1 /*
2 * Copyright (c) 1999, 2013, 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 */
24
25 // no precompiled headers
26 #include "classfile/classLoader.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "classfile/vmSymbols.hpp"
29 #include "code/icBuffer.hpp"
30 #include "code/vtableStubs.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "compiler/disassembler.hpp"
33 #include "interpreter/interpreter.hpp"
34 #include "jvm_linux.h"
35 #include "memory/allocation.inline.hpp"
36 #include "memory/filemap.hpp"
37 #include "mutex_linux.inline.hpp"
38 #include "oops/oop.inline.hpp"
39 #include "os_share_linux.hpp"
40 #include "prims/jniFastGetField.hpp"
41 #include "prims/jvm.h"
42 #include "prims/jvm_misc.hpp"
43 #include "runtime/arguments.hpp"
44 #include "runtime/extendedPC.hpp"
45 #include "runtime/globals.hpp"
46 #include "runtime/interfaceSupport.hpp"
47 #include "runtime/init.hpp"
48 #include "runtime/java.hpp"
49 #include "runtime/javaCalls.hpp"
50 #include "runtime/mutexLocker.hpp"
51 #include "runtime/objectMonitor.hpp"
52 #include "runtime/osThread.hpp"
53 #include "runtime/perfMemory.hpp"
54 #include "runtime/sharedRuntime.hpp"
55 #include "runtime/statSampler.hpp"
56 #include "runtime/stubRoutines.hpp"
57 #include "runtime/thread.inline.hpp"
58 #include "runtime/threadCritical.hpp"
59 #include "runtime/timer.hpp"
60 #include "services/attachListener.hpp"
61 #include "services/memTracker.hpp"
62 #include "services/runtimeService.hpp"
63 #include "utilities/decoder.hpp"
64 #include "utilities/defaultStream.hpp"
65 #include "utilities/events.hpp"
66 #include "utilities/elfFile.hpp"
67 #include "utilities/growableArray.hpp"
68 #include "utilities/vmError.hpp"
69
70 // put OS-includes here
71 # include <sys/types.h>
72 # include <sys/mman.h>
73 # include <sys/stat.h>
74 # include <sys/select.h>
75 # include <pthread.h>
76 # include <signal.h>
77 # include <errno.h>
78 # include <dlfcn.h>
79 # include <stdio.h>
80 # include <unistd.h>
81 # include <sys/resource.h>
82 # include <pthread.h>
83 # include <sys/stat.h>
84 # include <sys/time.h>
85 # include <sys/times.h>
86 # include <sys/utsname.h>
87 # include <sys/socket.h>
88 # include <sys/wait.h>
89 # include <pwd.h>
90 # include <poll.h>
91 # include <semaphore.h>
92 # include <fcntl.h>
93 # include <string.h>
94 # include <syscall.h>
95 # include <sys/sysinfo.h>
96 # include <gnu/libc-version.h>
97 # include <sys/ipc.h>
98 # include <sys/shm.h>
99 # include <link.h>
100 # include <stdint.h>
101 # include <inttypes.h>
102 # include <sys/ioctl.h>
103
104 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling
105 // getrusage() is prepared to handle the associated failure.
