Thu, 26 Jan 2012 20:06:06 -0500
7082553: Interpret Thread.setPriority(Thread.MAX_PRIORITY) to mean FX60 on Solaris 10 and 11
Summary: Add CriticalPriority == MaxPriority+1 and enable scheduling class as well as thread priority to change on Solaris.
Reviewed-by: dholmes, dcubed
1 /*
2 * Copyright (c) 1999, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
25 // no precompiled headers
26 #include "classfile/classLoader.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "classfile/vmSymbols.hpp"
29 #include "code/icBuffer.hpp"
30 #include "code/vtableStubs.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "jvm_linux.h"
34 #include "memory/allocation.inline.hpp"
35 #include "memory/filemap.hpp"
36 #include "mutex_linux.inline.hpp"
37 #include "oops/oop.inline.hpp"
38 #include "os_share_linux.hpp"
39 #include "prims/jniFastGetField.hpp"
40 #include "prims/jvm.h"
41 #include "prims/jvm_misc.hpp"
42 #include "runtime/arguments.hpp"
43 #include "runtime/extendedPC.hpp"
44 #include "runtime/globals.hpp"
45 #include "runtime/interfaceSupport.hpp"
46 #include "runtime/java.hpp"
47 #include "runtime/javaCalls.hpp"
48 #include "runtime/mutexLocker.hpp"
49 #include "runtime/objectMonitor.hpp"
50 #include "runtime/osThread.hpp"
51 #include "runtime/perfMemory.hpp"
52 #include "runtime/sharedRuntime.hpp"
53 #include "runtime/statSampler.hpp"
54 #include "runtime/stubRoutines.hpp"
55 #include "runtime/threadCritical.hpp"
56 #include "runtime/timer.hpp"
57 #include "services/attachListener.hpp"
58 #include "services/runtimeService.hpp"
59 #include "thread_linux.inline.hpp"
60 #include "utilities/decoder.hpp"
61 #include "utilities/defaultStream.hpp"
62 #include "utilities/events.hpp"
63 #include "utilities/growableArray.hpp"
64 #include "utilities/vmError.hpp"
65 #ifdef TARGET_ARCH_x86
66 # include "assembler_x86.inline.hpp"
67 # include "nativeInst_x86.hpp"
68 #endif
69 #ifdef TARGET_ARCH_sparc
70 # include "assembler_sparc.inline.hpp"
71 # include "nativeInst_sparc.hpp"
72 #endif
73 #ifdef TARGET_ARCH_zero
74 # include "assembler_zero.inline.hpp"
75 # include "nativeInst_zero.hpp"
76 #endif
77 #ifdef TARGET_ARCH_arm
78 # include "assembler_arm.inline.hpp"
79 # include "nativeInst_arm.hpp"
80 #endif
81 #ifdef TARGET_ARCH_ppc
82 # include "assembler_ppc.inline.hpp"
83 # include "nativeInst_ppc.hpp"
84 #endif
85 #ifdef COMPILER1
86 #include "c1/c1_Runtime1.hpp"
87 #endif
88 #ifdef COMPILER2
89 #include "opto/runtime.hpp"
90 #endif
92 // put OS-includes here
93 # include <sys/types.h>
94 # include <sys/mman.h>
95 # include <sys/stat.h>
96 # include <sys/select.h>
97 # include <pthread.h>
98 # include <signal.h>
99 # include <errno.h>
100 # include <dlfcn.h>
101 # include <stdio.h>
102 # include <unistd.h>
103 # include <sys/resource.h>
104 # include <pthread.h>
105 # include <sys/stat.h>
106 # include <sys/time.h>
107 # include <sys/times.h>
108 # include <sys/utsname.h>
109 # include <sys/socket.h>
110 # include <sys/wait.h>
111 # include <pwd.h>
112 # include <poll.h>
113 # include <semaphore.h>
114 # include <fcntl.h>
115 # include <string.h>
116 # include <syscall.h>
117 # include <sys/sysinfo.h>
118 # include <gnu/libc-version.h>
119 # include <sys/ipc.h>
120 # include <sys/shm.h>
121 # include <link.h>
122 # include <stdint.h>
123 # include <inttypes.h>
124 # include <sys/ioctl.h>
126 #define MAX_PATH (2 * K)
128 // for timer info max values which include all bits
129 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
131 #define LARGEPAGES_BIT (1 << 6)
132 ////////////////////////////////////////////////////////////////////////////////
133 // global variables
134 julong os::Linux::_physical_memory = 0;
136 address os::Linux::_initial_thread_stack_bottom = NULL;
137 uintptr_t os::Linux::_initial_thread_stack_size = 0;
139 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
140 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
141 Mutex* os::Linux::_createThread_lock = NULL;
142 pthread_t os::Linux::_main_thread;
143 int os::Linux::_page_size = -1;
144 bool os::Linux::_is_floating_stack = false;
145 bool os::Linux::_is_NPTL = false;
146 bool os::Linux::_supports_fast_thread_cpu_time = false;
147 const char * os::Linux::_glibc_version = NULL;
148 const char * os::Linux::_libpthread_version = NULL;
150 static jlong initial_time_count=0;
152 static int clock_tics_per_sec = 100;
154 // For diagnostics to print a message once. see run_periodic_checks
155 static sigset_t check_signal_done;
156 static bool check_signals = true;;
158 static pid_t _initial_pid = 0;
160 /* Signal number used to suspend/resume a thread */
162 /* do not use any signal number less than SIGSEGV, see 4355769 */
163 static int SR_signum = SIGUSR2;
164 sigset_t SR_sigset;
166 /* Used to protect dlsym() calls */
167 static pthread_mutex_t dl_mutex;
169 #ifdef JAVASE_EMBEDDED
170 class MemNotifyThread: public Thread {
171 friend class VMStructs;
172 public:
173 virtual void run();
175 private:
176 static MemNotifyThread* _memnotify_thread;
177 int _fd;
179 public:
181 // Constructor
182 MemNotifyThread(int fd);
184 // Tester
185 bool is_memnotify_thread() const { return true; }
187 // Printing
188 char* name() const { return (char*)"Linux MemNotify Thread"; }
190 // Returns the single instance of the MemNotifyThread
191 static MemNotifyThread* memnotify_thread() { return _memnotify_thread; }
193 // Create and start the single instance of MemNotifyThread
194 static void start();
195 };
196 #endif // JAVASE_EMBEDDED
198 // utility functions
200 static int SR_initialize();
201 static int SR_finalize();
203 julong os::available_memory() {
204 return Linux::available_memory();
205 }
207 julong os::Linux::available_memory() {
208 // values in struct sysinfo are "unsigned long"
209 struct sysinfo si;
210 sysinfo(&si);
212 return (julong)si.freeram * si.mem_unit;
213 }
215 julong os::physical_memory() {
216 return Linux::physical_memory();
217 }
219 julong os::allocatable_physical_memory(julong size) {
220 #ifdef _LP64
221 return size;
222 #else
223 julong result = MIN2(size, (julong)3800*M);
224 if (!is_allocatable(result)) {
225 // See comments under solaris for alignment considerations
226 julong reasonable_size = (julong)2*G - 2 * os::vm_page_size();
227 result = MIN2(size, reasonable_size);
228 }
229 return result;
230 #endif // _LP64
231 }
233 ////////////////////////////////////////////////////////////////////////////////
234 // environment support
236 bool os::getenv(const char* name, char* buf, int len) {
237 const char* val = ::getenv(name);
238 if (val != NULL && strlen(val) < (size_t)len) {
239 strcpy(buf, val);
240 return true;
241 }
242 if (len > 0) buf[0] = 0; // return a null string
243 return false;
244 }
247 // Return true if user is running as root.
249 bool os::have_special_privileges() {
250 static bool init = false;
251 static bool privileges = false;
252 if (!init) {
253 privileges = (getuid() != geteuid()) || (getgid() != getegid());
254 init = true;
255 }
256 return privileges;
257 }
260 #ifndef SYS_gettid
261 // i386: 224, ia64: 1105, amd64: 186, sparc 143
262 #ifdef __ia64__
263 #define SYS_gettid 1105
264 #elif __i386__
265 #define SYS_gettid 224
266 #elif __amd64__
267 #define SYS_gettid 186
268 #elif __sparc__
269 #define SYS_gettid 143
270 #else
271 #error define gettid for the arch
272 #endif
273 #endif
275 // Cpu architecture string
276 #if defined(ZERO)
277 static char cpu_arch[] = ZERO_LIBARCH;
278 #elif defined(IA64)
279 static char cpu_arch[] = "ia64";
280 #elif defined(IA32)
281 static char cpu_arch[] = "i386";
282 #elif defined(AMD64)
283 static char cpu_arch[] = "amd64";
284 #elif defined(ARM)
285 static char cpu_arch[] = "arm";
286 #elif defined(PPC)
287 static char cpu_arch[] = "ppc";
288 #elif defined(SPARC)
289 # ifdef _LP64
290 static char cpu_arch[] = "sparcv9";
291 # else
292 static char cpu_arch[] = "sparc";
293 # endif
294 #else
295 #error Add appropriate cpu_arch setting
296 #endif
299 // pid_t gettid()
300 //
301 // Returns the kernel thread id of the currently running thread. Kernel
302 // thread id is used to access /proc.
303 //
304 // (Note that getpid() on LinuxThreads returns kernel thread id too; but
305 // on NPTL, it returns the same pid for all threads, as required by POSIX.)
306 //
307 pid_t os::Linux::gettid() {
308 int rslt = syscall(SYS_gettid);
309 if (rslt == -1) {
310 // old kernel, no NPTL support
311 return getpid();
312 } else {
313 return (pid_t)rslt;
314 }
315 }
317 // Most versions of linux have a bug where the number of processors are
318 // determined by looking at the /proc file system. In a chroot environment,
319 // the system call returns 1. This causes the VM to act as if it is
320 // a single processor and elide locking (see is_MP() call).
321 static bool unsafe_chroot_detected = false;
322 static const char *unstable_chroot_error = "/proc file system not found.\n"
323 "Java may be unstable running multithreaded in a chroot "
324 "environment on Linux when /proc filesystem is not mounted.";
326 void os::Linux::initialize_system_info() {
327 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
328 if (processor_count() == 1) {
329 pid_t pid = os::Linux::gettid();
330 char fname[32];
331 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
332 FILE *fp = fopen(fname, "r");
333 if (fp == NULL) {
334 unsafe_chroot_detected = true;
335 } else {
336 fclose(fp);
337 }
338 }
339 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
340 assert(processor_count() > 0, "linux error");
341 }
343 void os::init_system_properties_values() {
344 // char arch[12];
345 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch));
347 // The next steps are taken in the product version:
348 //
349 // Obtain the JAVA_HOME value from the location of libjvm[_g].so.
350 // This library should be located at:
351 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm[_g].so.
352 //
353 // If "/jre/lib/" appears at the right place in the path, then we
354 // assume libjvm[_g].so is installed in a JDK and we use this path.
355 //
356 // Otherwise exit with message: "Could not create the Java virtual machine."
357 //
358 // The following extra steps are taken in the debugging version:
359 //
360 // If "/jre/lib/" does NOT appear at the right place in the path
361 // instead of exit check for $JAVA_HOME environment variable.
362 //
363 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
364 // then we append a fake suffix "hotspot/libjvm[_g].so" to this path so
365 // it looks like libjvm[_g].so is installed there
366 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm[_g].so.
367 //
368 // Otherwise exit.
369 //
370 // Important note: if the location of libjvm.so changes this
371 // code needs to be changed accordingly.
373 // The next few definitions allow the code to be verbatim:
374 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n))
375 #define getenv(n) ::getenv(n)
377 /*
378 * See ld(1):
379 * The linker uses the following search paths to locate required
380 * shared libraries:
381 * 1: ...
382 * ...
383 * 7: The default directories, normally /lib and /usr/lib.
384 */
385 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390))
386 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
387 #else
388 #define DEFAULT_LIBPATH "/lib:/usr/lib"
389 #endif
391 #define EXTENSIONS_DIR "/lib/ext"
392 #define ENDORSED_DIR "/lib/endorsed"
393 #define REG_DIR "/usr/java/packages"
395 {
396 /* sysclasspath, java_home, dll_dir */
397 {
398 char *home_path;
399 char *dll_path;
400 char *pslash;
401 char buf[MAXPATHLEN];
402 os::jvm_path(buf, sizeof(buf));
404 // Found the full path to libjvm.so.
405 // Now cut the path to <java_home>/jre if we can.
406 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */
407 pslash = strrchr(buf, '/');
408 if (pslash != NULL)
409 *pslash = '\0'; /* get rid of /{client|server|hotspot} */
410 dll_path = malloc(strlen(buf) + 1);
411 if (dll_path == NULL)
412 return;
413 strcpy(dll_path, buf);
414 Arguments::set_dll_dir(dll_path);
416 if (pslash != NULL) {
417 pslash = strrchr(buf, '/');
418 if (pslash != NULL) {
419 *pslash = '\0'; /* get rid of /<arch> */
420 pslash = strrchr(buf, '/');
421 if (pslash != NULL)
422 *pslash = '\0'; /* get rid of /lib */
423 }
424 }
426 home_path = malloc(strlen(buf) + 1);
427 if (home_path == NULL)
428 return;
429 strcpy(home_path, buf);
430 Arguments::set_java_home(home_path);
432 if (!set_boot_path('/', ':'))
433 return;
434 }
436 /*
437 * Where to look for native libraries
438 *
439 * Note: Due to a legacy implementation, most of the library path
440 * is set in the launcher. This was to accomodate linking restrictions
441 * on legacy Linux implementations (which are no longer supported).
442 * Eventually, all the library path setting will be done here.
443 *
444 * However, to prevent the proliferation of improperly built native
445 * libraries, the new path component /usr/java/packages is added here.
446 * Eventually, all the library path setting will be done here.
447 */
448 {
449 char *ld_library_path;
451 /*
452 * Construct the invariant part of ld_library_path. Note that the
453 * space for the colon and the trailing null are provided by the
454 * nulls included by the sizeof operator (so actually we allocate
455 * a byte more than necessary).
456 */
457 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") +
458 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH));
459 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch);
461 /*
462 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It
463 * should always exist (until the legacy problem cited above is
464 * addressed).
465 */
466 char *v = getenv("LD_LIBRARY_PATH");
467 if (v != NULL) {
468 char *t = ld_library_path;
469 /* That's +1 for the colon and +1 for the trailing '\0' */
470 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1);
471 sprintf(ld_library_path, "%s:%s", v, t);
472 }
473 Arguments::set_library_path(ld_library_path);
474 }
476 /*
477 * Extensions directories.
478 *
479 * Note that the space for the colon and the trailing null are provided
480 * by the nulls included by the sizeof operator (so actually one byte more
481 * than necessary is allocated).
482 */
483 {
484 char *buf = malloc(strlen(Arguments::get_java_home()) +
485 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR));
486 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR,
487 Arguments::get_java_home());
488 Arguments::set_ext_dirs(buf);
489 }
491 /* Endorsed standards default directory. */
492 {
493 char * buf;
494 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR));
495 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
496 Arguments::set_endorsed_dirs(buf);
497 }
498 }
500 #undef malloc
501 #undef getenv
502 #undef EXTENSIONS_DIR
503 #undef ENDORSED_DIR
505 // Done
506 return;
507 }
509 ////////////////////////////////////////////////////////////////////////////////
510 // breakpoint support
512 void os::breakpoint() {
513 BREAKPOINT;
514 }
516 extern "C" void breakpoint() {
517 // use debugger to set breakpoint here
518 }
520 ////////////////////////////////////////////////////////////////////////////////
521 // signal support
523 debug_only(static bool signal_sets_initialized = false);
524 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
526 bool os::Linux::is_sig_ignored(int sig) {
527 struct sigaction oact;
528 sigaction(sig, (struct sigaction*)NULL, &oact);
529 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
530 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
531 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))
532 return true;
533 else
534 return false;
535 }
537 void os::Linux::signal_sets_init() {
538 // Should also have an assertion stating we are still single-threaded.
539 assert(!signal_sets_initialized, "Already initialized");
540 // Fill in signals that are necessarily unblocked for all threads in
541 // the VM. Currently, we unblock the following signals:
542 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
543 // by -Xrs (=ReduceSignalUsage));
544 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
545 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
546 // the dispositions or masks wrt these signals.
547 // Programs embedding the VM that want to use the above signals for their
548 // own purposes must, at this time, use the "-Xrs" option to prevent
549 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
550 // (See bug 4345157, and other related bugs).
551 // In reality, though, unblocking these signals is really a nop, since
552 // these signals are not blocked by default.
553 sigemptyset(&unblocked_sigs);
554 sigemptyset(&allowdebug_blocked_sigs);
555 sigaddset(&unblocked_sigs, SIGILL);
556 sigaddset(&unblocked_sigs, SIGSEGV);
557 sigaddset(&unblocked_sigs, SIGBUS);
558 sigaddset(&unblocked_sigs, SIGFPE);
559 sigaddset(&unblocked_sigs, SR_signum);
561 if (!ReduceSignalUsage) {
562 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
563 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
564 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
565 }
566 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
567 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
568 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
569 }
570 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
571 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
572 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
573 }
574 }
575 // Fill in signals that are blocked by all but the VM thread.
576 sigemptyset(&vm_sigs);
577 if (!ReduceSignalUsage)
578 sigaddset(&vm_sigs, BREAK_SIGNAL);
579 debug_only(signal_sets_initialized = true);
581 }
583 // These are signals that are unblocked while a thread is running Java.
584 // (For some reason, they get blocked by default.)
585 sigset_t* os::Linux::unblocked_signals() {
586 assert(signal_sets_initialized, "Not initialized");
587 return &unblocked_sigs;
588 }
590 // These are the signals that are blocked while a (non-VM) thread is
591 // running Java. Only the VM thread handles these signals.
592 sigset_t* os::Linux::vm_signals() {
593 assert(signal_sets_initialized, "Not initialized");
594 return &vm_sigs;
595 }
597 // These are signals that are blocked during cond_wait to allow debugger in
598 sigset_t* os::Linux::allowdebug_blocked_signals() {
599 assert(signal_sets_initialized, "Not initialized");
600 return &allowdebug_blocked_sigs;
601 }
603 void os::Linux::hotspot_sigmask(Thread* thread) {
605 //Save caller's signal mask before setting VM signal mask
606 sigset_t caller_sigmask;
607 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
609 OSThread* osthread = thread->osthread();
610 osthread->set_caller_sigmask(caller_sigmask);
612 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
614 if (!ReduceSignalUsage) {
615 if (thread->is_VM_thread()) {
616 // Only the VM thread handles BREAK_SIGNAL ...
617 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
618 } else {
619 // ... all other threads block BREAK_SIGNAL
620 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
621 }
622 }
623 }
625 //////////////////////////////////////////////////////////////////////////////
626 // detecting pthread library
628 void os::Linux::libpthread_init() {
629 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION
630 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a
631 // generic name for earlier versions.
632 // Define macros here so we can build HotSpot on old systems.
633 # ifndef _CS_GNU_LIBC_VERSION
634 # define _CS_GNU_LIBC_VERSION 2
635 # endif
636 # ifndef _CS_GNU_LIBPTHREAD_VERSION
637 # define _CS_GNU_LIBPTHREAD_VERSION 3
638 # endif
640 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
641 if (n > 0) {
642 char *str = (char *)malloc(n);
643 confstr(_CS_GNU_LIBC_VERSION, str, n);
644 os::Linux::set_glibc_version(str);
645 } else {
646 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version()
647 static char _gnu_libc_version[32];
648 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version),
649 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release());
650 os::Linux::set_glibc_version(_gnu_libc_version);
651 }
653 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
654 if (n > 0) {
655 char *str = (char *)malloc(n);
656 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
657 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells
658 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this
659 // is the case. LinuxThreads has a hard limit on max number of threads.
660 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value.
661 // On the other hand, NPTL does not have such a limit, sysconf()
662 // will return -1 and errno is not changed. Check if it is really NPTL.
663 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 &&
664 strstr(str, "NPTL") &&
665 sysconf(_SC_THREAD_THREADS_MAX) > 0) {
666 free(str);
667 os::Linux::set_libpthread_version("linuxthreads");
668 } else {
669 os::Linux::set_libpthread_version(str);
670 }
671 } else {
672 // glibc before 2.3.2 only has LinuxThreads.
673 os::Linux::set_libpthread_version("linuxthreads");
674 }
676 if (strstr(libpthread_version(), "NPTL")) {
677 os::Linux::set_is_NPTL();
678 } else {
679 os::Linux::set_is_LinuxThreads();
680 }
682 // LinuxThreads have two flavors: floating-stack mode, which allows variable
683 // stack size; and fixed-stack mode. NPTL is always floating-stack.
684 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) {
685 os::Linux::set_is_floating_stack();
686 }
687 }
689 /////////////////////////////////////////////////////////////////////////////
690 // thread stack
692 // Force Linux kernel to expand current thread stack. If "bottom" is close
693 // to the stack guard, caller should block all signals.
694 //
695 // MAP_GROWSDOWN:
696 // A special mmap() flag that is used to implement thread stacks. It tells
697 // kernel that the memory region should extend downwards when needed. This
698 // allows early versions of LinuxThreads to only mmap the first few pages
699 // when creating a new thread. Linux kernel will automatically expand thread
700 // stack as needed (on page faults).
701 //
702 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
703 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
704 // region, it's hard to tell if the fault is due to a legitimate stack
705 // access or because of reading/writing non-exist memory (e.g. buffer
706 // overrun). As a rule, if the fault happens below current stack pointer,
707 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
708 // application (see Linux kernel fault.c).
