime);
5036 } else {
5037 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control
5038 // word back to default 64bit precision if condvar is signaled. Java
5039 // wants 53bit precision. Save and restore current value.
5040 int fpu = get_fpu_control_word();
5041 int status = pthread_cond_timedwait(_cond, _mutex, _abstime);
5042 set_fpu_control_word(fpu);
5043 return status;
5044 }
5045 }
5047 ////////////////////////////////////////////////////////////////////////////////
5048 // debug support
5050 bool os::find(address addr, outputStream* st) {
5051 Dl_info dlinfo;
5052 memset(&dlinfo, 0, sizeof(dlinfo));
5053 if (dladdr(addr, &dlinfo) != 0) {
5054 st->print(PTR_FORMAT ": ", addr);
5055 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
5056 st->print("%s+%#x", dlinfo.dli_sname,
5057 addr - (intptr_t)dlinfo.dli_saddr);
5058 } else if (dlinfo.dli_fbase != NULL) {
5059 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
5060 } else {
5061 st->print("<absolute address>");
5062 }
5063 if (dlinfo.dli_fname != NULL) {
5064 st->print(" in %s", dlinfo.dli_fname);
5065 }
5066 if (dlinfo.dli_fbase != NULL) {
5067 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
5068 }
5069 st->cr();
5071 if (Verbose) {
5072 // decode some bytes around the PC
5073 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
5074 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size());
5075 address lowest = (address) dlinfo.dli_sname;
5076 if (!lowest) lowest = (address) dlinfo.dli_fbase;
5077 if (begin < lowest) begin = lowest;
5078 Dl_info dlinfo2;
5079 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
5080 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin)
5081 end = (address) dlinfo2.dli_saddr;
5082 Disassembler::decode(begin, end, st);
5083 }
5084 return true;
5085 }
5086 return false;
5087 }
5089 ////////////////////////////////////////////////////////////////////////////////
5090 // misc
5092 // This does not do anything on Linux. This is basically a hook for being
5093 // able to use structured exception handling (thread-local exception filters)
5094 // on, e.g., Win32.
5095 void
5096 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method,
5097 JavaCallArguments* args, Thread* thread) {
5098 f(value, method, args, thread);
5099 }
5101 void os::print_statistics() {
5102 }
5104 int os::message_box(const char* title, const char* message) {
5105 int i;
5106 fdStream err(defaultStream::error_fd());
5107 for (i = 0; i < 78; i++) err.print_raw("=");
5108 err.cr();
5109 err.print_raw_cr(title);
5110 for (i = 0; i < 78; i++) err.print_raw("-");
5111 err.cr();
5112 err.print_raw_cr(message);
5113 for (i = 0; i < 78; i++) err.print_raw("=");
5114 err.cr();
5116 char buf[16];
5117 // Prevent process from exiting upon "read error" without consuming all CPU
5118 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
5120 return buf[0] == 'y' || buf[0] == 'Y';
5121 }
5123 int os::stat(const char *path, struct stat *sbuf) {
5124 char pathbuf[MAX_PATH];
5125 if (strlen(path) > MAX_PATH - 1) {
5126 errno = ENAMETOOLONG;
5127 return -1;
5128 }
5129 os::native_path(strcpy(pathbuf, path));
5130 return ::stat(pathbuf, sbuf);
5131 }
5133 bool os::check_heap(bool force) {
5134 return true;
5135 }
5137 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
5138 return ::vsnprintf(buf, count, format, args);
5139 }
5141 // Is a (classpath) directory empty?
5142 bool os::dir_is_empty(const char* path) {
5143 DIR *dir = NULL;
5144 struct dirent *ptr;
5146 dir = opendir(path);
5147 if (dir == NULL) return true;
5149 /* Scan the directory */
5150 bool result = true;
5151 char buf[sizeof(struct dirent) + MAX_PATH];
5152 while (result && (ptr = ::readdir(dir)) != NULL) {
5153 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
5154 result = false;
5155 }
5156 }
5157 closedir(dir);
5158 return result;
5159 }
5161 // This code originates from JDK's sysOpen and open64_w
5162 // from src/solaris/hpi/src/system_md.c
5164 #ifndef O_DELETE
5165 #define O_DELETE 0x10000
5166 #endif
5168 // Open a file. Unlink the file immediately after open returns
5169 // if the specified oflag has the O_DELETE flag set.