106 #ifndef RUSAGE_THREAD
107 #define RUSAGE_THREAD (1) /* only the calling thread */
108 #endif
109
110 #define MAX_PATH (2 * K)
111
112 // for timer info max values which include all bits
113 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
114
115 #define LARGEPAGES_BIT (1 << 6)
116 ////////////////////////////////////////////////////////////////////////////////
117 // global variables
118 julong os::Linux::_physical_memory = 0;
119
120 address os::Linux::_initial_thread_stack_bottom = NULL;
121 uintptr_t os::Linux::_initial_thread_stack_size = 0;
122
123 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
124 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
125 Mutex* os::Linux::_createThread_lock = NULL;
126 pthread_t os::Linux::_main_thread;
127 int os::Linux::_page_size = -1;
128 const int os::Linux::_vm_default_page_size = (8 * K);
129 bool os::Linux::_is_floating_stack = false;
130 bool os::Linux::_is_NPTL = false;
131 bool os::Linux::_supports_fast_thread_cpu_time = false;
132 const char * os::Linux::_glibc_version = NULL;
133 const char * os::Linux::_libpthread_version = NULL;
134
135 static jlong initial_time_count=0;
136
137 static int clock_tics_per_sec = 100;
138
139 // For diagnostics to print a message once. see run_periodic_checks
140 static sigset_t check_signal_done;
141 static bool check_signals = true;;
142
143 static pid_t _initial_pid = 0;
144
145 /* Signal number used to suspend/resume a thread */
146
147 /* do not use any signal number less than SIGSEGV, see 4355769 */
148 static int SR_signum = SIGUSR2;
149 sigset_t SR_sigset;
150
151 /* Used to protect dlsym() calls */
152 static pthread_mutex_t dl_mutex;
153
154 // Declarations
155 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time);
156
157 #ifdef JAVASE_EMBEDDED
158 class MemNotifyThread: public Thread {
159 friend class VMStructs;
160 public:
161 virtual void run();
162
163 private:
164 static MemNotifyThread* _memnotify_thread;
165 int _fd;
166
167 public:
168
169 // Constructor
170 MemNotifyThread(int fd);
171
172 // Tester
173 bool is_memnotify_thread() const { return true; }
174
175 // Printing
176 char* name() const { return (char*)"Linux MemNotify Thread"; }
177
178 // Returns the single instance of the MemNotifyThread
179 static MemNotifyThread* memnotify_thread() { return _memnotify_thread; }
180
181 // Create and start the single instance of MemNotifyThread
182 static void start();
183 };
184 #endif // JAVASE_EMBEDDED
185
186 // utility functions
187
188 static int SR_initialize();
189
190 julong os::available_memory() {
191 return Linux::available_memory();
192 }
193
194 julong os::Linux::available_memory() {
195 // values in struct sysinfo are "unsigned long"
196 struct sysinfo si;
197 sysinfo(&si);
198
199 return (julong)si.freeram * si.mem_unit;
200 }
201
202 julong os::physical_memory() {
203 return Linux::physical_memory();
204 }
205
206 ////////////////////////////////////////////////////////////////////////////////
207 // environment support
208
209 bool os::getenv(const char* name, char* buf, int len) {
210 const char* val = ::getenv(name);
211 if (val != NULL && strlen(val) < (size_t)len) {
212 strcpy(buf, val);
213 return true;
214 }
215 if (len > 0) buf[0] = 0; // return a null string
216 return false;
217 }
218
219
220 // Return true if user is running as root.
221
222 bool os::have_special_privileges() {
223 static bool init = false;
224 static bool privileges = false;
225 if (!init) {
226 privileges = (getuid() != geteuid()) || (getgid() != getegid());
227 init = true;
228 }
229 return privileges;
230 }
231
232
233 #ifndef SYS_gettid
234 // i386: 224, ia64: 1105, amd64: 186, sparc 143
235 #ifdef __ia64__
236 #define SYS_gettid 1105
237 #elif __i386__
238 #define SYS_gettid 224
239 #elif __amd64__
240 #define SYS_gettid 186
241 #elif __sparc__
242 #define SYS_gettid 143
243 #else
244 #error define gettid for the arch
245 #endif
246 #endif
247
248 // Cpu architecture string
249 #if defined(ZERO)
250 static char cpu_arch[] = ZERO_LIBARCH;
251 #elif defined(IA64)
252 static char cpu_arch[] = "ia64";
253 #elif defined(IA32)
254 static char cpu_arch[] = "i386";
255 #elif defined(AMD64)
256 static char cpu_arch[] = "amd64";
257 #elif defined(ARM)
258 static char cpu_arch[] = "arm";
259 #elif defined(PPC)
260 static char cpu_arch[] = "ppc";
261 #elif defined(SPARC)
262 # ifdef _LP64
263 static char cpu_arch[] = "sparcv9";
264 # else
265 static char cpu_arch[] = "sparc";
266 # endif
267 #else
268 #error Add appropriate cpu_arch setting
269 #endif
270
271
272 // pid_t gettid()
273 //
274 // Returns the kernel thread id of the currently running thread. Kernel
275 // thread id is used to access /proc.