709 //
710 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
711 // stack overflow detection.
712 //
713 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
714 // not use this flag. However, the stack of initial thread is not created
715 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though
716 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack
717 // and then attach the thread to JVM.
718 //
719 // To get around the problem and allow stack banging on Linux, we need to
720 // manually expand thread stack after receiving the SIGSEGV.
721 //
722 // There are two ways to expand thread stack to address "bottom", we used
723 // both of them in JVM before 1.5:
724 // 1. adjust stack pointer first so that it is below "bottom", and then
725 // touch "bottom"
726 // 2. mmap() the page in question
727 //
728 // Now alternate signal stack is gone, it's harder to use 2. For instance,
729 // if current sp is already near the lower end of page 101, and we need to
730 // call mmap() to map page 100, it is possible that part of the mmap() frame
731 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
732 // That will destroy the mmap() frame and cause VM to crash.
733 //
734 // The following code works by adjusting sp first, then accessing the "bottom"
735 // page to force a page fault. Linux kernel will then automatically expand the
736 // stack mapping.
737 //
738 // _expand_stack_to() assumes its frame size is less than page size, which
739 // should always be true if the function is not inlined.
741 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute
742 #define NOINLINE
743 #else
744 #define NOINLINE __attribute__ ((noinline))
745 #endif
747 static void _expand_stack_to(address bottom) NOINLINE;
749 static void _expand_stack_to(address bottom) {
750 address sp;
751 size_t size;
752 volatile char *p;
754 // Adjust bottom to point to the largest address within the same page, it
755 // gives us a one-page buffer if alloca() allocates slightly more memory.
756 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
757 bottom += os::Linux::page_size() - 1;
759 // sp might be slightly above current stack pointer; if that's the case, we
760 // will alloca() a little more space than necessary, which is OK. Don't use
761 // os::current_stack_pointer(), as its result can be slightly below current
762 // stack pointer, causing us to not alloca enough to reach "bottom".
763 sp = (address)&sp;
765 if (sp > bottom) {
766 size = sp - bottom;
767 p = (volatile char *)alloca(size);
768 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
769 p[0] = '\0';
770 }
771 }
773 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
774 assert(t!=NULL, "just checking");
775 assert(t->osthread()->expanding_stack(), "expand should be set");
776 assert(t->stack_base() != NULL, "stack_base was not initialized");
778 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) {
779 sigset_t mask_all, old_sigset;
780 sigfillset(&mask_all);
781 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
782 _expand_stack_to(addr);
783 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
784 return true;
785 }
786 return false;
787 }
789 //////////////////////////////////////////////////////////////////////////////
790 // create new thread
792 static address highest_vm_reserved_address();
794 // check if it's safe to start a new thread
795 static bool _thread_safety_check(Thread* thread) {
796 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) {
797 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat)
798 // Heap is mmap'ed at lower end of memory space. Thread stacks are
799 // allocated (MAP_FIXED) from high address space. Every thread stack
800 // occupies a fixed size slot (usually 2Mbytes, but user can change
801 // it to other values if they rebuild LinuxThreads).
802 //
803 // Problem with MAP_FIXED is that mmap() can still succeed even part of
804 // the memory region has already been mmap'ed. That means if we have too
805 // many threads and/or very large heap, eventually thread stack will
806 // collide with heap.
807 //
808 // Here we try to prevent heap/stack collision by comparing current
809 // stack bottom with the highest address that has been mmap'ed by JVM
810 // plus a safety margin for memory maps created by native code.
811 //
812 // This feature can be disabled by setting ThreadSafetyMargin to 0
813 //
814 if (ThreadSafetyMargin > 0) {
815 address stack_bottom = os::current_stack_base() - os::current_stack_size();
817 // not safe if our stack extends below the safety margin
818 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address();
819 } else {
820 return true;
821 }
822 } else {
823 // Floating stack LinuxThreads or NPTL:
824 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When
825 // there's not enough space left, pthread_create() will fail. If we come
826 // here, that means enough space has been reserved for stack.
827 return true;
828 }
829 }
831 // Thread start routine for all newly created threads
832 static void *java_start(Thread *thread) {
833 // Try to randomize the cache line index of hot stack frames.
834 // This helps when threads of the same stack traces evict each other's
835 // cache lines. The threads can be either from the same JVM instance, or
836 // from different JVM instances. The benefit is especially true for
837 // processors with hyperthreading technology.
838 static int counter = 0;
839 int pid = os::current_process_id();
840 alloca(((pid ^ counter++) & 7) * 128);
842 ThreadLocalStorage::set_thread(thread);
844 OSThread* osthread = thread->osthread();
845 Monitor* sync = osthread->startThread_lock();
847 // non floating stack LinuxThreads needs extra check, see above
848 if (!_thread_safety_check(thread)) {
849 // notify parent thread
850 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
851 osthread->set_state(ZOMBIE);
852 sync->notify_all();
853 return NULL;
854 }
856 // thread_id is kernel thread id (similar to Solaris LWP id)
857 osthread->set_thread_id(os::Linux::gettid());
859 if (UseNUMA) {
860 int lgrp_id = os::numa_get_group_id();
861 if (lgrp_id != -1) {
862 thread->set_lgrp_id(lgrp_id);
863 }
864 }
865 // initialize signal mask for this thread
866 os::Linux::hotspot_sigmask(thread);
868 // initialize floating point control register
869 os::Linux::init_thread_fpu_state();
871 // handshaking with parent thread
872 {
873 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
875 // notify parent thread
876 osthread->set_state(INITIALIZED);
877 sync->notify_all();
879 // wait until os::start_thread()
880 while (osthread->get_state() == INITIALIZED) {
881 sync->wait(Mutex::_no_safepoint_check_flag);
882 }
883 }
885 // call one more level start routine
886 thread->run();
888 return 0;
889 }
891 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
892 assert(thread->osthread() == NULL, "caller responsible");
894 // Allocate the OSThread object
895 OSThread* osthread = new OSThread(NULL, NULL);
896 if (osthread == NULL) {
897 return false;
898 }
900 // set the correct thread state
901 osthread->set_thread_type(thr_type);
903 // Initial state is ALLOCATED but not INITIALIZED
904 osthread->set_state(ALLOCATED);
906 thread->set_osthread(osthread);
908 // init thread attributes
909 pthread_attr_t attr;
910 pthread_attr_init(&attr);
911 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
913 // stack size
914 if (os::Linux::supports_variable_stack_size()) {
915 // calculate stack size if it's not specified by caller
916 if (stack_size == 0) {
917 stack_size = os::Linux::default_stack_size(thr_type);
919 switch (thr_type) {
920 case os::java_thread:
921 // Java threads use ThreadStackSize which default value can be
922 // changed with the flag -Xss
923 assert (JavaThread::stack_size_at_create() > 0, "this should be set");
924 stack_size = JavaThread::stack_size_at_create();
925 break;
926 case os::compiler_thread:
927 if (CompilerThreadStackSize > 0) {
928 stack_size = (size_t)(CompilerThreadStackSize * K);
929 break;
930 } // else fall through:
931 // use VMThreadStackSize if CompilerThreadStackSize is not defined
932 case os::vm_thread:
933 case os::pgc_thread:
934 case os::cgc_thread:
935 case os::watcher_thread:
936 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
937 break;
938 }
939 }
941 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
942 pthread_attr_setstacksize(&attr, stack_size);
943 } else {
944 // let pthread_create() pick the default value.
945 }
947 // glibc guard page
948 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
950 ThreadState state;
952 {
953 // Serialize thread creation if we are running with fixed stack LinuxThreads
954 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack();
955 if (lock) {
956 os::Linux::createThread_lock()->lock_without_safepoint_check();
957 }
959 pthread_t tid;
960 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
962 pthread_attr_destroy(&attr);
964 if (ret != 0) {
965 if (PrintMiscellaneous && (Verbose || WizardMode)) {
966 perror("pthread_create()");
967 }
968 // Need to clean up stuff we've allocated so far
969 thread->set_osthread(NULL);
970 delete osthread;
971 if (lock) os::Linux::createThread_lock()->unlock();
972 return false;
973 }
975 // Store pthread info into the OSThread
976 osthread->set_pthread_id(tid);
978 // Wait until child thread is either initialized or aborted
979 {
980 Monitor* sync_with_child = osthread->startThread_lock();
981 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
982 while ((state = osthread->get_state()) == ALLOCATED) {
983 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
984 }
985 }
987 if (lock) {
988 os::Linux::createThread_lock()->unlock();
989 }
990 }
992 // Aborted due to thread limit being reached
993 if (state == ZOMBIE) {
994 thread->set_osthread(NULL);
995 delete osthread;
996 return false;
997 }
999 // The thread is returned suspended (in state INITIALIZED),
1000 // and is started higher up in the call chain
1001 assert(state == INITIALIZED, "race condition");
1002 return true;
1003 }
1005 /////////////////////////////////////////////////////////////////////////////
1006 // attach existing thread
1008 // bootstrap the main thread
1009 bool os::create_main_thread(JavaThread* thread) {
1010 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
1011 return create_attached_thread(thread);
1012 }
1014 bool os::create_attached_thread(JavaThread* thread) {
1015 #ifdef ASSERT
1016 thread->verify_not_published();
1017 #endif
1019 // Allocate the OSThread object
1020 OSThread* osthread = new OSThread(NULL, NULL);
1022 if (osthread == NULL) {
1023 return false;
1024 }
1026 // Store pthread info into the OSThread
1027 osthread->set_thread_id(os::Linux::gettid());
1028 osthread->set_pthread_id(::pthread_self());
1030 // initialize floating point control register
1031 os::Linux::init_thread_fpu_state();
1033 // Initial thread state is RUNNABLE
1034 osthread->set_state(RUNNABLE);
1036 thread->set_osthread(osthread);
1038 if (UseNUMA) {
1039 int lgrp_id = os::numa_get_group_id();
1040 if (lgrp_id != -1) {
1041 thread->set_lgrp_id(lgrp_id);
1042 }
1043 }
1045 if (os::Linux::is_initial_thread()) {
1046 // If current thread is initial thread, its stack is mapped on demand,
1047 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
1048 // the entire stack region to avoid SEGV in stack banging.
1049 // It is also useful to get around the heap-stack-gap problem on SuSE
1050 // kernel (see 4821821 for details). We first expand stack to the top
1051 // of yellow zone, then enable stack yellow zone (order is significant,
1052 // enabling yellow zone first will crash JVM on SuSE Linux), so there
1053 // is no gap between the last two virtual memory regions.
1055 JavaThread *jt = (JavaThread *)thread;
1056 address addr = jt->stack_yellow_zone_base();
1057 assert(addr != NULL, "initialization problem?");
1058 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
1060 osthread->set_expanding_stack();
1061 os::Linux::manually_expand_stack(jt, addr);
1062 osthread->clear_expanding_stack();
1063 }
1065 // initialize signal mask for this thread
1066 // and save the caller's signal mask
1067 os::Linux::hotspot_sigmask(thread);
1069 return true;
1070 }
1072 void os::pd_start_thread(Thread* thread) {
1073 OSThread * osthread = thread->osthread();
1074 assert(osthread->get_state() != INITIALIZED, "just checking");
1075 Monitor* sync_with_child = osthread->startThread_lock();
1076 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
1077 sync_with_child->notify();
1078 }
1080 // Free Linux resources related to the OSThread
1081 void os::free_thread(OSThread* osthread) {
1082 assert(osthread != NULL, "osthread not set");
1084 if (Thread::current()->osthread() == osthread) {
1085 // Restore caller's signal mask
1086 sigset_t sigmask = osthread->caller_sigmask();
1087 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1088 }
1090 delete osthread;
1091 }
1093 //////////////////////////////////////////////////////////////////////////////
1094 // thread local storage
1096 int os::allocate_thread_local_storage() {
1097 pthread_key_t key;
1098 int rslt = pthread_key_create(&key, NULL);
1099 assert(rslt == 0, "cannot allocate thread local storage");
1100 return (int)key;
1101 }
1103 // Note: This is currently not used by VM, as we don't destroy TLS key
1104 // on VM exit.
1105 void os::free_thread_local_storage(int index) {
1106 int rslt = pthread_key_delete((pthread_key_t)index);
1107 assert(rslt == 0, "invalid index");
1108 }
1110 void os::thread_local_storage_at_put(int index, void* value) {
1111 int rslt = pthread_setspecific((pthread_key_t)index, value);
1112 assert(rslt == 0, "pthread_setspecific failed");
1113 }
1115 extern "C" Thread* get_thread() {
1116 return ThreadLocalStorage::thread();
1117 }
1119 //////////////////////////////////////////////////////////////////////////////
1120 // initial thread
1122 // Check if current thread is the initial thread, similar to Solaris thr_main.
1123 bool os::Linux::is_initial_thread(void) {
1124 char dummy;
1125 // If called before init complete, thread stack bottom will be null.
1126 // Can be called if fatal error occurs before initialization.
1127 if (initial_thread_stack_bottom() == NULL) return false;
1128 assert(initial_thread_stack_bottom() != NULL &&
1129 initial_thread_stack_size() != 0,
1130 "os::init did not locate initial thread's stack region");
1131 if ((address)&dummy >= initial_thread_stack_bottom() &&
1132 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size())
1133 return true;
1134 else return false;
1135 }
1137 // Find the virtual memory area that contains addr
1138 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1139 FILE *fp = fopen("/proc/self/maps", "r");
1140 if (fp) {
1141 address low, high;
1142 while (!feof(fp)) {
1143 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1144 if (low <= addr && addr < high) {
1145 if (vma_low) *vma_low = low;
1146 if (vma_high) *vma_high = high;
1147 fclose (fp);
1148 return true;
1149 }
1150 }
1151 for (;;) {
1152 int ch = fgetc(fp);
1153 if (ch == EOF || ch == (int)'\n') break;
1154 }
1155 }
1156 fclose(fp);
1157 }
1158 return false;
1159 }
1161 // Locate initial thread stack. This special handling of initial thread stack
1162 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1163 // bogus value for initial thread.
1164 void os::Linux::capture_initial_stack(size_t max_size) {
1165 // stack size is the easy part, get it from RLIMIT_STACK
1166 size_t stack_size;
1167 struct rlimit rlim;
1168 getrlimit(RLIMIT_STACK, &rlim);
1169 stack_size = rlim.rlim_cur;
1171 // 6308388: a bug in ld.so will relocate its own .data section to the
1172 // lower end of primordial stack; reduce ulimit -s value a little bit
1173 // so we won't install guard page on ld.so's data section.
1174 stack_size -= 2 * page_size();
1176 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
1177 // 7.1, in both cases we will get 2G in return value.
1178 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
1179 // SuSE 7.2, Debian) can not handle alternate signal stack correctly
1180 // for initial thread if its stack size exceeds 6M. Cap it at 2M,
1181 // in case other parts in glibc still assumes 2M max stack size.
1182 // FIXME: alt signal stack is gone, maybe we can relax this constraint?
1183 #ifndef IA64
1184 if (stack_size > 2 * K * K) stack_size = 2 * K * K;
1185 #else
1186 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
1187 if (stack_size > 4 * K * K) stack_size = 4 * K * K;
1188 #endif
1190 // Try to figure out where the stack base (top) is. This is harder.
1191 //
1192 // When an application is started, glibc saves the initial stack pointer in
1193 // a global variable "__libc_stack_end", which is then used by system
1194 // libraries. __libc_stack_end should be pretty close to stack top. The
1195 // variable is available since the very early days. However, because it is
1196 // a private interface, it could disappear in the future.
1197 //
1198 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1199 // to __libc_stack_end, it is very close to stack top, but isn't the real
1200 // stack top. Note that /proc may not exist if VM is running as a chroot
1201 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1202 // /proc/<pid>/stat could change in the future (though unlikely).
1203 //
1204 // We try __libc_stack_end first. If that doesn't work, look for
1205 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1206 // as a hint, which should work well in most cases.
1208 uintptr_t stack_start;
1210 // try __libc_stack_end first
1211 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1212 if (p && *p) {
1213 stack_start = *p;
1214 } else {
1215 // see if we can get the start_stack field from /proc/self/stat
1216 FILE *fp;
1217 int pid;
1218 char state;
1219 int ppid;
1220 int pgrp;
1221 int session;
1222 int nr;
1223 int tpgrp;
1224 unsigned long flags;
1225 unsigned long minflt;
1226 unsigned long cminflt;
1227 unsigned long majflt;
1228 unsigned long cmajflt;
1229 unsigned long utime;
1230 unsigned long stime;
1231 long cutime;
1232 long cstime;
1233 long prio;
1234 long nice;
1235 long junk;
1236 long it_real;
1237 uintptr_t start;
1238 uintptr_t vsize;
1239 intptr_t rss;
1240 uintptr_t rsslim;
1241 uintptr_t scodes;
1242 uintptr_t ecode;
1243 int i;
1245 // Figure what the primordial thread stack base is. Code is inspired
1246 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1247 // followed by command name surrounded by parentheses, state, etc.
1248 char stat[2048];
1249 int statlen;
1251 fp = fopen("/proc/self/stat", "r");
1252 if (fp) {
1253 statlen = fread(stat, 1, 2047, fp);
1254 stat[statlen] = '\0';
1255 fclose(fp);
1257 // Skip pid and the command string. Note that we could be dealing with
1258 // weird command names, e.g. user could decide to rename java launcher
1259 // to "java 1.4.2 :)", then the stat file would look like
1260 // 1234 (java 1.4.2 :)) R ... ...
1261 // We don't really need to know the command string, just find the last
1262 // occurrence of ")" and then start parsing from there. See bug 4726580.
1263 char * s = strrchr(stat, ')');
1265 i = 0;
1266 if (s) {
1267 // Skip blank chars
1268 do s++; while (isspace(*s));
1270 #define _UFM UINTX_FORMAT
1271 #define _DFM INTX_FORMAT
1273 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */
1274 /* 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 */
1275 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,
1276 &state, /* 3 %c */
1277 &ppid, /* 4 %d */
1278 &pgrp, /* 5 %d */
1279 &session, /* 6 %d */
1280 &nr, /* 7 %d */
1281 &tpgrp, /* 8 %d */
1282 &flags, /* 9 %lu */
1283 &minflt, /* 10 %lu */
1284 &cminflt, /* 11 %lu */
1285 &majflt, /* 12 %lu */
1286 &cmajflt, /* 13 %lu */
1287 &utime, /* 14 %lu */
1288 &stime, /* 15 %lu */
1289 &cutime, /* 16 %ld */
1290 &cstime, /* 17 %ld */
1291 &prio, /* 18 %ld */
1292 &nice, /* 19 %ld */
1293 &junk, /* 20 %ld */
1294 &it_real, /* 21 %ld */
1295 &start, /* 22 UINTX_FORMAT */
1296 &vsize, /* 23 UINTX_FORMAT */
1297 &rss, /* 24 INTX_FORMAT */
1298 &rsslim, /* 25 UINTX_FORMAT */
1299 &scodes, /* 26 UINTX_FORMAT */
1300 &ecode, /* 27 UINTX_FORMAT */
1301 &stack_start); /* 28 UINTX_FORMAT */
1302 }
1304 #undef _UFM
1305 #undef _DFM
1307 if (i != 28 - 2) {
1308 assert(false, "Bad conversion from /proc/self/stat");
1309 // product mode - assume we are the initial thread, good luck in the
1310 // embedded case.
1311 warning("Can't detect initial thread stack location - bad conversion");
1312 stack_start = (uintptr_t) &rlim;
1313 }
1314 } else {
1315 // For some reason we can't open /proc/self/stat (for example, running on
1316 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1317 // most cases, so don't abort:
1318 warning("Can't detect initial thread stack location - no /proc/self/stat");
1319 stack_start = (uintptr_t) &rlim;
1320 }
1321 }
1323 // Now we have a pointer (stack_start) very close to the stack top, the
1324 // next thing to do is to figure out the exact location of stack top. We
1325 // can find out the virtual memory area that contains stack_start by
1326 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1327 // and its upper limit is the real stack top. (again, this would fail if
1328 // running inside chroot, because /proc may not exist.)
1330 uintptr_t stack_top;
1331 address low, high;
1332 if (find_vma((address)stack_start, &low, &high)) {
1333 // success, "high" is the true stack top. (ignore "low", because initial
1334 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1335 stack_top = (uintptr_t)high;
1336 } else {
1337 // failed, likely because /proc/self/maps does not exist
1338 warning("Can't detect initial thread stack location - find_vma failed");
1339 // best effort: stack_start is normally within a few pages below the real
1340 // stack top, use it as stack top, and reduce stack size so we won't put
1341 // guard page outside stack.
1342 stack_top = stack_start;
1343 stack_size -= 16 * page_size();
1344 }
1346 // stack_top could be partially down the page so align it
1347 stack_top = align_size_up(stack_top, page_size());
1349 if (max_size && stack_size > max_size) {
1350 _initial_thread_stack_size = max_size;
1351 } else {
1352 _initial_thread_stack_size = stack_size;
1353 }
1355 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1356 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1357 }
1359 ////////////////////////////////////////////////////////////////////////////////
1360 // time support
1362 // Time since start-up in seconds to a fine granularity.
1363 // Used by VMSelfDestructTimer and the MemProfiler.
1364 double os::elapsedTime() {
1366 return (double)(os::elapsed_counter()) * 0.000001;
1367 }
1369 jlong os::elapsed_counter() {
1370 timeval time;
1371 int status = gettimeofday(&time, NULL);
1372 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count;
1373 }
1375 jlong os::elapsed_frequency() {
1376 return (1000 * 1000);
1377 }
1379 // For now, we say that linux does not support vtime. I have no idea
1380 // whether it can actually be made to (DLD, 9/13/05).
