Tue, 26 Apr 2011 11:46:34 -0700
7037939: NUMA: Disable adaptive resizing if SHM large pages are used
Summary: Make the NUMA allocator behave properly with SHM and ISM large pages.
Reviewed-by: ysr
1 /*
2 * Copyright (c) 1999, 2011, 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 # define __STDC_FORMAT_MACROS
27 // no precompiled headers
28 #include "classfile/classLoader.hpp"
29 #include "classfile/systemDictionary.hpp"
30 #include "classfile/vmSymbols.hpp"
31 #include "code/icBuffer.hpp"
32 #include "code/vtableStubs.hpp"
33 #include "compiler/compileBroker.hpp"
34 #include "interpreter/interpreter.hpp"
35 #include "jvm_linux.h"
36 #include "memory/allocation.inline.hpp"
37 #include "memory/filemap.hpp"
38 #include "mutex_linux.inline.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "os_share_linux.hpp"
41 #include "prims/jniFastGetField.hpp"
42 #include "prims/jvm.h"
43 #include "prims/jvm_misc.hpp"
44 #include "runtime/arguments.hpp"
45 #include "runtime/extendedPC.hpp"
46 #include "runtime/globals.hpp"
47 #include "runtime/interfaceSupport.hpp"
48 #include "runtime/java.hpp"
49 #include "runtime/javaCalls.hpp"
50 #include "runtime/mutexLocker.hpp"
51 #include "runtime/objectMonitor.hpp"
52 #include "runtime/osThread.hpp"
53 #include "runtime/perfMemory.hpp"
54 #include "runtime/sharedRuntime.hpp"
55 #include "runtime/statSampler.hpp"
56 #include "runtime/stubRoutines.hpp"
57 #include "runtime/threadCritical.hpp"
58 #include "runtime/timer.hpp"
59 #include "services/attachListener.hpp"
60 #include "services/runtimeService.hpp"
61 #include "thread_linux.inline.hpp"
62 #include "utilities/decoder.hpp"
63 #include "utilities/defaultStream.hpp"
64 #include "utilities/events.hpp"
65 #include "utilities/growableArray.hpp"
66 #include "utilities/vmError.hpp"
67 #ifdef TARGET_ARCH_x86
68 # include "assembler_x86.inline.hpp"
69 # include "nativeInst_x86.hpp"
70 #endif
71 #ifdef TARGET_ARCH_sparc
72 # include "assembler_sparc.inline.hpp"
73 # include "nativeInst_sparc.hpp"
74 #endif
75 #ifdef TARGET_ARCH_zero
76 # include "assembler_zero.inline.hpp"
77 # include "nativeInst_zero.hpp"
78 #endif
79 #ifdef TARGET_ARCH_arm
80 # include "assembler_arm.inline.hpp"
81 # include "nativeInst_arm.hpp"
82 #endif
83 #ifdef TARGET_ARCH_ppc
84 # include "assembler_ppc.inline.hpp"
85 # include "nativeInst_ppc.hpp"
86 #endif
87 #ifdef COMPILER1
88 #include "c1/c1_Runtime1.hpp"
89 #endif
90 #ifdef COMPILER2
91 #include "opto/runtime.hpp"
92 #endif
94 // put OS-includes here
95 # include <sys/types.h>
96 # include <sys/mman.h>
97 # include <sys/stat.h>
98 # include <sys/select.h>
99 # include <pthread.h>
100 # include <signal.h>
101 # include <errno.h>
102 # include <dlfcn.h>
103 # include <stdio.h>
104 # include <unistd.h>
105 # include <sys/resource.h>
106 # include <pthread.h>
107 # include <sys/stat.h>
108 # include <sys/time.h>
109 # include <sys/times.h>
110 # include <sys/utsname.h>
111 # include <sys/socket.h>
112 # include <sys/wait.h>
113 # include <pwd.h>
114 # include <poll.h>
115 # include <semaphore.h>
116 # include <fcntl.h>
117 # include <string.h>
118 # include <syscall.h>
119 # include <sys/sysinfo.h>
120 # include <gnu/libc-version.h>
121 # include <sys/ipc.h>
122 # include <sys/shm.h>
123 # include <link.h>
124 # include <stdint.h>
125 # include <inttypes.h>
126 # include <sys/ioctl.h>
128 #define MAX_PATH (2 * K)
130 // for timer info max values which include all bits
131 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
132 #define SEC_IN_NANOSECS 1000000000LL
134 #define LARGEPAGES_BIT (1 << 6)
135 ////////////////////////////////////////////////////////////////////////////////
136 // global variables
137 julong os::Linux::_physical_memory = 0;
139 address os::Linux::_initial_thread_stack_bottom = NULL;
140 uintptr_t os::Linux::_initial_thread_stack_size = 0;
142 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
143 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
144 Mutex* os::Linux::_createThread_lock = NULL;
145 pthread_t os::Linux::_main_thread;
146 int os::Linux::_page_size = -1;
147 bool os::Linux::_is_floating_stack = false;
148 bool os::Linux::_is_NPTL = false;
149 bool os::Linux::_supports_fast_thread_cpu_time = false;
150 const char * os::Linux::_glibc_version = NULL;
151 const char * os::Linux::_libpthread_version = NULL;
153 static jlong initial_time_count=0;
155 static int clock_tics_per_sec = 100;
157 // For diagnostics to print a message once. see run_periodic_checks
158 static sigset_t check_signal_done;
159 static bool check_signals = true;;
161 static pid_t _initial_pid = 0;
163 /* Signal number used to suspend/resume a thread */
165 /* do not use any signal number less than SIGSEGV, see 4355769 */
166 static int SR_signum = SIGUSR2;
167 sigset_t SR_sigset;
169 /* Used to protect dlsym() calls */
170 static pthread_mutex_t dl_mutex;
172 ////////////////////////////////////////////////////////////////////////////////
173 // utility functions
175 static int SR_initialize();
176 static int SR_finalize();
178 julong os::available_memory() {
179 return Linux::available_memory();
180 }
182 julong os::Linux::available_memory() {
183 // values in struct sysinfo are "unsigned long"
184 struct sysinfo si;
185 sysinfo(&si);
187 return (julong)si.freeram * si.mem_unit;
188 }
190 julong os::physical_memory() {
191 return Linux::physical_memory();
192 }
194 julong os::allocatable_physical_memory(julong size) {
195 #ifdef _LP64
196 return size;
197 #else
198 julong result = MIN2(size, (julong)3800*M);
199 if (!is_allocatable(result)) {
200 // See comments under solaris for alignment considerations
201 julong reasonable_size = (julong)2*G - 2 * os::vm_page_size();
202 result = MIN2(size, reasonable_size);
203 }
204 return result;
205 #endif // _LP64
206 }
208 ////////////////////////////////////////////////////////////////////////////////
209 // environment support
211 bool os::getenv(const char* name, char* buf, int len) {
212 const char* val = ::getenv(name);
213 if (val != NULL && strlen(val) < (size_t)len) {
214 strcpy(buf, val);
215 return true;
216 }
217 if (len > 0) buf[0] = 0; // return a null string
218 return false;
219 }
222 // Return true if user is running as root.
224 bool os::have_special_privileges() {
225 static bool init = false;
226 static bool privileges = false;
227 if (!init) {
228 privileges = (getuid() != geteuid()) || (getgid() != getegid());
229 init = true;
230 }
231 return privileges;
232 }
235 #ifndef SYS_gettid
236 // i386: 224, ia64: 1105, amd64: 186, sparc 143
237 #ifdef __ia64__
238 #define SYS_gettid 1105
239 #elif __i386__
240 #define SYS_gettid 224
241 #elif __amd64__
242 #define SYS_gettid 186
243 #elif __sparc__
244 #define SYS_gettid 143
245 #else
246 #error define gettid for the arch
247 #endif
248 #endif
250 // Cpu architecture string
251 #if defined(ZERO)
252 static char cpu_arch[] = ZERO_LIBARCH;
253 #elif defined(IA64)
254 static char cpu_arch[] = "ia64";
255 #elif defined(IA32)
256 static char cpu_arch[] = "i386";
257 #elif defined(AMD64)
258 static char cpu_arch[] = "amd64";
259 #elif defined(ARM)
260 static char cpu_arch[] = "arm";
261 #elif defined(PPC)
262 static char cpu_arch[] = "ppc";
263 #elif defined(SPARC)
264 # ifdef _LP64
265 static char cpu_arch[] = "sparcv9";
266 # else
267 static char cpu_arch[] = "sparc";
268 # endif
269 #else
270 #error Add appropriate cpu_arch setting
271 #endif
274 // pid_t gettid()
275 //
276 // Returns the kernel thread id of the currently running thread. Kernel
277 // thread id is used to access /proc.
278 //
279 // (Note that getpid() on LinuxThreads returns kernel thread id too; but
280 // on NPTL, it returns the same pid for all threads, as required by POSIX.)
281 //
282 pid_t os::Linux::gettid() {
283 int rslt = syscall(SYS_gettid);
284 if (rslt == -1) {
285 // old kernel, no NPTL support
286 return getpid();
287 } else {
288 return (pid_t)rslt;
289 }
290 }
292 // Most versions of linux have a bug where the number of processors are
293 // determined by looking at the /proc file system. In a chroot environment,
294 // the system call returns 1. This causes the VM to act as if it is
295 // a single processor and elide locking (see is_MP() call).
296 static bool unsafe_chroot_detected = false;
297 static const char *unstable_chroot_error = "/proc file system not found.\n"
298 "Java may be unstable running multithreaded in a chroot "
299 "environment on Linux when /proc filesystem is not mounted.";
301 void os::Linux::initialize_system_info() {
302 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
303 if (processor_count() == 1) {
304 pid_t pid = os::Linux::gettid();
305 char fname[32];
306 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
307 FILE *fp = fopen(fname, "r");
308 if (fp == NULL) {
309 unsafe_chroot_detected = true;
310 } else {
311 fclose(fp);
312 }
313 }
314 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
315 assert(processor_count() > 0, "linux error");
316 }
318 void os::init_system_properties_values() {
319 // char arch[12];
320 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch));
322 // The next steps are taken in the product version:
323 //
324 // Obtain the JAVA_HOME value from the location of libjvm[_g].so.
325 // This library should be located at:
326 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm[_g].so.
327 //
328 // If "/jre/lib/" appears at the right place in the path, then we
329 // assume libjvm[_g].so is installed in a JDK and we use this path.
330 //
331 // Otherwise exit with message: "Could not create the Java virtual machine."
332 //
333 // The following extra steps are taken in the debugging version:
334 //
335 // If "/jre/lib/" does NOT appear at the right place in the path
336 // instead of exit check for $JAVA_HOME environment variable.
337 //
338 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
339 // then we append a fake suffix "hotspot/libjvm[_g].so" to this path so
340 // it looks like libjvm[_g].so is installed there
341 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm[_g].so.
342 //
343 // Otherwise exit.
344 //
345 // Important note: if the location of libjvm.so changes this
346 // code needs to be changed accordingly.
348 // The next few definitions allow the code to be verbatim:
349 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n))
350 #define getenv(n) ::getenv(n)
352 /*
353 * See ld(1):
354 * The linker uses the following search paths to locate required
355 * shared libraries:
356 * 1: ...
357 * ...
358 * 7: The default directories, normally /lib and /usr/lib.
359 */
360 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390))
361 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
362 #else
363 #define DEFAULT_LIBPATH "/lib:/usr/lib"
364 #endif
366 #define EXTENSIONS_DIR "/lib/ext"
367 #define ENDORSED_DIR "/lib/endorsed"
368 #define REG_DIR "/usr/java/packages"
370 {
371 /* sysclasspath, java_home, dll_dir */
372 {
373 char *home_path;
374 char *dll_path;
375 char *pslash;
376 char buf[MAXPATHLEN];
377 os::jvm_path(buf, sizeof(buf));
379 // Found the full path to libjvm.so.
380 // Now cut the path to <java_home>/jre if we can.
381 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */
382 pslash = strrchr(buf, '/');
383 if (pslash != NULL)
384 *pslash = '\0'; /* get rid of /{client|server|hotspot} */
385 dll_path = malloc(strlen(buf) + 1);
386 if (dll_path == NULL)
387 return;
388 strcpy(dll_path, buf);
389 Arguments::set_dll_dir(dll_path);
391 if (pslash != NULL) {
392 pslash = strrchr(buf, '/');
393 if (pslash != NULL) {
394 *pslash = '\0'; /* get rid of /<arch> */
395 pslash = strrchr(buf, '/');
396 if (pslash != NULL)
397 *pslash = '\0'; /* get rid of /lib */
398 }
399 }
401 home_path = malloc(strlen(buf) + 1);
402 if (home_path == NULL)
403 return;
404 strcpy(home_path, buf);
405 Arguments::set_java_home(home_path);
407 if (!set_boot_path('/', ':'))
408 return;
409 }
411 /*
412 * Where to look for native libraries
413 *
414 * Note: Due to a legacy implementation, most of the library path
415 * is set in the launcher. This was to accomodate linking restrictions
416 * on legacy Linux implementations (which are no longer supported).
417 * Eventually, all the library path setting will be done here.
418 *
419 * However, to prevent the proliferation of improperly built native
420 * libraries, the new path component /usr/java/packages is added here.
421 * Eventually, all the library path setting will be done here.
422 */
423 {
424 char *ld_library_path;
426 /*
427 * Construct the invariant part of ld_library_path. Note that the
428 * space for the colon and the trailing null are provided by the
429 * nulls included by the sizeof operator (so actually we allocate
430 * a byte more than necessary).
431 */
432 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") +
433 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH));
434 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch);
436 /*
437 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It
438 * should always exist (until the legacy problem cited above is
439 * addressed).
440 */
441 char *v = getenv("LD_LIBRARY_PATH");
442 if (v != NULL) {
443 char *t = ld_library_path;
444 /* That's +1 for the colon and +1 for the trailing '\0' */
445 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1);
446 sprintf(ld_library_path, "%s:%s", v, t);
447 }
448 Arguments::set_library_path(ld_library_path);
449 }
451 /*
452 * Extensions directories.
453 *
454 * Note that the space for the colon and the trailing null are provided
455 * by the nulls included by the sizeof operator (so actually one byte more
456 * than necessary is allocated).
457 */
458 {
459 char *buf = malloc(strlen(Arguments::get_java_home()) +
460 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR));
461 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR,
462 Arguments::get_java_home());
463 Arguments::set_ext_dirs(buf);
464 }
466 /* Endorsed standards default directory. */
467 {
468 char * buf;
469 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR));
470 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
471 Arguments::set_endorsed_dirs(buf);
472 }
473 }
475 #undef malloc
476 #undef getenv
477 #undef EXTENSIONS_DIR
478 #undef ENDORSED_DIR
480 // Done
481 return;
482 }
484 ////////////////////////////////////////////////////////////////////////////////
485 // breakpoint support
487 void os::breakpoint() {
488 BREAKPOINT;
489 }
491 extern "C" void breakpoint() {
492 // use debugger to set breakpoint here
493 }
495 ////////////////////////////////////////////////////////////////////////////////
496 // signal support
498 debug_only(static bool signal_sets_initialized = false);
499 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
501 bool os::Linux::is_sig_ignored(int sig) {
502 struct sigaction oact;
503 sigaction(sig, (struct sigaction*)NULL, &oact);
504 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
505 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
506 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))
507 return true;
508 else
509 return false;
510 }
512 void os::Linux::signal_sets_init() {
513 // Should also have an assertion stating we are still single-threaded.
514 assert(!signal_sets_initialized, "Already initialized");
515 // Fill in signals that are necessarily unblocked for all threads in
516 // the VM. Currently, we unblock the following signals:
517 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
518 // by -Xrs (=ReduceSignalUsage));
519 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
520 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
521 // the dispositions or masks wrt these signals.
522 // Programs embedding the VM that want to use the above signals for their
523 // own purposes must, at this time, use the "-Xrs" option to prevent
524 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
525 // (See bug 4345157, and other related bugs).
526 // In reality, though, unblocking these signals is really a nop, since
527 // these signals are not blocked by default.
528 sigemptyset(&unblocked_sigs);
529 sigemptyset(&allowdebug_blocked_sigs);
530 sigaddset(&unblocked_sigs, SIGILL);
531 sigaddset(&unblocked_sigs, SIGSEGV);
532 sigaddset(&unblocked_sigs, SIGBUS);
533 sigaddset(&unblocked_sigs, SIGFPE);
534 sigaddset(&unblocked_sigs, SR_signum);
536 if (!ReduceSignalUsage) {
537 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
538 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
539 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
540 }
541 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
542 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
543 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
544 }
545 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
546 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
547 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
548 }
549 }
550 // Fill in signals that are blocked by all but the VM thread.
551 sigemptyset(&vm_sigs);
552 if (!ReduceSignalUsage)
553 sigaddset(&vm_sigs, BREAK_SIGNAL);
554 debug_only(signal_sets_initialized = true);
556 }
558 // These are signals that are unblocked while a thread is running Java.
559 // (For some reason, they get blocked by default.)
560 sigset_t* os::Linux::unblocked_signals() {
561 assert(signal_sets_initialized, "Not initialized");
562 return &unblocked_sigs;
563 }
565 // These are the signals that are blocked while a (non-VM) thread is
566 // running Java. Only the VM thread handles these signals.
567 sigset_t* os::Linux::vm_signals() {
568 assert(signal_sets_initialized, "Not initialized");
569 return &vm_sigs;
570 }
572 // These are signals that are blocked during cond_wait to allow debugger in
573 sigset_t* os::Linux::allowdebug_blocked_signals() {
574 assert(signal_sets_initialized, "Not initialized");
575 return &allowdebug_blocked_sigs;
576 }
578 void os::Linux::hotspot_sigmask(Thread* thread) {
580 //Save caller's signal mask before setting VM signal mask
581 sigset_t caller_sigmask;
582 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
584 OSThread* osthread = thread->osthread();
585 osthread->set_caller_sigmask(caller_sigmask);
587 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
589 if (!ReduceSignalUsage) {
590 if (thread->is_VM_thread()) {
591 // Only the VM thread handles BREAK_SIGNAL ...
592 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
593 } else {
594 // ... all other threads block BREAK_SIGNAL
595 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
596 }
597 }
598 }
600 //////////////////////////////////////////////////////////////////////////////
601 // detecting pthread library
603 void os::Linux::libpthread_init() {
604 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION
605 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a
606 // generic name for earlier versions.
607 // Define macros here so we can build HotSpot on old systems.
608 # ifndef _CS_GNU_LIBC_VERSION
609 # define _CS_GNU_LIBC_VERSION 2
610 # endif
611 # ifndef _CS_GNU_LIBPTHREAD_VERSION
612 # define _CS_GNU_LIBPTHREAD_VERSION 3
613 # endif
615 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
616 if (n > 0) {
617 char *str = (char *)malloc(n);
618 confstr(_CS_GNU_LIBC_VERSION, str, n);
619 os::Linux::set_glibc_version(str);
620 } else {
621 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version()
622 static char _gnu_libc_version[32];
623 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version),
624 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release());
625 os::Linux::set_glibc_version(_gnu_libc_version);
626 }
628 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
629 if (n > 0) {
630 char *str = (char *)malloc(n);
631 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
632 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells
633 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this
634 // is the case. LinuxThreads has a hard limit on max number of threads.
635 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value.
636 // On the other hand, NPTL does not have such a limit, sysconf()
637 // will return -1 and errno is not changed. Check if it is really NPTL.
638 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 &&
639 strstr(str, "NPTL") &&
640 sysconf(_SC_THREAD_THREADS_MAX) > 0) {
641 free(str);
642 os::Linux::set_libpthread_version("linuxthreads");
643 } else {
644 os::Linux::set_libpthread_version(str);
645 }
646 } else {
647 // glibc before 2.3.2 only has LinuxThreads.
648 os::Linux::set_libpthread_version("linuxthreads");
649 }
651 if (strstr(libpthread_version(), "NPTL")) {
652 os::Linux::set_is_NPTL();
653 } else {
654 os::Linux::set_is_LinuxThreads();
655 }
657 // LinuxThreads have two flavors: floating-stack mode, which allows variable
658 // stack size; and fixed-stack mode. NPTL is always floating-stack.
659 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) {
660 os::Linux::set_is_floating_stack();
661 }
662 }
664 /////////////////////////////////////////////////////////////////////////////
665 // thread stack
667 // Force Linux kernel to expand current thread stack. If "bottom" is close
668 // to the stack guard, caller should block all signals.
669 //
670 // MAP_GROWSDOWN:
671 // A special mmap() flag that is used to implement thread stacks. It tells
672 // kernel that the memory region should extend downwards when needed. This
673 // allows early versions of LinuxThreads to only mmap the first few pages
674 // when creating a new thread. Linux kernel will automatically expand thread
675 // stack as needed (on page faults).