5170 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c
5172 int os::open(const char *path, int oflag, int mode) {
5174 if (strlen(path) > MAX_PATH - 1) {
5175 errno = ENAMETOOLONG;
5176 return -1;
5177 }
5178 int fd;
5179 int o_delete = (oflag & O_DELETE);
5180 oflag = oflag & ~O_DELETE;
5182 fd = ::open64(path, oflag, mode);
5183 if (fd == -1) return -1;
5185 //If the open succeeded, the file might still be a directory
5186 {
5187 struct stat64 buf64;
5188 int ret = ::fstat64(fd, &buf64);
5189 int st_mode = buf64.st_mode;
5191 if (ret != -1) {
5192 if ((st_mode & S_IFMT) == S_IFDIR) {
5193 errno = EISDIR;
5194 ::close(fd);
5195 return -1;
5196 }
5197 } else {
5198 ::close(fd);
5199 return -1;
5200 }
5201 }
5203 /*
5204 * All file descriptors that are opened in the JVM and not
5205 * specifically destined for a subprocess should have the
5206 * close-on-exec flag set. If we don't set it, then careless 3rd
5207 * party native code might fork and exec without closing all
5208 * appropriate file descriptors (e.g. as we do in closeDescriptors in
5209 * UNIXProcess.c), and this in turn might:
5210 *
5211 * - cause end-of-file to fail to be detected on some file
5212 * descriptors, resulting in mysterious hangs, or
5213 *
5214 * - might cause an fopen in the subprocess to fail on a system
5215 * suffering from bug 1085341.
5216 *
5217 * (Yes, the default setting of the close-on-exec flag is a Unix
5218 * design flaw)
5219 *
5220 * See:
5221 * 1085341: 32-bit stdio routines should support file descriptors >255
5222 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed
5223 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
5224 */
5225 #ifdef FD_CLOEXEC
5226 {
5227 int flags = ::fcntl(fd, F_GETFD);
5228 if (flags != -1)
5229 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
5230 }
5231 #endif
5233 if (o_delete != 0) {
5234 ::unlink(path);
5235 }
5236 return fd;
5237 }
5240 // create binary file, rewriting existing file if required
5241 int os::create_binary_file(const char* path, bool rewrite_existing) {
5242 int oflags = O_WRONLY | O_CREAT;
5243 if (!rewrite_existing) {
5244 oflags |= O_EXCL;
5245 }
5246 return ::open64(path, oflags, S_IREAD | S_IWRITE);
5247 }
5249 // return current position of file pointer
5250 jlong os::current_file_offset(int fd) {
5251 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
5252 }
5254 // move file pointer to the specified offset
5255 jlong os::seek_to_file_offset(int fd, jlong offset) {
5256 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
5257 }
5259 // This code originates from JDK's sysAvailable
5260 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
5262 int os::available(int fd, jlong *bytes) {
5263 jlong cur, end;
5264 int mode;
5265 struct stat64 buf64;
5267 if (::fstat64(fd, &buf64) >= 0) {
5268 mode = buf64.st_mode;
5269 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
5270 /*
5271 * XXX: is the following call interruptible? If so, this might
5272 * need to go through the INTERRUPT_IO() wrapper as for other
5273 * blocking, interruptible calls in this file.
5274 */
5275 int n;
5276 if (::ioctl(fd, FIONREAD, &n) >= 0) {
5277 *bytes = n;
5278 return 1;
5279 }
5280 }
5281 }
5282 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
5283 return 0;
5284 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
5285 return 0;
5286 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
5287 return 0;
5288 }
5289 *bytes = end - cur;
5290 return 1;
5291 }
5293 int os::socket_available(int fd, jint *pbytes) {
5294 // Linux doc says EINTR not returned, unlike Solaris
5295 int ret = ::ioctl(fd, FIONREAD, pbytes);
5297 //%% note ioctl can return 0 when successful, JVM_SocketAvailable
5298 // is expected to return 0 on failure and 1 on success to the jdk.
5299 return (ret < 0) ? 0 : 1;
5300 }
5302 // Map a block of memory.
5303 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
5304 char *addr, size_t bytes, bool read_only,
5305 bool allow_exec) {
5306 int prot;
5307 int flags = MAP_PRIVATE;
5309 if (read_only) {
5310 prot = PROT_READ;
5311 } else {
5312 prot = PROT_READ | PROT_WRITE;
5313 }
5315 if (allow_exec) {
5316 prot |= PROT_EXEC;
5317 }
5319 if (addr != NULL) {
5320 flags |= MAP_FIXED;
5321 }
5323 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
5324 fd, file_offset);
5325 if (mapped_address == MAP_FAILED) {
5326 return NULL;
5327 }
5328 return mapped_address;
5329 }
5332 // Remap a block of memory.
5333 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
5334 char *addr, size_t bytes, bool read_only,
5335 bool allow_exec) {
5336 // same as map_memory() on this OS
5337 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
5338 allow_exec);
5339 }
5342 // Unmap a block of memory.
5343 bool os::pd_unmap_memory(char* addr, size_t bytes) {
5344 return munmap(addr, bytes) == 0;
5345 }
5347 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
5349 static clockid_t thread_cpu_clockid(Thread* thread) {
5350 pthread_t tid = thread->osthread()->pthread_id();
5351 clockid_t clockid;
5353 // Get thread clockid
5354 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
5355 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
5356 return clockid;
5357 }
5359 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
5360 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
5361 // of a thread.
5362 //
5363 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
5364 // the fast estimate available on the platform.