1382 bool os::supports_vtime() { return false; }
1383 bool os::enable_vtime() { return false; }
1384 bool os::vtime_enabled() { return false; }
1385 double os::elapsedVTime() {
1386 // better than nothing, but not much
1387 return elapsedTime();
1388 }
1390 jlong os::javaTimeMillis() {
1391 timeval time;
1392 int status = gettimeofday(&time, NULL);
1393 assert(status != -1, "linux error");
1394 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1395 }
1397 #ifndef CLOCK_MONOTONIC
1398 #define CLOCK_MONOTONIC (1)
1399 #endif
1401 void os::Linux::clock_init() {
1402 // we do dlopen's in this particular order due to bug in linux
1403 // dynamical loader (see 6348968) leading to crash on exit
1404 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1405 if (handle == NULL) {
1406 handle = dlopen("librt.so", RTLD_LAZY);
1407 }
1409 if (handle) {
1410 int (*clock_getres_func)(clockid_t, struct timespec*) =
1411 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1412 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1413 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1414 if (clock_getres_func && clock_gettime_func) {
1415 // See if monotonic clock is supported by the kernel. Note that some
1416 // early implementations simply return kernel jiffies (updated every
1417 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1418 // for nano time (though the monotonic property is still nice to have).
1419 // It's fixed in newer kernels, however clock_getres() still returns
1420 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1421 // resolution for now. Hopefully as people move to new kernels, this
1422 // won't be a problem.
1423 struct timespec res;
1424 struct timespec tp;
1425 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1426 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1427 // yes, monotonic clock is supported
1428 _clock_gettime = clock_gettime_func;
1429 } else {
1430 // close librt if there is no monotonic clock
1431 dlclose(handle);
1432 }
1433 }
1434 }
1435 }
1437 #ifndef SYS_clock_getres
1439 #if defined(IA32) || defined(AMD64)
1440 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229)
1441 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1442 #else
1443 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1444 #define sys_clock_getres(x,y) -1
1445 #endif
1447 #else
1448 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1449 #endif
1451 void os::Linux::fast_thread_clock_init() {
1452 if (!UseLinuxPosixThreadCPUClocks) {
1453 return;
1454 }
1455 clockid_t clockid;
1456 struct timespec tp;
1457 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1458 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1460 // Switch to using fast clocks for thread cpu time if
1461 // the sys_clock_getres() returns 0 error code.
1462 // Note, that some kernels may support the current thread
1463 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1464 // returned by the pthread_getcpuclockid().
1465 // If the fast Posix clocks are supported then the sys_clock_getres()
1466 // must return at least tp.tv_sec == 0 which means a resolution
1467 // better than 1 sec. This is extra check for reliability.
1469 if(pthread_getcpuclockid_func &&
1470 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1471 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1473 _supports_fast_thread_cpu_time = true;
1474 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1475 }
1476 }
1478 jlong os::javaTimeNanos() {
1479 if (Linux::supports_monotonic_clock()) {
1480 struct timespec tp;
1481 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1482 assert(status == 0, "gettime error");
1483 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1484 return result;
1485 } else {
1486 timeval time;
1487 int status = gettimeofday(&time, NULL);
1488 assert(status != -1, "linux error");
1489 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1490 return 1000 * usecs;
1491 }
1492 }
1494 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1495 if (Linux::supports_monotonic_clock()) {
1496 info_ptr->max_value = ALL_64_BITS;
1498 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1499 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1500 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1501 } else {
1502 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1503 info_ptr->max_value = ALL_64_BITS;
1505 // gettimeofday is a real time clock so it skips
1506 info_ptr->may_skip_backward = true;
1507 info_ptr->may_skip_forward = true;
1508 }
1510 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1511 }
1513 // Return the real, user, and system times in seconds from an
1514 // arbitrary fixed point in the past.
1515 bool os::getTimesSecs(double* process_real_time,
1516 double* process_user_time,
1517 double* process_system_time) {
1518 struct tms ticks;
1519 clock_t real_ticks = times(&ticks);
1521 if (real_ticks == (clock_t) (-1)) {
1522 return false;
1523 } else {
1524 double ticks_per_second = (double) clock_tics_per_sec;
1525 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1526 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1527 *process_real_time = ((double) real_ticks) / ticks_per_second;
1529 return true;
1530 }
1531 }
1534 char * os::local_time_string(char *buf, size_t buflen) {
1535 struct tm t;
1536 time_t long_time;
1537 time(&long_time);
1538 localtime_r(&long_time, &t);
1539 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1540 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1541 t.tm_hour, t.tm_min, t.tm_sec);
1542 return buf;
1543 }
1545 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1546 return localtime_r(clock, res);
1547 }
1549 ////////////////////////////////////////////////////////////////////////////////
1550 // runtime exit support
1552 // Note: os::shutdown() might be called very early during initialization, or
1553 // called from signal handler. Before adding something to os::shutdown(), make
1554 // sure it is async-safe and can handle partially initialized VM.
1555 void os::shutdown() {
1557 // allow PerfMemory to attempt cleanup of any persistent resources
1558 perfMemory_exit();
1560 // needs to remove object in file system
1561 AttachListener::abort();
1563 // flush buffered output, finish log files
1564 ostream_abort();
1566 // Check for abort hook
1567 abort_hook_t abort_hook = Arguments::abort_hook();
1568 if (abort_hook != NULL) {
1569 abort_hook();
1570 }
1572 }
1574 // Note: os::abort() might be called very early during initialization, or
1575 // called from signal handler. Before adding something to os::abort(), make
1576 // sure it is async-safe and can handle partially initialized VM.
1577 void os::abort(bool dump_core) {
1578 os::shutdown();
1579 if (dump_core) {
1580 #ifndef PRODUCT
1581 fdStream out(defaultStream::output_fd());
1582 out.print_raw("Current thread is ");
1583 char buf[16];
1584 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1585 out.print_raw_cr(buf);
1586 out.print_raw_cr("Dumping core ...");
1587 #endif
1588 ::abort(); // dump core
1589 }
1591 ::exit(1);
1592 }
1594 // Die immediately, no exit hook, no abort hook, no cleanup.
1595 void os::die() {
1596 // _exit() on LinuxThreads only kills current thread
1597 ::abort();
1598 }
1600 // unused on linux for now.
1601 void os::set_error_file(const char *logfile) {}
1604 // This method is a copy of JDK's sysGetLastErrorString
1605 // from src/solaris/hpi/src/system_md.c
1607 size_t os::lasterror(char *buf, size_t len) {
1609 if (errno == 0) return 0;
1611 const char *s = ::strerror(errno);
1612 size_t n = ::strlen(s);
1613 if (n >= len) {
1614 n = len - 1;
1615 }
1616 ::strncpy(buf, s, n);
1617 buf[n] = '\0';
1618 return n;
1619 }
1621 intx os::current_thread_id() { return (intx)pthread_self(); }
1622 int os::current_process_id() {
1624 // Under the old linux thread library, linux gives each thread
1625 // its own process id. Because of this each thread will return
1626 // a different pid if this method were to return the result
1627 // of getpid(2). Linux provides no api that returns the pid
1628 // of the launcher thread for the vm. This implementation
1629 // returns a unique pid, the pid of the launcher thread
1630 // that starts the vm 'process'.
1632 // Under the NPTL, getpid() returns the same pid as the
1633 // launcher thread rather than a unique pid per thread.
1634 // Use gettid() if you want the old pre NPTL behaviour.
1636 // if you are looking for the result of a call to getpid() that
1637 // returns a unique pid for the calling thread, then look at the
1638 // OSThread::thread_id() method in osThread_linux.hpp file
1640 return (int)(_initial_pid ? _initial_pid : getpid());
1641 }
1643 // DLL functions
1645 const char* os::dll_file_extension() { return ".so"; }
1647 // This must be hard coded because it's the system's temporary
1648 // directory not the java application's temp directory, ala java.io.tmpdir.
1649 const char* os::get_temp_directory() { return "/tmp"; }
1651 static bool file_exists(const char* filename) {
1652 struct stat statbuf;
1653 if (filename == NULL || strlen(filename) == 0) {
1654 return false;
1655 }
1656 return os::stat(filename, &statbuf) == 0;
1657 }
1659 void os::dll_build_name(char* buffer, size_t buflen,
1660 const char* pname, const char* fname) {
1661 // Copied from libhpi
1662 const size_t pnamelen = pname ? strlen(pname) : 0;
1664 // Quietly truncate on buffer overflow. Should be an error.
1665 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1666 *buffer = '\0';
1667 return;
1668 }
1670 if (pnamelen == 0) {
1671 snprintf(buffer, buflen, "lib%s.so", fname);
1672 } else if (strchr(pname, *os::path_separator()) != NULL) {
1673 int n;
1674 char** pelements = split_path(pname, &n);
1675 for (int i = 0 ; i < n ; i++) {
1676 // Really shouldn't be NULL, but check can't hurt
1677 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1678 continue; // skip the empty path values
1679 }
1680 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1681 if (file_exists(buffer)) {
1682 break;
1683 }
1684 }
1685 // release the storage
1686 for (int i = 0 ; i < n ; i++) {
1687 if (pelements[i] != NULL) {
1688 FREE_C_HEAP_ARRAY(char, pelements[i]);
1689 }
1690 }
1691 if (pelements != NULL) {
1692 FREE_C_HEAP_ARRAY(char*, pelements);
1693 }
1694 } else {
1695 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1696 }
1697 }
1699 const char* os::get_current_directory(char *buf, int buflen) {
1700 return getcwd(buf, buflen);
1701 }
1703 // check if addr is inside libjvm[_g].so
1704 bool os::address_is_in_vm(address addr) {
1705 static address libjvm_base_addr;
1706 Dl_info dlinfo;
1708 if (libjvm_base_addr == NULL) {
1709 dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo);
1710 libjvm_base_addr = (address)dlinfo.dli_fbase;
1711 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1712 }
1714 if (dladdr((void *)addr, &dlinfo)) {
1715 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1716 }
1718 return false;
1719 }
1721 bool os::dll_address_to_function_name(address addr, char *buf,
1722 int buflen, int *offset) {
1723 Dl_info dlinfo;
1725 if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) {
1726 if (buf != NULL) {
1727 if(!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) {
1728 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1729 }
1730 }
1731 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1732 return true;
1733 } else if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != 0) {
1734 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1735 buf, buflen, offset, dlinfo.dli_fname)) {
1736 return true;
1737 }
1738 }
1740 if (buf != NULL) buf[0] = '\0';
1741 if (offset != NULL) *offset = -1;
1742 return false;
1743 }
1745 struct _address_to_library_name {
1746 address addr; // input : memory address
1747 size_t buflen; // size of fname
1748 char* fname; // output: library name
1749 address base; // library base addr
1750 };
1752 static int address_to_library_name_callback(struct dl_phdr_info *info,
1753 size_t size, void *data) {
1754 int i;
1755 bool found = false;
1756 address libbase = NULL;
1757 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1759 // iterate through all loadable segments
1760 for (i = 0; i < info->dlpi_phnum; i++) {
1761 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1762 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1763 // base address of a library is the lowest address of its loaded
1764 // segments.
1765 if (libbase == NULL || libbase > segbase) {
1766 libbase = segbase;
1767 }
1768 // see if 'addr' is within current segment
1769 if (segbase <= d->addr &&
1770 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1771 found = true;
1772 }
1773 }
1774 }
1776 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1777 // so dll_address_to_library_name() can fall through to use dladdr() which
1778 // can figure out executable name from argv[0].
1779 if (found && info->dlpi_name && info->dlpi_name[0]) {
1780 d->base = libbase;
1781 if (d->fname) {
1782 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1783 }
1784 return 1;
1785 }
1786 return 0;
1787 }
1789 bool os::dll_address_to_library_name(address addr, char* buf,
1790 int buflen, int* offset) {
1791 Dl_info dlinfo;
1792 struct _address_to_library_name data;
1794 // There is a bug in old glibc dladdr() implementation that it could resolve
1795 // to wrong library name if the .so file has a base address != NULL. Here
1796 // we iterate through the program headers of all loaded libraries to find
1797 // out which library 'addr' really belongs to. This workaround can be
1798 // removed once the minimum requirement for glibc is moved to 2.3.x.
1799 data.addr = addr;
1800 data.fname = buf;
1801 data.buflen = buflen;
1802 data.base = NULL;
1803 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1805 if (rslt) {
1806 // buf already contains library name
1807 if (offset) *offset = addr - data.base;
1808 return true;
1809 } else if (dladdr((void*)addr, &dlinfo)){
1810 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1811 if (offset) *offset = addr - (address)dlinfo.dli_fbase;
1812 return true;
1813 } else {
1814 if (buf) buf[0] = '\0';
1815 if (offset) *offset = -1;
1816 return false;
1817 }
1818 }
1820 // Loads .dll/.so and
1821 // in case of error it checks if .dll/.so was built for the
1822 // same architecture as Hotspot is running on
1824 void * os::dll_load(const char *filename, char *ebuf, int ebuflen)
1825 {
1826 void * result= ::dlopen(filename, RTLD_LAZY);
1827 if (result != NULL) {
1828 // Successful loading
1829 return result;
1830 }
1832 Elf32_Ehdr elf_head;
1834 // Read system error message into ebuf
1835 // It may or may not be overwritten below
1836 ::strncpy(ebuf, ::dlerror(), ebuflen-1);
1837 ebuf[ebuflen-1]='\0';
1838 int diag_msg_max_length=ebuflen-strlen(ebuf);
1839 char* diag_msg_buf=ebuf+strlen(ebuf);
1841 if (diag_msg_max_length==0) {
1842 // No more space in ebuf for additional diagnostics message
1843 return NULL;
1844 }
1847 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1849 if (file_descriptor < 0) {
1850 // Can't open library, report dlerror() message
1851 return NULL;
1852 }
1854 bool failed_to_read_elf_head=
1855 (sizeof(elf_head)!=
1856 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ;
1858 ::close(file_descriptor);
1859 if (failed_to_read_elf_head) {
1860 // file i/o error - report dlerror() msg
1861 return NULL;
1862 }
1864 typedef struct {
1865 Elf32_Half code; // Actual value as defined in elf.h
1866 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1867 char elf_class; // 32 or 64 bit
1868 char endianess; // MSB or LSB
1869 char* name; // String representation
1870 } arch_t;
1872 #ifndef EM_486
1873 #define EM_486 6 /* Intel 80486 */
1874 #endif
1876 static const arch_t arch_array[]={
1877 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1878 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1879 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1880 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1881 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1882 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1883 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1884 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1885 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1886 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1887 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1888 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1889 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1890 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1891 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1892 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}
1893 };
1895 #if (defined IA32)
1896 static Elf32_Half running_arch_code=EM_386;
1897 #elif (defined AMD64)
1898 static Elf32_Half running_arch_code=EM_X86_64;
1899 #elif (defined IA64)
1900 static Elf32_Half running_arch_code=EM_IA_64;
1901 #elif (defined __sparc) && (defined _LP64)
1902 static Elf32_Half running_arch_code=EM_SPARCV9;
1903 #elif (defined __sparc) && (!defined _LP64)
1904 static Elf32_Half running_arch_code=EM_SPARC;
1905 #elif (defined __powerpc64__)
1906 static Elf32_Half running_arch_code=EM_PPC64;
1907 #elif (defined __powerpc__)
1908 static Elf32_Half running_arch_code=EM_PPC;
1909 #elif (defined ARM)
1910 static Elf32_Half running_arch_code=EM_ARM;
1911 #elif (defined S390)
1912 static Elf32_Half running_arch_code=EM_S390;
1913 #elif (defined ALPHA)
1914 static Elf32_Half running_arch_code=EM_ALPHA;
1915 #elif (defined MIPSEL)
1916 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1917 #elif (defined PARISC)
1918 static Elf32_Half running_arch_code=EM_PARISC;
1919 #elif (defined MIPS)
1920 static Elf32_Half running_arch_code=EM_MIPS;
1921 #elif (defined M68K)
1922 static Elf32_Half running_arch_code=EM_68K;
1923 #else
1924 #error Method os::dll_load requires that one of following is defined:\
1925 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K
1926 #endif
1928 // Identify compatability class for VM's architecture and library's architecture
1929 // Obtain string descriptions for architectures
1931 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1932 int running_arch_index=-1;
1934 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) {
1935 if (running_arch_code == arch_array[i].code) {
1936 running_arch_index = i;
1937 }
1938 if (lib_arch.code == arch_array[i].code) {
1939 lib_arch.compat_class = arch_array[i].compat_class;
1940 lib_arch.name = arch_array[i].name;
1941 }
1942 }
1944 assert(running_arch_index != -1,
1945 "Didn't find running architecture code (running_arch_code) in arch_array");
1946 if (running_arch_index == -1) {
1947 // Even though running architecture detection failed
1948 // we may still continue with reporting dlerror() message
1949 return NULL;
1950 }
1952 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1953 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1954 return NULL;
1955 }
1957 #ifndef S390
1958 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1959 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1960 return NULL;
1961 }
1962 #endif // !S390
1964 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1965 if ( lib_arch.name!=NULL ) {
1966 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1967 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1968 lib_arch.name, arch_array[running_arch_index].name);
1969 } else {
1970 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1971 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1972 lib_arch.code,
1973 arch_array[running_arch_index].name);
1974 }
1975 }
1977 return NULL;
1978 }
1980 /*
1981 * glibc-2.0 libdl is not MT safe. If you are building with any glibc,
1982 * chances are you might want to run the generated bits against glibc-2.0
1983 * libdl.so, so always use locking for any version of glibc.
1984 */
1985 void* os::dll_lookup(void* handle, const char* name) {
1986 pthread_mutex_lock(&dl_mutex);
1987 void* res = dlsym(handle, name);
1988 pthread_mutex_unlock(&dl_mutex);
1989 return res;
1990 }
1993 static bool _print_ascii_file(const char* filename, outputStream* st) {
1994 int fd = ::open(filename, O_RDONLY);
1995 if (fd == -1) {
1996 return false;
1997 }
1999 char buf[32];
2000 int bytes;
2001 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) {
2002 st->print_raw(buf, bytes);
2003 }
2005 ::close(fd);
2007 return true;
2008 }
2010 void os::print_dll_info(outputStream *st) {
2011 st->print_cr("Dynamic libraries:");
2013 char fname[32];
2014 pid_t pid = os::Linux::gettid();
2016 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
2018 if (!_print_ascii_file(fname, st)) {
2019 st->print("Can not get library information for pid = %d\n", pid);
2020 }
2021 }
2024 void os::print_os_info(outputStream* st) {
2025 st->print("OS:");
2027 // Try to identify popular distros.
2028 // Most Linux distributions have /etc/XXX-release file, which contains
2029 // the OS version string. Some have more than one /etc/XXX-release file
2030 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.),
2031 // so the order is important.
2032 if (!_print_ascii_file("/etc/mandrake-release", st) &&
2033 !_print_ascii_file("/etc/sun-release", st) &&
2034 !_print_ascii_file("/etc/redhat-release", st) &&
2035 !_print_ascii_file("/etc/SuSE-release", st) &&
2036 !_print_ascii_file("/etc/turbolinux-release", st) &&
2037 !_print_ascii_file("/etc/gentoo-release", st) &&
2038 !_print_ascii_file("/etc/debian_version", st) &&
2039 !_print_ascii_file("/etc/ltib-release", st) &&
2040 !_print_ascii_file("/etc/angstrom-version", st)) {
2041 st->print("Linux");
2042 }
2043 st->cr();
2045 // kernel
2046 st->print("uname:");
2047 struct utsname name;
2048 uname(&name);
2049 st->print(name.sysname); st->print(" ");
2050 st->print(name.release); st->print(" ");
2051 st->print(name.version); st->print(" ");
2052 st->print(name.machine);
2053 st->cr();
2055 // Print warning if unsafe chroot environment detected
2056 if (unsafe_chroot_detected) {
2057 st->print("WARNING!! ");
2058 st->print_cr(unstable_chroot_error);
2059 }
2061 // libc, pthread
2062 st->print("libc:");
2063 st->print(os::Linux::glibc_version()); st->print(" ");
2064 st->print(os::Linux::libpthread_version()); st->print(" ");
2065 if (os::Linux::is_LinuxThreads()) {
2066 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed");
2067 }
2068 st->cr();
2070 // rlimit
2071 st->print("rlimit:");
2072 struct rlimit rlim;
2074 st->print(" STACK ");
2075 getrlimit(RLIMIT_STACK, &rlim);
2076 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2077 else st->print("%uk", rlim.rlim_cur >> 10);
2079 st->print(", CORE ");
2080 getrlimit(RLIMIT_CORE, &rlim);
2081 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2082 else st->print("%uk", rlim.rlim_cur >> 10);
2084 st->print(", NPROC ");
2085 getrlimit(RLIMIT_NPROC, &rlim);
2086 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2087 else st->print("%d", rlim.rlim_cur);
2089 st->print(", NOFILE ");
2090 getrlimit(RLIMIT_NOFILE, &rlim);
2091 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2092 else st->print("%d", rlim.rlim_cur);
2094 st->print(", AS ");
2095 getrlimit(RLIMIT_AS, &rlim);
2096 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2097 else st->print("%uk", rlim.rlim_cur >> 10);
2098 st->cr();
2100 // load average
2101 st->print("load average:");
2102 double loadavg[3];
2103 os::loadavg(loadavg, 3);
2104 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
2105 st->cr();
2107 // meminfo
2108 st->print("\n/proc/meminfo:\n");
2109 _print_ascii_file("/proc/meminfo", st);
2110 st->cr();
2111 }
2113 void os::pd_print_cpu_info(outputStream* st) {
2114 st->print("\n/proc/cpuinfo:\n");
2115 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2116 st->print(" <Not Available>");
2117 }
2118 st->cr();
2119 }
2121 void os::print_memory_info(outputStream* st) {
2123 st->print("Memory:");
2124 st->print(" %dk page", os::vm_page_size()>>10);
2126 // values in struct sysinfo are "unsigned long"
2127 struct sysinfo si;
2128 sysinfo(&si);
2130 st->print(", physical " UINT64_FORMAT "k",
2131 os::physical_memory() >> 10);
2132 st->print("(" UINT64_FORMAT "k free)",
2133 os::available_memory() >> 10);
2134 st->print(", swap " UINT64_FORMAT "k",
2135 ((jlong)si.totalswap * si.mem_unit) >> 10);
2136 st->print("(" UINT64_FORMAT "k free)",
2137 ((jlong)si.freeswap * si.mem_unit) >> 10);
2138 st->cr();
2139 }
2141 // Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific
2142 // but they're the same for all the linux arch that we support
2143 // and they're the same for solaris but there's no common place to put this.