676 //
677 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
678 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
679 // region, it's hard to tell if the fault is due to a legitimate stack
680 // access or because of reading/writing non-exist memory (e.g. buffer
681 // overrun). As a rule, if the fault happens below current stack pointer,
682 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
683 // application (see Linux kernel fault.c).
684 //
685 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
686 // stack overflow detection.
687 //
688 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
689 // not use this flag. However, the stack of initial thread is not created
690 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though
691 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack
692 // and then attach the thread to JVM.
693 //
694 // To get around the problem and allow stack banging on Linux, we need to
695 // manually expand thread stack after receiving the SIGSEGV.
696 //
697 // There are two ways to expand thread stack to address "bottom", we used
698 // both of them in JVM before 1.5:
699 // 1. adjust stack pointer first so that it is below "bottom", and then
700 // touch "bottom"
701 // 2. mmap() the page in question
702 //
703 // Now alternate signal stack is gone, it's harder to use 2. For instance,
704 // if current sp is already near the lower end of page 101, and we need to
705 // call mmap() to map page 100, it is possible that part of the mmap() frame
706 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
707 // That will destroy the mmap() frame and cause VM to crash.
708 //
709 // The following code works by adjusting sp first, then accessing the "bottom"
710 // page to force a page fault. Linux kernel will then automatically expand the
711 // stack mapping.
712 //
713 // _expand_stack_to() assumes its frame size is less than page size, which
714 // should always be true if the function is not inlined.
716 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute
717 #define NOINLINE
718 #else
719 #define NOINLINE __attribute__ ((noinline))
720 #endif
722 static void _expand_stack_to(address bottom) NOINLINE;
724 static void _expand_stack_to(address bottom) {
725 address sp;
726 size_t size;
727 volatile char *p;
729 // Adjust bottom to point to the largest address within the same page, it
730 // gives us a one-page buffer if alloca() allocates slightly more memory.
731 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
732 bottom += os::Linux::page_size() - 1;
734 // sp might be slightly above current stack pointer; if that's the case, we
735 // will alloca() a little more space than necessary, which is OK. Don't use
736 // os::current_stack_pointer(), as its result can be slightly below current
737 // stack pointer, causing us to not alloca enough to reach "bottom".
738 sp = (address)&sp;
740 if (sp > bottom) {
741 size = sp - bottom;
742 p = (volatile char *)alloca(size);
743 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
744 p[0] = '\0';
745 }
746 }
748 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
749 assert(t!=NULL, "just checking");
750 assert(t->osthread()->expanding_stack(), "expand should be set");
751 assert(t->stack_base() != NULL, "stack_base was not initialized");
753 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) {
754 sigset_t mask_all, old_sigset;
755 sigfillset(&mask_all);
756 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
757 _expand_stack_to(addr);
758 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
759 return true;
760 }
761 return false;
762 }
764 //////////////////////////////////////////////////////////////////////////////
765 // create new thread
767 static address highest_vm_reserved_address();
769 // check if it's safe to start a new thread
770 static bool _thread_safety_check(Thread* thread) {
771 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) {
772 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat)
773 // Heap is mmap'ed at lower end of memory space. Thread stacks are
774 // allocated (MAP_FIXED) from high address space. Every thread stack
775 // occupies a fixed size slot (usually 2Mbytes, but user can change
776 // it to other values if they rebuild LinuxThreads).
777 //
778 // Problem with MAP_FIXED is that mmap() can still succeed even part of
779 // the memory region has already been mmap'ed. That means if we have too
780 // many threads and/or very large heap, eventually thread stack will
781 // collide with heap.
782 //
783 // Here we try to prevent heap/stack collision by comparing current
784 // stack bottom with the highest address that has been mmap'ed by JVM
785 // plus a safety margin for memory maps created by native code.
786 //
787 // This feature can be disabled by setting ThreadSafetyMargin to 0
788 //
789 if (ThreadSafetyMargin > 0) {
790 address stack_bottom = os::current_stack_base() - os::current_stack_size();
792 // not safe if our stack extends below the safety margin
793 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address();
794 } else {
795 return true;
796 }
797 } else {
798 // Floating stack LinuxThreads or NPTL:
799 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When
800 // there's not enough space left, pthread_create() will fail. If we come
801 // here, that means enough space has been reserved for stack.
802 return true;
803 }
804 }
806 // Thread start routine for all newly created threads
807 static void *java_start(Thread *thread) {
808 // Try to randomize the cache line index of hot stack frames.
809 // This helps when threads of the same stack traces evict each other's
810 // cache lines. The threads can be either from the same JVM instance, or
811 // from different JVM instances. The benefit is especially true for
812 // processors with hyperthreading technology.
813 static int counter = 0;
814 int pid = os::current_process_id();
815 alloca(((pid ^ counter++) & 7) * 128);
817 ThreadLocalStorage::set_thread(thread);
819 OSThread* osthread = thread->osthread();
820 Monitor* sync = osthread->startThread_lock();
822 // non floating stack LinuxThreads needs extra check, see above
823 if (!_thread_safety_check(thread)) {
824 // notify parent thread
825 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
826 osthread->set_state(ZOMBIE);
827 sync->notify_all();
828 return NULL;
829 }
831 // thread_id is kernel thread id (similar to Solaris LWP id)
832 osthread->set_thread_id(os::Linux::gettid());
834 if (UseNUMA) {
835 int lgrp_id = os::numa_get_group_id();
836 if (lgrp_id != -1) {
837 thread->set_lgrp_id(lgrp_id);
838 }
839 }
840 // initialize signal mask for this thread
841 os::Linux::hotspot_sigmask(thread);
843 // initialize floating point control register
844 os::Linux::init_thread_fpu_state();
846 // handshaking with parent thread
847 {
848 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
850 // notify parent thread
851 osthread->set_state(INITIALIZED);
852 sync->notify_all();
854 // wait until os::start_thread()
855 while (osthread->get_state() == INITIALIZED) {
856 sync->wait(Mutex::_no_safepoint_check_flag);
857 }
858 }
860 // call one more level start routine
861 thread->run();
863 return 0;
864 }
866 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
867 assert(thread->osthread() == NULL, "caller responsible");
869 // Allocate the OSThread object
870 OSThread* osthread = new OSThread(NULL, NULL);
871 if (osthread == NULL) {
872 return false;
873 }
875 // set the correct thread state
876 osthread->set_thread_type(thr_type);
878 // Initial state is ALLOCATED but not INITIALIZED
879 osthread->set_state(ALLOCATED);
881 thread->set_osthread(osthread);
883 // init thread attributes
884 pthread_attr_t attr;
885 pthread_attr_init(&attr);
886 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
888 // stack size
889 if (os::Linux::supports_variable_stack_size()) {
890 // calculate stack size if it's not specified by caller
891 if (stack_size == 0) {
892 stack_size = os::Linux::default_stack_size(thr_type);
894 switch (thr_type) {
895 case os::java_thread:
896 // Java threads use ThreadStackSize which default value can be
897 // changed with the flag -Xss
898 assert (JavaThread::stack_size_at_create() > 0, "this should be set");
899 stack_size = JavaThread::stack_size_at_create();
900 break;
901 case os::compiler_thread:
902 if (CompilerThreadStackSize > 0) {
903 stack_size = (size_t)(CompilerThreadStackSize * K);
904 break;
905 } // else fall through:
906 // use VMThreadStackSize if CompilerThreadStackSize is not defined
907 case os::vm_thread:
908 case os::pgc_thread:
909 case os::cgc_thread:
910 case os::watcher_thread:
911 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
912 break;
913 }
914 }
916 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
917 pthread_attr_setstacksize(&attr, stack_size);
918 } else {
919 // let pthread_create() pick the default value.
920 }
922 // glibc guard page
923 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
925 ThreadState state;
927 {
928 // Serialize thread creation if we are running with fixed stack LinuxThreads
929 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack();
930 if (lock) {
931 os::Linux::createThread_lock()->lock_without_safepoint_check();
932 }
934 pthread_t tid;
935 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
937 pthread_attr_destroy(&attr);
939 if (ret != 0) {
940 if (PrintMiscellaneous && (Verbose || WizardMode)) {
941 perror("pthread_create()");
942 }
943 // Need to clean up stuff we've allocated so far
944 thread->set_osthread(NULL);
945 delete osthread;
946 if (lock) os::Linux::createThread_lock()->unlock();
947 return false;
948 }
950 // Store pthread info into the OSThread
951 osthread->set_pthread_id(tid);
953 // Wait until child thread is either initialized or aborted
954 {
955 Monitor* sync_with_child = osthread->startThread_lock();
956 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
957 while ((state = osthread->get_state()) == ALLOCATED) {
958 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
959 }
960 }
962 if (lock) {
963 os::Linux::createThread_lock()->unlock();
964 }
965 }
967 // Aborted due to thread limit being reached
968 if (state == ZOMBIE) {
969 thread->set_osthread(NULL);
970 delete osthread;
971 return false;
972 }
974 // The thread is returned suspended (in state INITIALIZED),
975 // and is started higher up in the call chain
976 assert(state == INITIALIZED, "race condition");
977 return true;
978 }
980 /////////////////////////////////////////////////////////////////////////////
981 // attach existing thread
983 // bootstrap the main thread
984 bool os::create_main_thread(JavaThread* thread) {
985 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
986 return create_attached_thread(thread);
987 }
989 bool os::create_attached_thread(JavaThread* thread) {
990 #ifdef ASSERT
991 thread->verify_not_published();
992 #endif
994 // Allocate the OSThread object
995 OSThread* osthread = new OSThread(NULL, NULL);
997 if (osthread == NULL) {
998 return false;
999 }
1001 // Store pthread info into the OSThread
1002 osthread->set_thread_id(os::Linux::gettid());
1003 osthread->set_pthread_id(::pthread_self());
1005 // initialize floating point control register
1006 os::Linux::init_thread_fpu_state();
1008 // Initial thread state is RUNNABLE
1009 osthread->set_state(RUNNABLE);
1011 thread->set_osthread(osthread);
1013 if (UseNUMA) {
1014 int lgrp_id = os::numa_get_group_id();
1015 if (lgrp_id != -1) {
1016 thread->set_lgrp_id(lgrp_id);
1017 }
1018 }
1020 if (os::Linux::is_initial_thread()) {
1021 // If current thread is initial thread, its stack is mapped on demand,
1022 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
1023 // the entire stack region to avoid SEGV in stack banging.
1024 // It is also useful to get around the heap-stack-gap problem on SuSE
1025 // kernel (see 4821821 for details). We first expand stack to the top
1026 // of yellow zone, then enable stack yellow zone (order is significant,
1027 // enabling yellow zone first will crash JVM on SuSE Linux), so there
1028 // is no gap between the last two virtual memory regions.
1030 JavaThread *jt = (JavaThread *)thread;
1031 address addr = jt->stack_yellow_zone_base();
1032 assert(addr != NULL, "initialization problem?");
1033 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
1035 osthread->set_expanding_stack();
1036 os::Linux::manually_expand_stack(jt, addr);
1037 osthread->clear_expanding_stack();
1038 }
1040 // initialize signal mask for this thread
1041 // and save the caller's signal mask
1042 os::Linux::hotspot_sigmask(thread);
1044 return true;
1045 }
1047 void os::pd_start_thread(Thread* thread) {
1048 OSThread * osthread = thread->osthread();
1049 assert(osthread->get_state() != INITIALIZED, "just checking");
1050 Monitor* sync_with_child = osthread->startThread_lock();
1051 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
1052 sync_with_child->notify();
1053 }
1055 // Free Linux resources related to the OSThread
1056 void os::free_thread(OSThread* osthread) {
1057 assert(osthread != NULL, "osthread not set");
1059 if (Thread::current()->osthread() == osthread) {
1060 // Restore caller's signal mask
1061 sigset_t sigmask = osthread->caller_sigmask();
1062 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1063 }
1065 delete osthread;
1066 }
1068 //////////////////////////////////////////////////////////////////////////////
1069 // thread local storage
1071 int os::allocate_thread_local_storage() {
1072 pthread_key_t key;
1073 int rslt = pthread_key_create(&key, NULL);
1074 assert(rslt == 0, "cannot allocate thread local storage");
1075 return (int)key;
1076 }
1078 // Note: This is currently not used by VM, as we don't destroy TLS key
1079 // on VM exit.
1080 void os::free_thread_local_storage(int index) {
1081 int rslt = pthread_key_delete((pthread_key_t)index);
1082 assert(rslt == 0, "invalid index");
1083 }
1085 void os::thread_local_storage_at_put(int index, void* value) {
1086 int rslt = pthread_setspecific((pthread_key_t)index, value);
1087 assert(rslt == 0, "pthread_setspecific failed");
1088 }
1090 extern "C" Thread* get_thread() {
1091 return ThreadLocalStorage::thread();
1092 }
1094 //////////////////////////////////////////////////////////////////////////////
1095 // initial thread
1097 // Check if current thread is the initial thread, similar to Solaris thr_main.
1098 bool os::Linux::is_initial_thread(void) {
1099 char dummy;
1100 // If called before init complete, thread stack bottom will be null.
1101 // Can be called if fatal error occurs before initialization.
1102 if (initial_thread_stack_bottom() == NULL) return false;
1103 assert(initial_thread_stack_bottom() != NULL &&
1104 initial_thread_stack_size() != 0,
1105 "os::init did not locate initial thread's stack region");
1106 if ((address)&dummy >= initial_thread_stack_bottom() &&
1107 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size())
1108 return true;
1109 else return false;
1110 }
1112 // Find the virtual memory area that contains addr
1113 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1114 FILE *fp = fopen("/proc/self/maps", "r");
1115 if (fp) {
1116 address low, high;
1117 while (!feof(fp)) {
1118 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1119 if (low <= addr && addr < high) {
1120 if (vma_low) *vma_low = low;
1121 if (vma_high) *vma_high = high;
1122 fclose (fp);
1123 return true;
1124 }
1125 }
1126 for (;;) {
1127 int ch = fgetc(fp);
1128 if (ch == EOF || ch == (int)'\n') break;
1129 }
1130 }
1131 fclose(fp);
1132 }
1133 return false;
1134 }
1136 // Locate initial thread stack. This special handling of initial thread stack
1137 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1138 // bogus value for initial thread.
1139 void os::Linux::capture_initial_stack(size_t max_size) {
1140 // stack size is the easy part, get it from RLIMIT_STACK
1141 size_t stack_size;
1142 struct rlimit rlim;
1143 getrlimit(RLIMIT_STACK, &rlim);
1144 stack_size = rlim.rlim_cur;
1146 // 6308388: a bug in ld.so will relocate its own .data section to the
1147 // lower end of primordial stack; reduce ulimit -s value a little bit
1148 // so we won't install guard page on ld.so's data section.
1149 stack_size -= 2 * page_size();
1151 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
1152 // 7.1, in both cases we will get 2G in return value.
1153 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
1154 // SuSE 7.2, Debian) can not handle alternate signal stack correctly
1155 // for initial thread if its stack size exceeds 6M. Cap it at 2M,
1156 // in case other parts in glibc still assumes 2M max stack size.
1157 // FIXME: alt signal stack is gone, maybe we can relax this constraint?
1158 #ifndef IA64
1159 if (stack_size > 2 * K * K) stack_size = 2 * K * K;
1160 #else
1161 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
1162 if (stack_size > 4 * K * K) stack_size = 4 * K * K;
1163 #endif
1165 // Try to figure out where the stack base (top) is. This is harder.
1166 //
1167 // When an application is started, glibc saves the initial stack pointer in
1168 // a global variable "__libc_stack_end", which is then used by system
1169 // libraries. __libc_stack_end should be pretty close to stack top. The
1170 // variable is available since the very early days. However, because it is
1171 // a private interface, it could disappear in the future.
1172 //
1173 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1174 // to __libc_stack_end, it is very close to stack top, but isn't the real
1175 // stack top. Note that /proc may not exist if VM is running as a chroot
1176 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1177 // /proc/<pid>/stat could change in the future (though unlikely).
1178 //
1179 // We try __libc_stack_end first. If that doesn't work, look for
1180 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1181 // as a hint, which should work well in most cases.
1183 uintptr_t stack_start;
1185 // try __libc_stack_end first
1186 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1187 if (p && *p) {
1188 stack_start = *p;
1189 } else {
1190 // see if we can get the start_stack field from /proc/self/stat
1191 FILE *fp;
1192 int pid;
1193 char state;
1194 int ppid;
1195 int pgrp;
1196 int session;
1197 int nr;
1198 int tpgrp;
1199 unsigned long flags;
1200 unsigned long minflt;
1201 unsigned long cminflt;
1202 unsigned long majflt;
1203 unsigned long cmajflt;
1204 unsigned long utime;
1205 unsigned long stime;
1206 long cutime;
1207 long cstime;
1208 long prio;
1209 long nice;
1210 long junk;
1211 long it_real;
1212 uintptr_t start;
1213 uintptr_t vsize;
1214 intptr_t rss;
1215 uintptr_t rsslim;
1216 uintptr_t scodes;
1217 uintptr_t ecode;
1218 int i;
1220 // Figure what the primordial thread stack base is. Code is inspired
1221 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1222 // followed by command name surrounded by parentheses, state, etc.
1223 char stat[2048];
1224 int statlen;
1226 fp = fopen("/proc/self/stat", "r");
1227 if (fp) {
1228 statlen = fread(stat, 1, 2047, fp);
1229 stat[statlen] = '\0';
1230 fclose(fp);
1232 // Skip pid and the command string. Note that we could be dealing with
1233 // weird command names, e.g. user could decide to rename java launcher
1234 // to "java 1.4.2 :)", then the stat file would look like
1235 // 1234 (java 1.4.2 :)) R ... ...
1236 // We don't really need to know the command string, just find the last
1237 // occurrence of ")" and then start parsing from there. See bug 4726580.
1238 char * s = strrchr(stat, ')');
1240 i = 0;
1241 if (s) {
1242 // Skip blank chars
1243 do s++; while (isspace(*s));
1245 #define _UFM UINTX_FORMAT
1246 #define _DFM INTX_FORMAT
1248 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */
1249 /* 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 */
1250 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,
1251 &state, /* 3 %c */
1252 &ppid, /* 4 %d */
1253 &pgrp, /* 5 %d */
1254 &session, /* 6 %d */
1255 &nr, /* 7 %d */
1256 &tpgrp, /* 8 %d */
1257 &flags, /* 9 %lu */
1258 &minflt, /* 10 %lu */
1259 &cminflt, /* 11 %lu */
1260 &majflt, /* 12 %lu */
1261 &cmajflt, /* 13 %lu */
1262 &utime, /* 14 %lu */
1263 &stime, /* 15 %lu */
1264 &cutime, /* 16 %ld */
1265 &cstime, /* 17 %ld */
1266 &prio, /* 18 %ld */
1267 &nice, /* 19 %ld */
1268 &junk, /* 20 %ld */
1269 &it_real, /* 21 %ld */
1270 &start, /* 22 UINTX_FORMAT */
1271 &vsize, /* 23 UINTX_FORMAT */
1272 &rss, /* 24 INTX_FORMAT */
1273 &rsslim, /* 25 UINTX_FORMAT */
1274 &scodes, /* 26 UINTX_FORMAT */
1275 &ecode, /* 27 UINTX_FORMAT */
1276 &stack_start); /* 28 UINTX_FORMAT */
1277 }
1279 #undef _UFM
1280 #undef _DFM
1282 if (i != 28 - 2) {
1283 assert(false, "Bad conversion from /proc/self/stat");
1284 // product mode - assume we are the initial thread, good luck in the
1285 // embedded case.
1286 warning("Can't detect initial thread stack location - bad conversion");
1287 stack_start = (uintptr_t) &rlim;
1288 }
1289 } else {
1290 // For some reason we can't open /proc/self/stat (for example, running on
1291 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1292 // most cases, so don't abort:
1293 warning("Can't detect initial thread stack location - no /proc/self/stat");
1294 stack_start = (uintptr_t) &rlim;
1295 }
1296 }
1298 // Now we have a pointer (stack_start) very close to the stack top, the
1299 // next thing to do is to figure out the exact location of stack top. We
1300 // can find out the virtual memory area that contains stack_start by
1301 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1302 // and its upper limit is the real stack top. (again, this would fail if
1303 // running inside chroot, because /proc may not exist.)
1305 uintptr_t stack_top;
1306 address low, high;
1307 if (find_vma((address)stack_start, &low, &high)) {
1308 // success, "high" is the true stack top. (ignore "low", because initial
1309 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1310 stack_top = (uintptr_t)high;
1311 } else {
1312 // failed, likely because /proc/self/maps does not exist
1313 warning("Can't detect initial thread stack location - find_vma failed");
1314 // best effort: stack_start is normally within a few pages below the real
1315 // stack top, use it as stack top, and reduce stack size so we won't put
1316 // guard page outside stack.