5366 jlong os::current_thread_cpu_time() {
5367 if (os::Linux::supports_fast_thread_cpu_time()) {
5368 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5369 } else {
5370 // return user + sys since the cost is the same
5371 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
5372 }
5373 }
5375 jlong os::thread_cpu_time(Thread* thread) {
5376 // consistent with what current_thread_cpu_time() returns
5377 if (os::Linux::supports_fast_thread_cpu_time()) {
5378 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5379 } else {
5380 return slow_thread_cpu_time(thread, true /* user + sys */);
5381 }
5382 }
5384 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
5385 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5386 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5387 } else {
5388 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
5389 }
5390 }
5392 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5393 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5394 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5395 } else {
5396 return slow_thread_cpu_time(thread, user_sys_cpu_time);
5397 }
5398 }
5400 //
5401 // -1 on error.
5402 //
5404 PRAGMA_DIAG_PUSH
5405 PRAGMA_FORMAT_NONLITERAL_IGNORED
5406 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5407 static bool proc_task_unchecked = true;
5408 static const char *proc_stat_path = "/proc/%d/stat";
5409 pid_t tid = thread->osthread()->thread_id();
5410 char *s;
5411 char stat[2048];
5412 int statlen;
5413 char proc_name[64];
5414 int count;
5415 long sys_time, user_time;
5416 char cdummy;
5417 int idummy;
5418 long ldummy;
5419 FILE *fp;
5421 // The /proc/<tid>/stat aggregates per-process usage on
5422 // new Linux kernels 2.6+ where NPTL is supported.
5423 // The /proc/self/task/<tid>/stat still has the per-thread usage.
5424 // See bug 6328462.
5425 // There possibly can be cases where there is no directory
5426 // /proc/self/task, so we check its availability.
5427 if (proc_task_unchecked && os::Linux::is_NPTL()) {
5428 // This is executed only once
5429 proc_task_unchecked = false;
5430 fp = fopen("/proc/self/task", "r");
5431 if (fp != NULL) {
5432 proc_stat_path = "/proc/self/task/%d/stat";
5433 fclose(fp);
5434 }
5435 }
5437 sprintf(proc_name, proc_stat_path, tid);
5438 fp = fopen(proc_name, "r");
5439 if ( fp == NULL ) return -1;
5440 statlen = fread(stat, 1, 2047, fp);
5441 stat[statlen] = '\0';
5442 fclose(fp);
5444 // Skip pid and the command string. Note that we could be dealing with
5445 // weird command names, e.g. user could decide to rename java launcher
5446 // to "java 1.4.2 :)", then the stat file would look like
5447 // 1234 (java 1.4.2 :)) R ... ...
5448 // We don't really need to know the command string, just find the last
5449 // occurrence of ")" and then start parsing from there. See bug 4726580.
5450 s = strrchr(stat, ')');
5451 if (s == NULL ) return -1;
5453 // Skip blank chars
5454 do s++; while (isspace(*s));
5456 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
5457 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
5458 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
5459 &user_time, &sys_time);
5460 if ( count != 13 ) return -1;
5461 if (user_sys_cpu_time) {
5462 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5463 } else {
5464 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5465 }
5466 }
5467 PRAGMA_DIAG_POP
5469 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5470 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5471 info_ptr->may_skip_backward = false; // elapsed time not wall time
5472 info_ptr->may_skip_forward = false; // elapsed time not wall time
5473 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5474 }
5476 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5477 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5478 info_ptr->may_skip_backward = false; // elapsed time not wall time
5479 info_ptr->may_skip_forward = false; // elapsed time not wall time
5480 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5481 }
5483 bool os::is_thread_cpu_time_supported() {
5484 return true;
5485 }
5487 // System loadavg support. Returns -1 if load average cannot be obtained.
5488 // Linux doesn't yet have a (official) notion of processor sets,
5489 // so just return the system wide load average.
5490 int os::loadavg(double loadavg[], int nelem) {
5491 return ::getloadavg(loadavg, nelem);
5492 }
5494 void os::pause() {
5495 char filename[MAX_PATH];
5496 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
5497 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
5498 } else {
5499 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
5500 }
5502 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
5503 if (fd != -1) {
5504 struct stat buf;
5505 ::close(fd);
5506 while (::stat(filename, &buf) == 0) {
5507 (void)::poll(NULL, 0, 100);
5508 }
5509 } else {
5510 jio_fprintf(stderr,
5511 "Could not open pause file '%s', continuing immediately.\n", filename);
5512 }
5513 }
5516 // Refer to the comments in os_solaris.cpp park-unpark.
5517 //
5518 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
5519 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
5520 // For specifics regarding the bug see GLIBC BUGID 261237 :
5521 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
5522 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
5523 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
5524 // is used. (The simple C test-case provided in the GLIBC bug report manifests the
5525 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
5526 // and monitorenter when we're using 1-0 locking. All those operations may result in
5527 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version
5528 // of libpthread avoids the problem, but isn't practical.
5529 //
5530 // Possible remedies:
5531 //
5532 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work.