2144 const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR",
2145 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG",
2146 "ILL_COPROC", "ILL_BADSTK" };
2148 const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV",
2149 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES",
2150 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" };
2152 const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" };
2154 const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" };
2156 void os::print_siginfo(outputStream* st, void* siginfo) {
2157 st->print("siginfo:");
2159 const int buflen = 100;
2160 char buf[buflen];
2161 siginfo_t *si = (siginfo_t*)siginfo;
2162 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen));
2163 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) {
2164 st->print("si_errno=%s", buf);
2165 } else {
2166 st->print("si_errno=%d", si->si_errno);
2167 }
2168 const int c = si->si_code;
2169 assert(c > 0, "unexpected si_code");
2170 switch (si->si_signo) {
2171 case SIGILL:
2172 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]);
2173 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2174 break;
2175 case SIGFPE:
2176 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]);
2177 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2178 break;
2179 case SIGSEGV:
2180 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]);
2181 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2182 break;
2183 case SIGBUS:
2184 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]);
2185 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2186 break;
2187 default:
2188 st->print(", si_code=%d", si->si_code);
2189 // no si_addr
2190 }
2192 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
2193 UseSharedSpaces) {
2194 FileMapInfo* mapinfo = FileMapInfo::current_info();
2195 if (mapinfo->is_in_shared_space(si->si_addr)) {
2196 st->print("\n\nError accessing class data sharing archive." \
2197 " Mapped file inaccessible during execution, " \
2198 " possible disk/network problem.");
2199 }
2200 }
2201 st->cr();
2202 }
2205 static void print_signal_handler(outputStream* st, int sig,
2206 char* buf, size_t buflen);
2208 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2209 st->print_cr("Signal Handlers:");
2210 print_signal_handler(st, SIGSEGV, buf, buflen);
2211 print_signal_handler(st, SIGBUS , buf, buflen);
2212 print_signal_handler(st, SIGFPE , buf, buflen);
2213 print_signal_handler(st, SIGPIPE, buf, buflen);
2214 print_signal_handler(st, SIGXFSZ, buf, buflen);
2215 print_signal_handler(st, SIGILL , buf, buflen);
2216 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
2217 print_signal_handler(st, SR_signum, buf, buflen);
2218 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2219 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2220 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2221 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2222 }
2224 static char saved_jvm_path[MAXPATHLEN] = {0};
2226 // Find the full path to the current module, libjvm.so or libjvm_g.so
2227 void os::jvm_path(char *buf, jint buflen) {
2228 // Error checking.
2229 if (buflen < MAXPATHLEN) {
2230 assert(false, "must use a large-enough buffer");
2231 buf[0] = '\0';
2232 return;
2233 }
2234 // Lazy resolve the path to current module.
2235 if (saved_jvm_path[0] != 0) {
2236 strcpy(buf, saved_jvm_path);
2237 return;
2238 }
2240 char dli_fname[MAXPATHLEN];
2241 bool ret = dll_address_to_library_name(
2242 CAST_FROM_FN_PTR(address, os::jvm_path),
2243 dli_fname, sizeof(dli_fname), NULL);
2244 assert(ret != 0, "cannot locate libjvm");
2245 char *rp = realpath(dli_fname, buf);
2246 if (rp == NULL)
2247 return;
2249 if (Arguments::created_by_gamma_launcher()) {
2250 // Support for the gamma launcher. Typical value for buf is
2251 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at
2252 // the right place in the string, then assume we are installed in a JDK and
2253 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix
2254 // up the path so it looks like libjvm.so is installed there (append a
2255 // fake suffix hotspot/libjvm.so).
2256 const char *p = buf + strlen(buf) - 1;
2257 for (int count = 0; p > buf && count < 5; ++count) {
2258 for (--p; p > buf && *p != '/'; --p)
2259 /* empty */ ;
2260 }
2262 if (strncmp(p, "/jre/lib/", 9) != 0) {
2263 // Look for JAVA_HOME in the environment.
2264 char* java_home_var = ::getenv("JAVA_HOME");
2265 if (java_home_var != NULL && java_home_var[0] != 0) {
2266 char* jrelib_p;
2267 int len;
2269 // Check the current module name "libjvm.so" or "libjvm_g.so".
2270 p = strrchr(buf, '/');
2271 assert(strstr(p, "/libjvm") == p, "invalid library name");
2272 p = strstr(p, "_g") ? "_g" : "";
2274 rp = realpath(java_home_var, buf);
2275 if (rp == NULL)
2276 return;
2278 // determine if this is a legacy image or modules image
2279 // modules image doesn't have "jre" subdirectory
2280 len = strlen(buf);
2281 jrelib_p = buf + len;
2282 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch);
2283 if (0 != access(buf, F_OK)) {
2284 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch);
2285 }
2287 if (0 == access(buf, F_OK)) {
2288 // Use current module name "libjvm[_g].so" instead of
2289 // "libjvm"debug_only("_g")".so" since for fastdebug version
2290 // we should have "libjvm.so" but debug_only("_g") adds "_g"!
2291 len = strlen(buf);
2292 snprintf(buf + len, buflen-len, "/hotspot/libjvm%s.so", p);
2293 } else {
2294 // Go back to path of .so
2295 rp = realpath(dli_fname, buf);
2296 if (rp == NULL)
2297 return;
2298 }
2299 }
2300 }
2301 }
2303 strcpy(saved_jvm_path, buf);
2304 }
2306 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2307 // no prefix required, not even "_"
2308 }
2310 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2311 // no suffix required
2312 }
2314 ////////////////////////////////////////////////////////////////////////////////
2315 // sun.misc.Signal support
2317 static volatile jint sigint_count = 0;
2319 static void
2320 UserHandler(int sig, void *siginfo, void *context) {
2321 // 4511530 - sem_post is serialized and handled by the manager thread. When
2322 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2323 // don't want to flood the manager thread with sem_post requests.
2324 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
2325 return;
2327 // Ctrl-C is pressed during error reporting, likely because the error
2328 // handler fails to abort. Let VM die immediately.
2329 if (sig == SIGINT && is_error_reported()) {
2330 os::die();
2331 }
2333 os::signal_notify(sig);
2334 }
2336 void* os::user_handler() {
2337 return CAST_FROM_FN_PTR(void*, UserHandler);
2338 }
2340 extern "C" {
2341 typedef void (*sa_handler_t)(int);
2342 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2343 }
2345 void* os::signal(int signal_number, void* handler) {
2346 struct sigaction sigAct, oldSigAct;
2348 sigfillset(&(sigAct.sa_mask));
2349 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2350 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2352 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2353 // -1 means registration failed
2354 return (void *)-1;
2355 }
2357 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2358 }
2360 void os::signal_raise(int signal_number) {
2361 ::raise(signal_number);
2362 }
2364 /*
2365 * The following code is moved from os.cpp for making this
2366 * code platform specific, which it is by its very nature.
2367 */
2369 // Will be modified when max signal is changed to be dynamic
2370 int os::sigexitnum_pd() {
2371 return NSIG;
2372 }
2374 // a counter for each possible signal value
2375 static volatile jint pending_signals[NSIG+1] = { 0 };
2377 // Linux(POSIX) specific hand shaking semaphore.
2378 static sem_t sig_sem;
2380 void os::signal_init_pd() {
2381 // Initialize signal structures
2382 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2384 // Initialize signal semaphore
2385 ::sem_init(&sig_sem, 0, 0);
2386 }
2388 void os::signal_notify(int sig) {
2389 Atomic::inc(&pending_signals[sig]);
2390 ::sem_post(&sig_sem);
2391 }
2393 static int check_pending_signals(bool wait) {
2394 Atomic::store(0, &sigint_count);
2395 for (;;) {
2396 for (int i = 0; i < NSIG + 1; i++) {
2397 jint n = pending_signals[i];
2398 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2399 return i;
2400 }
2401 }
2402 if (!wait) {
2403 return -1;
2404 }
2405 JavaThread *thread = JavaThread::current();
2406 ThreadBlockInVM tbivm(thread);
2408 bool threadIsSuspended;
2409 do {
2410 thread->set_suspend_equivalent();
2411 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2412 ::sem_wait(&sig_sem);
2414 // were we externally suspended while we were waiting?
2415 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2416 if (threadIsSuspended) {
2417 //
2418 // The semaphore has been incremented, but while we were waiting
2419 // another thread suspended us. We don't want to continue running
2420 // while suspended because that would surprise the thread that
2421 // suspended us.
2422 //
2423 ::sem_post(&sig_sem);
2425 thread->java_suspend_self();
2426 }
2427 } while (threadIsSuspended);
2428 }
2429 }
2431 int os::signal_lookup() {
2432 return check_pending_signals(false);
2433 }
2435 int os::signal_wait() {
2436 return check_pending_signals(true);
2437 }
2439 ////////////////////////////////////////////////////////////////////////////////
2440 // Virtual Memory
2442 int os::vm_page_size() {
2443 // Seems redundant as all get out
2444 assert(os::Linux::page_size() != -1, "must call os::init");
2445 return os::Linux::page_size();
2446 }
2448 // Solaris allocates memory by pages.
2449 int os::vm_allocation_granularity() {
2450 assert(os::Linux::page_size() != -1, "must call os::init");
2451 return os::Linux::page_size();
2452 }
2454 // Rationale behind this function:
2455 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2456 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2457 // samples for JITted code. Here we create private executable mapping over the code cache
2458 // and then we can use standard (well, almost, as mapping can change) way to provide
2459 // info for the reporting script by storing timestamp and location of symbol
2460 void linux_wrap_code(char* base, size_t size) {
2461 static volatile jint cnt = 0;
2463 if (!UseOprofile) {
2464 return;
2465 }
2467 char buf[PATH_MAX+1];
2468 int num = Atomic::add(1, &cnt);
2470 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2471 os::get_temp_directory(), os::current_process_id(), num);
2472 unlink(buf);
2474 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2476 if (fd != -1) {
2477 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2478 if (rv != (off_t)-1) {
2479 if (::write(fd, "", 1) == 1) {
2480 mmap(base, size,
2481 PROT_READ|PROT_WRITE|PROT_EXEC,
2482 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2483 }
2484 }
2485 ::close(fd);
2486 unlink(buf);
2487 }
2488 }
2490 // NOTE: Linux kernel does not really reserve the pages for us.
2491 // All it does is to check if there are enough free pages
2492 // left at the time of mmap(). This could be a potential
2493 // problem.
2494 bool os::commit_memory(char* addr, size_t size, bool exec) {
2495 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2496 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2497 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2498 if (res != (uintptr_t) MAP_FAILED) {
2499 if (UseNUMAInterleaving) {
2500 numa_make_global(addr, size);
2501 }
2502 return true;
2503 }
2504 return false;
2505 }
2507 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2508 #ifndef MAP_HUGETLB
2509 #define MAP_HUGETLB 0x40000
2510 #endif
2512 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2513 #ifndef MADV_HUGEPAGE
2514 #define MADV_HUGEPAGE 14
2515 #endif
2517 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
2518 bool exec) {
2519 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) {
2520 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2521 uintptr_t res =
2522 (uintptr_t) ::mmap(addr, size, prot,
2523 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS|MAP_HUGETLB,
2524 -1, 0);
2525 if (res != (uintptr_t) MAP_FAILED) {
2526 if (UseNUMAInterleaving) {
2527 numa_make_global(addr, size);
2528 }
2529 return true;
2530 }
2531 // Fall through and try to use small pages
2532 }
2534 if (commit_memory(addr, size, exec)) {
2535 realign_memory(addr, size, alignment_hint);
2536 return true;
2537 }
2538 return false;
2539 }
2541 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2542 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) {
2543 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2544 // be supported or the memory may already be backed by huge pages.
2545 ::madvise(addr, bytes, MADV_HUGEPAGE);
2546 }
2547 }
2549 void os::free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2550 commit_memory(addr, bytes, alignment_hint, false);
2551 }
2553 void os::numa_make_global(char *addr, size_t bytes) {
2554 Linux::numa_interleave_memory(addr, bytes);
2555 }
2557 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2558 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2559 }
2561 bool os::numa_topology_changed() { return false; }
2563 size_t os::numa_get_groups_num() {
2564 int max_node = Linux::numa_max_node();
2565 return max_node > 0 ? max_node + 1 : 1;
2566 }
2568 int os::numa_get_group_id() {
2569 int cpu_id = Linux::sched_getcpu();
2570 if (cpu_id != -1) {
2571 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2572 if (lgrp_id != -1) {
2573 return lgrp_id;
2574 }
2575 }
2576 return 0;
2577 }
2579 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2580 for (size_t i = 0; i < size; i++) {
2581 ids[i] = i;
2582 }
2583 return size;
2584 }
2586 bool os::get_page_info(char *start, page_info* info) {
2587 return false;
2588 }
2590 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2591 return end;
2592 }
2595 int os::Linux::sched_getcpu_syscall(void) {
2596 unsigned int cpu;
2597 int retval = -1;
2599 #if defined(IA32)
2600 # ifndef SYS_getcpu
2601 # define SYS_getcpu 318
2602 # endif
2603 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2604 #elif defined(AMD64)
2605 // Unfortunately we have to bring all these macros here from vsyscall.h
2606 // to be able to compile on old linuxes.
2607 # define __NR_vgetcpu 2
2608 # define VSYSCALL_START (-10UL << 20)
2609 # define VSYSCALL_SIZE 1024
2610 # define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2611 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2612 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2613 retval = vgetcpu(&cpu, NULL, NULL);
2614 #endif
2616 return (retval == -1) ? retval : cpu;
2617 }
2619 // Something to do with the numa-aware allocator needs these symbols
2620 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2621 extern "C" JNIEXPORT void numa_error(char *where) { }
2622 extern "C" JNIEXPORT int fork1() { return fork(); }
2625 // If we are running with libnuma version > 2, then we should
2626 // be trying to use symbols with versions 1.1
2627 // If we are running with earlier version, which did not have symbol versions,
2628 // we should use the base version.
2629 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2630 void *f = dlvsym(handle, name, "libnuma_1.1");
2631 if (f == NULL) {
2632 f = dlsym(handle, name);
2633 }
2634 return f;
2635 }
2637 bool os::Linux::libnuma_init() {
2638 // sched_getcpu() should be in libc.
2639 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2640 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2642 // If it's not, try a direct syscall.
2643 if (sched_getcpu() == -1)
2644 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, (void*)&sched_getcpu_syscall));
2646 if (sched_getcpu() != -1) { // Does it work?
2647 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2648 if (handle != NULL) {
2649 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2650 libnuma_dlsym(handle, "numa_node_to_cpus")));
2651 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2652 libnuma_dlsym(handle, "numa_max_node")));
2653 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2654 libnuma_dlsym(handle, "numa_available")));
2655 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2656 libnuma_dlsym(handle, "numa_tonode_memory")));
2657 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2658 libnuma_dlsym(handle, "numa_interleave_memory")));
2661 if (numa_available() != -1) {
2662 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2663 // Create a cpu -> node mapping
2664 _cpu_to_node = new (ResourceObj::C_HEAP) GrowableArray<int>(0, true);
2665 rebuild_cpu_to_node_map();
2666 return true;
2667 }
2668 }
2669 }
2670 return false;
2671 }
2673 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2674 // The table is later used in get_node_by_cpu().
2675 void os::Linux::rebuild_cpu_to_node_map() {
2676 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2677 // in libnuma (possible values are starting from 16,
2678 // and continuing up with every other power of 2, but less
2679 // than the maximum number of CPUs supported by kernel), and
2680 // is a subject to change (in libnuma version 2 the requirements
2681 // are more reasonable) we'll just hardcode the number they use
2682 // in the library.
2683 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2685 size_t cpu_num = os::active_processor_count();
2686 size_t cpu_map_size = NCPUS / BitsPerCLong;
2687 size_t cpu_map_valid_size =
2688 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2690 cpu_to_node()->clear();
2691 cpu_to_node()->at_grow(cpu_num - 1);
2692 size_t node_num = numa_get_groups_num();
2694 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size);
2695 for (size_t i = 0; i < node_num; i++) {
2696 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2697 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2698 if (cpu_map[j] != 0) {
2699 for (size_t k = 0; k < BitsPerCLong; k++) {
2700 if (cpu_map[j] & (1UL << k)) {
2701 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
2702 }
2703 }
2704 }
2705 }
2706 }
2707 }
2708 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
2709 }
2711 int os::Linux::get_node_by_cpu(int cpu_id) {
2712 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2713 return cpu_to_node()->at(cpu_id);
2714 }
2715 return -1;
2716 }
2718 GrowableArray<int>* os::Linux::_cpu_to_node;
2719 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2720 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2721 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2722 os::Linux::numa_available_func_t os::Linux::_numa_available;
2723 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2724 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2725 unsigned long* os::Linux::_numa_all_nodes;
2727 bool os::uncommit_memory(char* addr, size_t size) {
2728 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2729 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2730 return res != (uintptr_t) MAP_FAILED;
2731 }
2733 // Linux uses a growable mapping for the stack, and if the mapping for
2734 // the stack guard pages is not removed when we detach a thread the
2735 // stack cannot grow beyond the pages where the stack guard was
2736 // mapped. If at some point later in the process the stack expands to
2737 // that point, the Linux kernel cannot expand the stack any further
2738 // because the guard pages are in the way, and a segfault occurs.
2739 //
2740 // However, it's essential not to split the stack region by unmapping
2741 // a region (leaving a hole) that's already part of the stack mapping,
2742 // so if the stack mapping has already grown beyond the guard pages at
2743 // the time we create them, we have to truncate the stack mapping.
2744 // So, we need to know the extent of the stack mapping when
2745 // create_stack_guard_pages() is called.
2747 // Find the bounds of the stack mapping. Return true for success.
2748 //
2749 // We only need this for stacks that are growable: at the time of
2750 // writing thread stacks don't use growable mappings (i.e. those
2751 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
2752 // only applies to the main thread.
2754 static
2755 bool get_stack_bounds(uintptr_t *bottom, uintptr_t *top) {
2757 char buf[128];
2758 int fd, sz;
2760 if ((fd = ::open("/proc/self/maps", O_RDONLY)) < 0) {
2761 return false;
2762 }
2764 const char kw[] = "[stack]";
2765 const int kwlen = sizeof(kw)-1;
2767 // Address part of /proc/self/maps couldn't be more than 128 bytes
2768 while ((sz = os::get_line_chars(fd, buf, sizeof(buf))) > 0) {
2769 if (sz > kwlen && ::memcmp(buf+sz-kwlen, kw, kwlen) == 0) {
2770 // Extract addresses
2771 if (sscanf(buf, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) {
2772 uintptr_t sp = (uintptr_t) __builtin_frame_address(0);
2773 if (sp >= *bottom && sp <= *top) {
2774 ::close(fd);
2775 return true;
2776 }
2777 }
2778 }
2779 }
2781 ::close(fd);
2782 return false;
2783 }
2786 // If the (growable) stack mapping already extends beyond the point
2787 // where we're going to put our guard pages, truncate the mapping at
2788 // that point by munmap()ping it. This ensures that when we later
2789 // munmap() the guard pages we don't leave a hole in the stack
2790 // mapping. This only affects the main/initial thread, but guard
2791 // against future OS changes
2792 bool os::create_stack_guard_pages(char* addr, size_t size) {
2793 uintptr_t stack_extent, stack_base;
2794 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true);
2795 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) {
2796 assert(os::Linux::is_initial_thread(),
2797 "growable stack in non-initial thread");
2798 if (stack_extent < (uintptr_t)addr)
2799 ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent);
2800 }
2802 return os::commit_memory(addr, size);
2803 }
2805 // If this is a growable mapping, remove the guard pages entirely by
2806 // munmap()ping them. If not, just call uncommit_memory(). This only
2807 // affects the main/initial thread, but guard against future OS changes
2808 bool os::remove_stack_guard_pages(char* addr, size_t size) {
2809 uintptr_t stack_extent, stack_base;
2810 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true);
2811 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) {
2812 assert(os::Linux::is_initial_thread(),
2813 "growable stack in non-initial thread");
2815 return ::munmap(addr, size) == 0;
2816 }
2818 return os::uncommit_memory(addr, size);
2819 }
2821 static address _highest_vm_reserved_address = NULL;
2823 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
2824 // at 'requested_addr'. If there are existing memory mappings at the same
2825 // location, however, they will be overwritten. If 'fixed' is false,
2826 // 'requested_addr' is only treated as a hint, the return value may or
2827 // may not start from the requested address. Unlike Linux mmap(), this
2828 // function returns NULL to indicate failure.