1317 stack_top = stack_start;
1318 stack_size -= 16 * page_size();
1319 }
1321 // stack_top could be partially down the page so align it
1322 stack_top = align_size_up(stack_top, page_size());
1324 if (max_size && stack_size > max_size) {
1325 _initial_thread_stack_size = max_size;
1326 } else {
1327 _initial_thread_stack_size = stack_size;
1328 }
1330 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1331 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1332 }
1334 ////////////////////////////////////////////////////////////////////////////////
1335 // time support
1337 // Time since start-up in seconds to a fine granularity.
1338 // Used by VMSelfDestructTimer and the MemProfiler.
1339 double os::elapsedTime() {
1341 return (double)(os::elapsed_counter()) * 0.000001;
1342 }
1344 jlong os::elapsed_counter() {
1345 timeval time;
1346 int status = gettimeofday(&time, NULL);
1347 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count;
1348 }
1350 jlong os::elapsed_frequency() {
1351 return (1000 * 1000);
1352 }
1354 // For now, we say that linux does not support vtime. I have no idea
1355 // whether it can actually be made to (DLD, 9/13/05).
1357 bool os::supports_vtime() { return false; }
1358 bool os::enable_vtime() { return false; }
1359 bool os::vtime_enabled() { return false; }
1360 double os::elapsedVTime() {
1361 // better than nothing, but not much
1362 return elapsedTime();
1363 }
1365 jlong os::javaTimeMillis() {
1366 timeval time;
1367 int status = gettimeofday(&time, NULL);
1368 assert(status != -1, "linux error");
1369 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1370 }
1372 #ifndef CLOCK_MONOTONIC
1373 #define CLOCK_MONOTONIC (1)
1374 #endif
1376 void os::Linux::clock_init() {
1377 // we do dlopen's in this particular order due to bug in linux
1378 // dynamical loader (see 6348968) leading to crash on exit
1379 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1380 if (handle == NULL) {
1381 handle = dlopen("librt.so", RTLD_LAZY);
1382 }
1384 if (handle) {
1385 int (*clock_getres_func)(clockid_t, struct timespec*) =
1386 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1387 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1388 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1389 if (clock_getres_func && clock_gettime_func) {
1390 // See if monotonic clock is supported by the kernel. Note that some
1391 // early implementations simply return kernel jiffies (updated every
1392 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1393 // for nano time (though the monotonic property is still nice to have).
1394 // It's fixed in newer kernels, however clock_getres() still returns
1395 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1396 // resolution for now. Hopefully as people move to new kernels, this
1397 // won't be a problem.
1398 struct timespec res;
1399 struct timespec tp;
1400 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1401 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1402 // yes, monotonic clock is supported
1403 _clock_gettime = clock_gettime_func;
1404 } else {
1405 // close librt if there is no monotonic clock
1406 dlclose(handle);
1407 }
1408 }
1409 }
1410 }
1412 #ifndef SYS_clock_getres
1414 #if defined(IA32) || defined(AMD64)
1415 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229)
1416 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1417 #else
1418 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1419 #define sys_clock_getres(x,y) -1
1420 #endif
1422 #else
1423 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1424 #endif
1426 void os::Linux::fast_thread_clock_init() {
1427 if (!UseLinuxPosixThreadCPUClocks) {
1428 return;
1429 }
1430 clockid_t clockid;
1431 struct timespec tp;
1432 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1433 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1435 // Switch to using fast clocks for thread cpu time if
1436 // the sys_clock_getres() returns 0 error code.
1437 // Note, that some kernels may support the current thread
1438 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1439 // returned by the pthread_getcpuclockid().
1440 // If the fast Posix clocks are supported then the sys_clock_getres()
1441 // must return at least tp.tv_sec == 0 which means a resolution
1442 // better than 1 sec. This is extra check for reliability.
1444 if(pthread_getcpuclockid_func &&
1445 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1446 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1448 _supports_fast_thread_cpu_time = true;
1449 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1450 }
1451 }
1453 jlong os::javaTimeNanos() {
1454 if (Linux::supports_monotonic_clock()) {
1455 struct timespec tp;
1456 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1457 assert(status == 0, "gettime error");
1458 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1459 return result;
1460 } else {
1461 timeval time;
1462 int status = gettimeofday(&time, NULL);
1463 assert(status != -1, "linux error");
1464 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1465 return 1000 * usecs;
1466 }
1467 }
1469 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1470 if (Linux::supports_monotonic_clock()) {
1471 info_ptr->max_value = ALL_64_BITS;
1473 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1474 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1475 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1476 } else {
1477 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1478 info_ptr->max_value = ALL_64_BITS;
1480 // gettimeofday is a real time clock so it skips
1481 info_ptr->may_skip_backward = true;
1482 info_ptr->may_skip_forward = true;
1483 }
1485 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1486 }
1488 // Return the real, user, and system times in seconds from an
1489 // arbitrary fixed point in the past.
1490 bool os::getTimesSecs(double* process_real_time,
1491 double* process_user_time,
1492 double* process_system_time) {
1493 struct tms ticks;
1494 clock_t real_ticks = times(&ticks);
1496 if (real_ticks == (clock_t) (-1)) {
1497 return false;
1498 } else {
1499 double ticks_per_second = (double) clock_tics_per_sec;
1500 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1501 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1502 *process_real_time = ((double) real_ticks) / ticks_per_second;
1504 return true;
1505 }
1506 }
1509 char * os::local_time_string(char *buf, size_t buflen) {
1510 struct tm t;
1511 time_t long_time;
1512 time(&long_time);
1513 localtime_r(&long_time, &t);
1514 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1515 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1516 t.tm_hour, t.tm_min, t.tm_sec);
1517 return buf;
1518 }
1520 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1521 return localtime_r(clock, res);
1522 }
1524 ////////////////////////////////////////////////////////////////////////////////
1525 // runtime exit support
1527 // Note: os::shutdown() might be called very early during initialization, or
1528 // called from signal handler. Before adding something to os::shutdown(), make
1529 // sure it is async-safe and can handle partially initialized VM.
1530 void os::shutdown() {
1532 // allow PerfMemory to attempt cleanup of any persistent resources
1533 perfMemory_exit();
1535 // needs to remove object in file system
1536 AttachListener::abort();
1538 // flush buffered output, finish log files
1539 ostream_abort();
1541 // Check for abort hook
1542 abort_hook_t abort_hook = Arguments::abort_hook();
1543 if (abort_hook != NULL) {
1544 abort_hook();
1545 }
1547 }
1549 // Note: os::abort() might be called very early during initialization, or
1550 // called from signal handler. Before adding something to os::abort(), make
1551 // sure it is async-safe and can handle partially initialized VM.
1552 void os::abort(bool dump_core) {
1553 os::shutdown();
1554 if (dump_core) {
1555 #ifndef PRODUCT
1556 fdStream out(defaultStream::output_fd());
1557 out.print_raw("Current thread is ");
1558 char buf[16];
1559 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1560 out.print_raw_cr(buf);
1561 out.print_raw_cr("Dumping core ...");
1562 #endif
1563 ::abort(); // dump core
1564 }
1566 ::exit(1);
1567 }
1569 // Die immediately, no exit hook, no abort hook, no cleanup.
1570 void os::die() {
1571 // _exit() on LinuxThreads only kills current thread
1572 ::abort();
1573 }
1575 // unused on linux for now.
1576 void os::set_error_file(const char *logfile) {}
1579 // This method is a copy of JDK's sysGetLastErrorString
1580 // from src/solaris/hpi/src/system_md.c
1582 size_t os::lasterror(char *buf, size_t len) {
1584 if (errno == 0) return 0;
1586 const char *s = ::strerror(errno);
1587 size_t n = ::strlen(s);
1588 if (n >= len) {
1589 n = len - 1;
1590 }
1591 ::strncpy(buf, s, n);
1592 buf[n] = '\0';
1593 return n;
1594 }
1596 intx os::current_thread_id() { return (intx)pthread_self(); }
1597 int os::current_process_id() {
1599 // Under the old linux thread library, linux gives each thread
1600 // its own process id. Because of this each thread will return
1601 // a different pid if this method were to return the result
1602 // of getpid(2). Linux provides no api that returns the pid
1603 // of the launcher thread for the vm. This implementation
1604 // returns a unique pid, the pid of the launcher thread
1605 // that starts the vm 'process'.
1607 // Under the NPTL, getpid() returns the same pid as the
1608 // launcher thread rather than a unique pid per thread.
1609 // Use gettid() if you want the old pre NPTL behaviour.
1611 // if you are looking for the result of a call to getpid() that
1612 // returns a unique pid for the calling thread, then look at the
1613 // OSThread::thread_id() method in osThread_linux.hpp file
1615 return (int)(_initial_pid ? _initial_pid : getpid());
1616 }
1618 // DLL functions
1620 const char* os::dll_file_extension() { return ".so"; }
1622 // This must be hard coded because it's the system's temporary
1623 // directory not the java application's temp directory, ala java.io.tmpdir.
1624 const char* os::get_temp_directory() { return "/tmp"; }
1626 static bool file_exists(const char* filename) {
1627 struct stat statbuf;
1628 if (filename == NULL || strlen(filename) == 0) {
1629 return false;
1630 }
1631 return os::stat(filename, &statbuf) == 0;
1632 }
1634 void os::dll_build_name(char* buffer, size_t buflen,
1635 const char* pname, const char* fname) {
1636 // Copied from libhpi
1637 const size_t pnamelen = pname ? strlen(pname) : 0;
1639 // Quietly truncate on buffer overflow. Should be an error.
1640 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1641 *buffer = '\0';
1642 return;
1643 }
1645 if (pnamelen == 0) {
1646 snprintf(buffer, buflen, "lib%s.so", fname);
1647 } else if (strchr(pname, *os::path_separator()) != NULL) {
1648 int n;
1649 char** pelements = split_path(pname, &n);
1650 for (int i = 0 ; i < n ; i++) {
1651 // Really shouldn't be NULL, but check can't hurt
1652 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1653 continue; // skip the empty path values
1654 }
1655 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1656 if (file_exists(buffer)) {
1657 break;
1658 }
1659 }
1660 // release the storage
1661 for (int i = 0 ; i < n ; i++) {
1662 if (pelements[i] != NULL) {
1663 FREE_C_HEAP_ARRAY(char, pelements[i]);
1664 }
1665 }
1666 if (pelements != NULL) {
1667 FREE_C_HEAP_ARRAY(char*, pelements);
1668 }
1669 } else {
1670 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1671 }
1672 }
1674 const char* os::get_current_directory(char *buf, int buflen) {
1675 return getcwd(buf, buflen);
1676 }
1678 // check if addr is inside libjvm[_g].so
1679 bool os::address_is_in_vm(address addr) {
1680 static address libjvm_base_addr;
1681 Dl_info dlinfo;
1683 if (libjvm_base_addr == NULL) {
1684 dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo);
1685 libjvm_base_addr = (address)dlinfo.dli_fbase;
1686 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1687 }
1689 if (dladdr((void *)addr, &dlinfo)) {
1690 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1691 }
1693 return false;
1694 }
1696 bool os::dll_address_to_function_name(address addr, char *buf,
1697 int buflen, int *offset) {
1698 Dl_info dlinfo;
1700 if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) {
1701 if (buf != NULL) {
1702 if(!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) {
1703 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1704 }
1705 }
1706 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1707 return true;
1708 } else if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != 0) {
1709 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1710 dlinfo.dli_fname, buf, buflen, offset) == Decoder::no_error) {
1711 return true;
1712 }
1713 }
1715 if (buf != NULL) buf[0] = '\0';
1716 if (offset != NULL) *offset = -1;
1717 return false;
1718 }
1720 struct _address_to_library_name {
1721 address addr; // input : memory address
1722 size_t buflen; // size of fname
1723 char* fname; // output: library name
1724 address base; // library base addr
1725 };
1727 static int address_to_library_name_callback(struct dl_phdr_info *info,
1728 size_t size, void *data) {
1729 int i;
1730 bool found = false;
1731 address libbase = NULL;
1732 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1734 // iterate through all loadable segments
1735 for (i = 0; i < info->dlpi_phnum; i++) {
1736 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1737 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1738 // base address of a library is the lowest address of its loaded
1739 // segments.
1740 if (libbase == NULL || libbase > segbase) {
1741 libbase = segbase;
1742 }
1743 // see if 'addr' is within current segment
1744 if (segbase <= d->addr &&
1745 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1746 found = true;
1747 }
1748 }
1749 }
1751 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1752 // so dll_address_to_library_name() can fall through to use dladdr() which
1753 // can figure out executable name from argv[0].
1754 if (found && info->dlpi_name && info->dlpi_name[0]) {
1755 d->base = libbase;
1756 if (d->fname) {
1757 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1758 }
1759 return 1;
1760 }
1761 return 0;
1762 }
1764 bool os::dll_address_to_library_name(address addr, char* buf,
1765 int buflen, int* offset) {
1766 Dl_info dlinfo;
1767 struct _address_to_library_name data;
1769 // There is a bug in old glibc dladdr() implementation that it could resolve
1770 // to wrong library name if the .so file has a base address != NULL. Here
1771 // we iterate through the program headers of all loaded libraries to find
1772 // out which library 'addr' really belongs to. This workaround can be
1773 // removed once the minimum requirement for glibc is moved to 2.3.x.
1774 data.addr = addr;
1775 data.fname = buf;
1776 data.buflen = buflen;
1777 data.base = NULL;
1778 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1780 if (rslt) {
1781 // buf already contains library name
1782 if (offset) *offset = addr - data.base;
1783 return true;
1784 } else if (dladdr((void*)addr, &dlinfo)){
1785 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1786 if (offset) *offset = addr - (address)dlinfo.dli_fbase;
1787 return true;
1788 } else {
1789 if (buf) buf[0] = '\0';
1790 if (offset) *offset = -1;
1791 return false;
1792 }
1793 }
1795 // Loads .dll/.so and
1796 // in case of error it checks if .dll/.so was built for the
1797 // same architecture as Hotspot is running on
1799 void * os::dll_load(const char *filename, char *ebuf, int ebuflen)
1800 {
1801 void * result= ::dlopen(filename, RTLD_LAZY);
1802 if (result != NULL) {
1803 // Successful loading
1804 return result;
1805 }
1807 Elf32_Ehdr elf_head;
1809 // Read system error message into ebuf
1810 // It may or may not be overwritten below
1811 ::strncpy(ebuf, ::dlerror(), ebuflen-1);
1812 ebuf[ebuflen-1]='\0';
1813 int diag_msg_max_length=ebuflen-strlen(ebuf);
1814 char* diag_msg_buf=ebuf+strlen(ebuf);
1816 if (diag_msg_max_length==0) {
1817 // No more space in ebuf for additional diagnostics message
1818 return NULL;
1819 }
1822 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1824 if (file_descriptor < 0) {
1825 // Can't open library, report dlerror() message
1826 return NULL;
1827 }
1829 bool failed_to_read_elf_head=
1830 (sizeof(elf_head)!=
1831 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ;
1833 ::close(file_descriptor);
1834 if (failed_to_read_elf_head) {
1835 // file i/o error - report dlerror() msg
1836 return NULL;
1837 }
1839 typedef struct {
1840 Elf32_Half code; // Actual value as defined in elf.h
1841 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1842 char elf_class; // 32 or 64 bit
1843 char endianess; // MSB or LSB
1844 char* name; // String representation
1845 } arch_t;
1847 #ifndef EM_486
1848 #define EM_486 6 /* Intel 80486 */
1849 #endif
1851 static const arch_t arch_array[]={
1852 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1853 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1854 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1855 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1856 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1857 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1858 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1859 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1860 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1861 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1862 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1863 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1864 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1865 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1866 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1867 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}
1868 };
1870 #if (defined IA32)
1871 static Elf32_Half running_arch_code=EM_386;
1872 #elif (defined AMD64)
1873 static Elf32_Half running_arch_code=EM_X86_64;
1874 #elif (defined IA64)
1875 static Elf32_Half running_arch_code=EM_IA_64;
1876 #elif (defined __sparc) && (defined _LP64)
1877 static Elf32_Half running_arch_code=EM_SPARCV9;
1878 #elif (defined __sparc) && (!defined _LP64)
1879 static Elf32_Half running_arch_code=EM_SPARC;
1880 #elif (defined __powerpc64__)
1881 static Elf32_Half running_arch_code=EM_PPC64;
1882 #elif (defined __powerpc__)
1883 static Elf32_Half running_arch_code=EM_PPC;
1884 #elif (defined ARM)
1885 static Elf32_Half running_arch_code=EM_ARM;
1886 #elif (defined S390)
1887 static Elf32_Half running_arch_code=EM_S390;
1888 #elif (defined ALPHA)
1889 static Elf32_Half running_arch_code=EM_ALPHA;
1890 #elif (defined MIPSEL)
1891 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1892 #elif (defined PARISC)
1893 static Elf32_Half running_arch_code=EM_PARISC;
1894 #elif (defined MIPS)
1895 static Elf32_Half running_arch_code=EM_MIPS;
1896 #elif (defined M68K)
1897 static Elf32_Half running_arch_code=EM_68K;
1898 #else
1899 #error Method os::dll_load requires that one of following is defined:\
1900 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K
1901 #endif
1903 // Identify compatability class for VM's architecture and library's architecture
1904 // Obtain string descriptions for architectures
1906 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1907 int running_arch_index=-1;
1909 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) {
1910 if (running_arch_code == arch_array[i].code) {
1911 running_arch_index = i;
1912 }
1913 if (lib_arch.code == arch_array[i].code) {
1914 lib_arch.compat_class = arch_array[i].compat_class;
1915 lib_arch.name = arch_array[i].name;
1916 }
1917 }
1919 assert(running_arch_index != -1,
1920 "Didn't find running architecture code (running_arch_code) in arch_array");
1921 if (running_arch_index == -1) {
1922 // Even though running architecture detection failed
1923 // we may still continue with reporting dlerror() message
1924 return NULL;
1925 }
1927 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1928 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1929 return NULL;
1930 }
1932 #ifndef S390
1933 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1934 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1935 return NULL;
1936 }
1937 #endif // !S390
1939 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1940 if ( lib_arch.name!=NULL ) {
1941 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1942 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1943 lib_arch.name, arch_array[running_arch_index].name);
1944 } else {
1945 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1946 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1947 lib_arch.code,
1948 arch_array[running_arch_index].name);
1949 }
1950 }
1952 return NULL;
1953 }
1955 /*
1956 * glibc-2.0 libdl is not MT safe. If you are building with any glibc,
1957 * chances are you might want to run the generated bits against glibc-2.0
1958 * libdl.so, so always use locking for any version of glibc.
1959 */
1960 void* os::dll_lookup(void* handle, const char* name) {
1961 pthread_mutex_lock(&dl_mutex);
1962 void* res = dlsym(handle, name);
1963 pthread_mutex_unlock(&dl_mutex);
1964 return res;
1965 }
1968 static bool _print_ascii_file(const char* filename, outputStream* st) {
1969 int fd = ::open(filename, O_RDONLY);
1970 if (fd == -1) {
1971 return false;
1972 }
1974 char buf[32];
1975 int bytes;
1976 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) {
1977 st->print_raw(buf, bytes);
1978 }
1980 ::close(fd);
1982 return true;
1983 }
1985 void os::print_dll_info(outputStream *st) {
1986 st->print_cr("Dynamic libraries:");
1988 char fname[32];
1989 pid_t pid = os::Linux::gettid();
1991 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
1993 if (!_print_ascii_file(fname, st)) {
1994 st->print("Can not get library information for pid = %d\n", pid);
1995 }
1996 }
1999 void os::print_os_info(outputStream* st) {
2000 st->print("OS:");
2002 // Try to identify popular distros.
2003 // Most Linux distributions have /etc/XXX-release file, which contains
2004 // the OS version string. Some have more than one /etc/XXX-release file
2005 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.),
2006 // so the order is important.