5533 // This is palliative and probabilistic, however. If the thread is preempted
5534 // between the call to compute_abstime() and pthread_cond_timedwait(), more
5535 // than the minimum period may have passed, and the abstime may be stale (in the
5536 // past) resultin in a hang. Using this technique reduces the odds of a hang
5537 // but the JVM is still vulnerable, particularly on heavily loaded systems.
5538 //
5539 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
5540 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set
5541 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
5542 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant
5543 // thread.
5544 //
5545 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread
5546 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing
5547 // a timeout request to the chron thread and then blocking via pthread_cond_wait().
5548 // This also works well. In fact it avoids kernel-level scalability impediments
5549 // on certain platforms that don't handle lots of active pthread_cond_timedwait()
5550 // timers in a graceful fashion.
5551 //
5552 // 4. When the abstime value is in the past it appears that control returns
5553 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
5554 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we
5555 // can avoid the problem by reinitializing the condvar -- by cond_destroy()
5556 // followed by cond_init() -- after all calls to pthread_cond_timedwait().
5557 // It may be possible to avoid reinitialization by checking the return
5558 // value from pthread_cond_timedwait(). In addition to reinitializing the
5559 // condvar we must establish the invariant that cond_signal() is only called
5560 // within critical sections protected by the adjunct mutex. This prevents
5561 // cond_signal() from "seeing" a condvar that's in the midst of being
5562 // reinitialized or that is corrupt. Sadly, this invariant obviates the
5563 // desirable signal-after-unlock optimization that avoids futile context switching.
5564 //
5565 // I'm also concerned that some versions of NTPL might allocate an auxilliary
5566 // structure when a condvar is used or initialized. cond_destroy() would
5567 // release the helper structure. Our reinitialize-after-timedwait fix
5568 // put excessive stress on malloc/free and locks protecting the c-heap.
5569 //
5570 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag.
5571 // It may be possible to refine (4) by checking the kernel and NTPL verisons
5572 // and only enabling the work-around for vulnerable environments.
5574 // utility to compute the abstime argument to timedwait:
5575 // millis is the relative timeout time
5576 // abstime will be the absolute timeout time
5577 // TODO: replace compute_abstime() with unpackTime()
5579 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
5580 if (millis < 0) millis = 0;
5582 jlong seconds = millis / 1000;
5583 millis %= 1000;
5584 if (seconds > 50000000) { // see man cond_timedwait(3T)
5585 seconds = 50000000;
5586 }
5588 if (os::Linux::supports_monotonic_clock()) {
5589 struct timespec now;
5590 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now);
5591 assert_status(status == 0, status, "clock_gettime");
5592 abstime->tv_sec = now.tv_sec + seconds;
5593 long nanos = now.tv_nsec + millis * NANOSECS_PER_MILLISEC;
5594 if (nanos >= NANOSECS_PER_SEC) {
5595 abstime->tv_sec += 1;
5596 nanos -= NANOSECS_PER_SEC;
5597 }
5598 abstime->tv_nsec = nanos;
5599 } else {
5600 struct timeval now;
5601 int status = gettimeofday(&now, NULL);
5602 assert(status == 0, "gettimeofday");
5603 abstime->tv_sec = now.tv_sec + seconds;
5604 long usec = now.tv_usec + millis * 1000;
5605 if (usec >= 1000000) {
5606 abstime->tv_sec += 1;
5607 usec -= 1000000;
5608 }
5609 abstime->tv_nsec = usec * 1000;
5610 }
5611 return abstime;
5612 }
5615 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately.
5616 // Conceptually TryPark() should be equivalent to park(0).
5618 int os::PlatformEvent::TryPark() {
5619 for (;;) {
5620 const int v = _Event ;
5621 guarantee ((v == 0) || (v == 1), "invariant") ;
5622 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ;
5623 }
5624 }
5626 void os::PlatformEvent::park() { // AKA "down()"
5627 // Invariant: Only the thread associated with the Event/PlatformEvent
5628 // may call park().
5629 // TODO: assert that _Assoc != NULL or _Assoc == Self
5630 int v ;
5631 for (;;) {
5632 v = _Event ;
5633 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5634 }
5635 guarantee (v >= 0, "invariant") ;
5636 if (v == 0) {
5637 // Do this the hard way by blocking ...
5638 int status = pthread_mutex_lock(_mutex);
5639 assert_status(status == 0, status, "mutex_lock");
5640 guarantee (_nParked == 0, "invariant") ;
5641 ++ _nParked ;
5642 while (_Event < 0) {
5643 status = pthread_cond_wait(_cond, _mutex);
5644 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
5645 // Treat this the same as if the wait was interrupted
5646 if (status == ETIME) { status = EINTR; }
5647 assert_status(status == 0 || status == EINTR, status, "cond_wait");
5648 }
5649 -- _nParked ;
5651 _Event = 0 ;
5652 status = pthread_mutex_unlock(_mutex);
5653 assert_status(status == 0, status, "mutex_unlock");
5654 // Paranoia to ensure our locked and lock-free paths interact
5655 // correctly with each other.