276 //
277 // (Note that getpid() on LinuxThreads returns kernel thread id too; but
278 // on NPTL, it returns the same pid for all threads, as required by POSIX.)
279 //
280 pid_t os::Linux::gettid() {
281 int rslt = syscall(SYS_gettid);
282 if (rslt == -1) {
283 // old kernel, no NPTL support
284 return getpid();
285 } else {
286 return (pid_t)rslt;
287 }
288 }
289
290 // Most versions of linux have a bug where the number of processors are
291 // determined by looking at the /proc file system. In a chroot environment,
292 // the system call returns 1. This causes the VM to act as if it is
293 // a single processor and elide locking (see is_MP() call).
294 static bool unsafe_chroot_detected = false;
295 static const char *unstable_chroot_error = "/proc file system not found.\n"
296 "Java may be unstable running multithreaded in a chroot "
297 "environment on Linux when /proc filesystem is not mounted.";
298
299 void os::Linux::initialize_system_info() {
300 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
301 if (processor_count() == 1) {
302 pid_t pid = os::Linux::gettid();
303 char fname[32];
304 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
305 FILE *fp = fopen(fname, "r");
306 if (fp == NULL) {
307 unsafe_chroot_detected = true;
308 } else {
309 fclose(fp);
310 }
311 }
312 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
313 assert(processor_count() > 0, "linux error");
314 }
315
316 void os::init_system_properties_values() {
317 // char arch[12];
318 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch));
319
320 // The next steps are taken in the product version:
321 //
322 // Obtain the JAVA_HOME value from the location of libjvm.so.
323 // This library should be located at:
324 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so.
325 //
326 // If "/jre/lib/" appears at the right place in the path, then we
327 // assume libjvm.so is installed in a JDK and we use this path.
328 //
329 // Otherwise exit with message: "Could not create the Java virtual machine."
330 //
331 // The following extra steps are taken in the debugging version:
332 //
333 // If "/jre/lib/" does NOT appear at the right place in the path
334 // instead of exit check for $JAVA_HOME environment variable.
335 //
336 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
337 // then we append a fake suffix "hotspot/libjvm.so" to this path so
338 // it looks like libjvm.so is installed there
339 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
340 //
341 // Otherwise exit.
342 //
343 // Important note: if the location of libjvm.so changes this
344 // code needs to be changed accordingly.
345
346 // The next few definitions allow the code to be verbatim:
347 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n), mtInternal)
348 #define getenv(n) ::getenv(n)
349
350 /*
351 * See ld(1):
352 * The linker uses the following search paths to locate required
353 * shared libraries:
354 * 1: ...
355 * ...
356 * 7: The default directories, normally /lib and /usr/lib.
357 */
358 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390))
359 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
360 #else
361 #define DEFAULT_LIBPATH "/lib:/usr/lib"
362 #endif
363
364 #define EXTENSIONS_DIR "/lib/ext"
365 #define ENDORSED_DIR "/lib/endorsed"
366 #define REG_DIR "/usr/java/packages"
367
368 {
369 /* sysclasspath, java_home, dll_dir */
370 {
371 char *home_path;
372 char *dll_path;
373 char *pslash;
374 char buf[MAXPATHLEN];
375 os::jvm_path(buf, sizeof(buf));
376
377 // Found the full path to libjvm.so.
378 // Now cut the path to <java_home>/jre if we can.