2007 if (!_print_ascii_file("/etc/mandrake-release", st) &&
2008 !_print_ascii_file("/etc/sun-release", st) &&
2009 !_print_ascii_file("/etc/redhat-release", st) &&
2010 !_print_ascii_file("/etc/SuSE-release", st) &&
2011 !_print_ascii_file("/etc/turbolinux-release", st) &&
2012 !_print_ascii_file("/etc/gentoo-release", st) &&
2013 !_print_ascii_file("/etc/debian_version", st) &&
2014 !_print_ascii_file("/etc/ltib-release", st) &&
2015 !_print_ascii_file("/etc/angstrom-version", st)) {
2016 st->print("Linux");
2017 }
2018 st->cr();
2020 // kernel
2021 st->print("uname:");
2022 struct utsname name;
2023 uname(&name);
2024 st->print(name.sysname); st->print(" ");
2025 st->print(name.release); st->print(" ");
2026 st->print(name.version); st->print(" ");
2027 st->print(name.machine);
2028 st->cr();
2030 // Print warning if unsafe chroot environment detected
2031 if (unsafe_chroot_detected) {
2032 st->print("WARNING!! ");
2033 st->print_cr(unstable_chroot_error);
2034 }
2036 // libc, pthread
2037 st->print("libc:");
2038 st->print(os::Linux::glibc_version()); st->print(" ");
2039 st->print(os::Linux::libpthread_version()); st->print(" ");
2040 if (os::Linux::is_LinuxThreads()) {
2041 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed");
2042 }
2043 st->cr();
2045 // rlimit
2046 st->print("rlimit:");
2047 struct rlimit rlim;
2049 st->print(" STACK ");
2050 getrlimit(RLIMIT_STACK, &rlim);
2051 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2052 else st->print("%uk", rlim.rlim_cur >> 10);
2054 st->print(", CORE ");
2055 getrlimit(RLIMIT_CORE, &rlim);
2056 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2057 else st->print("%uk", rlim.rlim_cur >> 10);
2059 st->print(", NPROC ");
2060 getrlimit(RLIMIT_NPROC, &rlim);
2061 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2062 else st->print("%d", rlim.rlim_cur);
2064 st->print(", NOFILE ");
2065 getrlimit(RLIMIT_NOFILE, &rlim);
2066 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2067 else st->print("%d", rlim.rlim_cur);
2069 st->print(", AS ");
2070 getrlimit(RLIMIT_AS, &rlim);
2071 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2072 else st->print("%uk", rlim.rlim_cur >> 10);
2073 st->cr();
2075 // load average
2076 st->print("load average:");
2077 double loadavg[3];
2078 os::loadavg(loadavg, 3);
2079 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
2080 st->cr();
2082 // meminfo
2083 st->print("\n/proc/meminfo:\n");
2084 _print_ascii_file("/proc/meminfo", st);
2085 st->cr();
2086 }
2088 void os::print_memory_info(outputStream* st) {
2090 st->print("Memory:");
2091 st->print(" %dk page", os::vm_page_size()>>10);
2093 // values in struct sysinfo are "unsigned long"
2094 struct sysinfo si;
2095 sysinfo(&si);
2097 st->print(", physical " UINT64_FORMAT "k",
2098 os::physical_memory() >> 10);
2099 st->print("(" UINT64_FORMAT "k free)",
2100 os::available_memory() >> 10);
2101 st->print(", swap " UINT64_FORMAT "k",
2102 ((jlong)si.totalswap * si.mem_unit) >> 10);
2103 st->print("(" UINT64_FORMAT "k free)",
2104 ((jlong)si.freeswap * si.mem_unit) >> 10);
2105 st->cr();
2106 }
2108 // Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific
2109 // but they're the same for all the linux arch that we support
2110 // and they're the same for solaris but there's no common place to put this.
2111 const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR",
2112 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG",
2113 "ILL_COPROC", "ILL_BADSTK" };
2115 const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV",
2116 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES",
2117 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" };
2119 const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" };
2121 const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" };
2123 void os::print_siginfo(outputStream* st, void* siginfo) {
2124 st->print("siginfo:");
2126 const int buflen = 100;
2127 char buf[buflen];
2128 siginfo_t *si = (siginfo_t*)siginfo;
2129 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen));
2130 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) {
2131 st->print("si_errno=%s", buf);
2132 } else {
2133 st->print("si_errno=%d", si->si_errno);
2134 }
2135 const int c = si->si_code;
2136 assert(c > 0, "unexpected si_code");
2137 switch (si->si_signo) {
2138 case SIGILL:
2139 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]);
2140 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2141 break;
2142 case SIGFPE:
2143 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]);
2144 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2145 break;
2146 case SIGSEGV:
2147 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]);
2148 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2149 break;
2150 case SIGBUS:
2151 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]);
2152 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2153 break;
2154 default:
2155 st->print(", si_code=%d", si->si_code);
2156 // no si_addr
2157 }
2159 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
2160 UseSharedSpaces) {
2161 FileMapInfo* mapinfo = FileMapInfo::current_info();
2162 if (mapinfo->is_in_shared_space(si->si_addr)) {
2163 st->print("\n\nError accessing class data sharing archive." \
2164 " Mapped file inaccessible during execution, " \
2165 " possible disk/network problem.");
2166 }
2167 }
2168 st->cr();
2169 }
2172 static void print_signal_handler(outputStream* st, int sig,
2173 char* buf, size_t buflen);
2175 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2176 st->print_cr("Signal Handlers:");
2177 print_signal_handler(st, SIGSEGV, buf, buflen);
2178 print_signal_handler(st, SIGBUS , buf, buflen);
2179 print_signal_handler(st, SIGFPE , buf, buflen);
2180 print_signal_handler(st, SIGPIPE, buf, buflen);
2181 print_signal_handler(st, SIGXFSZ, buf, buflen);
2182 print_signal_handler(st, SIGILL , buf, buflen);
2183 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
2184 print_signal_handler(st, SR_signum, buf, buflen);
2185 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2186 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2187 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2188 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2189 }
2191 static char saved_jvm_path[MAXPATHLEN] = {0};
2193 // Find the full path to the current module, libjvm.so or libjvm_g.so
2194 void os::jvm_path(char *buf, jint buflen) {
2195 // Error checking.
2196 if (buflen < MAXPATHLEN) {
2197 assert(false, "must use a large-enough buffer");
2198 buf[0] = '\0';
2199 return;
2200 }
2201 // Lazy resolve the path to current module.
2202 if (saved_jvm_path[0] != 0) {
2203 strcpy(buf, saved_jvm_path);
2204 return;
2205 }
2207 char dli_fname[MAXPATHLEN];
2208 bool ret = dll_address_to_library_name(
2209 CAST_FROM_FN_PTR(address, os::jvm_path),
2210 dli_fname, sizeof(dli_fname), NULL);
2211 assert(ret != 0, "cannot locate libjvm");
2212 char *rp = realpath(dli_fname, buf);
2213 if (rp == NULL)
2214 return;
2216 if (Arguments::created_by_gamma_launcher()) {
2217 // Support for the gamma launcher. Typical value for buf is
2218 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at
2219 // the right place in the string, then assume we are installed in a JDK and
2220 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix
2221 // up the path so it looks like libjvm.so is installed there (append a
2222 // fake suffix hotspot/libjvm.so).
2223 const char *p = buf + strlen(buf) - 1;
2224 for (int count = 0; p > buf && count < 5; ++count) {
2225 for (--p; p > buf && *p != '/'; --p)
2226 /* empty */ ;
2227 }
2229 if (strncmp(p, "/jre/lib/", 9) != 0) {
2230 // Look for JAVA_HOME in the environment.
2231 char* java_home_var = ::getenv("JAVA_HOME");
2232 if (java_home_var != NULL && java_home_var[0] != 0) {
2233 char* jrelib_p;
2234 int len;
2236 // Check the current module name "libjvm.so" or "libjvm_g.so".
2237 p = strrchr(buf, '/');
2238 assert(strstr(p, "/libjvm") == p, "invalid library name");
2239 p = strstr(p, "_g") ? "_g" : "";
2241 rp = realpath(java_home_var, buf);
2242 if (rp == NULL)
2243 return;
2245 // determine if this is a legacy image or modules image
2246 // modules image doesn't have "jre" subdirectory
2247 len = strlen(buf);
2248 jrelib_p = buf + len;
2249 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch);
2250 if (0 != access(buf, F_OK)) {
2251 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch);
2252 }
2254 if (0 == access(buf, F_OK)) {
2255 // Use current module name "libjvm[_g].so" instead of
2256 // "libjvm"debug_only("_g")".so" since for fastdebug version
2257 // we should have "libjvm.so" but debug_only("_g") adds "_g"!
2258 len = strlen(buf);
2259 snprintf(buf + len, buflen-len, "/hotspot/libjvm%s.so", p);
2260 } else {
2261 // Go back to path of .so
2262 rp = realpath(dli_fname, buf);
2263 if (rp == NULL)
2264 return;
2265 }
2266 }
2267 }
2268 }
2270 strcpy(saved_jvm_path, buf);
2271 }
2273 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2274 // no prefix required, not even "_"
2275 }
2277 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2278 // no suffix required
2279 }
2281 ////////////////////////////////////////////////////////////////////////////////
2282 // sun.misc.Signal support
2284 static volatile jint sigint_count = 0;
2286 static void
2287 UserHandler(int sig, void *siginfo, void *context) {
2288 // 4511530 - sem_post is serialized and handled by the manager thread. When
2289 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2290 // don't want to flood the manager thread with sem_post requests.
2291 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
2292 return;
2294 // Ctrl-C is pressed during error reporting, likely because the error
2295 // handler fails to abort. Let VM die immediately.
2296 if (sig == SIGINT && is_error_reported()) {
2297 os::die();
2298 }
2300 os::signal_notify(sig);
2301 }
2303 void* os::user_handler() {
2304 return CAST_FROM_FN_PTR(void*, UserHandler);
2305 }
2307 extern "C" {
2308 typedef void (*sa_handler_t)(int);
2309 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2310 }
2312 void* os::signal(int signal_number, void* handler) {
2313 struct sigaction sigAct, oldSigAct;
2315 sigfillset(&(sigAct.sa_mask));
2316 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2317 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2319 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2320 // -1 means registration failed
2321 return (void *)-1;
2322 }
2324 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2325 }
2327 void os::signal_raise(int signal_number) {
2328 ::raise(signal_number);
2329 }
2331 /*
2332 * The following code is moved from os.cpp for making this
2333 * code platform specific, which it is by its very nature.
2334 */
2336 // Will be modified when max signal is changed to be dynamic
2337 int os::sigexitnum_pd() {
2338 return NSIG;
2339 }
2341 // a counter for each possible signal value
2342 static volatile jint pending_signals[NSIG+1] = { 0 };
2344 // Linux(POSIX) specific hand shaking semaphore.
2345 static sem_t sig_sem;
2347 void os::signal_init_pd() {
2348 // Initialize signal structures
2349 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2351 // Initialize signal semaphore
2352 ::sem_init(&sig_sem, 0, 0);
2353 }
2355 void os::signal_notify(int sig) {
2356 Atomic::inc(&pending_signals[sig]);
2357 ::sem_post(&sig_sem);
2358 }
2360 static int check_pending_signals(bool wait) {
2361 Atomic::store(0, &sigint_count);
2362 for (;;) {
2363 for (int i = 0; i < NSIG + 1; i++) {
2364 jint n = pending_signals[i];
2365 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2366 return i;
2367 }
2368 }
2369 if (!wait) {
2370 return -1;
2371 }
2372 JavaThread *thread = JavaThread::current();
2373 ThreadBlockInVM tbivm(thread);
2375 bool threadIsSuspended;
2376 do {
2377 thread->set_suspend_equivalent();
2378 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2379 ::sem_wait(&sig_sem);
2381 // were we externally suspended while we were waiting?
2382 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2383 if (threadIsSuspended) {
2384 //
2385 // The semaphore has been incremented, but while we were waiting
2386 // another thread suspended us. We don't want to continue running
2387 // while suspended because that would surprise the thread that
2388 // suspended us.
2389 //
2390 ::sem_post(&sig_sem);
2392 thread->java_suspend_self();
2393 }
2394 } while (threadIsSuspended);
2395 }
2396 }
2398 int os::signal_lookup() {
2399 return check_pending_signals(false);
2400 }
2402 int os::signal_wait() {
2403 return check_pending_signals(true);
2404 }
2406 ////////////////////////////////////////////////////////////////////////////////
2407 // Virtual Memory
2409 int os::vm_page_size() {
2410 // Seems redundant as all get out
2411 assert(os::Linux::page_size() != -1, "must call os::init");
2412 return os::Linux::page_size();
2413 }
2415 // Solaris allocates memory by pages.
2416 int os::vm_allocation_granularity() {
2417 assert(os::Linux::page_size() != -1, "must call os::init");
2418 return os::Linux::page_size();
2419 }
2421 // Rationale behind this function:
2422 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2423 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2424 // samples for JITted code. Here we create private executable mapping over the code cache
2425 // and then we can use standard (well, almost, as mapping can change) way to provide
2426 // info for the reporting script by storing timestamp and location of symbol
2427 void linux_wrap_code(char* base, size_t size) {
2428 static volatile jint cnt = 0;
2430 if (!UseOprofile) {
2431 return;
2432 }
2434 char buf[PATH_MAX+1];
2435 int num = Atomic::add(1, &cnt);
2437 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2438 os::get_temp_directory(), os::current_process_id(), num);
2439 unlink(buf);
2441 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2443 if (fd != -1) {
2444 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2445 if (rv != (off_t)-1) {
2446 if (::write(fd, "", 1) == 1) {
2447 mmap(base, size,
2448 PROT_READ|PROT_WRITE|PROT_EXEC,
2449 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2450 }
2451 }
2452 ::close(fd);
2453 unlink(buf);
2454 }
2455 }
2457 // NOTE: Linux kernel does not really reserve the pages for us.
2458 // All it does is to check if there are enough free pages
2459 // left at the time of mmap(). This could be a potential
2460 // problem.
2461 bool os::commit_memory(char* addr, size_t size, bool exec) {
2462 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2463 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2464 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2465 return res != (uintptr_t) MAP_FAILED;
2466 }
2468 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2469 #ifndef MAP_HUGETLB
2470 #define MAP_HUGETLB 0x40000
2471 #endif
2473 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2474 #ifndef MADV_HUGEPAGE
2475 #define MADV_HUGEPAGE 14
2476 #endif
2478 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
2479 bool exec) {
2480 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) {
2481 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2482 uintptr_t res =
2483 (uintptr_t) ::mmap(addr, size, prot,
2484 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS|MAP_HUGETLB,
2485 -1, 0);
2486 return res != (uintptr_t) MAP_FAILED;
2487 }
2489 return commit_memory(addr, size, exec);
2490 }
2492 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2493 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) {
2494 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2495 // be supported or the memory may already be backed by huge pages.
2496 ::madvise(addr, bytes, MADV_HUGEPAGE);
2497 }
2498 }
2500 void os::free_memory(char *addr, size_t bytes) {
2501 ::madvise(addr, bytes, MADV_DONTNEED);
2502 }
2504 void os::numa_make_global(char *addr, size_t bytes) {
2505 Linux::numa_interleave_memory(addr, bytes);
2506 }
2508 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2509 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2510 }
2512 bool os::numa_topology_changed() { return false; }
2514 size_t os::numa_get_groups_num() {
2515 int max_node = Linux::numa_max_node();
2516 return max_node > 0 ? max_node + 1 : 1;
2517 }
2519 int os::numa_get_group_id() {
2520 int cpu_id = Linux::sched_getcpu();
2521 if (cpu_id != -1) {
2522 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2523 if (lgrp_id != -1) {
2524 return lgrp_id;
2525 }
2526 }
2527 return 0;
2528 }
2530 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2531 for (size_t i = 0; i < size; i++) {
2532 ids[i] = i;
2533 }
2534 return size;
2535 }
2537 bool os::get_page_info(char *start, page_info* info) {
2538 return false;
2539 }
2541 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2542 return end;
2543 }
2545 // Something to do with the numa-aware allocator needs these symbols
2546 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2547 extern "C" JNIEXPORT void numa_error(char *where) { }
2548 extern "C" JNIEXPORT int fork1() { return fork(); }
2551 // If we are running with libnuma version > 2, then we should
2552 // be trying to use symbols with versions 1.1
2553 // If we are running with earlier version, which did not have symbol versions,
2554 // we should use the base version.
2555 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2556 void *f = dlvsym(handle, name, "libnuma_1.1");
2557 if (f == NULL) {
2558 f = dlsym(handle, name);
2559 }
2560 return f;
2561 }
2563 bool os::Linux::libnuma_init() {
2564 // sched_getcpu() should be in libc.
2565 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2566 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2568 if (sched_getcpu() != -1) { // Does it work?
2569 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2570 if (handle != NULL) {
2571 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2572 libnuma_dlsym(handle, "numa_node_to_cpus")));
2573 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2574 libnuma_dlsym(handle, "numa_max_node")));
2575 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2576 libnuma_dlsym(handle, "numa_available")));
2577 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2578 libnuma_dlsym(handle, "numa_tonode_memory")));
2579 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2580 libnuma_dlsym(handle, "numa_interleave_memory")));
2583 if (numa_available() != -1) {
2584 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2585 // Create a cpu -> node mapping
2586 _cpu_to_node = new (ResourceObj::C_HEAP) GrowableArray<int>(0, true);
2587 rebuild_cpu_to_node_map();
2588 return true;
2589 }
2590 }
2591 }
2592 return false;
2593 }
2595 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2596 // The table is later used in get_node_by_cpu().
2597 void os::Linux::rebuild_cpu_to_node_map() {
2598 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2599 // in libnuma (possible values are starting from 16,
2600 // and continuing up with every other power of 2, but less
2601 // than the maximum number of CPUs supported by kernel), and
2602 // is a subject to change (in libnuma version 2 the requirements
2603 // are more reasonable) we'll just hardcode the number they use
2604 // in the library.
2605 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2607 size_t cpu_num = os::active_processor_count();
2608 size_t cpu_map_size = NCPUS / BitsPerCLong;
2609 size_t cpu_map_valid_size =
2610 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2612 cpu_to_node()->clear();
2613 cpu_to_node()->at_grow(cpu_num - 1);
2614 size_t node_num = numa_get_groups_num();
2616 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size);
2617 for (size_t i = 0; i < node_num; i++) {
2618 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2619 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2620 if (cpu_map[j] != 0) {
2621 for (size_t k = 0; k < BitsPerCLong; k++) {
2622 if (cpu_map[j] & (1UL << k)) {
2623 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
2624 }
2625 }
2626 }
2627 }
2628 }
2629 }
2630 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
2631 }
2633 int os::Linux::get_node_by_cpu(int cpu_id) {
2634 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2635 return cpu_to_node()->at(cpu_id);
2636 }
2637 return -1;
2638 }
2640 GrowableArray<int>* os::Linux::_cpu_to_node;
2641 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2642 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2643 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2644 os::Linux::numa_available_func_t os::Linux::_numa_available;
2645 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2646 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2647 unsigned long* os::Linux::_numa_all_nodes;
2649 bool os::uncommit_memory(char* addr, size_t size) {
2650 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2651 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2652 return res != (uintptr_t) MAP_FAILED;
2653 }
2655 // Linux uses a growable mapping for the stack, and if the mapping for
2656 // the stack guard pages is not removed when we detach a thread the
2657 // stack cannot grow beyond the pages where the stack guard was
2658 // mapped. If at some point later in the process the stack expands to
2659 // that point, the Linux kernel cannot expand the stack any further
2660 // because the guard pages are in the way, and a segfault occurs.
2661 //
2662 // However, it's essential not to split the stack region by unmapping
2663 // a region (leaving a hole) that's already part of the stack mapping,
2664 // so if the stack mapping has already grown beyond the guard pages at
2665 // the time we create them, we have to truncate the stack mapping.
2666 // So, we need to know the extent of the stack mapping when
2667 // create_stack_guard_pages() is called.
2669 // Find the bounds of the stack mapping. Return true for success.
2670 //
2671 // We only need this for stacks that are growable: at the time of
2672 // writing thread stacks don't use growable mappings (i.e. those
2673 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
2674 // only applies to the main thread.
2676 static
2677 bool get_stack_bounds(uintptr_t *bottom, uintptr_t *top) {
2679 char buf[128];
2680 int fd, sz;
2682 if ((fd = ::open("/proc/self/maps", O_RDONLY)) < 0) {
2683 return false;
2684 }
2686 const char kw[] = "[stack]";
2687 const int kwlen = sizeof(kw)-1;
2689 // Address part of /proc/self/maps couldn't be more than 128 bytes
2690 while ((sz = os::get_line_chars(fd, buf, sizeof(buf))) > 0) {
2691 if (sz > kwlen && ::memcmp(buf+sz-kwlen, kw, kwlen) == 0) {
2692 // Extract addresses
2693 if (sscanf(buf, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) {
2694 uintptr_t sp = (uintptr_t) __builtin_frame_address(0);
2695 if (sp >= *bottom && sp <= *top) {
2696 ::close(fd);
2697 return true;
2698 }
2699 }
2700 }
2701 }
2703 ::close(fd);
2704 return false;
2705 }
2708 // If the (growable) stack mapping already extends beyond the point
2709 // where we're going to put our guard pages, truncate the mapping at
2710 // that point by munmap()ping it. This ensures that when we later
2711 // munmap() the guard pages we don't leave a hole in the stack
2712 // mapping. This only affects the main/initial thread, but guard
2713 // against future OS changes
2714 bool os::create_stack_guard_pages(char* addr, size_t size) {
2715 uintptr_t stack_extent, stack_base;
2716 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true);
2717 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) {
2718 assert(os::Linux::is_initial_thread(),
2719 "growable stack in non-initial thread");
2720 if (stack_extent < (uintptr_t)addr)
2721 ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent);
2722 }
2724 return os::commit_memory(addr, size);
2725 }
2727 // If this is a growable mapping, remove the guard pages entirely by
2728 // munmap()ping them. If not, just call uncommit_memory(). This only
2729 // affects the main/initial thread, but guard against future OS changes
2730 bool os::remove_stack_guard_pages(char* addr, size_t size) {
2731 uintptr_t stack_extent, stack_base;
2732 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true);
2733 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) {
2734 assert(os::Linux::is_initial_thread(),
2735 "growable stack in non-initial thread");
2737 return ::munmap(addr, size) == 0;
2738 }
2740 return os::uncommit_memory(addr, size);
2741 }
2743 static address _highest_vm_reserved_address = NULL;
2745 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
2746 // at 'requested_addr'. If there are existing memory mappings at the same
2747 // location, however, they will be overwritten. If 'fixed' is false,
2748 // 'requested_addr' is only treated as a hint, the return value may or
2749 // may not start from the requested address. Unlike Linux mmap(), this
2750 // function returns NULL to indicate failure.