5656 OrderAccess::fence();
5657 }
5658 guarantee (_Event >= 0, "invariant") ;
5659 }
5661 int os::PlatformEvent::park(jlong millis) {
5662 guarantee (_nParked == 0, "invariant") ;
5664 int v ;
5665 for (;;) {
5666 v = _Event ;
5667 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5668 }
5669 guarantee (v >= 0, "invariant") ;
5670 if (v != 0) return OS_OK ;
5672 // We do this the hard way, by blocking the thread.
5673 // Consider enforcing a minimum timeout value.
5674 struct timespec abst;
5675 compute_abstime(&abst, millis);
5677 int ret = OS_TIMEOUT;
5678 int status = pthread_mutex_lock(_mutex);
5679 assert_status(status == 0, status, "mutex_lock");
5680 guarantee (_nParked == 0, "invariant") ;
5681 ++_nParked ;
5683 // Object.wait(timo) will return because of
5684 // (a) notification
5685 // (b) timeout
5686 // (c) thread.interrupt
5687 //
5688 // Thread.interrupt and object.notify{All} both call Event::set.
5689 // That is, we treat thread.interrupt as a special case of notification.
5690 // The underlying Solaris implementation, cond_timedwait, admits
5691 // spurious/premature wakeups, but the JLS/JVM spec prevents the
5692 // JVM from making those visible to Java code. As such, we must
5693 // filter out spurious wakeups. We assume all ETIME returns are valid.
5694 //
5695 // TODO: properly differentiate simultaneous notify+interrupt.
5696 // In that case, we should propagate the notify to another waiter.
5698 while (_Event < 0) {
5699 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst);
5700 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5701 pthread_cond_destroy (_cond);
5702 pthread_cond_init (_cond, os::Linux::condAttr()) ;
5703 }
5704 assert_status(status == 0 || status == EINTR ||
5705 status == ETIME || status == ETIMEDOUT,
5706 status, "cond_timedwait");
5707 if (!FilterSpuriousWakeups) break ; // previous semantics
5708 if (status == ETIME || status == ETIMEDOUT) break ;
5709 // We consume and ignore EINTR and spurious wakeups.
5710 }
5711 --_nParked ;
5712 if (_Event >= 0) {
5713 ret = OS_OK;
5714 }
5715 _Event = 0 ;
5716 status = pthread_mutex_unlock(_mutex);
5717 assert_status(status == 0, status, "mutex_unlock");
5718 assert (_nParked == 0, "invariant") ;
5719 // Paranoia to ensure our locked and lock-free paths interact
5720 // correctly with each other.
5721 OrderAccess::fence();
5722 return ret;
5723 }
5725 void os::PlatformEvent::unpark() {
5726 // Transitions for _Event:
5727 // 0 :=> 1
5728 // 1 :=> 1
5729 // -1 :=> either 0 or 1; must signal target thread
5730 // That is, we can safely transition _Event from -1 to either
5731 // 0 or 1. Forcing 1 is slightly more efficient for back-to-back
5732 // unpark() calls.
5733 // See also: "Semaphores in Plan 9" by Mullender & Cox
5734 //
5735 // Note: Forcing a transition from "-1" to "1" on an unpark() means
5736 // that it will take two back-to-back park() calls for the owning
5737 // thread to block. This has the benefit of forcing a spurious return
5738 // from the first park() call after an unpark() call which will help
5739 // shake out uses of park() and unpark() without condition variables.
5741 if (Atomic::xchg(1, &_Event) >= 0) return;
5743 // Wait for the thread associated with the event to vacate
5744 int status = pthread_mutex_lock(_mutex);
5745 assert_status(status == 0, status, "mutex_lock");
5746 int AnyWaiters = _nParked;
5747 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant");
5748 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
5749 AnyWaiters = 0;
5750 pthread_cond_signal(_cond);
5751 }
5752 status = pthread_mutex_unlock(_mutex);
5753 assert_status(status == 0, status, "mutex_unlock");
5754 if (AnyWaiters != 0) {
5755 status = pthread_cond_signal(_cond);
5756 assert_status(status == 0, status, "cond_signal");
5757 }
5759 // Note that we signal() _after dropping the lock for "immortal" Events.
5760 // This is safe and avoids a common class of futile wakeups. In rare
5761 // circumstances this can cause a thread to return prematurely from
5762 // cond_{timed}wait() but the spurious wakeup is benign and the victim will
5763 // simply re-test the condition and re-park itself.
5764 }
5767 // JSR166
5768 // -------------------------------------------------------
5770 /*
5771 * The solaris and linux implementations of park/unpark are fairly
5772 * conservative for now, but can be improved. They currently use a
5773 * mutex/condvar pair, plus a a count.
5774 * Park decrements count if > 0, else does a condvar wait. Unpark
5775 * sets count to 1 and signals condvar. Only one thread ever waits
5776 * on the condvar. Contention seen when trying to park implies that someone
5777 * is unparking you, so don't wait. And spurious returns are fine, so there
5778 * is no need to track notifications.