379 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */
380 pslash = strrchr(buf, '/');
381 if (pslash != NULL)
382 *pslash = '\0'; /* get rid of /{client|server|hotspot} */
383 dll_path = malloc(strlen(buf) + 1);
384 if (dll_path == NULL)
385 return;
386 strcpy(dll_path, buf);
387 Arguments::set_dll_dir(dll_path);
388
389 if (pslash != NULL) {
390 pslash = strrchr(buf, '/');
391 if (pslash != NULL) {
392 *pslash = '\0'; /* get rid of /<arch> */
393 pslash = strrchr(buf, '/');
394 if (pslash != NULL)
395 *pslash = '\0'; /* get rid of /lib */
396 }
397 }
398
399 home_path = malloc(strlen(buf) + 1);
400 if (home_path == NULL)
401 return;
402 strcpy(home_path, buf);
403 Arguments::set_java_home(home_path);
404
405 if (!set_boot_path('/', ':'))
406 return;
407 }
408
409 /*
410 * Where to look for native libraries
411 *
412 * Note: Due to a legacy implementation, most of the library path
413 * is set in the launcher. This was to accomodate linking restrictions
414 * on legacy Linux implementations (which are no longer supported).
415 * Eventually, all the library path setting will be done here.
416 *
417 * However, to prevent the proliferation of improperly built native
418 * libraries, the new path component /usr/java/packages is added here.
419 * Eventually, all the library path setting will be done here.
420 */
421 {
422 char *ld_library_path;
423
424 /*
425 * Construct the invariant part of ld_library_path. Note that the
426 * space for the colon and the trailing null are provided by the
427 * nulls included by the sizeof operator (so actually we allocate
428 * a byte more than necessary).
429 */
430 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") +
431 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH));
432 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch);
433
434 /*
435 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It
436 * should always exist (until the legacy problem cited above is
437 * addressed).
438 */
439 char *v = getenv("LD_LIBRARY_PATH");
440 if (v != NULL) {
441 char *t = ld_library_path;
442 /* That's +1 for the colon and +1 for the trailing '\0' */
443 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1);
444 sprintf(ld_library_path, "%s:%s", v, t);
445 }
446 Arguments::set_library_path(ld_library_path);
447 }
448
449 /*
450 * Extensions directories.
451 *
452 * Note that the space for the colon and the trailing null are provided
453 * by the nulls included by the sizeof operator (so actually one byte more
454 * than necessary is allocated).
455 */
456 {
457 char *buf = malloc(strlen(Arguments::get_java_home()) +
458 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR));
459 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR,
460 Arguments::get_java_home());
461 Arguments::set_ext_dirs(buf);
462 }
463
464 /* Endorsed standards default directory. */
465 {
466 char * buf;
467 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR));
468 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
469 Arguments::set_endorsed_dirs(buf);
470 }
471 }
472
473 #undef malloc
474 #undef getenv
475 #undef EXTENSIONS_DIR
476 #undef ENDORSED_DIR
477
478 // Done
479 return;
480 }
481
482 ////////////////////////////////////////////////////////////////////////////////
483 // breakpoint support
484
485 void os::breakpoint() {
486 BREAKPOINT;
487 }
488
489 extern "C" void breakpoint() {
490 // use debugger to set breakpoint here
491 }
492
493 ////////////////////////////////////////////////////////////////////////////////
494 // signal support
495
496 debug_only(static bool signal_sets_initialized = false);
497 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
498
499 bool os::Linux::is_sig_ignored(int sig) {
500 struct sigaction oact;
501 sigaction(sig, (struct sigaction*)NULL, &oact);
502 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
503 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
504 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))
505 return true;
506 else
507 return false;
508 }
509
510 void os::Linux::signal_sets_init() {
511 // Should also have an assertion stating we are still single-threaded.
512 assert(!signal_sets_initialized, "Already initialized");
513 // Fill in signals that are necessarily unblocked for all threads in
514 // the VM. Currently, we unblock the following signals:
515 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
516 // by -Xrs (=ReduceSignalUsage));
517 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
518 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
519 // the dispositions or masks wrt these signals.
520 // Programs embedding the VM that want to use the above signals for their
521 // own purposes must, at this time, use the "-Xrs" option to prevent
522 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
523 // (See bug 4345157, and other related bugs).
524 // In reality, though, unblocking these signals is really a nop, since
525 // these signals are not blocked by default.