2751 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
2752 char * addr;
2753 int flags;
2755 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
2756 if (fixed) {
2757 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
2758 flags |= MAP_FIXED;
2759 }
2761 // Map uncommitted pages PROT_READ and PROT_WRITE, change access
2762 // to PROT_EXEC if executable when we commit the page.
2763 addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE,
2764 flags, -1, 0);
2766 if (addr != MAP_FAILED) {
2767 // anon_mmap() should only get called during VM initialization,
2768 // don't need lock (actually we can skip locking even it can be called
2769 // from multiple threads, because _highest_vm_reserved_address is just a
2770 // hint about the upper limit of non-stack memory regions.)
2771 if ((address)addr + bytes > _highest_vm_reserved_address) {
2772 _highest_vm_reserved_address = (address)addr + bytes;
2773 }
2774 }
2776 return addr == MAP_FAILED ? NULL : addr;
2777 }
2779 // Don't update _highest_vm_reserved_address, because there might be memory
2780 // regions above addr + size. If so, releasing a memory region only creates
2781 // a hole in the address space, it doesn't help prevent heap-stack collision.
2782 //
2783 static int anon_munmap(char * addr, size_t size) {
2784 return ::munmap(addr, size) == 0;
2785 }
2787 char* os::reserve_memory(size_t bytes, char* requested_addr,
2788 size_t alignment_hint) {
2789 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
2790 }
2792 bool os::release_memory(char* addr, size_t size) {
2793 return anon_munmap(addr, size);
2794 }
2796 static address highest_vm_reserved_address() {
2797 return _highest_vm_reserved_address;
2798 }
2800 static bool linux_mprotect(char* addr, size_t size, int prot) {
2801 // Linux wants the mprotect address argument to be page aligned.
2802 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
2804 // According to SUSv3, mprotect() should only be used with mappings
2805 // established by mmap(), and mmap() always maps whole pages. Unaligned
2806 // 'addr' likely indicates problem in the VM (e.g. trying to change
2807 // protection of malloc'ed or statically allocated memory). Check the
2808 // caller if you hit this assert.
2809 assert(addr == bottom, "sanity check");
2811 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
2812 return ::mprotect(bottom, size, prot) == 0;
2813 }
2815 // Set protections specified
2816 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
2817 bool is_committed) {
2818 unsigned int p = 0;
2819 switch (prot) {
2820 case MEM_PROT_NONE: p = PROT_NONE; break;
2821 case MEM_PROT_READ: p = PROT_READ; break;
2822 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
2823 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
2824 default:
2825 ShouldNotReachHere();
2826 }
2827 // is_committed is unused.
2828 return linux_mprotect(addr, bytes, p);
2829 }
2831 bool os::guard_memory(char* addr, size_t size) {
2832 return linux_mprotect(addr, size, PROT_NONE);
2833 }
2835 bool os::unguard_memory(char* addr, size_t size) {
2836 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
2837 }
2839 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
2840 bool result = false;
2841 void *p = mmap (NULL, page_size, PROT_READ|PROT_WRITE,
2842 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
2843 -1, 0);
2845 if (p != (void *) -1) {
2846 // We don't know if this really is a huge page or not.
2847 FILE *fp = fopen("/proc/self/maps", "r");
2848 if (fp) {
2849 while (!feof(fp)) {
2850 char chars[257];
2851 long x = 0;
2852 if (fgets(chars, sizeof(chars), fp)) {
2853 if (sscanf(chars, "%lx-%*lx", &x) == 1
2854 && x == (long)p) {
2855 if (strstr (chars, "hugepage")) {
2856 result = true;
2857 break;
2858 }
2859 }
2860 }
2861 }
2862 fclose(fp);
2863 }
2864 munmap (p, page_size);
2865 if (result)
2866 return true;
2867 }
2869 if (warn) {
2870 warning("HugeTLBFS is not supported by the operating system.");
2871 }
2873 return result;
2874 }
2876 /*
2877 * Set the coredump_filter bits to include largepages in core dump (bit 6)
2878 *
2879 * From the coredump_filter documentation:
2880 *
2881 * - (bit 0) anonymous private memory
2882 * - (bit 1) anonymous shared memory
2883 * - (bit 2) file-backed private memory
2884 * - (bit 3) file-backed shared memory
2885 * - (bit 4) ELF header pages in file-backed private memory areas (it is
2886 * effective only if the bit 2 is cleared)
2887 * - (bit 5) hugetlb private memory
2888 * - (bit 6) hugetlb shared memory
2889 */
2890 static void set_coredump_filter(void) {
2891 FILE *f;
2892 long cdm;
2894 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
2895 return;
2896 }
2898 if (fscanf(f, "%lx", &cdm) != 1) {
2899 fclose(f);
2900 return;
2901 }
2903 rewind(f);
2905 if ((cdm & LARGEPAGES_BIT) == 0) {
2906 cdm |= LARGEPAGES_BIT;
2907 fprintf(f, "%#lx", cdm);
2908 }
2910 fclose(f);
2911 }
2913 // Large page support
2915 static size_t _large_page_size = 0;
2917 bool os::large_page_init() {
2918 if (!UseLargePages) {
2919 UseHugeTLBFS = false;
2920 UseSHM = false;
2921 return false;
2922 }
2924 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && FLAG_IS_DEFAULT(UseSHM)) {
2925 // Our user has not expressed a preference, so we'll try both.
2926 UseHugeTLBFS = UseSHM = true;
2927 }
2929 if (LargePageSizeInBytes) {
2930 _large_page_size = LargePageSizeInBytes;
2931 } else {
2932 // large_page_size on Linux is used to round up heap size. x86 uses either
2933 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
2934 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
2935 // page as large as 256M.
2936 //
2937 // Here we try to figure out page size by parsing /proc/meminfo and looking
2938 // for a line with the following format:
2939 // Hugepagesize: 2048 kB
2940 //
2941 // If we can't determine the value (e.g. /proc is not mounted, or the text
2942 // format has been changed), we'll use the largest page size supported by
2943 // the processor.
2945 #ifndef ZERO
2946 _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M)
2947 ARM_ONLY(2 * M) PPC_ONLY(4 * M);
2948 #endif // ZERO
2950 FILE *fp = fopen("/proc/meminfo", "r");
2951 if (fp) {
2952 while (!feof(fp)) {
2953 int x = 0;
2954 char buf[16];
2955 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
2956 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
2957 _large_page_size = x * K;
2958 break;
2959 }
2960 } else {
2961 // skip to next line
2962 for (;;) {
2963 int ch = fgetc(fp);
2964 if (ch == EOF || ch == (int)'\n') break;
2965 }
2966 }
2967 }
2968 fclose(fp);
2969 }
2970 }
2972 // print a warning if any large page related flag is specified on command line
2973 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
2975 const size_t default_page_size = (size_t)Linux::page_size();
2976 if (_large_page_size > default_page_size) {
2977 _page_sizes[0] = _large_page_size;
2978 _page_sizes[1] = default_page_size;
2979 _page_sizes[2] = 0;
2980 }
2982 UseHugeTLBFS = UseHugeTLBFS &&
2983 Linux::hugetlbfs_sanity_check(warn_on_failure, _large_page_size);
2985 if (UseHugeTLBFS)
2986 UseSHM = false;
2988 UseLargePages = UseHugeTLBFS || UseSHM;
2990 set_coredump_filter();
2992 // Large page support is available on 2.6 or newer kernel, some vendors
2993 // (e.g. Redhat) have backported it to their 2.4 based distributions.
2994 // We optimistically assume the support is available. If later it turns out
2995 // not true, VM will automatically switch to use regular page size.
2996 return true;
2997 }
2999 #ifndef SHM_HUGETLB
3000 #define SHM_HUGETLB 04000
3001 #endif
3003 char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) {
3004 // "exec" is passed in but not used. Creating the shared image for
3005 // the code cache doesn't have an SHM_X executable permission to check.
3006 assert(UseLargePages && UseSHM, "only for SHM large pages");
3008 key_t key = IPC_PRIVATE;
3009 char *addr;
3011 bool warn_on_failure = UseLargePages &&
3012 (!FLAG_IS_DEFAULT(UseLargePages) ||
3013 !FLAG_IS_DEFAULT(LargePageSizeInBytes)
3014 );
3015 char msg[128];
3017 // Create a large shared memory region to attach to based on size.
3018 // Currently, size is the total size of the heap
3019 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3020 if (shmid == -1) {
3021 // Possible reasons for shmget failure:
3022 // 1. shmmax is too small for Java heap.
3023 // > check shmmax value: cat /proc/sys/kernel/shmmax
3024 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3025 // 2. not enough large page memory.
3026 // > check available large pages: cat /proc/meminfo
3027 // > increase amount of large pages:
3028 // echo new_value > /proc/sys/vm/nr_hugepages
3029 // Note 1: different Linux may use different name for this property,
3030 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3031 // Note 2: it's possible there's enough physical memory available but
3032 // they are so fragmented after a long run that they can't
3033 // coalesce into large pages. Try to reserve large pages when
3034 // the system is still "fresh".
3035 if (warn_on_failure) {
3036 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno);
3037 warning(msg);
3038 }
3039 return NULL;
3040 }
3042 // attach to the region
3043 addr = (char*)shmat(shmid, req_addr, 0);
3044 int err = errno;
3046 // Remove shmid. If shmat() is successful, the actual shared memory segment
3047 // will be deleted when it's detached by shmdt() or when the process
3048 // terminates. If shmat() is not successful this will remove the shared
3049 // segment immediately.
3050 shmctl(shmid, IPC_RMID, NULL);
3052 if ((intptr_t)addr == -1) {
3053 if (warn_on_failure) {
3054 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err);
3055 warning(msg);
3056 }
3057 return NULL;
3058 }
3060 return addr;
3061 }
3063 bool os::release_memory_special(char* base, size_t bytes) {
3064 // detaching the SHM segment will also delete it, see reserve_memory_special()
3065 int rslt = shmdt(base);
3066 return rslt == 0;
3067 }
3069 size_t os::large_page_size() {
3070 return _large_page_size;
3071 }
3073 // HugeTLBFS allows application to commit large page memory on demand;
3074 // with SysV SHM the entire memory region must be allocated as shared
3075 // memory.
3076 bool os::can_commit_large_page_memory() {
3077 return UseHugeTLBFS;
3078 }
3080 bool os::can_execute_large_page_memory() {
3081 return UseHugeTLBFS;
3082 }
3084 // Reserve memory at an arbitrary address, only if that area is
3085 // available (and not reserved for something else).
3087 char* os::attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3088 const int max_tries = 10;
3089 char* base[max_tries];
3090 size_t size[max_tries];
3091 const size_t gap = 0x000000;
3093 // Assert only that the size is a multiple of the page size, since
3094 // that's all that mmap requires, and since that's all we really know
3095 // about at this low abstraction level. If we need higher alignment,
3096 // we can either pass an alignment to this method or verify alignment
3097 // in one of the methods further up the call chain. See bug 5044738.
3098 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3100 // Repeatedly allocate blocks until the block is allocated at the
3101 // right spot. Give up after max_tries. Note that reserve_memory() will
3102 // automatically update _highest_vm_reserved_address if the call is
3103 // successful. The variable tracks the highest memory address every reserved
3104 // by JVM. It is used to detect heap-stack collision if running with
3105 // fixed-stack LinuxThreads. Because here we may attempt to reserve more
3106 // space than needed, it could confuse the collision detecting code. To
3107 // solve the problem, save current _highest_vm_reserved_address and
3108 // calculate the correct value before return.
3109 address old_highest = _highest_vm_reserved_address;
3111 // Linux mmap allows caller to pass an address as hint; give it a try first,
3112 // if kernel honors the hint then we can return immediately.
3113 char * addr = anon_mmap(requested_addr, bytes, false);
3114 if (addr == requested_addr) {
3115 return requested_addr;
3116 }
3118 if (addr != NULL) {
3119 // mmap() is successful but it fails to reserve at the requested address
3120 anon_munmap(addr, bytes);
3121 }
3123 int i;
3124 for (i = 0; i < max_tries; ++i) {
3125 base[i] = reserve_memory(bytes);
3127 if (base[i] != NULL) {
3128 // Is this the block we wanted?
3129 if (base[i] == requested_addr) {
3130 size[i] = bytes;
3131 break;
3132 }
3134 // Does this overlap the block we wanted? Give back the overlapped
3135 // parts and try again.
3137 size_t top_overlap = requested_addr + (bytes + gap) - base[i];
3138 if (top_overlap >= 0 && top_overlap < bytes) {
3139 unmap_memory(base[i], top_overlap);
3140 base[i] += top_overlap;
3141 size[i] = bytes - top_overlap;
3142 } else {
3143 size_t bottom_overlap = base[i] + bytes - requested_addr;
3144 if (bottom_overlap >= 0 && bottom_overlap < bytes) {
3145 unmap_memory(requested_addr, bottom_overlap);
3146 size[i] = bytes - bottom_overlap;
3147 } else {
3148 size[i] = bytes;
3149 }
3150 }
3151 }
3152 }
3154 // Give back the unused reserved pieces.
3156 for (int j = 0; j < i; ++j) {
3157 if (base[j] != NULL) {
3158 unmap_memory(base[j], size[j]);
3159 }
3160 }
3162 if (i < max_tries) {
3163 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes);
3164 return requested_addr;
3165 } else {
3166 _highest_vm_reserved_address = old_highest;
3167 return NULL;
3168 }
3169 }
3171 size_t os::read(int fd, void *buf, unsigned int nBytes) {
3172 return ::read(fd, buf, nBytes);
3173 }
3175 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation.
3176 // Solaris uses poll(), linux uses park().
3177 // Poll() is likely a better choice, assuming that Thread.interrupt()
3178 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with
3179 // SIGSEGV, see 4355769.
3181 const int NANOSECS_PER_MILLISECS = 1000000;
3183 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
3184 assert(thread == Thread::current(), "thread consistency check");
3186 ParkEvent * const slp = thread->_SleepEvent ;
3187 slp->reset() ;
3188 OrderAccess::fence() ;
3190 if (interruptible) {
3191 jlong prevtime = javaTimeNanos();
3193 for (;;) {
3194 if (os::is_interrupted(thread, true)) {
3195 return OS_INTRPT;
3196 }
3198 jlong newtime = javaTimeNanos();
3200 if (newtime - prevtime < 0) {
3201 // time moving backwards, should only happen if no monotonic clock
3202 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3203 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3204 } else {
3205 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS;
3206 }
3208 if(millis <= 0) {
3209 return OS_OK;
3210 }
3212 prevtime = newtime;
3214 {
3215 assert(thread->is_Java_thread(), "sanity check");
3216 JavaThread *jt = (JavaThread *) thread;
3217 ThreadBlockInVM tbivm(jt);
3218 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
3220 jt->set_suspend_equivalent();
3221 // cleared by handle_special_suspend_equivalent_condition() or
3222 // java_suspend_self() via check_and_wait_while_suspended()
3224 slp->park(millis);
3226 // were we externally suspended while we were waiting?
3227 jt->check_and_wait_while_suspended();
3228 }
3229 }
3230 } else {
3231 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
3232 jlong prevtime = javaTimeNanos();
3234 for (;;) {
3235 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
3236 // the 1st iteration ...
3237 jlong newtime = javaTimeNanos();
3239 if (newtime - prevtime < 0) {
3240 // time moving backwards, should only happen if no monotonic clock
3241 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3242 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3243 } else {
3244 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS;
3245 }
3247 if(millis <= 0) break ;
3249 prevtime = newtime;
3250 slp->park(millis);
3251 }
3252 return OS_OK ;
3253 }
3254 }
3256 int os::naked_sleep() {
3257 // %% make the sleep time an integer flag. for now use 1 millisec.
3258 return os::sleep(Thread::current(), 1, false);
3259 }
3261 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3262 void os::infinite_sleep() {
3263 while (true) { // sleep forever ...
3264 ::sleep(100); // ... 100 seconds at a time
3265 }
3266 }
3268 // Used to convert frequent JVM_Yield() to nops
3269 bool os::dont_yield() {
3270 return DontYieldALot;
3271 }
3273 void os::yield() {
3274 sched_yield();
3275 }
3277 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;}
3279 void os::yield_all(int attempts) {
3280 // Yields to all threads, including threads with lower priorities
3281 // Threads on Linux are all with same priority. The Solaris style
3282 // os::yield_all() with nanosleep(1ms) is not necessary.
3283 sched_yield();
3284 }
3286 // Called from the tight loops to possibly influence time-sharing heuristics
3287 void os::loop_breaker(int attempts) {
3288 os::yield_all(attempts);
3289 }
3291 ////////////////////////////////////////////////////////////////////////////////
3292 // thread priority support
3294 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
3295 // only supports dynamic priority, static priority must be zero. For real-time
3296 // applications, Linux supports SCHED_RR which allows static priority (1-99).
3297 // However, for large multi-threaded applications, SCHED_RR is not only slower
3298 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
3299 // of 5 runs - Sep 2005).
3300 //
3301 // The following code actually changes the niceness of kernel-thread/LWP. It
3302 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
3303 // not the entire user process, and user level threads are 1:1 mapped to kernel
3304 // threads. It has always been the case, but could change in the future. For
3305 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
3306 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
3308 int os::java_to_os_priority[MaxPriority + 1] = {
3309 19, // 0 Entry should never be used
3311 4, // 1 MinPriority
3312 3, // 2
3313 2, // 3
3315 1, // 4
3316 0, // 5 NormPriority
3317 -1, // 6
3319 -2, // 7
3320 -3, // 8
3321 -4, // 9 NearMaxPriority
3323 -5 // 10 MaxPriority
3324 };
3326 static int prio_init() {
3327 if (ThreadPriorityPolicy == 1) {
3328 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
3329 // if effective uid is not root. Perhaps, a more elegant way of doing
3330 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
3331 if (geteuid() != 0) {
3332 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
3333 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
3334 }
3335 ThreadPriorityPolicy = 0;
3336 }
3337 }
3338 return 0;
3339 }
3341 OSReturn os::set_native_priority(Thread* thread, int newpri) {
3342 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK;
3344 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
3345 return (ret == 0) ? OS_OK : OS_ERR;
3346 }
3348 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
3349 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) {
3350 *priority_ptr = java_to_os_priority[NormPriority];
3351 return OS_OK;
3352 }
3354 errno = 0;
3355 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
3356 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
3357 }
3359 // Hint to the underlying OS that a task switch would not be good.
3360 // Void return because it's a hint and can fail.
3361 void os::hint_no_preempt() {}
3363 ////////////////////////////////////////////////////////////////////////////////
3364 // suspend/resume support
3366 // the low-level signal-based suspend/resume support is a remnant from the
3367 // old VM-suspension that used to be for java-suspension, safepoints etc,
3368 // within hotspot. Now there is a single use-case for this:
3369 // - calling get_thread_pc() on the VMThread by the flat-profiler task
3370 // that runs in the watcher thread.
3371 // The remaining code is greatly simplified from the more general suspension
3372 // code that used to be used.
3373 //
3374 // The protocol is quite simple:
3375 // - suspend:
3376 // - sends a signal to the target thread
3377 // - polls the suspend state of the osthread using a yield loop
3378 // - target thread signal handler (SR_handler) sets suspend state
3379 // and blocks in sigsuspend until continued
3380 // - resume:
3381 // - sets target osthread state to continue
3382 // - sends signal to end the sigsuspend loop in the SR_handler
3383 //
3384 // Note that the SR_lock plays no role in this suspend/resume protocol.
3385 //
3387 static void resume_clear_context(OSThread *osthread) {
3388 osthread->set_ucontext(NULL);
3389 osthread->set_siginfo(NULL);
3391 // notify the suspend action is completed, we have now resumed
3392 osthread->sr.clear_suspended();
3393 }
3395 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
3396 osthread->set_ucontext(context);
3397 osthread->set_siginfo(siginfo);
3398 }
3400 //
3401 // Handler function invoked when a thread's execution is suspended or
3402 // resumed. We have to be careful that only async-safe functions are
3403 // called here (Note: most pthread functions are not async safe and
3404 // should be avoided.)