5779 */
5781 /*
5782 * This code is common to linux and solaris and will be moved to a
5783 * common place in dolphin.
5784 *
5785 * The passed in time value is either a relative time in nanoseconds
5786 * or an absolute time in milliseconds. Either way it has to be unpacked
5787 * into suitable seconds and nanoseconds components and stored in the
5788 * given timespec structure.
5789 * Given time is a 64-bit value and the time_t used in the timespec is only
5790 * a signed-32-bit value (except on 64-bit Linux) we have to watch for
5791 * overflow if times way in the future are given. Further on Solaris versions
5792 * prior to 10 there is a restriction (see cond_timedwait) that the specified
5793 * number of seconds, in abstime, is less than current_time + 100,000,000.
5794 * As it will be 28 years before "now + 100000000" will overflow we can
5795 * ignore overflow and just impose a hard-limit on seconds using the value
5796 * of "now + 100,000,000". This places a limit on the timeout of about 3.17
5797 * years from "now".
5798 */
5800 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
5801 assert (time > 0, "convertTime");
5802 time_t max_secs = 0;
5804 if (!os::Linux::supports_monotonic_clock() || isAbsolute) {
5805 struct timeval now;
5806 int status = gettimeofday(&now, NULL);
5807 assert(status == 0, "gettimeofday");
5809 max_secs = now.tv_sec + MAX_SECS;
5811 if (isAbsolute) {
5812 jlong secs = time / 1000;
5813 if (secs > max_secs) {
5814 absTime->tv_sec = max_secs;
5815 } else {
5816 absTime->tv_sec = secs;
5817 }
5818 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
5819 } else {
5820 jlong secs = time / NANOSECS_PER_SEC;
5821 if (secs >= MAX_SECS) {
5822 absTime->tv_sec = max_secs;
5823 absTime->tv_nsec = 0;
5824 } else {
5825 absTime->tv_sec = now.tv_sec + secs;
5826 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
5827 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5828 absTime->tv_nsec -= NANOSECS_PER_SEC;
5829 ++absTime->tv_sec; // note: this must be <= max_secs
5830 }
5831 }
5832 }
5833 } else {
5834 // must be relative using monotonic clock
5835 struct timespec now;
5836 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now);
5837 assert_status(status == 0, status, "clock_gettime");
5838 max_secs = now.tv_sec + MAX_SECS;
5839 jlong secs = time / NANOSECS_PER_SEC;
5840 if (secs >= MAX_SECS) {
5841 absTime->tv_sec = max_secs;
5842 absTime->tv_nsec = 0;
5843 } else {
5844 absTime->tv_sec = now.tv_sec + secs;
5845 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_nsec;
5846 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5847 absTime->tv_nsec -= NANOSECS_PER_SEC;
5848 ++absTime->tv_sec; // note: this must be <= max_secs
5849 }
5850 }
5851 }
5852 assert(absTime->tv_sec >= 0, "tv_sec < 0");
5853 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
5854 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
5855 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
5856 }
5858 void Parker::park(bool isAbsolute, jlong time) {
5859 // Ideally we'd do something useful while spinning, such
5860 // as calling unpackTime().
5862 // Optional fast-path check:
5863 // Return immediately if a permit is available.
5864 // We depend on Atomic::xchg() having full barrier semantics
5865 // since we are doing a lock-free update to _counter.
5866 if (Atomic::xchg(0, &_counter) > 0) return;
5868 Thread* thread = Thread::current();
5869 assert(thread->is_Java_thread(), "Must be JavaThread");
5870 JavaThread *jt = (JavaThread *)thread;
5872 // Optional optimization -- avoid state transitions if there's an interrupt pending.
5873 // Check interrupt before trying to wait
5874 if (Thread::is_interrupted(thread, false)) {
5875 return;
5876 }
5878 // Next, demultiplex/decode time arguments
5879 timespec absTime;
5880 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all
5881 return;
5882 }
5883 if (time > 0) {
5884 unpackTime(&absTime, isAbsolute, time);
5885 }
5888 // Enter safepoint region
5889 // Beware of deadlocks such as 6317397.
5890 // The per-thread Parker:: mutex is a classic leaf-lock.
5891 // In particular a thread must never block on the Threads_lock while
5892 // holding the Parker:: mutex. If safepoints are pending both the
5893 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
5894 ThreadBlockInVM tbivm(jt);
5896 // Don't wait if cannot get lock since interference arises from
5897 // unblocking. Also. check interrupt before trying wait
5898 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
5899 return;
5900 }
5902 int status ;
5903 if (_counter > 0) { // no wait needed
5904 _counter = 0;
5905 status = pthread_mutex_unlock(_mutex);
5906 assert (status == 0, "invariant") ;
5907 // Paranoia to ensure our locked and lock-free paths interact
5908 // correctly with each other and Java-level accesses.
5909 OrderAccess::fence();
5910 return;
5911 }
5913 #ifdef ASSERT
5914 // Don't catch signals while blocked; let the running threads have the signals.
5915 // (This allows a debugger to break into the running thread.)