2829 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
2830 char * addr;
2831 int flags;
2833 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
2834 if (fixed) {
2835 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
2836 flags |= MAP_FIXED;
2837 }
2839 // Map uncommitted pages PROT_READ and PROT_WRITE, change access
2840 // to PROT_EXEC if executable when we commit the page.
2841 addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE,
2842 flags, -1, 0);
2844 if (addr != MAP_FAILED) {
2845 // anon_mmap() should only get called during VM initialization,
2846 // don't need lock (actually we can skip locking even it can be called
2847 // from multiple threads, because _highest_vm_reserved_address is just a
2848 // hint about the upper limit of non-stack memory regions.)
2849 if ((address)addr + bytes > _highest_vm_reserved_address) {
2850 _highest_vm_reserved_address = (address)addr + bytes;
2851 }
2852 }
2854 return addr == MAP_FAILED ? NULL : addr;
2855 }
2857 // Don't update _highest_vm_reserved_address, because there might be memory
2858 // regions above addr + size. If so, releasing a memory region only creates
2859 // a hole in the address space, it doesn't help prevent heap-stack collision.
2860 //
2861 static int anon_munmap(char * addr, size_t size) {
2862 return ::munmap(addr, size) == 0;
2863 }
2865 char* os::reserve_memory(size_t bytes, char* requested_addr,
2866 size_t alignment_hint) {
2867 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
2868 }
2870 bool os::release_memory(char* addr, size_t size) {
2871 return anon_munmap(addr, size);
2872 }
2874 static address highest_vm_reserved_address() {
2875 return _highest_vm_reserved_address;
2876 }
2878 static bool linux_mprotect(char* addr, size_t size, int prot) {
2879 // Linux wants the mprotect address argument to be page aligned.
2880 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
2882 // According to SUSv3, mprotect() should only be used with mappings
2883 // established by mmap(), and mmap() always maps whole pages. Unaligned
2884 // 'addr' likely indicates problem in the VM (e.g. trying to change
2885 // protection of malloc'ed or statically allocated memory). Check the
2886 // caller if you hit this assert.
2887 assert(addr == bottom, "sanity check");
2889 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
2890 return ::mprotect(bottom, size, prot) == 0;
2891 }
2893 // Set protections specified
2894 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
2895 bool is_committed) {
2896 unsigned int p = 0;
2897 switch (prot) {
2898 case MEM_PROT_NONE: p = PROT_NONE; break;
2899 case MEM_PROT_READ: p = PROT_READ; break;
2900 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
2901 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
2902 default:
2903 ShouldNotReachHere();
2904 }
2905 // is_committed is unused.
2906 return linux_mprotect(addr, bytes, p);
2907 }
2909 bool os::guard_memory(char* addr, size_t size) {
2910 return linux_mprotect(addr, size, PROT_NONE);
2911 }
2913 bool os::unguard_memory(char* addr, size_t size) {
2914 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
2915 }
2917 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
2918 bool result = false;
2919 void *p = mmap (NULL, page_size, PROT_READ|PROT_WRITE,
2920 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
2921 -1, 0);
2923 if (p != (void *) -1) {
2924 // We don't know if this really is a huge page or not.
2925 FILE *fp = fopen("/proc/self/maps", "r");
2926 if (fp) {
2927 while (!feof(fp)) {
2928 char chars[257];
2929 long x = 0;
2930 if (fgets(chars, sizeof(chars), fp)) {
2931 if (sscanf(chars, "%lx-%*x", &x) == 1
2932 && x == (long)p) {
2933 if (strstr (chars, "hugepage")) {
2934 result = true;
2935 break;
2936 }
2937 }
2938 }
2939 }
2940 fclose(fp);
2941 }
2942 munmap (p, page_size);
2943 if (result)
2944 return true;
2945 }
2947 if (warn) {
2948 warning("HugeTLBFS is not supported by the operating system.");
2949 }
2951 return result;
2952 }
2954 /*
2955 * Set the coredump_filter bits to include largepages in core dump (bit 6)
2956 *
2957 * From the coredump_filter documentation:
2958 *
2959 * - (bit 0) anonymous private memory
2960 * - (bit 1) anonymous shared memory
2961 * - (bit 2) file-backed private memory
2962 * - (bit 3) file-backed shared memory
2963 * - (bit 4) ELF header pages in file-backed private memory areas (it is
2964 * effective only if the bit 2 is cleared)
2965 * - (bit 5) hugetlb private memory
2966 * - (bit 6) hugetlb shared memory
2967 */
2968 static void set_coredump_filter(void) {
2969 FILE *f;
2970 long cdm;
2972 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
2973 return;
2974 }
2976 if (fscanf(f, "%lx", &cdm) != 1) {
2977 fclose(f);
2978 return;
2979 }
2981 rewind(f);
2983 if ((cdm & LARGEPAGES_BIT) == 0) {
2984 cdm |= LARGEPAGES_BIT;
2985 fprintf(f, "%#lx", cdm);
2986 }
2988 fclose(f);
2989 }
2991 // Large page support
2993 static size_t _large_page_size = 0;
2995 void os::large_page_init() {
2996 if (!UseLargePages) {
2997 UseHugeTLBFS = false;
2998 UseSHM = false;
2999 return;
3000 }
3002 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && FLAG_IS_DEFAULT(UseSHM)) {
3003 // If UseLargePages is specified on the command line try both methods,
3004 // if it's default, then try only HugeTLBFS.
3005 if (FLAG_IS_DEFAULT(UseLargePages)) {
3006 UseHugeTLBFS = true;
3007 } else {
3008 UseHugeTLBFS = UseSHM = true;
3009 }
3010 }
3012 if (LargePageSizeInBytes) {
3013 _large_page_size = LargePageSizeInBytes;
3014 } else {
3015 // large_page_size on Linux is used to round up heap size. x86 uses either
3016 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3017 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3018 // page as large as 256M.
3019 //
3020 // Here we try to figure out page size by parsing /proc/meminfo and looking
3021 // for a line with the following format:
3022 // Hugepagesize: 2048 kB
3023 //
3024 // If we can't determine the value (e.g. /proc is not mounted, or the text
3025 // format has been changed), we'll use the largest page size supported by
3026 // the processor.
3028 #ifndef ZERO
3029 _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M)
3030 ARM_ONLY(2 * M) PPC_ONLY(4 * M);
3031 #endif // ZERO
3033 FILE *fp = fopen("/proc/meminfo", "r");
3034 if (fp) {
3035 while (!feof(fp)) {
3036 int x = 0;
3037 char buf[16];
3038 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3039 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3040 _large_page_size = x * K;
3041 break;
3042 }
3043 } else {
3044 // skip to next line
3045 for (;;) {
3046 int ch = fgetc(fp);
3047 if (ch == EOF || ch == (int)'\n') break;
3048 }
3049 }
3050 }
3051 fclose(fp);
3052 }
3053 }
3055 // print a warning if any large page related flag is specified on command line
3056 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3058 const size_t default_page_size = (size_t)Linux::page_size();
3059 if (_large_page_size > default_page_size) {
3060 _page_sizes[0] = _large_page_size;
3061 _page_sizes[1] = default_page_size;
3062 _page_sizes[2] = 0;
3063 }
3064 UseHugeTLBFS = UseHugeTLBFS &&
3065 Linux::hugetlbfs_sanity_check(warn_on_failure, _large_page_size);
3067 if (UseHugeTLBFS)
3068 UseSHM = false;
3070 UseLargePages = UseHugeTLBFS || UseSHM;
3072 set_coredump_filter();
3073 }
3075 #ifndef SHM_HUGETLB
3076 #define SHM_HUGETLB 04000
3077 #endif
3079 char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) {
3080 // "exec" is passed in but not used. Creating the shared image for
3081 // the code cache doesn't have an SHM_X executable permission to check.
3082 assert(UseLargePages && UseSHM, "only for SHM large pages");
3084 key_t key = IPC_PRIVATE;
3085 char *addr;
3087 bool warn_on_failure = UseLargePages &&
3088 (!FLAG_IS_DEFAULT(UseLargePages) ||
3089 !FLAG_IS_DEFAULT(LargePageSizeInBytes)
3090 );
3091 char msg[128];
3093 // Create a large shared memory region to attach to based on size.
3094 // Currently, size is the total size of the heap
3095 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3096 if (shmid == -1) {
3097 // Possible reasons for shmget failure:
3098 // 1. shmmax is too small for Java heap.
3099 // > check shmmax value: cat /proc/sys/kernel/shmmax
3100 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3101 // 2. not enough large page memory.
3102 // > check available large pages: cat /proc/meminfo
3103 // > increase amount of large pages:
3104 // echo new_value > /proc/sys/vm/nr_hugepages
3105 // Note 1: different Linux may use different name for this property,
3106 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3107 // Note 2: it's possible there's enough physical memory available but
3108 // they are so fragmented after a long run that they can't
3109 // coalesce into large pages. Try to reserve large pages when
3110 // the system is still "fresh".
3111 if (warn_on_failure) {
3112 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno);
3113 warning(msg);
3114 }
3115 return NULL;
3116 }
3118 // attach to the region
3119 addr = (char*)shmat(shmid, req_addr, 0);
3120 int err = errno;
3122 // Remove shmid. If shmat() is successful, the actual shared memory segment
3123 // will be deleted when it's detached by shmdt() or when the process
3124 // terminates. If shmat() is not successful this will remove the shared
3125 // segment immediately.
3126 shmctl(shmid, IPC_RMID, NULL);
3128 if ((intptr_t)addr == -1) {
3129 if (warn_on_failure) {
3130 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err);
3131 warning(msg);
3132 }
3133 return NULL;
3134 }
3136 if ((addr != NULL) && UseNUMAInterleaving) {
3137 numa_make_global(addr, bytes);
3138 }
3140 return addr;
3141 }
3143 bool os::release_memory_special(char* base, size_t bytes) {
3144 // detaching the SHM segment will also delete it, see reserve_memory_special()
3145 int rslt = shmdt(base);
3146 return rslt == 0;
3147 }
3149 size_t os::large_page_size() {
3150 return _large_page_size;
3151 }
3153 // HugeTLBFS allows application to commit large page memory on demand;
3154 // with SysV SHM the entire memory region must be allocated as shared
3155 // memory.
3156 bool os::can_commit_large_page_memory() {
3157 return UseHugeTLBFS;
3158 }
3160 bool os::can_execute_large_page_memory() {
3161 return UseHugeTLBFS;
3162 }
3164 // Reserve memory at an arbitrary address, only if that area is
3165 // available (and not reserved for something else).
3167 char* os::attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3168 const int max_tries = 10;
3169 char* base[max_tries];
3170 size_t size[max_tries];
3171 const size_t gap = 0x000000;
3173 // Assert only that the size is a multiple of the page size, since
3174 // that's all that mmap requires, and since that's all we really know
3175 // about at this low abstraction level. If we need higher alignment,
3176 // we can either pass an alignment to this method or verify alignment
3177 // in one of the methods further up the call chain. See bug 5044738.
3178 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3180 // Repeatedly allocate blocks until the block is allocated at the
3181 // right spot. Give up after max_tries. Note that reserve_memory() will
3182 // automatically update _highest_vm_reserved_address if the call is
3183 // successful. The variable tracks the highest memory address every reserved
3184 // by JVM. It is used to detect heap-stack collision if running with
3185 // fixed-stack LinuxThreads. Because here we may attempt to reserve more
3186 // space than needed, it could confuse the collision detecting code. To
3187 // solve the problem, save current _highest_vm_reserved_address and
3188 // calculate the correct value before return.
3189 address old_highest = _highest_vm_reserved_address;
3191 // Linux mmap allows caller to pass an address as hint; give it a try first,
3192 // if kernel honors the hint then we can return immediately.
3193 char * addr = anon_mmap(requested_addr, bytes, false);
3194 if (addr == requested_addr) {
3195 return requested_addr;
3196 }
3198 if (addr != NULL) {
3199 // mmap() is successful but it fails to reserve at the requested address
3200 anon_munmap(addr, bytes);
3201 }
3203 int i;
3204 for (i = 0; i < max_tries; ++i) {
3205 base[i] = reserve_memory(bytes);
3207 if (base[i] != NULL) {
3208 // Is this the block we wanted?
3209 if (base[i] == requested_addr) {
3210 size[i] = bytes;
3211 break;
3212 }
3214 // Does this overlap the block we wanted? Give back the overlapped
3215 // parts and try again.
3217 size_t top_overlap = requested_addr + (bytes + gap) - base[i];
3218 if (top_overlap >= 0 && top_overlap < bytes) {
3219 unmap_memory(base[i], top_overlap);
3220 base[i] += top_overlap;
3221 size[i] = bytes - top_overlap;
3222 } else {
3223 size_t bottom_overlap = base[i] + bytes - requested_addr;
3224 if (bottom_overlap >= 0 && bottom_overlap < bytes) {
3225 unmap_memory(requested_addr, bottom_overlap);
3226 size[i] = bytes - bottom_overlap;
3227 } else {
3228 size[i] = bytes;
3229 }
3230 }
3231 }
3232 }
3234 // Give back the unused reserved pieces.
3236 for (int j = 0; j < i; ++j) {
3237 if (base[j] != NULL) {
3238 unmap_memory(base[j], size[j]);
3239 }
3240 }
3242 if (i < max_tries) {
3243 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes);
3244 return requested_addr;
3245 } else {
3246 _highest_vm_reserved_address = old_highest;
3247 return NULL;
3248 }
3249 }
3251 size_t os::read(int fd, void *buf, unsigned int nBytes) {
3252 return ::read(fd, buf, nBytes);
3253 }
3255 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation.
3256 // Solaris uses poll(), linux uses park().
3257 // Poll() is likely a better choice, assuming that Thread.interrupt()
3258 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with
3259 // SIGSEGV, see 4355769.
3261 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
3262 assert(thread == Thread::current(), "thread consistency check");
3264 ParkEvent * const slp = thread->_SleepEvent ;
3265 slp->reset() ;
3266 OrderAccess::fence() ;
3268 if (interruptible) {
3269 jlong prevtime = javaTimeNanos();
3271 for (;;) {
3272 if (os::is_interrupted(thread, true)) {
3273 return OS_INTRPT;
3274 }
3276 jlong newtime = javaTimeNanos();
3278 if (newtime - prevtime < 0) {
3279 // time moving backwards, should only happen if no monotonic clock
3280 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3281 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3282 } else {
3283 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
3284 }
3286 if(millis <= 0) {
3287 return OS_OK;
3288 }
3290 prevtime = newtime;
3292 {
3293 assert(thread->is_Java_thread(), "sanity check");
3294 JavaThread *jt = (JavaThread *) thread;
3295 ThreadBlockInVM tbivm(jt);
3296 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
3298 jt->set_suspend_equivalent();
3299 // cleared by handle_special_suspend_equivalent_condition() or
3300 // java_suspend_self() via check_and_wait_while_suspended()
3302 slp->park(millis);
3304 // were we externally suspended while we were waiting?
3305 jt->check_and_wait_while_suspended();
3306 }
3307 }
3308 } else {
3309 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
3310 jlong prevtime = javaTimeNanos();
3312 for (;;) {
3313 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
3314 // the 1st iteration ...
3315 jlong newtime = javaTimeNanos();
3317 if (newtime - prevtime < 0) {
3318 // time moving backwards, should only happen if no monotonic clock
3319 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3320 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3321 } else {
3322 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
3323 }
3325 if(millis <= 0) break ;
3327 prevtime = newtime;
3328 slp->park(millis);
3329 }
3330 return OS_OK ;
3331 }
3332 }
3334 int os::naked_sleep() {
3335 // %% make the sleep time an integer flag. for now use 1 millisec.
3336 return os::sleep(Thread::current(), 1, false);
3337 }
3339 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3340 void os::infinite_sleep() {
3341 while (true) { // sleep forever ...
3342 ::sleep(100); // ... 100 seconds at a time
3343 }
3344 }
3346 // Used to convert frequent JVM_Yield() to nops
3347 bool os::dont_yield() {
3348 return DontYieldALot;
3349 }
3351 void os::yield() {
3352 sched_yield();
3353 }
3355 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;}
3357 void os::yield_all(int attempts) {
3358 // Yields to all threads, including threads with lower priorities
3359 // Threads on Linux are all with same priority. The Solaris style
3360 // os::yield_all() with nanosleep(1ms) is not necessary.
3361 sched_yield();
3362 }
3364 // Called from the tight loops to possibly influence time-sharing heuristics
3365 void os::loop_breaker(int attempts) {
3366 os::yield_all(attempts);
3367 }
3369 ////////////////////////////////////////////////////////////////////////////////
3370 // thread priority support
3372 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
3373 // only supports dynamic priority, static priority must be zero. For real-time
3374 // applications, Linux supports SCHED_RR which allows static priority (1-99).
3375 // However, for large multi-threaded applications, SCHED_RR is not only slower
3376 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
3377 // of 5 runs - Sep 2005).
3378 //
3379 // The following code actually changes the niceness of kernel-thread/LWP. It
3380 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
3381 // not the entire user process, and user level threads are 1:1 mapped to kernel
3382 // threads. It has always been the case, but could change in the future. For
3383 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
3384 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
3386 int os::java_to_os_priority[CriticalPriority + 1] = {
3387 19, // 0 Entry should never be used
3389 4, // 1 MinPriority
3390 3, // 2
3391 2, // 3
3393 1, // 4
3394 0, // 5 NormPriority
3395 -1, // 6
3397 -2, // 7
3398 -3, // 8
3399 -4, // 9 NearMaxPriority
3401 -5, // 10 MaxPriority
3403 -5 // 11 CriticalPriority
3404 };
3406 static int prio_init() {
3407 if (ThreadPriorityPolicy == 1) {
3408 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
3409 // if effective uid is not root. Perhaps, a more elegant way of doing
3410 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
3411 if (geteuid() != 0) {
3412 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
3413 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
3414 }
3415 ThreadPriorityPolicy = 0;
3416 }
3417 }
3418 if (UseCriticalJavaThreadPriority) {
3419 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
3420 }
3421 return 0;
3422 }
3424 OSReturn os::set_native_priority(Thread* thread, int newpri) {
3425 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK;
3427 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
3428 return (ret == 0) ? OS_OK : OS_ERR;
3429 }
3431 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
3432 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) {
3433 *priority_ptr = java_to_os_priority[NormPriority];
3434 return OS_OK;
3435 }
3437 errno = 0;
3438 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
3439 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
3440 }
3442 // Hint to the underlying OS that a task switch would not be good.
3443 // Void return because it's a hint and can fail.
3444 void os::hint_no_preempt() {}
3446 ////////////////////////////////////////////////////////////////////////////////
3447 // suspend/resume support
3449 // the low-level signal-based suspend/resume support is a remnant from the
3450 // old VM-suspension that used to be for java-suspension, safepoints etc,
3451 // within hotspot. Now there is a single use-case for this:
3452 // - calling get_thread_pc() on the VMThread by the flat-profiler task
3453 // that runs in the watcher thread.
3454 // The remaining code is greatly simplified from the more general suspension
3455 // code that used to be used.
3456 //
3457 // The protocol is quite simple:
3458 // - suspend:
3459 // - sends a signal to the target thread
3460 // - polls the suspend state of the osthread using a yield loop
3461 // - target thread signal handler (SR_handler) sets suspend state
3462 // and blocks in sigsuspend until continued
3463 // - resume:
3464 // - sets target osthread state to continue
3465 // - sends signal to end the sigsuspend loop in the SR_handler
3466 //
3467 // Note that the SR_lock plays no role in this suspend/resume protocol.
3468 //
3470 static void resume_clear_context(OSThread *osthread) {
3471 osthread->set_ucontext(NULL);
3472 osthread->set_siginfo(NULL);
3474 // notify the suspend action is completed, we have now resumed
3475 osthread->sr.clear_suspended();
3476 }
3478 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
3479 osthread->set_ucontext(context);
3480 osthread->set_siginfo(siginfo);
3481 }
3483 //
3484 // Handler function invoked when a thread's execution is suspended or
3485 // resumed. We have to be careful that only async-safe functions are
3486 // called here (Note: most pthread functions are not async safe and
3487 // should be avoided.)
3488 //
3489 // Note: sigwait() is a more natural fit than sigsuspend() from an
3490 // interface point of view, but sigwait() prevents the signal hander
3491 // from being run. libpthread would get very confused by not having
3492 // its signal handlers run and prevents sigwait()'s use with the
3493 // mutex granting granting signal.
3494 //
3495 // Currently only ever called on the VMThread
3496 //
3497 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
3498 // Save and restore errno to avoid confusing native code with EINTR
3499 // after sigsuspend.