3405 //
3406 // Note: sigwait() is a more natural fit than sigsuspend() from an
3407 // interface point of view, but sigwait() prevents the signal hander
3408 // from being run. libpthread would get very confused by not having
3409 // its signal handlers run and prevents sigwait()'s use with the
3410 // mutex granting granting signal.
3411 //
3412 // Currently only ever called on the VMThread
3413 //
3414 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
3415 // Save and restore errno to avoid confusing native code with EINTR
3416 // after sigsuspend.
3417 int old_errno = errno;
3419 Thread* thread = Thread::current();
3420 OSThread* osthread = thread->osthread();
3421 assert(thread->is_VM_thread(), "Must be VMThread");
3422 // read current suspend action
3423 int action = osthread->sr.suspend_action();
3424 if (action == SR_SUSPEND) {
3425 suspend_save_context(osthread, siginfo, context);
3427 // Notify the suspend action is about to be completed. do_suspend()
3428 // waits until SR_SUSPENDED is set and then returns. We will wait
3429 // here for a resume signal and that completes the suspend-other
3430 // action. do_suspend/do_resume is always called as a pair from
3431 // the same thread - so there are no races
3433 // notify the caller
3434 osthread->sr.set_suspended();
3436 sigset_t suspend_set; // signals for sigsuspend()
3438 // get current set of blocked signals and unblock resume signal
3439 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
3440 sigdelset(&suspend_set, SR_signum);
3442 // wait here until we are resumed
3443 do {
3444 sigsuspend(&suspend_set);
3445 // ignore all returns until we get a resume signal
3446 } while (osthread->sr.suspend_action() != SR_CONTINUE);
3448 resume_clear_context(osthread);
3450 } else {
3451 assert(action == SR_CONTINUE, "unexpected sr action");
3452 // nothing special to do - just leave the handler
3453 }
3455 errno = old_errno;
3456 }
3459 static int SR_initialize() {
3460 struct sigaction act;
3461 char *s;
3462 /* Get signal number to use for suspend/resume */
3463 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
3464 int sig = ::strtol(s, 0, 10);
3465 if (sig > 0 || sig < _NSIG) {
3466 SR_signum = sig;
3467 }
3468 }
3470 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
3471 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
3473 sigemptyset(&SR_sigset);
3474 sigaddset(&SR_sigset, SR_signum);
3476 /* Set up signal handler for suspend/resume */
3477 act.sa_flags = SA_RESTART|SA_SIGINFO;
3478 act.sa_handler = (void (*)(int)) SR_handler;
3480 // SR_signum is blocked by default.
3481 // 4528190 - We also need to block pthread restart signal (32 on all
3482 // supported Linux platforms). Note that LinuxThreads need to block
3483 // this signal for all threads to work properly. So we don't have
3484 // to use hard-coded signal number when setting up the mask.
3485 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
3487 if (sigaction(SR_signum, &act, 0) == -1) {
3488 return -1;
3489 }
3491 // Save signal flag
3492 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
3493 return 0;
3494 }
3496 static int SR_finalize() {
3497 return 0;
3498 }
3501 // returns true on success and false on error - really an error is fatal
3502 // but this seems the normal response to library errors
3503 static bool do_suspend(OSThread* osthread) {
3504 // mark as suspended and send signal
3505 osthread->sr.set_suspend_action(SR_SUSPEND);
3506 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3507 assert_status(status == 0, status, "pthread_kill");
3509 // check status and wait until notified of suspension
3510 if (status == 0) {
3511 for (int i = 0; !osthread->sr.is_suspended(); i++) {
3512 os::yield_all(i);
3513 }
3514 osthread->sr.set_suspend_action(SR_NONE);
3515 return true;
3516 }
3517 else {
3518 osthread->sr.set_suspend_action(SR_NONE);
3519 return false;
3520 }
3521 }
3523 static void do_resume(OSThread* osthread) {
3524 assert(osthread->sr.is_suspended(), "thread should be suspended");
3525 osthread->sr.set_suspend_action(SR_CONTINUE);
3527 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3528 assert_status(status == 0, status, "pthread_kill");
3529 // check status and wait unit notified of resumption
3530 if (status == 0) {
3531 for (int i = 0; osthread->sr.is_suspended(); i++) {
3532 os::yield_all(i);
3533 }
3534 }
3535 osthread->sr.set_suspend_action(SR_NONE);
3536 }
3538 ////////////////////////////////////////////////////////////////////////////////
3539 // interrupt support
3541 void os::interrupt(Thread* thread) {
3542 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3543 "possibility of dangling Thread pointer");
3545 OSThread* osthread = thread->osthread();
3547 if (!osthread->interrupted()) {
3548 osthread->set_interrupted(true);
3549 // More than one thread can get here with the same value of osthread,
3550 // resulting in multiple notifications. We do, however, want the store
3551 // to interrupted() to be visible to other threads before we execute unpark().
3552 OrderAccess::fence();
3553 ParkEvent * const slp = thread->_SleepEvent ;
3554 if (slp != NULL) slp->unpark() ;
3555 }
3557 // For JSR166. Unpark even if interrupt status already was set
3558 if (thread->is_Java_thread())
3559 ((JavaThread*)thread)->parker()->unpark();
3561 ParkEvent * ev = thread->_ParkEvent ;
3562 if (ev != NULL) ev->unpark() ;
3564 }
3566 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
3567 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3568 "possibility of dangling Thread pointer");
3570 OSThread* osthread = thread->osthread();
3572 bool interrupted = osthread->interrupted();
3574 if (interrupted && clear_interrupted) {
3575 osthread->set_interrupted(false);
3576 // consider thread->_SleepEvent->reset() ... optional optimization
3577 }
3579 return interrupted;
3580 }
3582 ///////////////////////////////////////////////////////////////////////////////////
3583 // signal handling (except suspend/resume)
3585 // This routine may be used by user applications as a "hook" to catch signals.
3586 // The user-defined signal handler must pass unrecognized signals to this
3587 // routine, and if it returns true (non-zero), then the signal handler must
3588 // return immediately. If the flag "abort_if_unrecognized" is true, then this
3589 // routine will never retun false (zero), but instead will execute a VM panic
3590 // routine kill the process.
3591 //
3592 // If this routine returns false, it is OK to call it again. This allows
3593 // the user-defined signal handler to perform checks either before or after
3594 // the VM performs its own checks. Naturally, the user code would be making
3595 // a serious error if it tried to handle an exception (such as a null check
3596 // or breakpoint) that the VM was generating for its own correct operation.
3597 //
3598 // This routine may recognize any of the following kinds of signals:
3599 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
3600 // It should be consulted by handlers for any of those signals.
3601 //
3602 // The caller of this routine must pass in the three arguments supplied
3603 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
3604 // field of the structure passed to sigaction(). This routine assumes that
3605 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
3606 //
3607 // Note that the VM will print warnings if it detects conflicting signal
3608 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
3609 //
3610 extern "C" JNIEXPORT int
3611 JVM_handle_linux_signal(int signo, siginfo_t* siginfo,
3612 void* ucontext, int abort_if_unrecognized);
3614 void signalHandler(int sig, siginfo_t* info, void* uc) {
3615 assert(info != NULL && uc != NULL, "it must be old kernel");
3616 JVM_handle_linux_signal(sig, info, uc, true);
3617 }
3620 // This boolean allows users to forward their own non-matching signals
3621 // to JVM_handle_linux_signal, harmlessly.
3622 bool os::Linux::signal_handlers_are_installed = false;
3624 // For signal-chaining
3625 struct sigaction os::Linux::sigact[MAXSIGNUM];
3626 unsigned int os::Linux::sigs = 0;
3627 bool os::Linux::libjsig_is_loaded = false;
3628 typedef struct sigaction *(*get_signal_t)(int);
3629 get_signal_t os::Linux::get_signal_action = NULL;
3631 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
3632 struct sigaction *actp = NULL;
3634 if (libjsig_is_loaded) {
3635 // Retrieve the old signal handler from libjsig
3636 actp = (*get_signal_action)(sig);
3637 }
3638 if (actp == NULL) {
3639 // Retrieve the preinstalled signal handler from jvm
3640 actp = get_preinstalled_handler(sig);
3641 }
3643 return actp;
3644 }
3646 static bool call_chained_handler(struct sigaction *actp, int sig,
3647 siginfo_t *siginfo, void *context) {
3648 // Call the old signal handler
3649 if (actp->sa_handler == SIG_DFL) {
3650 // It's more reasonable to let jvm treat it as an unexpected exception
3651 // instead of taking the default action.
3652 return false;
3653 } else if (actp->sa_handler != SIG_IGN) {
3654 if ((actp->sa_flags & SA_NODEFER) == 0) {
3655 // automaticlly block the signal
3656 sigaddset(&(actp->sa_mask), sig);
3657 }
3659 sa_handler_t hand;
3660 sa_sigaction_t sa;
3661 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
3662 // retrieve the chained handler
3663 if (siginfo_flag_set) {
3664 sa = actp->sa_sigaction;
3665 } else {
3666 hand = actp->sa_handler;
3667 }
3669 if ((actp->sa_flags & SA_RESETHAND) != 0) {
3670 actp->sa_handler = SIG_DFL;
3671 }
3673 // try to honor the signal mask
3674 sigset_t oset;
3675 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
3677 // call into the chained handler
3678 if (siginfo_flag_set) {
3679 (*sa)(sig, siginfo, context);
3680 } else {
3681 (*hand)(sig);
3682 }
3684 // restore the signal mask
3685 pthread_sigmask(SIG_SETMASK, &oset, 0);
3686 }
3687 // Tell jvm's signal handler the signal is taken care of.
3688 return true;
3689 }
3691 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
3692 bool chained = false;
3693 // signal-chaining
3694 if (UseSignalChaining) {
3695 struct sigaction *actp = get_chained_signal_action(sig);
3696 if (actp != NULL) {
3697 chained = call_chained_handler(actp, sig, siginfo, context);
3698 }
3699 }
3700 return chained;
3701 }
3703 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
3704 if ((( (unsigned int)1 << sig ) & sigs) != 0) {
3705 return &sigact[sig];
3706 }
3707 return NULL;
3708 }
3710 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
3711 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3712 sigact[sig] = oldAct;
3713 sigs |= (unsigned int)1 << sig;
3714 }
3716 // for diagnostic
3717 int os::Linux::sigflags[MAXSIGNUM];
3719 int os::Linux::get_our_sigflags(int sig) {
3720 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3721 return sigflags[sig];
3722 }
3724 void os::Linux::set_our_sigflags(int sig, int flags) {
3725 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3726 sigflags[sig] = flags;
3727 }
3729 void os::Linux::set_signal_handler(int sig, bool set_installed) {
3730 // Check for overwrite.
3731 struct sigaction oldAct;
3732 sigaction(sig, (struct sigaction*)NULL, &oldAct);
3734 void* oldhand = oldAct.sa_sigaction
3735 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3736 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3737 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
3738 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
3739 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
3740 if (AllowUserSignalHandlers || !set_installed) {
3741 // Do not overwrite; user takes responsibility to forward to us.
3742 return;
3743 } else if (UseSignalChaining) {
3744 // save the old handler in jvm
3745 save_preinstalled_handler(sig, oldAct);
3746 // libjsig also interposes the sigaction() call below and saves the
3747 // old sigaction on it own.
3748 } else {
3749 fatal(err_msg("Encountered unexpected pre-existing sigaction handler "
3750 "%#lx for signal %d.", (long)oldhand, sig));
3751 }
3752 }
3754 struct sigaction sigAct;
3755 sigfillset(&(sigAct.sa_mask));
3756 sigAct.sa_handler = SIG_DFL;
3757 if (!set_installed) {
3758 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3759 } else {
3760 sigAct.sa_sigaction = signalHandler;
3761 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3762 }
3763 // Save flags, which are set by ours
3764 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3765 sigflags[sig] = sigAct.sa_flags;
3767 int ret = sigaction(sig, &sigAct, &oldAct);
3768 assert(ret == 0, "check");
3770 void* oldhand2 = oldAct.sa_sigaction
3771 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3772 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3773 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
3774 }
3776 // install signal handlers for signals that HotSpot needs to
3777 // handle in order to support Java-level exception handling.
3779 void os::Linux::install_signal_handlers() {
3780 if (!signal_handlers_are_installed) {
3781 signal_handlers_are_installed = true;
3783 // signal-chaining
3784 typedef void (*signal_setting_t)();
3785 signal_setting_t begin_signal_setting = NULL;
3786 signal_setting_t end_signal_setting = NULL;
3787 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3788 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
3789 if (begin_signal_setting != NULL) {
3790 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3791 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
3792 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
3793 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
3794 libjsig_is_loaded = true;
3795 assert(UseSignalChaining, "should enable signal-chaining");
3796 }
3797 if (libjsig_is_loaded) {
3798 // Tell libjsig jvm is setting signal handlers
3799 (*begin_signal_setting)();
3800 }
3802 set_signal_handler(SIGSEGV, true);
3803 set_signal_handler(SIGPIPE, true);
3804 set_signal_handler(SIGBUS, true);
3805 set_signal_handler(SIGILL, true);
3806 set_signal_handler(SIGFPE, true);
3807 set_signal_handler(SIGXFSZ, true);
3809 if (libjsig_is_loaded) {
3810 // Tell libjsig jvm finishes setting signal handlers
3811 (*end_signal_setting)();
3812 }
3814 // We don't activate signal checker if libjsig is in place, we trust ourselves
3815 // and if UserSignalHandler is installed all bets are off
3816 if (CheckJNICalls) {
3817 if (libjsig_is_loaded) {
3818 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
3819 check_signals = false;
3820 }
3821 if (AllowUserSignalHandlers) {
3822 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
3823 check_signals = false;
3824 }
3825 }
3826 }
3827 }
3829 // This is the fastest way to get thread cpu time on Linux.
3830 // Returns cpu time (user+sys) for any thread, not only for current.
3831 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
3832 // It might work on 2.6.10+ with a special kernel/glibc patch.
3833 // For reference, please, see IEEE Std 1003.1-2004:
3834 // http://www.unix.org/single_unix_specification
3836 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
3837 struct timespec tp;
3838 int rc = os::Linux::clock_gettime(clockid, &tp);
3839 assert(rc == 0, "clock_gettime is expected to return 0 code");
3841 return (tp.tv_sec * SEC_IN_NANOSECS) + tp.tv_nsec;
3842 }
3844 /////
3845 // glibc on Linux platform uses non-documented flag
3846 // to indicate, that some special sort of signal
3847 // trampoline is used.
3848 // We will never set this flag, and we should
3849 // ignore this flag in our diagnostic
3850 #ifdef SIGNIFICANT_SIGNAL_MASK
3851 #undef SIGNIFICANT_SIGNAL_MASK
3852 #endif
3853 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
3855 static const char* get_signal_handler_name(address handler,
3856 char* buf, int buflen) {
3857 int offset;
3858 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
3859 if (found) {
3860 // skip directory names
3861 const char *p1, *p2;
3862 p1 = buf;
3863 size_t len = strlen(os::file_separator());
3864 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
3865 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
3866 } else {
3867 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
3868 }
3869 return buf;
3870 }
3872 static void print_signal_handler(outputStream* st, int sig,
3873 char* buf, size_t buflen) {
3874 struct sigaction sa;
3876 sigaction(sig, NULL, &sa);
3878 // See comment for SIGNIFICANT_SIGNAL_MASK define
3879 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
3881 st->print("%s: ", os::exception_name(sig, buf, buflen));
3883 address handler = (sa.sa_flags & SA_SIGINFO)
3884 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
3885 : CAST_FROM_FN_PTR(address, sa.sa_handler);
3887 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
3888 st->print("SIG_DFL");
3889 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
3890 st->print("SIG_IGN");
3891 } else {
3892 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
3893 }
3895 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask);
3897 address rh = VMError::get_resetted_sighandler(sig);
3898 // May be, handler was resetted by VMError?
3899 if(rh != NULL) {
3900 handler = rh;
3901 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
3902 }
3904 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags);
3906 // Check: is it our handler?
3907 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
3908 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
3909 // It is our signal handler
3910 // check for flags, reset system-used one!
3911 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
3912 st->print(
3913 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
3914 os::Linux::get_our_sigflags(sig));
3915 }
3916 }
3917 st->cr();
3918 }
3921 #define DO_SIGNAL_CHECK(sig) \
3922 if (!sigismember(&check_signal_done, sig)) \
3923 os::Linux::check_signal_handler(sig)
3925 // This method is a periodic task to check for misbehaving JNI applications
3926 // under CheckJNI, we can add any periodic checks here
3928 void os::run_periodic_checks() {
3930 if (check_signals == false) return;
3932 // SEGV and BUS if overridden could potentially prevent
3933 // generation of hs*.log in the event of a crash, debugging
3934 // such a case can be very challenging, so we absolutely
3935 // check the following for a good measure:
3936 DO_SIGNAL_CHECK(SIGSEGV);
3937 DO_SIGNAL_CHECK(SIGILL);
3938 DO_SIGNAL_CHECK(SIGFPE);
3939 DO_SIGNAL_CHECK(SIGBUS);
3940 DO_SIGNAL_CHECK(SIGPIPE);
3941 DO_SIGNAL_CHECK(SIGXFSZ);
3944 // ReduceSignalUsage allows the user to override these handlers
3945 // see comments at the very top and jvm_solaris.h
3946 if (!ReduceSignalUsage) {
3947 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
3948 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
3949 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
3950 DO_SIGNAL_CHECK(BREAK_SIGNAL);
3951 }
3953 DO_SIGNAL_CHECK(SR_signum);
3954 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
3955 }
3957 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
3959 static os_sigaction_t os_sigaction = NULL;
3961 void os::Linux::check_signal_handler(int sig) {
3962 char buf[O_BUFLEN];
3963 address jvmHandler = NULL;
3966 struct sigaction act;
3967 if (os_sigaction == NULL) {
3968 // only trust the default sigaction, in case it has been interposed
3969 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
3970 if (os_sigaction == NULL) return;
3971 }
3973 os_sigaction(sig, (struct sigaction*)NULL, &act);
3976 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
3978 address thisHandler = (act.sa_flags & SA_SIGINFO)
3979 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
3980 : CAST_FROM_FN_PTR(address, act.sa_handler) ;
3983 switch(sig) {
3984 case SIGSEGV:
3985 case SIGBUS:
3986 case SIGFPE:
3987 case SIGPIPE:
3988 case SIGILL:
3989 case SIGXFSZ:
3990 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
3991 break;
3993 case SHUTDOWN1_SIGNAL:
3994 case SHUTDOWN2_SIGNAL:
3995 case SHUTDOWN3_SIGNAL:
3996 case BREAK_SIGNAL:
3997 jvmHandler = (address)user_handler();
3998 break;
4000 case INTERRUPT_SIGNAL:
4001 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
4002 break;
4004 default:
4005 if (sig == SR_signum) {
4006 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4007 } else {
4008 return;
4009 }
4010 break;
4011 }
4013 if (thisHandler != jvmHandler) {
4014 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4015 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4016 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4017 // No need to check this sig any longer
4018 sigaddset(&check_signal_done, sig);
4019 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4020 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4021 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig));
4022 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags);
4023 // No need to check this sig any longer
4024 sigaddset(&check_signal_done, sig);
4025 }
4027 // Dump all the signal
4028 if (sigismember(&check_signal_done, sig)) {
4029 print_signal_handlers(tty, buf, O_BUFLEN);
4030 }
4031 }
4033 extern void report_error(char* file_name, int line_no, char* title, char* format, ...);
4035 extern bool signal_name(int signo, char* buf, size_t len);
4037 const char* os::exception_name(int exception_code, char* buf, size_t size) {
4038 if (0 < exception_code && exception_code <= SIGRTMAX) {
4039 // signal
4040 if (!signal_name(exception_code, buf, size)) {
4041 jio_snprintf(buf, size, "SIG%d", exception_code);
4042 }
4043 return buf;
4044 } else {
4045 return NULL;
4046 }
4047 }
4049 // this is called _before_ the most of global arguments have been parsed
4050 void os::init(void) {
4051 char dummy; /* used to get a guess on initial stack address */
4052 // first_hrtime = gethrtime();
4054 // With LinuxThreads the JavaMain thread pid (primordial thread)
4055 // is different than the pid of the java launcher thread.
4056 // So, on Linux, the launcher thread pid is passed to the VM
4057 // via the sun.java.launcher.pid property.
4058 // Use this property instead of getpid() if it was correctly passed.
4059 // See bug 6351349.