5916 sigset_t oldsigs;
5917 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
5918 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
5919 #endif
5921 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
5922 jt->set_suspend_equivalent();
5923 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
5925 assert(_cur_index == -1, "invariant");
5926 if (time == 0) {
5927 _cur_index = REL_INDEX; // arbitrary choice when not timed
5928 status = pthread_cond_wait (&_cond[_cur_index], _mutex) ;
5929 } else {
5930 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX;
5931 status = os::Linux::safe_cond_timedwait (&_cond[_cur_index], _mutex, &absTime) ;
5932 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5933 pthread_cond_destroy (&_cond[_cur_index]) ;
5934 pthread_cond_init (&_cond[_cur_index], isAbsolute ? NULL : os::Linux::condAttr());
5935 }
5936 }
5937 _cur_index = -1;
5938 assert_status(status == 0 || status == EINTR ||
5939 status == ETIME || status == ETIMEDOUT,
5940 status, "cond_timedwait");
5942 #ifdef ASSERT
5943 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
5944 #endif
5946 _counter = 0 ;
5947 status = pthread_mutex_unlock(_mutex) ;
5948 assert_status(status == 0, status, "invariant") ;
5949 // Paranoia to ensure our locked and lock-free paths interact
5950 // correctly with each other and Java-level accesses.
5951 OrderAccess::fence();
5953 // If externally suspended while waiting, re-suspend
5954 if (jt->handle_special_suspend_equivalent_condition()) {
5955 jt->java_suspend_self();
5956 }
5957 }
5959 void Parker::unpark() {
5960 int s, status ;
5961 status = pthread_mutex_lock(_mutex);
5962 assert (status == 0, "invariant") ;
5963 s = _counter;
5964 _counter = 1;
5965 if (s < 1) {
5966 // thread might be parked
5967 if (_cur_index != -1) {
5968 // thread is definitely parked
5969 if (WorkAroundNPTLTimedWaitHang) {
5970 status = pthread_cond_signal (&_cond[_cur_index]);
5971 assert (status == 0, "invariant");
5972 status = pthread_mutex_unlock(_mutex);
5973 assert (status == 0, "invariant");
5974 } else {
5975 status = pthread_mutex_unlock(_mutex);
5976 assert (status == 0, "invariant");
5977 status = pthread_cond_signal (&_cond[_cur_index]);
5978 assert (status == 0, "invariant");
5979 }
5980 } else {
5981 pthread_mutex_unlock(_mutex);
5982 assert (status == 0, "invariant") ;
5983 }
5984 } else {
5985 pthread_mutex_unlock(_mutex);
5986 assert (status == 0, "invariant") ;
5987 }
5988 }
5991 extern char** environ;
5993 // Run the specified command in a separate process. Return its exit value,
5994 // or -1 on failure (e.g. can't fork a new process).
5995 // Unlike system(), this function can be called from signal handler. It
5996 // doesn't block SIGINT et al.
5997 int os::fork_and_exec(char* cmd) {
5998 const char * argv[4] = {"sh", "-c", cmd, NULL};
6000 pid_t pid = fork();
6002 if (pid < 0) {
6003 // fork failed
6004 return -1;
6006 } else if (pid == 0) {
6007 // child process
6009 execve("/bin/sh", (char* const*)argv, environ);
6011 // execve failed
6012 _exit(-1);
6014 } else {
6015 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
6016 // care about the actual exit code, for now.
6018 int status;
6020 // Wait for the child process to exit. This returns immediately if
6021 // the child has already exited. */
6022 while (waitpid(pid, &status, 0) < 0) {
6023 switch (errno) {
6024 case ECHILD: return 0;
6025 case EINTR: break;
6026 default: return -1;
6027 }
6028 }
6030 if (WIFEXITED(status)) {
6031 // The child exited normally; get its exit code.
6032 return WEXITSTATUS(status);
6033 } else if (WIFSIGNALED(status)) {
6034 // The child exited because of a signal
6035 // The best value to return is 0x80 + signal number,
6036 // because that is what all Unix shells do, and because
6037 // it allows callers to distinguish between process exit and
6038 // process death by signal.