526 sigemptyset(&unblocked_sigs);
527 sigemptyset(&allowdebug_blocked_sigs);
528 sigaddset(&unblocked_sigs, SIGILL);
529 sigaddset(&unblocked_sigs, SIGSEGV);
530 sigaddset(&unblocked_sigs, SIGBUS);
531 sigaddset(&unblocked_sigs, SIGFPE);
532 sigaddset(&unblocked_sigs, SR_signum);
533
534 if (!ReduceSignalUsage) {
535 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
536 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
537 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
538 }
539 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
540 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
541 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
542 }
543 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
544 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
545 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
546 }
547 }
548 // Fill in signals that are blocked by all but the VM thread.
549 sigemptyset(&vm_sigs);
550 if (!ReduceSignalUsage)
551 sigaddset(&vm_sigs, BREAK_SIGNAL);
552 debug_only(signal_sets_initialized = true);
553
554 }
555
556 // These are signals that are unblocked while a thread is running Java.
557 // (For some reason, they get blocked by default.)
558 sigset_t* os::Linux::unblocked_signals() {
559 assert(signal_sets_initialized, "Not initialized");
560 return &unblocked_sigs;
561 }
562
563 // These are the signals that are blocked while a (non-VM) thread is
564 // running Java. Only the VM thread handles these signals.
565 sigset_t* os::Linux::vm_signals() {
566 assert(signal_sets_initialized, "Not initialized");
567 return &vm_sigs;
568 }
569
570 // These are signals that are blocked during cond_wait to allow debugger in
571 sigset_t* os::Linux::allowdebug_blocked_signals() {
572 assert(signal_sets_initialized, "Not initialized");
573 return &allowdebug_blocked_sigs;
574 }
575
576 void os::Linux::hotspot_sigmask(Thread* thread) {
577
578 //Save caller's signal mask before setting VM signal mask
579 sigset_t caller_sigmask;
580 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
581
582 OSThread* osthread = thread->osthread();
583 osthread->set_caller_sigmask(caller_sigmask);
584
585 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
586
587 if (!ReduceSignalUsage) {
588 if (thread->is_VM_thread()) {
589 // Only the VM thread handles BREAK_SIGNAL ...
590 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
591 } else {
592 // ... all other threads block BREAK_SIGNAL
593 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
594 }
595 }
596 }
597
598 //////////////////////////////////////////////////////////////////////////////
599 // detecting pthread library
600
601 void os::Linux::libpthread_init() {
602 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION
603 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a
604 // generic name for earlier versions.
605 // Define macros here so we can build HotSpot on old systems.
606 # ifndef _CS_GNU_LIBC_VERSION
607 # define _CS_GNU_LIBC_VERSION 2
608 # endif
609 # ifndef _CS_GNU_LIBPTHREAD_VERSION
610 # define _CS_GNU_LIBPTHREAD_VERSION 3
611 # endif
612
613 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
614 if (n > 0) {
615 char *str = (char *)malloc(n, mtInternal);
616 confstr(_CS_GNU_LIBC_VERSION, str, n);
617 os::Linux::set_glibc_version(str);
618 } else {
619 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version()
620 static char _gnu_libc_version[32];
621 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version),
622 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release());
623 os::Linux::set_glibc_version(_gnu_libc_version);
624 }
625
626 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
627 if (n > 0) {
628 char *str = (char *)malloc(n, mtInternal);
629 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
630 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells
631 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this
632 // is the case. LinuxThreads has a hard limit on max number of threads.
633 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value.
634 // On the other hand, NPTL does not have such a limit, sysconf()
635 // will return -1 and errno is not changed. Check if it is really NPTL.
636 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 &&
637 strstr(str, "NPTL") &&
638 sysconf(_SC_THREAD_THREADS_MAX) > 0) {
639 free(str);
640 os::Linux::set_libpthread_version("linuxthreads");
641 } else {
642 os::Linux::set_libpthread_version(str);
643 }
644 } else {
645 // glibc before 2.3.2 only has LinuxThreads.