4060 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
4062 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
4064 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4066 init_random(1234567);
4068 ThreadCritical::initialize();
4070 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4071 if (Linux::page_size() == -1) {
4072 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)",
4073 strerror(errno)));
4074 }
4075 init_page_sizes((size_t) Linux::page_size());
4077 Linux::initialize_system_info();
4079 // main_thread points to the aboriginal thread
4080 Linux::_main_thread = pthread_self();
4082 Linux::clock_init();
4083 initial_time_count = os::elapsed_counter();
4084 pthread_mutex_init(&dl_mutex, NULL);
4085 }
4087 // To install functions for atexit system call
4088 extern "C" {
4089 static void perfMemory_exit_helper() {
4090 perfMemory_exit();
4091 }
4092 }
4094 // this is called _after_ the global arguments have been parsed
4095 jint os::init_2(void)
4096 {
4097 Linux::fast_thread_clock_init();
4099 // Allocate a single page and mark it as readable for safepoint polling
4100 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4101 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" );
4103 os::set_polling_page( polling_page );
4105 #ifndef PRODUCT
4106 if(Verbose && PrintMiscellaneous)
4107 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
4108 #endif
4110 if (!UseMembar) {
4111 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4112 guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page");
4113 os::set_memory_serialize_page( mem_serialize_page );
4115 #ifndef PRODUCT
4116 if(Verbose && PrintMiscellaneous)
4117 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
4118 #endif
4119 }
4121 FLAG_SET_DEFAULT(UseLargePages, os::large_page_init());
4123 // initialize suspend/resume support - must do this before signal_sets_init()
4124 if (SR_initialize() != 0) {
4125 perror("SR_initialize failed");
4126 return JNI_ERR;
4127 }
4129 Linux::signal_sets_init();
4130 Linux::install_signal_handlers();
4132 // Check minimum allowable stack size for thread creation and to initialize
4133 // the java system classes, including StackOverflowError - depends on page
4134 // size. Add a page for compiler2 recursion in main thread.
4135 // Add in 2*BytesPerWord times page size to account for VM stack during
4136 // class initialization depending on 32 or 64 bit VM.
4137 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed,
4138 (size_t)(StackYellowPages+StackRedPages+StackShadowPages+
4139 2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::page_size());
4141 size_t threadStackSizeInBytes = ThreadStackSize * K;
4142 if (threadStackSizeInBytes != 0 &&
4143 threadStackSizeInBytes < os::Linux::min_stack_allowed) {
4144 tty->print_cr("\nThe stack size specified is too small, "
4145 "Specify at least %dk",
4146 os::Linux::min_stack_allowed/ K);
4147 return JNI_ERR;
4148 }
4150 // Make the stack size a multiple of the page size so that
4151 // the yellow/red zones can be guarded.
4152 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
4153 vm_page_size()));
4155 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4157 Linux::libpthread_init();
4158 if (PrintMiscellaneous && (Verbose || WizardMode)) {
4159 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n",
4160 Linux::glibc_version(), Linux::libpthread_version(),
4161 Linux::is_floating_stack() ? "floating stack" : "fixed stack");
4162 }
4164 if (UseNUMA) {
4165 if (!Linux::libnuma_init()) {
4166 UseNUMA = false;
4167 } else {
4168 if ((Linux::numa_max_node() < 1)) {
4169 // There's only one node(they start from 0), disable NUMA.
4170 UseNUMA = false;
4171 }
4172 }
4173 // With SHM large pages we cannot uncommit a page, so there's not way
4174 // we can make the adaptive lgrp chunk resizing work. If the user specified
4175 // both UseNUMA and UseLargePages (or UseSHM) on the command line - warn and
4176 // disable adaptive resizing.
4177 if (UseNUMA && UseLargePages && UseSHM) {
4178 if (!FLAG_IS_DEFAULT(UseNUMA)) {
4179 if (FLAG_IS_DEFAULT(UseLargePages) && FLAG_IS_DEFAULT(UseSHM)) {
4180 UseLargePages = false;
4181 } else {
4182 warning("UseNUMA is not fully compatible with SHM large pages, disabling adaptive resizing");
4183 UseAdaptiveSizePolicy = false;
4184 UseAdaptiveNUMAChunkSizing = false;
4185 }
4186 } else {
4187 UseNUMA = false;
4188 }
4189 }
4190 if (!UseNUMA && ForceNUMA) {
4191 UseNUMA = true;
4192 }
4193 }
4195 if (MaxFDLimit) {
4196 // set the number of file descriptors to max. print out error
4197 // if getrlimit/setrlimit fails but continue regardless.
4198 struct rlimit nbr_files;
4199 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
4200 if (status != 0) {
4201 if (PrintMiscellaneous && (Verbose || WizardMode))
4202 perror("os::init_2 getrlimit failed");
4203 } else {
4204 nbr_files.rlim_cur = nbr_files.rlim_max;
4205 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
4206 if (status != 0) {
4207 if (PrintMiscellaneous && (Verbose || WizardMode))
4208 perror("os::init_2 setrlimit failed");
4209 }
4210 }
4211 }
4213 // Initialize lock used to serialize thread creation (see os::create_thread)
4214 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
4216 // at-exit methods are called in the reverse order of their registration.
4217 // atexit functions are called on return from main or as a result of a
4218 // call to exit(3C). There can be only 32 of these functions registered
4219 // and atexit() does not set errno.
4221 if (PerfAllowAtExitRegistration) {
4222 // only register atexit functions if PerfAllowAtExitRegistration is set.
4223 // atexit functions can be delayed until process exit time, which
4224 // can be problematic for embedded VM situations. Embedded VMs should
4225 // call DestroyJavaVM() to assure that VM resources are released.
4227 // note: perfMemory_exit_helper atexit function may be removed in
4228 // the future if the appropriate cleanup code can be added to the
4229 // VM_Exit VMOperation's doit method.
4230 if (atexit(perfMemory_exit_helper) != 0) {
4231 warning("os::init2 atexit(perfMemory_exit_helper) failed");
4232 }
4233 }
4235 // initialize thread priority policy
4236 prio_init();
4238 return JNI_OK;
4239 }
4241 // this is called at the end of vm_initialization
4242 void os::init_3(void) { }
4244 // Mark the polling page as unreadable
4245 void os::make_polling_page_unreadable(void) {
4246 if( !guard_memory((char*)_polling_page, Linux::page_size()) )
4247 fatal("Could not disable polling page");
4248 };
4250 // Mark the polling page as readable
4251 void os::make_polling_page_readable(void) {
4252 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
4253 fatal("Could not enable polling page");
4254 }
4255 };
4257 int os::active_processor_count() {
4258 // Linux doesn't yet have a (official) notion of processor sets,
4259 // so just return the number of online processors.
4260 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
4261 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
4262 return online_cpus;
4263 }
4265 bool os::distribute_processes(uint length, uint* distribution) {
4266 // Not yet implemented.
4267 return false;
4268 }
4270 bool os::bind_to_processor(uint processor_id) {
4271 // Not yet implemented.
4272 return false;
4273 }
4275 ///
4277 // Suspends the target using the signal mechanism and then grabs the PC before
4278 // resuming the target. Used by the flat-profiler only
4279 ExtendedPC os::get_thread_pc(Thread* thread) {
4280 // Make sure that it is called by the watcher for the VMThread
4281 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
4282 assert(thread->is_VM_thread(), "Can only be called for VMThread");
4284 ExtendedPC epc;
4286 OSThread* osthread = thread->osthread();
4287 if (do_suspend(osthread)) {
4288 if (osthread->ucontext() != NULL) {
4289 epc = os::Linux::ucontext_get_pc(osthread->ucontext());
4290 } else {
4291 // NULL context is unexpected, double-check this is the VMThread
4292 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
4293 }
4294 do_resume(osthread);
4295 }
4296 // failure means pthread_kill failed for some reason - arguably this is
4297 // a fatal problem, but such problems are ignored elsewhere
4299 return epc;
4300 }
4302 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime)
4303 {
4304 if (is_NPTL()) {
4305 return pthread_cond_timedwait(_cond, _mutex, _abstime);
4306 } else {
4307 #ifndef IA64
4308 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control
4309 // word back to default 64bit precision if condvar is signaled. Java
4310 // wants 53bit precision. Save and restore current value.
4311 int fpu = get_fpu_control_word();
4312 #endif // IA64
4313 int status = pthread_cond_timedwait(_cond, _mutex, _abstime);
4314 #ifndef IA64
4315 set_fpu_control_word(fpu);
4316 #endif // IA64
4317 return status;
4318 }
4319 }
4321 ////////////////////////////////////////////////////////////////////////////////
4322 // debug support
4324 static address same_page(address x, address y) {
4325 int page_bits = -os::vm_page_size();
4326 if ((intptr_t(x) & page_bits) == (intptr_t(y) & page_bits))
4327 return x;
4328 else if (x > y)
4329 return (address)(intptr_t(y) | ~page_bits) + 1;
4330 else
4331 return (address)(intptr_t(y) & page_bits);
4332 }
4334 bool os::find(address addr, outputStream* st) {
4335 Dl_info dlinfo;
4336 memset(&dlinfo, 0, sizeof(dlinfo));
4337 if (dladdr(addr, &dlinfo)) {
4338 st->print(PTR_FORMAT ": ", addr);
4339 if (dlinfo.dli_sname != NULL) {
4340 st->print("%s+%#x", dlinfo.dli_sname,
4341 addr - (intptr_t)dlinfo.dli_saddr);
4342 } else if (dlinfo.dli_fname) {
4343 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
4344 } else {
4345 st->print("<absolute address>");
4346 }
4347 if (dlinfo.dli_fname) {
4348 st->print(" in %s", dlinfo.dli_fname);
4349 }
4350 if (dlinfo.dli_fbase) {
4351 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
4352 }
4353 st->cr();
4355 if (Verbose) {
4356 // decode some bytes around the PC
4357 address begin = same_page(addr-40, addr);
4358 address end = same_page(addr+40, addr);
4359 address lowest = (address) dlinfo.dli_sname;
4360 if (!lowest) lowest = (address) dlinfo.dli_fbase;
4361 if (begin < lowest) begin = lowest;
4362 Dl_info dlinfo2;
4363 if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr
4364 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin)
4365 end = (address) dlinfo2.dli_saddr;
4366 Disassembler::decode(begin, end, st);
4367 }
4368 return true;
4369 }
4370 return false;
4371 }
4373 ////////////////////////////////////////////////////////////////////////////////
4374 // misc
4376 // This does not do anything on Linux. This is basically a hook for being
4377 // able to use structured exception handling (thread-local exception filters)
4378 // on, e.g., Win32.
4379 void
4380 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method,
4381 JavaCallArguments* args, Thread* thread) {
4382 f(value, method, args, thread);
4383 }
4385 void os::print_statistics() {
4386 }
4388 int os::message_box(const char* title, const char* message) {
4389 int i;
4390 fdStream err(defaultStream::error_fd());
4391 for (i = 0; i < 78; i++) err.print_raw("=");
4392 err.cr();
4393 err.print_raw_cr(title);
4394 for (i = 0; i < 78; i++) err.print_raw("-");
4395 err.cr();
4396 err.print_raw_cr(message);
4397 for (i = 0; i < 78; i++) err.print_raw("=");
4398 err.cr();
4400 char buf[16];
4401 // Prevent process from exiting upon "read error" without consuming all CPU
4402 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
4404 return buf[0] == 'y' || buf[0] == 'Y';
4405 }
4407 int os::stat(const char *path, struct stat *sbuf) {
4408 char pathbuf[MAX_PATH];
4409 if (strlen(path) > MAX_PATH - 1) {
4410 errno = ENAMETOOLONG;
4411 return -1;
4412 }
4413 os::native_path(strcpy(pathbuf, path));
4414 return ::stat(pathbuf, sbuf);
4415 }
4417 bool os::check_heap(bool force) {
4418 return true;
4419 }
4421 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
4422 return ::vsnprintf(buf, count, format, args);
4423 }
4425 // Is a (classpath) directory empty?
4426 bool os::dir_is_empty(const char* path) {
4427 DIR *dir = NULL;
4428 struct dirent *ptr;
4430 dir = opendir(path);
4431 if (dir == NULL) return true;
4433 /* Scan the directory */
4434 bool result = true;
4435 char buf[sizeof(struct dirent) + MAX_PATH];
4436 while (result && (ptr = ::readdir(dir)) != NULL) {
4437 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
4438 result = false;
4439 }
4440 }
4441 closedir(dir);
4442 return result;
4443 }
4445 // This code originates from JDK's sysOpen and open64_w
4446 // from src/solaris/hpi/src/system_md.c
4448 #ifndef O_DELETE
4449 #define O_DELETE 0x10000
4450 #endif
4452 // Open a file. Unlink the file immediately after open returns
4453 // if the specified oflag has the O_DELETE flag set.
4454 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c
4456 int os::open(const char *path, int oflag, int mode) {
4458 if (strlen(path) > MAX_PATH - 1) {
4459 errno = ENAMETOOLONG;
4460 return -1;
4461 }
4462 int fd;
4463 int o_delete = (oflag & O_DELETE);
4464 oflag = oflag & ~O_DELETE;
4466 fd = ::open64(path, oflag, mode);
4467 if (fd == -1) return -1;
4469 //If the open succeeded, the file might still be a directory
4470 {
4471 struct stat64 buf64;
4472 int ret = ::fstat64(fd, &buf64);
4473 int st_mode = buf64.st_mode;
4475 if (ret != -1) {
4476 if ((st_mode & S_IFMT) == S_IFDIR) {
4477 errno = EISDIR;
4478 ::close(fd);
4479 return -1;
4480 }
4481 } else {
4482 ::close(fd);
4483 return -1;
4484 }
4485 }
4487 /*
4488 * All file descriptors that are opened in the JVM and not
4489 * specifically destined for a subprocess should have the
4490 * close-on-exec flag set. If we don't set it, then careless 3rd
4491 * party native code might fork and exec without closing all
4492 * appropriate file descriptors (e.g. as we do in closeDescriptors in
4493 * UNIXProcess.c), and this in turn might:
4494 *
4495 * - cause end-of-file to fail to be detected on some file
4496 * descriptors, resulting in mysterious hangs, or
4497 *
4498 * - might cause an fopen in the subprocess to fail on a system
4499 * suffering from bug 1085341.
4500 *
4501 * (Yes, the default setting of the close-on-exec flag is a Unix
4502 * design flaw)
4503 *
4504 * See:
4505 * 1085341: 32-bit stdio routines should support file descriptors >255
4506 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed
4507 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
4508 */
4509 #ifdef FD_CLOEXEC
4510 {
4511 int flags = ::fcntl(fd, F_GETFD);
4512 if (flags != -1)
4513 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
4514 }
4515 #endif
4517 if (o_delete != 0) {
4518 ::unlink(path);
4519 }
4520 return fd;
4521 }
4524 // create binary file, rewriting existing file if required
4525 int os::create_binary_file(const char* path, bool rewrite_existing) {
4526 int oflags = O_WRONLY | O_CREAT;
4527 if (!rewrite_existing) {
4528 oflags |= O_EXCL;
4529 }
4530 return ::open64(path, oflags, S_IREAD | S_IWRITE);
4531 }
4533 // return current position of file pointer
4534 jlong os::current_file_offset(int fd) {
4535 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
4536 }
4538 // move file pointer to the specified offset
4539 jlong os::seek_to_file_offset(int fd, jlong offset) {
4540 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
4541 }
4543 // This code originates from JDK's sysAvailable
4544 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
4546 int os::available(int fd, jlong *bytes) {
4547 jlong cur, end;
4548 int mode;
4549 struct stat64 buf64;
4551 if (::fstat64(fd, &buf64) >= 0) {
4552 mode = buf64.st_mode;
4553 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
4554 /*
4555 * XXX: is the following call interruptible? If so, this might
4556 * need to go through the INTERRUPT_IO() wrapper as for other
4557 * blocking, interruptible calls in this file.
4558 */
4559 int n;
4560 if (::ioctl(fd, FIONREAD, &n) >= 0) {
4561 *bytes = n;
4562 return 1;
4563 }
4564 }
4565 }
4566 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
4567 return 0;
4568 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
4569 return 0;
4570 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
4571 return 0;
4572 }
4573 *bytes = end - cur;
4574 return 1;
4575 }
4577 int os::socket_available(int fd, jint *pbytes) {
4578 // Linux doc says EINTR not returned, unlike Solaris
4579 int ret = ::ioctl(fd, FIONREAD, pbytes);
4581 //%% note ioctl can return 0 when successful, JVM_SocketAvailable
4582 // is expected to return 0 on failure and 1 on success to the jdk.
4583 return (ret < 0) ? 0 : 1;
4584 }
4586 // Map a block of memory.
4587 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
4588 char *addr, size_t bytes, bool read_only,
4589 bool allow_exec) {
4590 int prot;
4591 int flags;
4593 if (read_only) {
4594 prot = PROT_READ;
4595 flags = MAP_SHARED;
4596 } else {
4597 prot = PROT_READ | PROT_WRITE;
4598 flags = MAP_PRIVATE;
4599 }
4601 if (allow_exec) {
4602 prot |= PROT_EXEC;
4603 }
4605 if (addr != NULL) {
4606 flags |= MAP_FIXED;
4607 }
4609 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
4610 fd, file_offset);
4611 if (mapped_address == MAP_FAILED) {
4612 return NULL;
4613 }
4614 return mapped_address;
4615 }
4618 // Remap a block of memory.
4619 char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
4620 char *addr, size_t bytes, bool read_only,
4621 bool allow_exec) {
4622 // same as map_memory() on this OS
4623 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
4624 allow_exec);
4625 }
4628 // Unmap a block of memory.
4629 bool os::unmap_memory(char* addr, size_t bytes) {
4630 return munmap(addr, bytes) == 0;
4631 }
4633 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
4635 static clockid_t thread_cpu_clockid(Thread* thread) {
4636 pthread_t tid = thread->osthread()->pthread_id();
4637 clockid_t clockid;
4639 // Get thread clockid
4640 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
4641 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
4642 return clockid;
4643 }
4645 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
4646 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
4647 // of a thread.
4648 //
4649 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
4650 // the fast estimate available on the platform.
4652 jlong os::current_thread_cpu_time() {
4653 if (os::Linux::supports_fast_thread_cpu_time()) {
4654 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4655 } else {
4656 // return user + sys since the cost is the same
4657 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
4658 }
4659 }
4661 jlong os::thread_cpu_time(Thread* thread) {
4662 // consistent with what current_thread_cpu_time() returns
4663 if (os::Linux::supports_fast_thread_cpu_time()) {
4664 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4665 } else {
4666 return slow_thread_cpu_time(thread, true /* user + sys */);
4667 }
4668 }
4670 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
4671 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4672 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4673 } else {
4674 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
4675 }
4676 }
4678 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4679 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4680 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4681 } else {
4682 return slow_thread_cpu_time(thread, user_sys_cpu_time);
4683 }
4684 }
4686 //
4687 // -1 on error.
4688 //
4690 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4691 static bool proc_pid_cpu_avail = true;
4692 static bool proc_task_unchecked = true;
4693 static const char *proc_stat_path = "/proc/%d/stat";
4694 pid_t tid = thread->osthread()->thread_id();
4695 int i;
4696 char *s;
4697 char stat[2048];
4698 int statlen;
4699 char proc_name[64];
4700 int count;
4701 long sys_time, user_time;
4702 char string[64];
4703 char cdummy;
4704 int idummy;
4705 long ldummy;
4706 FILE *fp;
4708 // We first try accessing /proc/<pid>/cpu since this is faster to
4709 // process. If this file is not present (linux kernels 2.5 and above)
4710 // then we open /proc/<pid>/stat.
4711 if ( proc_pid_cpu_avail ) {
4712 sprintf(proc_name, "/proc/%d/cpu", tid);
4713 fp = fopen(proc_name, "r");
4714 if ( fp != NULL ) {
4715 count = fscanf( fp, "%s %lu %lu\n", string, &user_time, &sys_time);
4716 fclose(fp);
4717 if ( count != 3 ) return -1;
4719 if (user_sys_cpu_time) {
4720 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4721 } else {
4722 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4723 }
4724 }
4725 else proc_pid_cpu_avail = false;
4726 }
4728 // The /proc/<tid>/stat aggregates per-process usage on
4729 // new Linux kernels 2.6+ where NPTL is supported.
4730 // The /proc/self/task/<tid>/stat still has the per-thread usage.
4731 // See bug 6328462.
4732 // There can be no directory /proc/self/task on kernels 2.4 with NPTL
4733 // and possibly in some other cases, so we check its availability.
4734 if (proc_task_unchecked && os::Linux::is_NPTL()) {
4735 // This is executed only once
4736 proc_task_unchecked = false;
4737 fp = fopen("/proc/self/task", "r");
4738 if (fp != NULL) {
4739 proc_stat_path = "/proc/self/task/%d/stat";
4740 fclose(fp);
4741 }
4742 }
4744 sprintf(proc_name, proc_stat_path, tid);
4745 fp = fopen(proc_name, "r");
4746 if ( fp == NULL ) return -1;
4747 statlen = fread(stat, 1, 2047, fp);
4748 stat[statlen] = '\0';
4749 fclose(fp);
4751 // Skip pid and the command string. Note that we could be dealing with
4752 // weird command names, e.g. user could decide to rename java launcher
4753 // to "java 1.4.2 :)", then the stat file would look like
4754 // 1234 (java 1.4.2 :)) R ... ...