6039 return 0x80 + WTERMSIG(status);
6040 } else {
6041 // Unknown exit code; pass it through
6042 return status;
6043 }
6044 }
6045 }
6047 // is_headless_jre()
6048 //
6049 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
6050 // in order to report if we are running in a headless jre
6051 //
6052 // Since JDK8 xawt/libmawt.so was moved into the same directory
6053 // as libawt.so, and renamed libawt_xawt.so
6054 //
6055 bool os::is_headless_jre() {
6056 struct stat statbuf;
6057 char buf[MAXPATHLEN];
6058 char libmawtpath[MAXPATHLEN];
6059 const char *xawtstr = "/xawt/libmawt.so";
6060 const char *new_xawtstr = "/libawt_xawt.so";
6061 char *p;
6063 // Get path to libjvm.so
6064 os::jvm_path(buf, sizeof(buf));
6066 // Get rid of libjvm.so
6067 p = strrchr(buf, '/');
6068 if (p == NULL) return false;
6069 else *p = '\0';
6071 // Get rid of client or server
6072 p = strrchr(buf, '/');
6073 if (p == NULL) return false;
6074 else *p = '\0';
6076 // check xawt/libmawt.so
6077 strcpy(libmawtpath, buf);
6078 strcat(libmawtpath, xawtstr);
6079 if (::stat(libmawtpath, &statbuf) == 0) return false;
6081 // check libawt_xawt.so
6082 strcpy(libmawtpath, buf);
6083 strcat(libmawtpath, new_xawtstr);
6084 if (::stat(libmawtpath, &statbuf) == 0) return false;
6086 return true;
6087 }
6089 // Get the default path to the core file
6090 // Returns the length of the string
6091 int os::get_core_path(char* buffer, size_t bufferSize) {
6092 const char* p = get_current_directory(buffer, bufferSize);
6094 if (p == NULL) {
6095 assert(p != NULL, "failed to get current directory");
6096 return 0;
6097 }
6099 return strlen(buffer);
6100 }
6102 /////////////// Unit tests ///////////////
6104 #ifndef PRODUCT
6106 #define test_log(...) \
6107 do {\
6108 if (VerboseInternalVMTests) { \
6109 tty->print_cr(__VA_ARGS__); \
6110 tty->flush(); \
6111 }\
6112 } while (false)
6114 class TestReserveMemorySpecial : AllStatic {
6115 public:
6116 static void small_page_write(void* addr, size_t size) {
6117 size_t page_size = os::vm_page_size();
6119 char* end = (char*)addr + size;
6120 for (char* p = (char*)addr; p < end; p += page_size) {
6121 *p = 1;
6122 }
6123 }
6125 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) {
6126 if (!UseHugeTLBFS) {
6127 return;
6128 }
6130 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size);
6132 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false);
6134 if (addr != NULL) {
6135 small_page_write(addr, size);
6137 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6138 }
6139 }
6141 static void test_reserve_memory_special_huge_tlbfs_only() {
6142 if (!UseHugeTLBFS) {
6143 return;
6144 }
6146 size_t lp = os::large_page_size();
6148 for (size_t size = lp; size <= lp * 10; size += lp) {
6149 test_reserve_memory_special_huge_tlbfs_only(size);
6150 }
6151 }
6153 static void test_reserve_memory_special_huge_tlbfs_mixed(size_t size, size_t alignment) {
6154 if (!UseHugeTLBFS) {
6155 return;
6156 }
6158 test_log("test_reserve_memory_special_huge_tlbfs_mixed(" SIZE_FORMAT ", " SIZE_FORMAT ")",
6159 size, alignment);
6161 assert(size >= os::large_page_size(), "Incorrect input to test");
6163 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false);
6165 if (addr != NULL) {
6166 small_page_write(addr, size);
6168 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6169 }
6170 }
6172 static void test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(size_t size) {
6173 size_t lp = os::large_page_size();
6174 size_t ag = os::vm_allocation_granularity();
6176 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6177 test_reserve_memory_special_huge_tlbfs_mixed(size, alignment);
6178 }
6179 }
6181 static void test_reserve_memory_special_huge_tlbfs_mixed() {
6182 size_t lp = os::large_page_size();
6183 size_t ag = os::vm_allocation_granularity();
6185 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp);
6186 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp + ag);
6187 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp + lp / 2);
6188 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2);
6189 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 + ag);
6190 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 - ag);
6191 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 + lp / 2);
6192 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 10);
6193 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 10 + lp / 2);
6194 }
6196 static void test_reserve_memory_special_huge_tlbfs() {
6197 if (!UseHugeTLBFS) {
6198 return;
6199 }
6201 test_reserve_memory_special_huge_tlbfs_only();
6202 test_reserve_memory_special_huge_tlbfs_mixed();
6203 }
6205 static void test_reserve_memory_special_shm(size_t size, size_t alignment) {
6206 if (!UseSHM) {
6207 return;
6208 }
6210 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment);
6212 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false);
6214 if (addr != NULL) {
6215 assert(is_ptr_aligned(addr, alignment), "Check");
6216 assert(is_ptr_aligned(addr, os::large_page_size()), "Check");
6218 small_page_write(addr, size);
6220 os::Linux::release_memory_special_shm(addr, size);
6221 }
6222 }
6224 static void test_reserve_memory_special_shm() {
6225 size_t lp = os::large_page_size();
6226 size_t ag = os::vm_allocation_granularity();
6228 for (size_t size = ag; size < lp * 3; size += ag) {
6229 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6230 test_reserve_memory_special_shm(size, alignment);
6231 }
6232 }
6233 }
6235 static void test() {
6236 test_reserve_memory_special_huge_tlbfs();
6237 test_reserve_memory_special_shm();
6238 }
6239 };
6241 void TestReserveMemorySpecial_test() {
6242 TestReserveMemorySpecial::test();
6243 }
6245 #endif