3500 int old_errno = errno;
3502 Thread* thread = Thread::current();
3503 OSThread* osthread = thread->osthread();
3504 assert(thread->is_VM_thread(), "Must be VMThread");
3505 // read current suspend action
3506 int action = osthread->sr.suspend_action();
3507 if (action == SR_SUSPEND) {
3508 suspend_save_context(osthread, siginfo, context);
3510 // Notify the suspend action is about to be completed. do_suspend()
3511 // waits until SR_SUSPENDED is set and then returns. We will wait
3512 // here for a resume signal and that completes the suspend-other
3513 // action. do_suspend/do_resume is always called as a pair from
3514 // the same thread - so there are no races
3516 // notify the caller
3517 osthread->sr.set_suspended();
3519 sigset_t suspend_set; // signals for sigsuspend()
3521 // get current set of blocked signals and unblock resume signal
3522 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
3523 sigdelset(&suspend_set, SR_signum);
3525 // wait here until we are resumed
3526 do {
3527 sigsuspend(&suspend_set);
3528 // ignore all returns until we get a resume signal
3529 } while (osthread->sr.suspend_action() != SR_CONTINUE);
3531 resume_clear_context(osthread);
3533 } else {
3534 assert(action == SR_CONTINUE, "unexpected sr action");
3535 // nothing special to do - just leave the handler
3536 }
3538 errno = old_errno;
3539 }
3542 static int SR_initialize() {
3543 struct sigaction act;
3544 char *s;
3545 /* Get signal number to use for suspend/resume */
3546 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
3547 int sig = ::strtol(s, 0, 10);
3548 if (sig > 0 || sig < _NSIG) {
3549 SR_signum = sig;
3550 }
3551 }
3553 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
3554 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
3556 sigemptyset(&SR_sigset);
3557 sigaddset(&SR_sigset, SR_signum);
3559 /* Set up signal handler for suspend/resume */
3560 act.sa_flags = SA_RESTART|SA_SIGINFO;
3561 act.sa_handler = (void (*)(int)) SR_handler;
3563 // SR_signum is blocked by default.
3564 // 4528190 - We also need to block pthread restart signal (32 on all
3565 // supported Linux platforms). Note that LinuxThreads need to block
3566 // this signal for all threads to work properly. So we don't have
3567 // to use hard-coded signal number when setting up the mask.
3568 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
3570 if (sigaction(SR_signum, &act, 0) == -1) {
3571 return -1;
3572 }
3574 // Save signal flag
3575 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
3576 return 0;
3577 }
3579 static int SR_finalize() {
3580 return 0;
3581 }
3584 // returns true on success and false on error - really an error is fatal
3585 // but this seems the normal response to library errors
3586 static bool do_suspend(OSThread* osthread) {
3587 // mark as suspended and send signal
3588 osthread->sr.set_suspend_action(SR_SUSPEND);
3589 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3590 assert_status(status == 0, status, "pthread_kill");
3592 // check status and wait until notified of suspension
3593 if (status == 0) {
3594 for (int i = 0; !osthread->sr.is_suspended(); i++) {
3595 os::yield_all(i);
3596 }
3597 osthread->sr.set_suspend_action(SR_NONE);
3598 return true;
3599 }
3600 else {
3601 osthread->sr.set_suspend_action(SR_NONE);
3602 return false;
3603 }
3604 }
3606 static void do_resume(OSThread* osthread) {
3607 assert(osthread->sr.is_suspended(), "thread should be suspended");
3608 osthread->sr.set_suspend_action(SR_CONTINUE);
3610 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3611 assert_status(status == 0, status, "pthread_kill");
3612 // check status and wait unit notified of resumption
3613 if (status == 0) {
3614 for (int i = 0; osthread->sr.is_suspended(); i++) {
3615 os::yield_all(i);
3616 }
3617 }
3618 osthread->sr.set_suspend_action(SR_NONE);
3619 }
3621 ////////////////////////////////////////////////////////////////////////////////
3622 // interrupt support
3624 void os::interrupt(Thread* thread) {
3625 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3626 "possibility of dangling Thread pointer");
3628 OSThread* osthread = thread->osthread();
3630 if (!osthread->interrupted()) {
3631 osthread->set_interrupted(true);
3632 // More than one thread can get here with the same value of osthread,
3633 // resulting in multiple notifications. We do, however, want the store
3634 // to interrupted() to be visible to other threads before we execute unpark().
3635 OrderAccess::fence();
3636 ParkEvent * const slp = thread->_SleepEvent ;
3637 if (slp != NULL) slp->unpark() ;
3638 }
3640 // For JSR166. Unpark even if interrupt status already was set
3641 if (thread->is_Java_thread())
3642 ((JavaThread*)thread)->parker()->unpark();
3644 ParkEvent * ev = thread->_ParkEvent ;
3645 if (ev != NULL) ev->unpark() ;
3647 }
3649 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
3650 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3651 "possibility of dangling Thread pointer");
3653 OSThread* osthread = thread->osthread();
3655 bool interrupted = osthread->interrupted();
3657 if (interrupted && clear_interrupted) {
3658 osthread->set_interrupted(false);
3659 // consider thread->_SleepEvent->reset() ... optional optimization
3660 }
3662 return interrupted;
3663 }
3665 ///////////////////////////////////////////////////////////////////////////////////
3666 // signal handling (except suspend/resume)
3668 // This routine may be used by user applications as a "hook" to catch signals.
3669 // The user-defined signal handler must pass unrecognized signals to this
3670 // routine, and if it returns true (non-zero), then the signal handler must
3671 // return immediately. If the flag "abort_if_unrecognized" is true, then this
3672 // routine will never retun false (zero), but instead will execute a VM panic
3673 // routine kill the process.
3674 //
3675 // If this routine returns false, it is OK to call it again. This allows
3676 // the user-defined signal handler to perform checks either before or after
3677 // the VM performs its own checks. Naturally, the user code would be making
3678 // a serious error if it tried to handle an exception (such as a null check
3679 // or breakpoint) that the VM was generating for its own correct operation.
3680 //
3681 // This routine may recognize any of the following kinds of signals:
3682 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
3683 // It should be consulted by handlers for any of those signals.
3684 //
3685 // The caller of this routine must pass in the three arguments supplied
3686 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
3687 // field of the structure passed to sigaction(). This routine assumes that
3688 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
3689 //
3690 // Note that the VM will print warnings if it detects conflicting signal
3691 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
3692 //
3693 extern "C" JNIEXPORT int
3694 JVM_handle_linux_signal(int signo, siginfo_t* siginfo,
3695 void* ucontext, int abort_if_unrecognized);
3697 void signalHandler(int sig, siginfo_t* info, void* uc) {
3698 assert(info != NULL && uc != NULL, "it must be old kernel");
3699 JVM_handle_linux_signal(sig, info, uc, true);
3700 }
3703 // This boolean allows users to forward their own non-matching signals
3704 // to JVM_handle_linux_signal, harmlessly.
3705 bool os::Linux::signal_handlers_are_installed = false;
3707 // For signal-chaining
3708 struct sigaction os::Linux::sigact[MAXSIGNUM];
3709 unsigned int os::Linux::sigs = 0;
3710 bool os::Linux::libjsig_is_loaded = false;
3711 typedef struct sigaction *(*get_signal_t)(int);
3712 get_signal_t os::Linux::get_signal_action = NULL;
3714 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
3715 struct sigaction *actp = NULL;
3717 if (libjsig_is_loaded) {
3718 // Retrieve the old signal handler from libjsig
3719 actp = (*get_signal_action)(sig);
3720 }
3721 if (actp == NULL) {
3722 // Retrieve the preinstalled signal handler from jvm
3723 actp = get_preinstalled_handler(sig);
3724 }
3726 return actp;
3727 }
3729 static bool call_chained_handler(struct sigaction *actp, int sig,
3730 siginfo_t *siginfo, void *context) {
3731 // Call the old signal handler
3732 if (actp->sa_handler == SIG_DFL) {
3733 // It's more reasonable to let jvm treat it as an unexpected exception
3734 // instead of taking the default action.
3735 return false;
3736 } else if (actp->sa_handler != SIG_IGN) {
3737 if ((actp->sa_flags & SA_NODEFER) == 0) {
3738 // automaticlly block the signal
3739 sigaddset(&(actp->sa_mask), sig);
3740 }
3742 sa_handler_t hand;
3743 sa_sigaction_t sa;
3744 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
3745 // retrieve the chained handler
3746 if (siginfo_flag_set) {
3747 sa = actp->sa_sigaction;
3748 } else {
3749 hand = actp->sa_handler;
3750 }
3752 if ((actp->sa_flags & SA_RESETHAND) != 0) {
3753 actp->sa_handler = SIG_DFL;
3754 }
3756 // try to honor the signal mask
3757 sigset_t oset;
3758 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
3760 // call into the chained handler
3761 if (siginfo_flag_set) {
3762 (*sa)(sig, siginfo, context);
3763 } else {
3764 (*hand)(sig);
3765 }
3767 // restore the signal mask
3768 pthread_sigmask(SIG_SETMASK, &oset, 0);
3769 }
3770 // Tell jvm's signal handler the signal is taken care of.
3771 return true;
3772 }
3774 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
3775 bool chained = false;
3776 // signal-chaining
3777 if (UseSignalChaining) {
3778 struct sigaction *actp = get_chained_signal_action(sig);
3779 if (actp != NULL) {
3780 chained = call_chained_handler(actp, sig, siginfo, context);
3781 }
3782 }
3783 return chained;
3784 }
3786 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
3787 if ((( (unsigned int)1 << sig ) & sigs) != 0) {
3788 return &sigact[sig];
3789 }
3790 return NULL;
3791 }
3793 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
3794 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3795 sigact[sig] = oldAct;
3796 sigs |= (unsigned int)1 << sig;
3797 }
3799 // for diagnostic
3800 int os::Linux::sigflags[MAXSIGNUM];
3802 int os::Linux::get_our_sigflags(int sig) {
3803 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3804 return sigflags[sig];
3805 }
3807 void os::Linux::set_our_sigflags(int sig, int flags) {
3808 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3809 sigflags[sig] = flags;
3810 }
3812 void os::Linux::set_signal_handler(int sig, bool set_installed) {
3813 // Check for overwrite.
3814 struct sigaction oldAct;
3815 sigaction(sig, (struct sigaction*)NULL, &oldAct);
3817 void* oldhand = oldAct.sa_sigaction
3818 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3819 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3820 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
3821 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
3822 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
3823 if (AllowUserSignalHandlers || !set_installed) {
3824 // Do not overwrite; user takes responsibility to forward to us.
3825 return;
3826 } else if (UseSignalChaining) {
3827 // save the old handler in jvm
3828 save_preinstalled_handler(sig, oldAct);
3829 // libjsig also interposes the sigaction() call below and saves the
3830 // old sigaction on it own.
3831 } else {
3832 fatal(err_msg("Encountered unexpected pre-existing sigaction handler "
3833 "%#lx for signal %d.", (long)oldhand, sig));
3834 }
3835 }
3837 struct sigaction sigAct;
3838 sigfillset(&(sigAct.sa_mask));
3839 sigAct.sa_handler = SIG_DFL;
3840 if (!set_installed) {
3841 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3842 } else {
3843 sigAct.sa_sigaction = signalHandler;
3844 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3845 }
3846 // Save flags, which are set by ours
3847 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3848 sigflags[sig] = sigAct.sa_flags;
3850 int ret = sigaction(sig, &sigAct, &oldAct);
3851 assert(ret == 0, "check");
3853 void* oldhand2 = oldAct.sa_sigaction
3854 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3855 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3856 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
3857 }
3859 // install signal handlers for signals that HotSpot needs to
3860 // handle in order to support Java-level exception handling.
3862 void os::Linux::install_signal_handlers() {
3863 if (!signal_handlers_are_installed) {
3864 signal_handlers_are_installed = true;
3866 // signal-chaining
3867 typedef void (*signal_setting_t)();
3868 signal_setting_t begin_signal_setting = NULL;
3869 signal_setting_t end_signal_setting = NULL;
3870 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3871 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
3872 if (begin_signal_setting != NULL) {
3873 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3874 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
3875 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
3876 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
3877 libjsig_is_loaded = true;
3878 assert(UseSignalChaining, "should enable signal-chaining");
3879 }
3880 if (libjsig_is_loaded) {
3881 // Tell libjsig jvm is setting signal handlers
3882 (*begin_signal_setting)();
3883 }
3885 set_signal_handler(SIGSEGV, true);
3886 set_signal_handler(SIGPIPE, true);
3887 set_signal_handler(SIGBUS, true);
3888 set_signal_handler(SIGILL, true);
3889 set_signal_handler(SIGFPE, true);
3890 set_signal_handler(SIGXFSZ, true);
3892 if (libjsig_is_loaded) {
3893 // Tell libjsig jvm finishes setting signal handlers
3894 (*end_signal_setting)();
3895 }
3897 // We don't activate signal checker if libjsig is in place, we trust ourselves
3898 // and if UserSignalHandler is installed all bets are off.
3899 // Log that signal checking is off only if -verbose:jni is specified.
3900 if (CheckJNICalls) {
3901 if (libjsig_is_loaded) {
3902 if (PrintJNIResolving) {
3903 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
3904 }
3905 check_signals = false;
3906 }
3907 if (AllowUserSignalHandlers) {
3908 if (PrintJNIResolving) {
3909 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
3910 }
3911 check_signals = false;
3912 }
3913 }
3914 }
3915 }
3917 // This is the fastest way to get thread cpu time on Linux.
3918 // Returns cpu time (user+sys) for any thread, not only for current.
3919 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
3920 // It might work on 2.6.10+ with a special kernel/glibc patch.
3921 // For reference, please, see IEEE Std 1003.1-2004:
3922 // http://www.unix.org/single_unix_specification
3924 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
3925 struct timespec tp;
3926 int rc = os::Linux::clock_gettime(clockid, &tp);
3927 assert(rc == 0, "clock_gettime is expected to return 0 code");
3929 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
3930 }
3932 /////
3933 // glibc on Linux platform uses non-documented flag
3934 // to indicate, that some special sort of signal
3935 // trampoline is used.
3936 // We will never set this flag, and we should
3937 // ignore this flag in our diagnostic
3938 #ifdef SIGNIFICANT_SIGNAL_MASK
3939 #undef SIGNIFICANT_SIGNAL_MASK
3940 #endif
3941 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
3943 static const char* get_signal_handler_name(address handler,
3944 char* buf, int buflen) {
3945 int offset;
3946 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
3947 if (found) {
3948 // skip directory names
3949 const char *p1, *p2;
3950 p1 = buf;
3951 size_t len = strlen(os::file_separator());
3952 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
3953 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
3954 } else {
3955 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
3956 }
3957 return buf;
3958 }
3960 static void print_signal_handler(outputStream* st, int sig,
3961 char* buf, size_t buflen) {
3962 struct sigaction sa;
3964 sigaction(sig, NULL, &sa);
3966 // See comment for SIGNIFICANT_SIGNAL_MASK define
3967 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
3969 st->print("%s: ", os::exception_name(sig, buf, buflen));
3971 address handler = (sa.sa_flags & SA_SIGINFO)
3972 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
3973 : CAST_FROM_FN_PTR(address, sa.sa_handler);
3975 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
3976 st->print("SIG_DFL");
3977 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
3978 st->print("SIG_IGN");
3979 } else {
3980 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
3981 }
3983 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask);
3985 address rh = VMError::get_resetted_sighandler(sig);
3986 // May be, handler was resetted by VMError?
3987 if(rh != NULL) {
3988 handler = rh;
3989 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
3990 }
3992 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags);
3994 // Check: is it our handler?
3995 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
3996 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
3997 // It is our signal handler
3998 // check for flags, reset system-used one!
3999 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
4000 st->print(
4001 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
4002 os::Linux::get_our_sigflags(sig));
4003 }
4004 }
4005 st->cr();
4006 }
4009 #define DO_SIGNAL_CHECK(sig) \
4010 if (!sigismember(&check_signal_done, sig)) \
4011 os::Linux::check_signal_handler(sig)
4013 // This method is a periodic task to check for misbehaving JNI applications
4014 // under CheckJNI, we can add any periodic checks here
4016 void os::run_periodic_checks() {
4018 if (check_signals == false) return;
4020 // SEGV and BUS if overridden could potentially prevent
4021 // generation of hs*.log in the event of a crash, debugging
4022 // such a case can be very challenging, so we absolutely
4023 // check the following for a good measure:
4024 DO_SIGNAL_CHECK(SIGSEGV);
4025 DO_SIGNAL_CHECK(SIGILL);
4026 DO_SIGNAL_CHECK(SIGFPE);
4027 DO_SIGNAL_CHECK(SIGBUS);
4028 DO_SIGNAL_CHECK(SIGPIPE);
4029 DO_SIGNAL_CHECK(SIGXFSZ);
4032 // ReduceSignalUsage allows the user to override these handlers
4033 // see comments at the very top and jvm_solaris.h
4034 if (!ReduceSignalUsage) {
4035 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4036 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4037 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4038 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4039 }
4041 DO_SIGNAL_CHECK(SR_signum);
4042 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
4043 }
4045 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4047 static os_sigaction_t os_sigaction = NULL;
4049 void os::Linux::check_signal_handler(int sig) {
4050 char buf[O_BUFLEN];
4051 address jvmHandler = NULL;
4054 struct sigaction act;
4055 if (os_sigaction == NULL) {
4056 // only trust the default sigaction, in case it has been interposed
4057 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4058 if (os_sigaction == NULL) return;
4059 }
4061 os_sigaction(sig, (struct sigaction*)NULL, &act);
4064 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4066 address thisHandler = (act.sa_flags & SA_SIGINFO)
4067 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4068 : CAST_FROM_FN_PTR(address, act.sa_handler) ;
4071 switch(sig) {
4072 case SIGSEGV:
4073 case SIGBUS:
4074 case SIGFPE:
4075 case SIGPIPE:
4076 case SIGILL:
4077 case SIGXFSZ:
4078 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4079 break;
4081 case SHUTDOWN1_SIGNAL:
4082 case SHUTDOWN2_SIGNAL:
4083 case SHUTDOWN3_SIGNAL:
4084 case BREAK_SIGNAL:
4085 jvmHandler = (address)user_handler();
4086 break;
4088 case INTERRUPT_SIGNAL:
4089 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
4090 break;
4092 default:
4093 if (sig == SR_signum) {
4094 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4095 } else {
4096 return;
4097 }
4098 break;
4099 }
4101 if (thisHandler != jvmHandler) {
4102 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4103 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4104 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4105 // No need to check this sig any longer
4106 sigaddset(&check_signal_done, sig);
4107 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4108 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4109 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig));
4110 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags);
4111 // No need to check this sig any longer
4112 sigaddset(&check_signal_done, sig);
4113 }
4115 // Dump all the signal
4116 if (sigismember(&check_signal_done, sig)) {
4117 print_signal_handlers(tty, buf, O_BUFLEN);
4118 }
4119 }
4121 extern void report_error(char* file_name, int line_no, char* title, char* format, ...);
4123 extern bool signal_name(int signo, char* buf, size_t len);
4125 const char* os::exception_name(int exception_code, char* buf, size_t size) {
4126 if (0 < exception_code && exception_code <= SIGRTMAX) {
4127 // signal
4128 if (!signal_name(exception_code, buf, size)) {
4129 jio_snprintf(buf, size, "SIG%d", exception_code);
4130 }
4131 return buf;
4132 } else {
4133 return NULL;
4134 }
4135 }
4137 // this is called _before_ the most of global arguments have been parsed
4138 void os::init(void) {
4139 char dummy; /* used to get a guess on initial stack address */
4140 // first_hrtime = gethrtime();
4142 // With LinuxThreads the JavaMain thread pid (primordial thread)
4143 // is different than the pid of the java launcher thread.
4144 // So, on Linux, the launcher thread pid is passed to the VM
4145 // via the sun.java.launcher.pid property.
4146 // Use this property instead of getpid() if it was correctly passed.
4147 // See bug 6351349.
4148 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
4150 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
4152 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4154 init_random(1234567);
4156 ThreadCritical::initialize();
4158 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4159 if (Linux::page_size() == -1) {
4160 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)",
4161 strerror(errno)));
4162 }
4163 init_page_sizes((size_t) Linux::page_size());
4165 Linux::initialize_system_info();
4167 // main_thread points to the aboriginal thread
4168 Linux::_main_thread = pthread_self();
4170 Linux::clock_init();
4171 initial_time_count = os::elapsed_counter();
4172 pthread_mutex_init(&dl_mutex, NULL);
4173 }
4175 // To install functions for atexit system call
4176 extern "C" {
4177 static void perfMemory_exit_helper() {
4178 perfMemory_exit();
4179 }
4180 }
4182 // this is called _after_ the global arguments have been parsed
4183 jint os::init_2(void)
4184 {
4185 Linux::fast_thread_clock_init();
4187 // Allocate a single page and mark it as readable for safepoint polling
4188 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4189 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" );
4191 os::set_polling_page( polling_page );
4193 #ifndef PRODUCT
4194 if(Verbose && PrintMiscellaneous)
4195 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
4196 #endif
4198 if (!UseMembar) {
4199 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4200 guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page");
4201 os::set_memory_serialize_page( mem_serialize_page );
4203 #ifndef PRODUCT
4204 if(Verbose && PrintMiscellaneous)
4205 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
4206 #endif
4207 }
4209 os::large_page_init();
4211 // initialize suspend/resume support - must do this before signal_sets_init()
4212 if (SR_initialize() != 0) {
4213 perror("SR_initialize failed");
4214 return JNI_ERR;
4215 }
4217 Linux::signal_sets_init();
4218 Linux::install_signal_handlers();
4220 // Check minimum allowable stack size for thread creation and to initialize
4221 // the java system classes, including StackOverflowError - depends on page
4222 // size. Add a page for compiler2 recursion in main thread.
4223 // Add in 2*BytesPerWord times page size to account for VM stack during
4224 // class initialization depending on 32 or 64 bit VM.