4755 // We don't really need to know the command string, just find the last
4756 // occurrence of ")" and then start parsing from there. See bug 4726580.
4757 s = strrchr(stat, ')');
4758 i = 0;
4759 if (s == NULL ) return -1;
4761 // Skip blank chars
4762 do s++; while (isspace(*s));
4764 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
4765 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
4766 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
4767 &user_time, &sys_time);
4768 if ( count != 13 ) return -1;
4769 if (user_sys_cpu_time) {
4770 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4771 } else {
4772 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4773 }
4774 }
4776 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4777 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4778 info_ptr->may_skip_backward = false; // elapsed time not wall time
4779 info_ptr->may_skip_forward = false; // elapsed time not wall time
4780 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4781 }
4783 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4784 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4785 info_ptr->may_skip_backward = false; // elapsed time not wall time
4786 info_ptr->may_skip_forward = false; // elapsed time not wall time
4787 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4788 }
4790 bool os::is_thread_cpu_time_supported() {
4791 return true;
4792 }
4794 // System loadavg support. Returns -1 if load average cannot be obtained.
4795 // Linux doesn't yet have a (official) notion of processor sets,
4796 // so just return the system wide load average.
4797 int os::loadavg(double loadavg[], int nelem) {
4798 return ::getloadavg(loadavg, nelem);
4799 }
4801 void os::pause() {
4802 char filename[MAX_PATH];
4803 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
4804 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
4805 } else {
4806 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
4807 }
4809 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
4810 if (fd != -1) {
4811 struct stat buf;
4812 ::close(fd);
4813 while (::stat(filename, &buf) == 0) {
4814 (void)::poll(NULL, 0, 100);
4815 }
4816 } else {
4817 jio_fprintf(stderr,
4818 "Could not open pause file '%s', continuing immediately.\n", filename);
4819 }
4820 }
4823 // Refer to the comments in os_solaris.cpp park-unpark.
4824 //
4825 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
4826 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
4827 // For specifics regarding the bug see GLIBC BUGID 261237 :
4828 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
4829 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
4830 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
4831 // is used. (The simple C test-case provided in the GLIBC bug report manifests the
4832 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
4833 // and monitorenter when we're using 1-0 locking. All those operations may result in
4834 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version
4835 // of libpthread avoids the problem, but isn't practical.
4836 //
4837 // Possible remedies:
4838 //
4839 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work.
4840 // This is palliative and probabilistic, however. If the thread is preempted
4841 // between the call to compute_abstime() and pthread_cond_timedwait(), more
4842 // than the minimum period may have passed, and the abstime may be stale (in the
4843 // past) resultin in a hang. Using this technique reduces the odds of a hang
4844 // but the JVM is still vulnerable, particularly on heavily loaded systems.
4845 //
4846 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
4847 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set
4848 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
4849 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant
4850 // thread.
4851 //
4852 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread
4853 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing
4854 // a timeout request to the chron thread and then blocking via pthread_cond_wait().
4855 // This also works well. In fact it avoids kernel-level scalability impediments
4856 // on certain platforms that don't handle lots of active pthread_cond_timedwait()
4857 // timers in a graceful fashion.
4858 //
4859 // 4. When the abstime value is in the past it appears that control returns
4860 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
4861 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we
4862 // can avoid the problem by reinitializing the condvar -- by cond_destroy()
4863 // followed by cond_init() -- after all calls to pthread_cond_timedwait().
4864 // It may be possible to avoid reinitialization by checking the return
4865 // value from pthread_cond_timedwait(). In addition to reinitializing the
4866 // condvar we must establish the invariant that cond_signal() is only called
4867 // within critical sections protected by the adjunct mutex. This prevents
4868 // cond_signal() from "seeing" a condvar that's in the midst of being
4869 // reinitialized or that is corrupt. Sadly, this invariant obviates the
4870 // desirable signal-after-unlock optimization that avoids futile context switching.
4871 //
4872 // I'm also concerned that some versions of NTPL might allocate an auxilliary
4873 // structure when a condvar is used or initialized. cond_destroy() would
4874 // release the helper structure. Our reinitialize-after-timedwait fix
4875 // put excessive stress on malloc/free and locks protecting the c-heap.
4876 //
4877 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag.
4878 // It may be possible to refine (4) by checking the kernel and NTPL verisons
4879 // and only enabling the work-around for vulnerable environments.
4881 // utility to compute the abstime argument to timedwait:
4882 // millis is the relative timeout time
4883 // abstime will be the absolute timeout time
4884 // TODO: replace compute_abstime() with unpackTime()
4886 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
4887 if (millis < 0) millis = 0;
4888 struct timeval now;
4889 int status = gettimeofday(&now, NULL);
4890 assert(status == 0, "gettimeofday");
4891 jlong seconds = millis / 1000;
4892 millis %= 1000;
4893 if (seconds > 50000000) { // see man cond_timedwait(3T)
4894 seconds = 50000000;
4895 }
4896 abstime->tv_sec = now.tv_sec + seconds;
4897 long usec = now.tv_usec + millis * 1000;
4898 if (usec >= 1000000) {
4899 abstime->tv_sec += 1;
4900 usec -= 1000000;
4901 }
4902 abstime->tv_nsec = usec * 1000;
4903 return abstime;
4904 }
4907 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately.
4908 // Conceptually TryPark() should be equivalent to park(0).
4910 int os::PlatformEvent::TryPark() {
4911 for (;;) {
4912 const int v = _Event ;
4913 guarantee ((v == 0) || (v == 1), "invariant") ;
4914 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ;
4915 }
4916 }
4918 void os::PlatformEvent::park() { // AKA "down()"
4919 // Invariant: Only the thread associated with the Event/PlatformEvent
4920 // may call park().
4921 // TODO: assert that _Assoc != NULL or _Assoc == Self
4922 int v ;
4923 for (;;) {
4924 v = _Event ;
4925 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
4926 }
4927 guarantee (v >= 0, "invariant") ;
4928 if (v == 0) {
4929 // Do this the hard way by blocking ...
4930 int status = pthread_mutex_lock(_mutex);
4931 assert_status(status == 0, status, "mutex_lock");
4932 guarantee (_nParked == 0, "invariant") ;
4933 ++ _nParked ;
4934 while (_Event < 0) {
4935 status = pthread_cond_wait(_cond, _mutex);
4936 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
4937 // Treat this the same as if the wait was interrupted
4938 if (status == ETIME) { status = EINTR; }
4939 assert_status(status == 0 || status == EINTR, status, "cond_wait");
4940 }
4941 -- _nParked ;
4943 // In theory we could move the ST of 0 into _Event past the unlock(),
4944 // but then we'd need a MEMBAR after the ST.
4945 _Event = 0 ;
4946 status = pthread_mutex_unlock(_mutex);
4947 assert_status(status == 0, status, "mutex_unlock");
4948 }
4949 guarantee (_Event >= 0, "invariant") ;
4950 }
4952 int os::PlatformEvent::park(jlong millis) {
4953 guarantee (_nParked == 0, "invariant") ;
4955 int v ;
4956 for (;;) {
4957 v = _Event ;
4958 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
4959 }
4960 guarantee (v >= 0, "invariant") ;
4961 if (v != 0) return OS_OK ;
4963 // We do this the hard way, by blocking the thread.
4964 // Consider enforcing a minimum timeout value.
4965 struct timespec abst;
4966 compute_abstime(&abst, millis);
4968 int ret = OS_TIMEOUT;
4969 int status = pthread_mutex_lock(_mutex);
4970 assert_status(status == 0, status, "mutex_lock");
4971 guarantee (_nParked == 0, "invariant") ;
4972 ++_nParked ;
4974 // Object.wait(timo) will return because of
4975 // (a) notification
4976 // (b) timeout
4977 // (c) thread.interrupt
4978 //
4979 // Thread.interrupt and object.notify{All} both call Event::set.
4980 // That is, we treat thread.interrupt as a special case of notification.
4981 // The underlying Solaris implementation, cond_timedwait, admits
4982 // spurious/premature wakeups, but the JLS/JVM spec prevents the
4983 // JVM from making those visible to Java code. As such, we must
4984 // filter out spurious wakeups. We assume all ETIME returns are valid.
4985 //
4986 // TODO: properly differentiate simultaneous notify+interrupt.
4987 // In that case, we should propagate the notify to another waiter.
4989 while (_Event < 0) {
4990 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst);
4991 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
4992 pthread_cond_destroy (_cond);
4993 pthread_cond_init (_cond, NULL) ;
4994 }
4995 assert_status(status == 0 || status == EINTR ||
4996 status == ETIME || status == ETIMEDOUT,
4997 status, "cond_timedwait");
4998 if (!FilterSpuriousWakeups) break ; // previous semantics
4999 if (status == ETIME || status == ETIMEDOUT) break ;
5000 // We consume and ignore EINTR and spurious wakeups.
5001 }
5002 --_nParked ;
5003 if (_Event >= 0) {
5004 ret = OS_OK;
5005 }
5006 _Event = 0 ;
5007 status = pthread_mutex_unlock(_mutex);
5008 assert_status(status == 0, status, "mutex_unlock");
5009 assert (_nParked == 0, "invariant") ;
5010 return ret;
5011 }
5013 void os::PlatformEvent::unpark() {
5014 int v, AnyWaiters ;
5015 for (;;) {
5016 v = _Event ;
5017 if (v > 0) {
5018 // The LD of _Event could have reordered or be satisfied
5019 // by a read-aside from this processor's write buffer.
5020 // To avoid problems execute a barrier and then
5021 // ratify the value.
5022 OrderAccess::fence() ;
5023 if (_Event == v) return ;
5024 continue ;
5025 }
5026 if (Atomic::cmpxchg (v+1, &_Event, v) == v) break ;
5027 }
5028 if (v < 0) {
5029 // Wait for the thread associated with the event to vacate
5030 int status = pthread_mutex_lock(_mutex);
5031 assert_status(status == 0, status, "mutex_lock");
5032 AnyWaiters = _nParked ;
5033 assert (AnyWaiters == 0 || AnyWaiters == 1, "invariant") ;
5034 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
5035 AnyWaiters = 0 ;
5036 pthread_cond_signal (_cond);
5037 }
5038 status = pthread_mutex_unlock(_mutex);
5039 assert_status(status == 0, status, "mutex_unlock");
5040 if (AnyWaiters != 0) {
5041 status = pthread_cond_signal(_cond);
5042 assert_status(status == 0, status, "cond_signal");
5043 }
5044 }
5046 // Note that we signal() _after dropping the lock for "immortal" Events.
5047 // This is safe and avoids a common class of futile wakeups. In rare
5048 // circumstances this can cause a thread to return prematurely from
5049 // cond_{timed}wait() but the spurious wakeup is benign and the victim will
5050 // simply re-test the condition and re-park itself.
5051 }
5054 // JSR166
5055 // -------------------------------------------------------
5057 /*
5058 * The solaris and linux implementations of park/unpark are fairly
5059 * conservative for now, but can be improved. They currently use a
5060 * mutex/condvar pair, plus a a count.
5061 * Park decrements count if > 0, else does a condvar wait. Unpark
5062 * sets count to 1 and signals condvar. Only one thread ever waits
5063 * on the condvar. Contention seen when trying to park implies that someone
5064 * is unparking you, so don't wait. And spurious returns are fine, so there
5065 * is no need to track notifications.
5066 */
5069 #define NANOSECS_PER_SEC 1000000000
5070 #define NANOSECS_PER_MILLISEC 1000000
5071 #define MAX_SECS 100000000
5072 /*
5073 * This code is common to linux and solaris and will be moved to a
5074 * common place in dolphin.
5075 *
5076 * The passed in time value is either a relative time in nanoseconds
5077 * or an absolute time in milliseconds. Either way it has to be unpacked
5078 * into suitable seconds and nanoseconds components and stored in the
5079 * given timespec structure.
5080 * Given time is a 64-bit value and the time_t used in the timespec is only
5081 * a signed-32-bit value (except on 64-bit Linux) we have to watch for
5082 * overflow if times way in the future are given. Further on Solaris versions
5083 * prior to 10 there is a restriction (see cond_timedwait) that the specified
5084 * number of seconds, in abstime, is less than current_time + 100,000,000.
5085 * As it will be 28 years before "now + 100000000" will overflow we can
5086 * ignore overflow and just impose a hard-limit on seconds using the value
5087 * of "now + 100,000,000". This places a limit on the timeout of about 3.17
5088 * years from "now".
5089 */
5091 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
5092 assert (time > 0, "convertTime");
5094 struct timeval now;
5095 int status = gettimeofday(&now, NULL);
5096 assert(status == 0, "gettimeofday");
5098 time_t max_secs = now.tv_sec + MAX_SECS;
5100 if (isAbsolute) {
5101 jlong secs = time / 1000;
5102 if (secs > max_secs) {
5103 absTime->tv_sec = max_secs;
5104 }
5105 else {
5106 absTime->tv_sec = secs;
5107 }
5108 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
5109 }
5110 else {
5111 jlong secs = time / NANOSECS_PER_SEC;
5112 if (secs >= MAX_SECS) {
5113 absTime->tv_sec = max_secs;
5114 absTime->tv_nsec = 0;
5115 }
5116 else {
5117 absTime->tv_sec = now.tv_sec + secs;
5118 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
5119 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5120 absTime->tv_nsec -= NANOSECS_PER_SEC;
5121 ++absTime->tv_sec; // note: this must be <= max_secs
5122 }
5123 }
5124 }
5125 assert(absTime->tv_sec >= 0, "tv_sec < 0");
5126 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
5127 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
5128 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
5129 }
5131 void Parker::park(bool isAbsolute, jlong time) {
5132 // Optional fast-path check:
5133 // Return immediately if a permit is available.
5134 if (_counter > 0) {
5135 _counter = 0 ;
5136 OrderAccess::fence();
5137 return ;
5138 }
5140 Thread* thread = Thread::current();
5141 assert(thread->is_Java_thread(), "Must be JavaThread");
5142 JavaThread *jt = (JavaThread *)thread;
5144 // Optional optimization -- avoid state transitions if there's an interrupt pending.
5145 // Check interrupt before trying to wait
5146 if (Thread::is_interrupted(thread, false)) {
5147 return;
5148 }
5150 // Next, demultiplex/decode time arguments
5151 timespec absTime;
5152 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all
5153 return;
5154 }
5155 if (time > 0) {
5156 unpackTime(&absTime, isAbsolute, time);
5157 }
5160 // Enter safepoint region
5161 // Beware of deadlocks such as 6317397.
5162 // The per-thread Parker:: mutex is a classic leaf-lock.
5163 // In particular a thread must never block on the Threads_lock while
5164 // holding the Parker:: mutex. If safepoints are pending both the
5165 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
5166 ThreadBlockInVM tbivm(jt);
5168 // Don't wait if cannot get lock since interference arises from
5169 // unblocking. Also. check interrupt before trying wait
5170 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
5171 return;
5172 }
5174 int status ;
5175 if (_counter > 0) { // no wait needed
5176 _counter = 0;
5177 status = pthread_mutex_unlock(_mutex);
5178 assert (status == 0, "invariant") ;
5179 OrderAccess::fence();
5180 return;
5181 }
5183 #ifdef ASSERT
5184 // Don't catch signals while blocked; let the running threads have the signals.
5185 // (This allows a debugger to break into the running thread.)
5186 sigset_t oldsigs;
5187 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
5188 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
5189 #endif
5191 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
5192 jt->set_suspend_equivalent();
5193 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
5195 if (time == 0) {
5196 status = pthread_cond_wait (_cond, _mutex) ;
5197 } else {
5198 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ;
5199 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5200 pthread_cond_destroy (_cond) ;
5201 pthread_cond_init (_cond, NULL);
5202 }
5203 }
5204 assert_status(status == 0 || status == EINTR ||
5205 status == ETIME || status == ETIMEDOUT,
5206 status, "cond_timedwait");
5208 #ifdef ASSERT
5209 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
5210 #endif
5212 _counter = 0 ;
5213 status = pthread_mutex_unlock(_mutex) ;
5214 assert_status(status == 0, status, "invariant") ;
5215 // If externally suspended while waiting, re-suspend
5216 if (jt->handle_special_suspend_equivalent_condition()) {
5217 jt->java_suspend_self();
5218 }
5220 OrderAccess::fence();
5221 }
5223 void Parker::unpark() {
5224 int s, status ;
5225 status = pthread_mutex_lock(_mutex);
5226 assert (status == 0, "invariant") ;
5227 s = _counter;
5228 _counter = 1;
5229 if (s < 1) {
5230 if (WorkAroundNPTLTimedWaitHang) {
5231 status = pthread_cond_signal (_cond) ;
5232 assert (status == 0, "invariant") ;
5233 status = pthread_mutex_unlock(_mutex);
5234 assert (status == 0, "invariant") ;
5235 } else {
5236 status = pthread_mutex_unlock(_mutex);
5237 assert (status == 0, "invariant") ;
5238 status = pthread_cond_signal (_cond) ;
5239 assert (status == 0, "invariant") ;
5240 }
5241 } else {
5242 pthread_mutex_unlock(_mutex);
5243 assert (status == 0, "invariant") ;
5244 }
5245 }
5248 extern char** environ;
5250 #ifndef __NR_fork
5251 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57)
5252 #endif
5254 #ifndef __NR_execve
5255 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59)
5256 #endif
5258 // Run the specified command in a separate process. Return its exit value,
5259 // or -1 on failure (e.g. can't fork a new process).
5260 // Unlike system(), this function can be called from signal handler. It
5261 // doesn't block SIGINT et al.
5262 int os::fork_and_exec(char* cmd) {
5263 const char * argv[4] = {"sh", "-c", cmd, NULL};
5265 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run
5266 // pthread_atfork handlers and reset pthread library. All we need is a
5267 // separate process to execve. Make a direct syscall to fork process.
5268 // On IA64 there's no fork syscall, we have to use fork() and hope for
5269 // the best...
5270 pid_t pid = NOT_IA64(syscall(__NR_fork);)
5271 IA64_ONLY(fork();)
5273 if (pid < 0) {
5274 // fork failed
5275 return -1;
5277 } else if (pid == 0) {
5278 // child process
5280 // execve() in LinuxThreads will call pthread_kill_other_threads_np()
5281 // first to kill every thread on the thread list. Because this list is
5282 // not reset by fork() (see notes above), execve() will instead kill
5283 // every thread in the parent process. We know this is the only thread
5284 // in the new process, so make a system call directly.
5285 // IA64 should use normal execve() from glibc to match the glibc fork()
5286 // above.
5287 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);)
5288 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);)
5290 // execve failed
5291 _exit(-1);
5293 } else {
5294 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5295 // care about the actual exit code, for now.
5297 int status;
5299 // Wait for the child process to exit. This returns immediately if
5300 // the child has already exited. */
5301 while (waitpid(pid, &status, 0) < 0) {
5302 switch (errno) {
5303 case ECHILD: return 0;
5304 case EINTR: break;
5305 default: return -1;
5306 }
5307 }
5309 if (WIFEXITED(status)) {
5310 // The child exited normally; get its exit code.
5311 return WEXITSTATUS(status);
5312 } else if (WIFSIGNALED(status)) {
5313 // The child exited because of a signal
5314 // The best value to return is 0x80 + signal number,
5315 // because that is what all Unix shells do, and because
5316 // it allows callers to distinguish between process exit and
5317 // process death by signal.
5318 return 0x80 + WTERMSIG(status);
5319 } else {
5320 // Unknown exit code; pass it through
5321 return status;
5322 }
5323 }
5324 }
5326 // is_headless_jre()
5327 //
5328 // Test for the existence of libmawt in motif21 or xawt directories
5329 // in order to report if we are running in a headless jre
5330 //
5331 bool os::is_headless_jre() {
5332 struct stat statbuf;
5333 char buf[MAXPATHLEN];
5334 char libmawtpath[MAXPATHLEN];
5335 const char *xawtstr = "/xawt/libmawt.so";
5336 const char *motifstr = "/motif21/libmawt.so";
5337 char *p;
5339 // Get path to libjvm.so
5340 os::jvm_path(buf, sizeof(buf));
5342 // Get rid of libjvm.so
5343 p = strrchr(buf, '/');
5344 if (p == NULL) return false;
5345 else *p = '\0';
5347 // Get rid of client or server
5348 p = strrchr(buf, '/');
5349 if (p == NULL) return false;
5350 else *p = '\0';
5352 // check xawt/libmawt.so
5353 strcpy(libmawtpath, buf);
5354 strcat(libmawtpath, xawtstr);
5355 if (::stat(libmawtpath, &statbuf) == 0) return false;
5357 // check motif21/libmawt.so
5358 strcpy(libmawtpath, buf);
5359 strcat(libmawtpath, motifstr);
5360 if (::stat(libmawtpath, &statbuf) == 0) return false;
5362 return true;
5363 }