4225 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed,
4226 (size_t)(StackYellowPages+StackRedPages+StackShadowPages+
4227 2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::page_size());
4229 size_t threadStackSizeInBytes = ThreadStackSize * K;
4230 if (threadStackSizeInBytes != 0 &&
4231 threadStackSizeInBytes < os::Linux::min_stack_allowed) {
4232 tty->print_cr("\nThe stack size specified is too small, "
4233 "Specify at least %dk",
4234 os::Linux::min_stack_allowed/ K);
4235 return JNI_ERR;
4236 }
4238 // Make the stack size a multiple of the page size so that
4239 // the yellow/red zones can be guarded.
4240 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
4241 vm_page_size()));
4243 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4245 Linux::libpthread_init();
4246 if (PrintMiscellaneous && (Verbose || WizardMode)) {
4247 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n",
4248 Linux::glibc_version(), Linux::libpthread_version(),
4249 Linux::is_floating_stack() ? "floating stack" : "fixed stack");
4250 }
4252 if (UseNUMA) {
4253 if (!Linux::libnuma_init()) {
4254 UseNUMA = false;
4255 } else {
4256 if ((Linux::numa_max_node() < 1)) {
4257 // There's only one node(they start from 0), disable NUMA.
4258 UseNUMA = false;
4259 }
4260 }
4261 // With SHM large pages we cannot uncommit a page, so there's not way
4262 // we can make the adaptive lgrp chunk resizing work. If the user specified
4263 // both UseNUMA and UseLargePages (or UseSHM) on the command line - warn and
4264 // disable adaptive resizing.
4265 if (UseNUMA && UseLargePages && UseSHM) {
4266 if (!FLAG_IS_DEFAULT(UseNUMA)) {
4267 if (FLAG_IS_DEFAULT(UseLargePages) && FLAG_IS_DEFAULT(UseSHM)) {
4268 UseLargePages = false;
4269 } else {
4270 warning("UseNUMA is not fully compatible with SHM large pages, disabling adaptive resizing");
4271 UseAdaptiveSizePolicy = false;
4272 UseAdaptiveNUMAChunkSizing = false;
4273 }
4274 } else {
4275 UseNUMA = false;
4276 }
4277 }
4278 if (!UseNUMA && ForceNUMA) {
4279 UseNUMA = true;
4280 }
4281 }
4283 if (MaxFDLimit) {
4284 // set the number of file descriptors to max. print out error
4285 // if getrlimit/setrlimit fails but continue regardless.
4286 struct rlimit nbr_files;
4287 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
4288 if (status != 0) {
4289 if (PrintMiscellaneous && (Verbose || WizardMode))
4290 perror("os::init_2 getrlimit failed");
4291 } else {
4292 nbr_files.rlim_cur = nbr_files.rlim_max;
4293 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
4294 if (status != 0) {
4295 if (PrintMiscellaneous && (Verbose || WizardMode))
4296 perror("os::init_2 setrlimit failed");
4297 }
4298 }
4299 }
4301 // Initialize lock used to serialize thread creation (see os::create_thread)
4302 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
4304 // at-exit methods are called in the reverse order of their registration.
4305 // atexit functions are called on return from main or as a result of a
4306 // call to exit(3C). There can be only 32 of these functions registered
4307 // and atexit() does not set errno.
4309 if (PerfAllowAtExitRegistration) {
4310 // only register atexit functions if PerfAllowAtExitRegistration is set.
4311 // atexit functions can be delayed until process exit time, which
4312 // can be problematic for embedded VM situations. Embedded VMs should
4313 // call DestroyJavaVM() to assure that VM resources are released.
4315 // note: perfMemory_exit_helper atexit function may be removed in
4316 // the future if the appropriate cleanup code can be added to the
4317 // VM_Exit VMOperation's doit method.
4318 if (atexit(perfMemory_exit_helper) != 0) {
4319 warning("os::init2 atexit(perfMemory_exit_helper) failed");
4320 }
4321 }
4323 // initialize thread priority policy
4324 prio_init();
4326 return JNI_OK;
4327 }
4329 // this is called at the end of vm_initialization
4330 void os::init_3(void)
4331 {
4332 #ifdef JAVASE_EMBEDDED
4333 // Start the MemNotifyThread
4334 if (LowMemoryProtection) {
4335 MemNotifyThread::start();
4336 }
4337 return;
4338 #endif
4339 }
4341 // Mark the polling page as unreadable
4342 void os::make_polling_page_unreadable(void) {
4343 if( !guard_memory((char*)_polling_page, Linux::page_size()) )
4344 fatal("Could not disable polling page");
4345 };
4347 // Mark the polling page as readable
4348 void os::make_polling_page_readable(void) {
4349 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
4350 fatal("Could not enable polling page");
4351 }
4352 };
4354 int os::active_processor_count() {
4355 // Linux doesn't yet have a (official) notion of processor sets,
4356 // so just return the number of online processors.
4357 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
4358 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
4359 return online_cpus;
4360 }
4362 void os::set_native_thread_name(const char *name) {
4363 // Not yet implemented.
4364 return;
4365 }
4367 bool os::distribute_processes(uint length, uint* distribution) {
4368 // Not yet implemented.
4369 return false;
4370 }
4372 bool os::bind_to_processor(uint processor_id) {
4373 // Not yet implemented.
4374 return false;
4375 }
4377 ///
4379 // Suspends the target using the signal mechanism and then grabs the PC before
4380 // resuming the target. Used by the flat-profiler only
4381 ExtendedPC os::get_thread_pc(Thread* thread) {
4382 // Make sure that it is called by the watcher for the VMThread
4383 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
4384 assert(thread->is_VM_thread(), "Can only be called for VMThread");
4386 ExtendedPC epc;
4388 OSThread* osthread = thread->osthread();
4389 if (do_suspend(osthread)) {
4390 if (osthread->ucontext() != NULL) {
4391 epc = os::Linux::ucontext_get_pc(osthread->ucontext());
4392 } else {
4393 // NULL context is unexpected, double-check this is the VMThread
4394 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
4395 }
4396 do_resume(osthread);
4397 }
4398 // failure means pthread_kill failed for some reason - arguably this is
4399 // a fatal problem, but such problems are ignored elsewhere
4401 return epc;
4402 }
4404 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime)
4405 {
4406 if (is_NPTL()) {
4407 return pthread_cond_timedwait(_cond, _mutex, _abstime);
4408 } else {
4409 #ifndef IA64
4410 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control
4411 // word back to default 64bit precision if condvar is signaled. Java
4412 // wants 53bit precision. Save and restore current value.
4413 int fpu = get_fpu_control_word();
4414 #endif // IA64
4415 int status = pthread_cond_timedwait(_cond, _mutex, _abstime);
4416 #ifndef IA64
4417 set_fpu_control_word(fpu);
4418 #endif // IA64
4419 return status;
4420 }
4421 }
4423 ////////////////////////////////////////////////////////////////////////////////
4424 // debug support
4426 static address same_page(address x, address y) {
4427 int page_bits = -os::vm_page_size();
4428 if ((intptr_t(x) & page_bits) == (intptr_t(y) & page_bits))
4429 return x;
4430 else if (x > y)
4431 return (address)(intptr_t(y) | ~page_bits) + 1;
4432 else
4433 return (address)(intptr_t(y) & page_bits);
4434 }
4436 bool os::find(address addr, outputStream* st) {
4437 Dl_info dlinfo;
4438 memset(&dlinfo, 0, sizeof(dlinfo));
4439 if (dladdr(addr, &dlinfo)) {
4440 st->print(PTR_FORMAT ": ", addr);
4441 if (dlinfo.dli_sname != NULL) {
4442 st->print("%s+%#x", dlinfo.dli_sname,
4443 addr - (intptr_t)dlinfo.dli_saddr);
4444 } else if (dlinfo.dli_fname) {
4445 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
4446 } else {
4447 st->print("<absolute address>");
4448 }
4449 if (dlinfo.dli_fname) {
4450 st->print(" in %s", dlinfo.dli_fname);
4451 }
4452 if (dlinfo.dli_fbase) {
4453 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
4454 }
4455 st->cr();
4457 if (Verbose) {
4458 // decode some bytes around the PC
4459 address begin = same_page(addr-40, addr);
4460 address end = same_page(addr+40, addr);
4461 address lowest = (address) dlinfo.dli_sname;
4462 if (!lowest) lowest = (address) dlinfo.dli_fbase;
4463 if (begin < lowest) begin = lowest;
4464 Dl_info dlinfo2;
4465 if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr
4466 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin)
4467 end = (address) dlinfo2.dli_saddr;
4468 Disassembler::decode(begin, end, st);
4469 }
4470 return true;
4471 }
4472 return false;
4473 }
4475 ////////////////////////////////////////////////////////////////////////////////
4476 // misc
4478 // This does not do anything on Linux. This is basically a hook for being
4479 // able to use structured exception handling (thread-local exception filters)
4480 // on, e.g., Win32.
4481 void
4482 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method,
4483 JavaCallArguments* args, Thread* thread) {
4484 f(value, method, args, thread);
4485 }
4487 void os::print_statistics() {
4488 }
4490 int os::message_box(const char* title, const char* message) {
4491 int i;
4492 fdStream err(defaultStream::error_fd());
4493 for (i = 0; i < 78; i++) err.print_raw("=");
4494 err.cr();
4495 err.print_raw_cr(title);
4496 for (i = 0; i < 78; i++) err.print_raw("-");
4497 err.cr();
4498 err.print_raw_cr(message);
4499 for (i = 0; i < 78; i++) err.print_raw("=");
4500 err.cr();
4502 char buf[16];
4503 // Prevent process from exiting upon "read error" without consuming all CPU
4504 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
4506 return buf[0] == 'y' || buf[0] == 'Y';
4507 }
4509 int os::stat(const char *path, struct stat *sbuf) {
4510 char pathbuf[MAX_PATH];
4511 if (strlen(path) > MAX_PATH - 1) {
4512 errno = ENAMETOOLONG;
4513 return -1;
4514 }
4515 os::native_path(strcpy(pathbuf, path));
4516 return ::stat(pathbuf, sbuf);
4517 }
4519 bool os::check_heap(bool force) {
4520 return true;
4521 }
4523 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
4524 return ::vsnprintf(buf, count, format, args);
4525 }
4527 // Is a (classpath) directory empty?
4528 bool os::dir_is_empty(const char* path) {
4529 DIR *dir = NULL;
4530 struct dirent *ptr;
4532 dir = opendir(path);
4533 if (dir == NULL) return true;
4535 /* Scan the directory */
4536 bool result = true;
4537 char buf[sizeof(struct dirent) + MAX_PATH];
4538 while (result && (ptr = ::readdir(dir)) != NULL) {
4539 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
4540 result = false;
4541 }
4542 }
4543 closedir(dir);
4544 return result;
4545 }
4547 // This code originates from JDK's sysOpen and open64_w
4548 // from src/solaris/hpi/src/system_md.c
4550 #ifndef O_DELETE
4551 #define O_DELETE 0x10000
4552 #endif
4554 // Open a file. Unlink the file immediately after open returns
4555 // if the specified oflag has the O_DELETE flag set.
4556 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c
4558 int os::open(const char *path, int oflag, int mode) {
4560 if (strlen(path) > MAX_PATH - 1) {
4561 errno = ENAMETOOLONG;
4562 return -1;
4563 }
4564 int fd;
4565 int o_delete = (oflag & O_DELETE);
4566 oflag = oflag & ~O_DELETE;
4568 fd = ::open64(path, oflag, mode);
4569 if (fd == -1) return -1;
4571 //If the open succeeded, the file might still be a directory
4572 {
4573 struct stat64 buf64;
4574 int ret = ::fstat64(fd, &buf64);
4575 int st_mode = buf64.st_mode;
4577 if (ret != -1) {
4578 if ((st_mode & S_IFMT) == S_IFDIR) {
4579 errno = EISDIR;
4580 ::close(fd);
4581 return -1;
4582 }
4583 } else {
4584 ::close(fd);
4585 return -1;
4586 }
4587 }
4589 /*
4590 * All file descriptors that are opened in the JVM and not
4591 * specifically destined for a subprocess should have the
4592 * close-on-exec flag set. If we don't set it, then careless 3rd
4593 * party native code might fork and exec without closing all
4594 * appropriate file descriptors (e.g. as we do in closeDescriptors in
4595 * UNIXProcess.c), and this in turn might:
4596 *
4597 * - cause end-of-file to fail to be detected on some file
4598 * descriptors, resulting in mysterious hangs, or
4599 *
4600 * - might cause an fopen in the subprocess to fail on a system
4601 * suffering from bug 1085341.
4602 *
4603 * (Yes, the default setting of the close-on-exec flag is a Unix
4604 * design flaw)
4605 *
4606 * See:
4607 * 1085341: 32-bit stdio routines should support file descriptors >255
4608 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed
4609 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
4610 */
4611 #ifdef FD_CLOEXEC
4612 {
4613 int flags = ::fcntl(fd, F_GETFD);
4614 if (flags != -1)
4615 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
4616 }
4617 #endif
4619 if (o_delete != 0) {
4620 ::unlink(path);
4621 }
4622 return fd;
4623 }
4626 // create binary file, rewriting existing file if required
4627 int os::create_binary_file(const char* path, bool rewrite_existing) {
4628 int oflags = O_WRONLY | O_CREAT;
4629 if (!rewrite_existing) {
4630 oflags |= O_EXCL;
4631 }
4632 return ::open64(path, oflags, S_IREAD | S_IWRITE);
4633 }
4635 // return current position of file pointer
4636 jlong os::current_file_offset(int fd) {
4637 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
4638 }
4640 // move file pointer to the specified offset
4641 jlong os::seek_to_file_offset(int fd, jlong offset) {
4642 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
4643 }
4645 // This code originates from JDK's sysAvailable
4646 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
4648 int os::available(int fd, jlong *bytes) {
4649 jlong cur, end;
4650 int mode;
4651 struct stat64 buf64;
4653 if (::fstat64(fd, &buf64) >= 0) {
4654 mode = buf64.st_mode;
4655 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
4656 /*
4657 * XXX: is the following call interruptible? If so, this might
4658 * need to go through the INTERRUPT_IO() wrapper as for other
4659 * blocking, interruptible calls in this file.
4660 */
4661 int n;
4662 if (::ioctl(fd, FIONREAD, &n) >= 0) {
4663 *bytes = n;
4664 return 1;
4665 }
4666 }
4667 }
4668 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
4669 return 0;
4670 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
4671 return 0;
4672 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
4673 return 0;
4674 }
4675 *bytes = end - cur;
4676 return 1;
4677 }
4679 int os::socket_available(int fd, jint *pbytes) {
4680 // Linux doc says EINTR not returned, unlike Solaris
4681 int ret = ::ioctl(fd, FIONREAD, pbytes);
4683 //%% note ioctl can return 0 when successful, JVM_SocketAvailable
4684 // is expected to return 0 on failure and 1 on success to the jdk.
4685 return (ret < 0) ? 0 : 1;
4686 }
4688 // Map a block of memory.
4689 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
4690 char *addr, size_t bytes, bool read_only,
4691 bool allow_exec) {
4692 int prot;
4693 int flags;
4695 if (read_only) {
4696 prot = PROT_READ;
4697 flags = MAP_SHARED;
4698 } else {
4699 prot = PROT_READ | PROT_WRITE;
4700 flags = MAP_PRIVATE;
4701 }
4703 if (allow_exec) {
4704 prot |= PROT_EXEC;
4705 }
4707 if (addr != NULL) {
4708 flags |= MAP_FIXED;
4709 }
4711 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
4712 fd, file_offset);
4713 if (mapped_address == MAP_FAILED) {
4714 return NULL;
4715 }
4716 return mapped_address;
4717 }
4720 // Remap a block of memory.
4721 char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
4722 char *addr, size_t bytes, bool read_only,
4723 bool allow_exec) {
4724 // same as map_memory() on this OS
4725 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
4726 allow_exec);
4727 }
4730 // Unmap a block of memory.
4731 bool os::unmap_memory(char* addr, size_t bytes) {
4732 return munmap(addr, bytes) == 0;
4733 }
4735 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
4737 static clockid_t thread_cpu_clockid(Thread* thread) {
4738 pthread_t tid = thread->osthread()->pthread_id();
4739 clockid_t clockid;
4741 // Get thread clockid
4742 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
4743 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
4744 return clockid;
4745 }
4747 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
4748 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
4749 // of a thread.
4750 //
4751 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
4752 // the fast estimate available on the platform.
4754 jlong os::current_thread_cpu_time() {
4755 if (os::Linux::supports_fast_thread_cpu_time()) {
4756 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4757 } else {
4758 // return user + sys since the cost is the same
4759 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
4760 }
4761 }
4763 jlong os::thread_cpu_time(Thread* thread) {
4764 // consistent with what current_thread_cpu_time() returns
4765 if (os::Linux::supports_fast_thread_cpu_time()) {
4766 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4767 } else {
4768 return slow_thread_cpu_time(thread, true /* user + sys */);
4769 }
4770 }
4772 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
4773 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4774 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4775 } else {
4776 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
4777 }
4778 }
4780 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4781 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4782 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4783 } else {
4784 return slow_thread_cpu_time(thread, user_sys_cpu_time);
4785 }
4786 }
4788 //
4789 // -1 on error.
4790 //
4792 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4793 static bool proc_pid_cpu_avail = true;
4794 static bool proc_task_unchecked = true;
4795 static const char *proc_stat_path = "/proc/%d/stat";
4796 pid_t tid = thread->osthread()->thread_id();
4797 int i;
4798 char *s;
4799 char stat[2048];
4800 int statlen;
4801 char proc_name[64];
4802 int count;
4803 long sys_time, user_time;
4804 char string[64];
4805 char cdummy;
4806 int idummy;
4807 long ldummy;
4808 FILE *fp;
4810 // We first try accessing /proc/<pid>/cpu since this is faster to
4811 // process. If this file is not present (linux kernels 2.5 and above)
4812 // then we open /proc/<pid>/stat.
4813 if ( proc_pid_cpu_avail ) {
4814 sprintf(proc_name, "/proc/%d/cpu", tid);
4815 fp = fopen(proc_name, "r");
4816 if ( fp != NULL ) {
4817 count = fscanf( fp, "%s %lu %lu\n", string, &user_time, &sys_time);
4818 fclose(fp);
4819 if ( count != 3 ) return -1;
4821 if (user_sys_cpu_time) {
4822 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4823 } else {
4824 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4825 }
4826 }
4827 else proc_pid_cpu_avail = false;
4828 }
4830 // The /proc/<tid>/stat aggregates per-process usage on
4831 // new Linux kernels 2.6+ where NPTL is supported.
4832 // The /proc/self/task/<tid>/stat still has the per-thread usage.
4833 // See bug 6328462.
4834 // There can be no directory /proc/self/task on kernels 2.4 with NPTL
4835 // and possibly in some other cases, so we check its availability.
4836 if (proc_task_unchecked && os::Linux::is_NPTL()) {
4837 // This is executed only once
4838 proc_task_unchecked = false;
4839 fp = fopen("/proc/self/task", "r");
4840 if (fp != NULL) {
4841 proc_stat_path = "/proc/self/task/%d/stat";
4842 fclose(fp);
4843 }
4844 }
4846 sprintf(proc_name, proc_stat_path, tid);
4847 fp = fopen(proc_name, "r");
4848 if ( fp == NULL ) return -1;
4849 statlen = fread(stat, 1, 2047, fp);
4850 stat[statlen] = '\0';
4851 fclose(fp);
4853 // Skip pid and the command string. Note that we could be dealing with
4854 // weird command names, e.g. user could decide to rename java launcher
4855 // to "java 1.4.2 :)", then the stat file would look like
4856 // 1234 (java 1.4.2 :)) R ... ...
4857 // We don't really need to know the command string, just find the last
4858 // occurrence of ")" and then start parsing from there. See bug 4726580.
4859 s = strrchr(stat, ')');
4860 i = 0;
4861 if (s == NULL ) return -1;
4863 // Skip blank chars
4864 do s++; while (isspace(*s));
4866 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
4867 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
4868 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
4869 &user_time, &sys_time);
4870 if ( count != 13 ) return -1;
4871 if (user_sys_cpu_time) {
4872 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4873 } else {
4874 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4875 }
4876 }
4878 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4879 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4880 info_ptr->may_skip_backward = false; // elapsed time not wall time
4881 info_ptr->may_skip_forward = false; // elapsed time not wall time
4882 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4883 }
4885 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4886 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4887 info_ptr->may_skip_backward = false; // elapsed time not wall time
4888 info_ptr->may_skip_forward = false; // elapsed time not wall time
4889 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4890 }
4892 bool os::is_thread_cpu_time_supported() {
4893 return true;
4894 }
4896 // System loadavg support. Returns -1 if load average cannot be obtained.
4897 // Linux doesn't yet have a (official) notion of processor sets,
4898 // so just return the system wide load average.
4899 int os::loadavg(double loadavg[], int nelem) {
4900 return ::getloadavg(loadavg, nelem);
4901 }
4903 void os::pause() {
4904 char filename[MAX_PATH];
4905 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
4906 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
4907 } else {
4908 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
4909 }
4911 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
4912 if (fd != -1) {
4913 struct stat buf;
4914 ::close(fd);
4915 while (::stat(filename, &buf) == 0) {
4916 (void)::poll(NULL, 0, 100);
4917 }
4918 } else {
4919 jio_fprintf(stderr,
4920 "Could not open pause file '%s', continuing immediately.\n", filename);
4921 }
4922 }
4925 // Refer to the comments in os_solaris.cpp park-unpark.
4926 //
4927 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
4928 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
4929 // For specifics regarding the bug see GLIBC BUGID 261237 :
4930 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
4931 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
4932 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
4933 // is used. (The simple C test-case provided in the GLIBC bug report manifests the
4934 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
4935 // and monitorenter when we're using 1-0 locking. All those operations may result in
4936 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version
4937 // of libpthread avoids the problem, but isn't practical.
4938 //
4939 // Possible remedies:
4940 //
4941 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work.
4942 // This is palliative and probabilistic, however. If the thread is preempted
4943 // between the call to compute_abstime() and pthread_cond_timedwait(), more
4944 // than the minimum period may have passed, and the abstime may be stale (in the
4945 // past) resultin in a hang. Using this technique reduces the odds of a hang
4946 // but the JVM is still vulnerable, particularly on heavily loaded systems.
4947 //
4948 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
4949 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set
4950 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
4951 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant
4952 // thread.
4953 //
4954 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread
4955 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing
4956 // a timeout request to the chron thread and then blocking via pthread_cond_wait().
4957 // This also works well. In fact it avoids kernel-level scalability impediments
4958 // on certain platforms that don't handle lots of active pthread_cond_timedwait()
4959 // timers in a graceful fashion.
4960 //
4961 // 4. When the abstime value is in the past it appears that control returns
4962 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
4963 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we
4964 // can avoid the problem by reinitializing the condvar -- by cond_destroy()
4965 // followed by cond_init() -- after all calls to pthread_cond_timedwait().
4966 // It may be possible to avoid reinitialization by checking the return
4967 // value from pthread_cond_timedwait(). In addition to reinitializing the
4968 // condvar we must establish the invariant that cond_signal() is only called
4969 // within critical sections protected by the adjunct mutex. This prevents
4970 // cond_signal() from "seeing" a condvar that's in the midst of being
4971 // reinitialized or that is corrupt. Sadly, this invariant obviates the
4972 // desirable signal-after-unlock optimization that avoids futile context switching.
4973 //
4974 // I'm also concerned that some versions of NTPL might allocate an auxilliary
4975 // structure when a condvar is used or initialized. cond_destroy() would
4976 // release the helper structure. Our reinitialize-after-timedwait fix
4977 // put excessive stress on malloc/free and locks protecting the c-heap.
4978 //
4979 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag.
4980 // It may be possible to refine (4) by checking the kernel and NTPL verisons
4981 // and only enabling the work-around for vulnerable environments.
4983 // utility to compute the abstime argument to timedwait:
4984 // millis is the relative timeout time
4985 // abstime will be the absolute timeout time
4986 // TODO: replace compute_abstime() with unpackTime()
4988 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
4989 if (millis < 0) millis = 0;
4990 struct timeval now;
4991 int status = gettimeofday(&now, NULL);
4992 assert(status == 0, "gettimeofday");
4993 jlong seconds = millis / 1000;
4994 millis %= 1000;
4995 if (seconds > 50000000) { // see man cond_timedwait(3T)
4996 seconds = 50000000;
4997 }
4998 abstime->tv_sec = now.tv_sec + seconds;
4999 long usec = now.tv_usec + millis * 1000;
5000 if (usec >= 1000000) {
5001 abstime->tv_sec += 1;
5002 usec -= 1000000;
5003 }
5004 abstime->tv_nsec = usec * 1000;
5005 return abstime;
5006 }
5009 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately.
5010 // Conceptually TryPark() should be equivalent to park(0).
5012 int os::PlatformEvent::TryPark() {
5013 for (;;) {
5014 const int v = _Event ;
5015 guarantee ((v == 0) || (v == 1), "invariant") ;
5016 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ;
5017 }
5018 }
5020 void os::PlatformEvent::park() { // AKA "down()"
5021 // Invariant: Only the thread associated with the Event/PlatformEvent
5022 // may call park().
5023 // TODO: assert that _Assoc != NULL or _Assoc == Self
5024 int v ;
5025 for (;;) {
5026 v = _Event ;
5027 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5028 }
5029 guarantee (v >= 0, "invariant") ;
5030 if (v == 0) {
5031 // Do this the hard way by blocking ...
5032 int status = pthread_mutex_lock(_mutex);
5033 assert_status(status == 0, status, "mutex_lock");
5034 guarantee (_nParked == 0, "invariant") ;
5035 ++ _nParked ;
5036 while (_Event < 0) {
5037 status = pthread_cond_wait(_cond, _mutex);
5038 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
5039 // Treat this the same as if the wait was interrupted
5040 if (status == ETIME) { status = EINTR; }
5041 assert_status(status == 0 || status == EINTR, status, "cond_wait");
5042 }
5043 -- _nParked ;
5045 // In theory we could move the ST of 0 into _Event past the unlock(),
5046 // but then we'd need a MEMBAR after the ST.
5047 _Event = 0 ;
5048 status = pthread_mutex_unlock(_mutex);
5049 assert_status(status == 0, status, "mutex_unlock");
5050 }
5051 guarantee (_Event >= 0, "invariant") ;
5052 }
5054 int os::PlatformEvent::park(jlong millis) {
5055 guarantee (_nParked == 0, "invariant") ;
5057 int v ;
5058 for (;;) {
5059 v = _Event ;
5060 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5061 }
5062 guarantee (v >= 0, "invariant") ;
5063 if (v != 0) return OS_OK ;
5065 // We do this the hard way, by blocking the thread.
5066 // Consider enforcing a minimum timeout value.
5067 struct timespec abst;
5068 compute_abstime(&abst, millis);
5070 int ret = OS_TIMEOUT;
5071 int status = pthread_mutex_lock(_mutex);
5072 assert_status(status == 0, status, "mutex_lock");
5073 guarantee (_nParked == 0, "invariant") ;
5074 ++_nParked ;
5076 // Object.wait(timo) will return because of
5077 // (a) notification
5078 // (b) timeout
5079 // (c) thread.interrupt
5080 //
5081 // Thread.interrupt and object.notify{All} both call Event::set.
5082 // That is, we treat thread.interrupt as a special case of notification.
5083 // The underlying Solaris implementation, cond_timedwait, admits
5084 // spurious/premature wakeups, but the JLS/JVM spec prevents the
5085 // JVM from making those visible to Java code. As such, we must
5086 // filter out spurious wakeups. We assume all ETIME returns are valid.
5087 //
5088 // TODO: properly differentiate simultaneous notify+interrupt.
5089 // In that case, we should propagate the notify to another waiter.
5091 while (_Event < 0) {
5092 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst);
5093 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5094 pthread_cond_destroy (_cond);
5095 pthread_cond_init (_cond, NULL) ;
5096 }
5097 assert_status(status == 0 || status == EINTR ||
5098 status == ETIME || status == ETIMEDOUT,
5099 status, "cond_timedwait");
5100 if (!FilterSpuriousWakeups) break ; // previous semantics
5101 if (status == ETIME || status == ETIMEDOUT) break ;
5102 // We consume and ignore EINTR and spurious wakeups.
5103 }
5104 --_nParked ;
5105 if (_Event >= 0) {
5106 ret = OS_OK;
5107 }
5108 _Event = 0 ;
5109 status = pthread_mutex_unlock(_mutex);
5110 assert_status(status == 0, status, "mutex_unlock");
5111 assert (_nParked == 0, "invariant") ;
5112 return ret;
5113 }
5115 void os::PlatformEvent::unpark() {
5116 int v, AnyWaiters ;
5117 for (;;) {
5118 v = _Event ;
5119 if (v > 0) {
5120 // The LD of _Event could have reordered or be satisfied
5121 // by a read-aside from this processor's write buffer.
5122 // To avoid problems execute a barrier and then
5123 // ratify the value.
5124 OrderAccess::fence() ;
5125 if (_Event == v) return ;
5126 continue ;
5127 }
5128 if (Atomic::cmpxchg (v+1, &_Event, v) == v) break ;
5129 }
5130 if (v < 0) {
5131 // Wait for the thread associated with the event to vacate
5132 int status = pthread_mutex_lock(_mutex);
5133 assert_status(status == 0, status, "mutex_lock");
5134 AnyWaiters = _nParked ;
5135 assert (AnyWaiters == 0 || AnyWaiters == 1, "invariant") ;
5136 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
5137 AnyWaiters = 0 ;
5138 pthread_cond_signal (_cond);
5139 }
5140 status = pthread_mutex_unlock(_mutex);
5141 assert_status(status == 0, status, "mutex_unlock");
5142 if (AnyWaiters != 0) {
5143 status = pthread_cond_signal(_cond);
5144 assert_status(status == 0, status, "cond_signal");
5145 }
5146 }
5148 // Note that we signal() _after dropping the lock for "immortal" Events.
5149 // This is safe and avoids a common class of futile wakeups. In rare
5150 // circumstances this can cause a thread to return prematurely from
5151 // cond_{timed}wait() but the spurious wakeup is benign and the victim will
5152 // simply re-test the condition and re-park itself.
5153 }
5156 // JSR166
5157 // -------------------------------------------------------
5159 /*
5160 * The solaris and linux implementations of park/unpark are fairly
5161 * conservative for now, but can be improved. They currently use a
5162 * mutex/condvar pair, plus a a count.
5163 * Park decrements count if > 0, else does a condvar wait. Unpark
5164 * sets count to 1 and signals condvar. Only one thread ever waits
5165 * on the condvar. Contention seen when trying to park implies that someone
5166 * is unparking you, so don't wait. And spurious returns are fine, so there
5167 * is no need to track notifications.
5168 */
5170 #define MAX_SECS 100000000
5171 /*
5172 * This code is common to linux and solaris and will be moved to a
5173 * common place in dolphin.
5174 *
5175 * The passed in time value is either a relative time in nanoseconds
5176 * or an absolute time in milliseconds. Either way it has to be unpacked
5177 * into suitable seconds and nanoseconds components and stored in the
5178 * given timespec structure.
5179 * Given time is a 64-bit value and the time_t used in the timespec is only
5180 * a signed-32-bit value (except on 64-bit Linux) we have to watch for
5181 * overflow if times way in the future are given. Further on Solaris versions
5182 * prior to 10 there is a restriction (see cond_timedwait) that the specified
5183 * number of seconds, in abstime, is less than current_time + 100,000,000.
5184 * As it will be 28 years before "now + 100000000" will overflow we can
5185 * ignore overflow and just impose a hard-limit on seconds using the value
5186 * of "now + 100,000,000". This places a limit on the timeout of about 3.17
5187 * years from "now".
5188 */
5190 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
5191 assert (time > 0, "convertTime");
5193 struct timeval now;
5194 int status = gettimeofday(&now, NULL);
5195 assert(status == 0, "gettimeofday");
5197 time_t max_secs = now.tv_sec + MAX_SECS;
5199 if (isAbsolute) {
5200 jlong secs = time / 1000;
5201 if (secs > max_secs) {
5202 absTime->tv_sec = max_secs;
5203 }
5204 else {
5205 absTime->tv_sec = secs;
5206 }
5207 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
5208 }
5209 else {
5210 jlong secs = time / NANOSECS_PER_SEC;
5211 if (secs >= MAX_SECS) {
5212 absTime->tv_sec = max_secs;
5213 absTime->tv_nsec = 0;
5214 }
5215 else {
5216 absTime->tv_sec = now.tv_sec + secs;
5217 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
5218 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5219 absTime->tv_nsec -= NANOSECS_PER_SEC;
5220 ++absTime->tv_sec; // note: this must be <= max_secs
5221 }
5222 }
5223 }
5224 assert(absTime->tv_sec >= 0, "tv_sec < 0");
5225 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
5226 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
5227 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
5228 }
5230 void Parker::park(bool isAbsolute, jlong time) {
5231 // Optional fast-path check:
5232 // Return immediately if a permit is available.
5233 if (_counter > 0) {
5234 _counter = 0 ;
5235 OrderAccess::fence();
5236 return ;
5237 }
5239 Thread* thread = Thread::current();
5240 assert(thread->is_Java_thread(), "Must be JavaThread");
5241 JavaThread *jt = (JavaThread *)thread;
5243 // Optional optimization -- avoid state transitions if there's an interrupt pending.
5244 // Check interrupt before trying to wait
5245 if (Thread::is_interrupted(thread, false)) {
5246 return;
5247 }
5249 // Next, demultiplex/decode time arguments
5250 timespec absTime;
5251 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all
5252 return;
5253 }
5254 if (time > 0) {
5255 unpackTime(&absTime, isAbsolute, time);
5256 }
5259 // Enter safepoint region
5260 // Beware of deadlocks such as 6317397.
5261 // The per-thread Parker:: mutex is a classic leaf-lock.
5262 // In particular a thread must never block on the Threads_lock while
5263 // holding the Parker:: mutex. If safepoints are pending both the
5264 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
5265 ThreadBlockInVM tbivm(jt);
5267 // Don't wait if cannot get lock since interference arises from
5268 // unblocking. Also. check interrupt before trying wait
5269 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
5270 return;
5271 }
5273 int status ;
5274 if (_counter > 0) { // no wait needed
5275 _counter = 0;
5276 status = pthread_mutex_unlock(_mutex);
5277 assert (status == 0, "invariant") ;
5278 OrderAccess::fence();
5279 return;
5280 }
5282 #ifdef ASSERT
5283 // Don't catch signals while blocked; let the running threads have the signals.
5284 // (This allows a debugger to break into the running thread.)
5285 sigset_t oldsigs;
5286 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
5287 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
5288 #endif
5290 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
5291 jt->set_suspend_equivalent();
5292 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
5294 if (time == 0) {
5295 status = pthread_cond_wait (_cond, _mutex) ;
5296 } else {
5297 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ;
5298 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5299 pthread_cond_destroy (_cond) ;
5300 pthread_cond_init (_cond, NULL);
5301 }
5302 }
5303 assert_status(status == 0 || status == EINTR ||
5304 status == ETIME || status == ETIMEDOUT,
5305 status, "cond_timedwait");
5307 #ifdef ASSERT
5308 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
5309 #endif
5311 _counter = 0 ;
5312 status = pthread_mutex_unlock(_mutex) ;
5313 assert_status(status == 0, status, "invariant") ;
5314 // If externally suspended while waiting, re-suspend
5315 if (jt->handle_special_suspend_equivalent_condition()) {
5316 jt->java_suspend_self();
5317 }
5319 OrderAccess::fence();
5320 }
5322 void Parker::unpark() {
5323 int s, status ;
5324 status = pthread_mutex_lock(_mutex);
5325 assert (status == 0, "invariant") ;
5326 s = _counter;
5327 _counter = 1;
5328 if (s < 1) {
5329 if (WorkAroundNPTLTimedWaitHang) {
5330 status = pthread_cond_signal (_cond) ;
5331 assert (status == 0, "invariant") ;
5332 status = pthread_mutex_unlock(_mutex);
5333 assert (status == 0, "invariant") ;
5334 } else {
5335 status = pthread_mutex_unlock(_mutex);
5336 assert (status == 0, "invariant") ;
5337 status = pthread_cond_signal (_cond) ;
5338 assert (status == 0, "invariant") ;
5339 }
5340 } else {
5341 pthread_mutex_unlock(_mutex);
5342 assert (status == 0, "invariant") ;
5343 }
5344 }
5347 extern char** environ;
5349 #ifndef __NR_fork
5350 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57)
5351 #endif
5353 #ifndef __NR_execve
5354 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59)
5355 #endif
5357 // Run the specified command in a separate process. Return its exit value,
5358 // or -1 on failure (e.g. can't fork a new process).
5359 // Unlike system(), this function can be called from signal handler. It
5360 // doesn't block SIGINT et al.
5361 int os::fork_and_exec(char* cmd) {
5362 const char * argv[4] = {"sh", "-c", cmd, NULL};
5364 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run
5365 // pthread_atfork handlers and reset pthread library. All we need is a
5366 // separate process to execve. Make a direct syscall to fork process.
5367 // On IA64 there's no fork syscall, we have to use fork() and hope for
5368 // the best...
5369 pid_t pid = NOT_IA64(syscall(__NR_fork);)
5370 IA64_ONLY(fork();)
5372 if (pid < 0) {
5373 // fork failed
5374 return -1;
5376 } else if (pid == 0) {
5377 // child process
5379 // execve() in LinuxThreads will call pthread_kill_other_threads_np()
5380 // first to kill every thread on the thread list. Because this list is
5381 // not reset by fork() (see notes above), execve() will instead kill
5382 // every thread in the parent process. We know this is the only thread
5383 // in the new process, so make a system call directly.
5384 // IA64 should use normal execve() from glibc to match the glibc fork()
5385 // above.
5386 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);)
5387 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);)
5389 // execve failed
5390 _exit(-1);
5392 } else {
5393 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5394 // care about the actual exit code, for now.
5396 int status;
5398 // Wait for the child process to exit. This returns immediately if
5399 // the child has already exited. */
5400 while (waitpid(pid, &status, 0) < 0) {
5401 switch (errno) {
5402 case ECHILD: return 0;
5403 case EINTR: break;
5404 default: return -1;
5405 }
5406 }
5408 if (WIFEXITED(status)) {
5409 // The child exited normally; get its exit code.
5410 return WEXITSTATUS(status);
5411 } else if (WIFSIGNALED(status)) {
5412 // The child exited because of a signal
5413 // The best value to return is 0x80 + signal number,
5414 // because that is what all Unix shells do, and because
5415 // it allows callers to distinguish between process exit and
5416 // process death by signal.
5417 return 0x80 + WTERMSIG(status);
5418 } else {
5419 // Unknown exit code; pass it through
5420 return status;
5421 }
5422 }
5423 }
5425 // is_headless_jre()
5426 //
5427 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
5428 // in order to report if we are running in a headless jre
5429 //
5430 // Since JDK8 xawt/libmawt.so was moved into the same directory
5431 // as libawt.so, and renamed libawt_xawt.so
5432 //
5433 bool os::is_headless_jre() {
5434 struct stat statbuf;
5435 char buf[MAXPATHLEN];
5436 char libmawtpath[MAXPATHLEN];
5437 const char *xawtstr = "/xawt/libmawt.so";
5438 const char *new_xawtstr = "/libawt_xawt.so";
5439 char *p;
5441 // Get path to libjvm.so
5442 os::jvm_path(buf, sizeof(buf));
5444 // Get rid of libjvm.so
5445 p = strrchr(buf, '/');
5446 if (p == NULL) return false;
5447 else *p = '\0';
5449 // Get rid of client or server
5450 p = strrchr(buf, '/');
5451 if (p == NULL) return false;
5452 else *p = '\0';
5454 // check xawt/libmawt.so
5455 strcpy(libmawtpath, buf);
5456 strcat(libmawtpath, xawtstr);
5457 if (::stat(libmawtpath, &statbuf) == 0) return false;
5459 // check libawt_xawt.so
5460 strcpy(libmawtpath, buf);
5461 strcat(libmawtpath, new_xawtstr);
5462 if (::stat(libmawtpath, &statbuf) == 0) return false;
5464 return true;
5465 }
5468 #ifdef JAVASE_EMBEDDED
5469 //
5470 // A thread to watch the '/dev/mem_notify' device, which will tell us when the OS is running low on memory.
5471 //
5472 MemNotifyThread* MemNotifyThread::_memnotify_thread = NULL;
5474 // ctor
5475 //
5476 MemNotifyThread::MemNotifyThread(int fd): Thread() {
5477 assert(memnotify_thread() == NULL, "we can only allocate one MemNotifyThread");
5478 _fd = fd;
5480 if (os::create_thread(this, os::os_thread)) {
5481 _memnotify_thread = this;
5482 os::set_priority(this, NearMaxPriority);
5483 os::start_thread(this);
5484 }
5485 }
5487 // Where all the work gets done
5488 //
5489 void MemNotifyThread::run() {
5490 assert(this == memnotify_thread(), "expected the singleton MemNotifyThread");
5492 // Set up the select arguments
5493 fd_set rfds;
5494 if (_fd != -1) {
5495 FD_ZERO(&rfds);
5496 FD_SET(_fd, &rfds);
5497 }
5499 // Now wait for the mem_notify device to wake up
5500 while (1) {
5501 // Wait for the mem_notify device to signal us..
5502 int rc = select(_fd+1, _fd != -1 ? &rfds : NULL, NULL, NULL, NULL);
5503 if (rc == -1) {
5504 perror("select!\n");
5505 break;
5506 } else if (rc) {
5507 //ssize_t free_before = os::available_memory();
5508 //tty->print ("Notified: Free: %dK \n",os::available_memory()/1024);
5510 // The kernel is telling us there is not much memory left...
5511 // try to do something about that
5513 // If we are not already in a GC, try one.
5514 if (!Universe::heap()->is_gc_active()) {
5515 Universe::heap()->collect(GCCause::_allocation_failure);
5517 //ssize_t free_after = os::available_memory();
5518 //tty->print ("Post-Notify: Free: %dK\n",free_after/1024);
5519 //tty->print ("GC freed: %dK\n", (free_after - free_before)/1024);
5520 }
5521 // We might want to do something like the following if we find the GC's are not helping...
5522 // Universe::heap()->size_policy()->set_gc_time_limit_exceeded(true);
5523 }
5524 }
5525 }
5527 //
5528 // See if the /dev/mem_notify device exists, and if so, start a thread to monitor it.
5529 //
5530 void MemNotifyThread::start() {
5531 int fd;
5532 fd = open ("/dev/mem_notify", O_RDONLY, 0);
5533 if (fd < 0) {
5534 return;
5535 }
5537 if (memnotify_thread() == NULL) {
5538 new MemNotifyThread(fd);
5539 }
5540 }
5541 #endif // JAVASE_EMBEDDED