646 os::Linux::set_libpthread_version("linuxthreads");
647 }
648
649 if (strstr(libpthread_version(), "NPTL")) {
650 os::Linux::set_is_NPTL();
651 } else {
652 os::Linux::set_is_LinuxThreads();
653 }
654
655 // LinuxThreads have two flavors: floating-stack mode, which allows variable
656 // stack size; and fixed-stack mode. NPTL is always floating-stack.
657 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) {
658 os::Linux::set_is_floating_stack();
659 }
660 }
661
662 /////////////////////////////////////////////////////////////////////////////
663 // thread stack
664
665 // Force Linux kernel to expand current thread stack. If "bottom" is close
666 // to the stack guard, caller should block all signals.
667 //
668 // MAP_GROWSDOWN:
669 // A special mmap() flag that is used to implement thread stacks. It tells
670 // kernel that the memory region should extend downwards when needed. This
671 // allows early versions of LinuxThreads to only mmap the first few pages
672 // when creating a new thread. Linux kernel will automatically expand thread
673 // stack as needed (on page faults).
674 //
675 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
676 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
677 // region, it's hard to tell if the fault is due to a legitimate stack
678 // access or because of reading/writing non-exist memory (e.g. buffer
679 // overrun). As a rule, if the fault happens below current stack pointer,
680 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
681 // application (see Linux kernel fault.c).
682 //
683 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
684 // stack overflow detection.
685 //
686 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
687 // not use this flag. However, the stack of initial thread is not created
688 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though
689 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack
690 // and then attach the thread to JVM.
691 //
692 // To get around the problem and allow stack banging on Linux, we need to
693 // manually expand thread stack after receiving the SIGSEGV.
694 //
695 // There are two ways to expand thread stack to address "bottom", we used
696 // both of them in JVM before 1.5:
697 // 1. adjust stack pointer first so that it is below "bottom", and then
698 // touch "bottom"
699 // 2. mmap() the page in question
700 //
701 // Now alternate signal stack is gone, it's harder to use 2. For instance,
702 // if current sp is already near the lower end of page 101, and we need to
703 // call mmap() to map page 100, it is possible that part of the mmap() frame
704 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
705 // That will destroy the mmap() frame and cause VM to crash.
706 //
707 // The following code works by adjusting sp first, then accessing the "bottom"
708 // page to force a page fault. Linux kernel will then automatically expand the
709 // stack mapping.
710 //
711 // _expand_stack_to() assumes its frame size is less than page size, which
712 // should always be true if the function is not inlined.
713
714 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute
715 #define NOINLINE
716 #else
717 #define NOINLINE __attribute__ ((noinline))
718 #endif
719
720 static void _expand_stack_to(address bottom) NOINLINE;
721
722 static void _expand_stack_to(address bottom) {
723 address sp;
724 size_t size;
725 volatile char *p;
726
727 // Adjust bottom to point to the largest address within the same page, it
728 // gives us a one-page buffer if alloca() allocates slightly more memory.
729 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
730 bottom += os::Linux::page_size() - 1;
731
732 // sp might be slightly above current stack pointer; if that's the case, we
733 // will alloca() a little more space than necessary, which is OK. Don't use
734 // os::current_stack_pointer(), as its result can be slightly below current
735 // stack pointer, causing us to not alloca enough to reach "bottom".
736 sp = (address)&sp;
737
738 if (sp > bottom) {
739 size = sp - bottom;
740 p = (volatile char *)alloca(size);
741 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
742 p[0] = '\0';
743 }
744 }
745
746 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
747 assert(t!=NULL, "just checking");
748 assert(t->osthread()->expanding_stack(), "expand should be set");
749 assert(t->stack_base() != NULL, "stack_base was not initialized");
750
751 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) {
752 sigset_t mask_all, old_sigset;
753 sigfillset(&mask_all);
754 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
755 _expand_stack_to(addr);
756 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
757 return true;
758 }
759 return false;
760 }
761
762 //////////////////////////////////////////////////////////////////////////////
763 // create new thread
764
765 static address highest_vm_reserved_address();
766
767 // check if it's safe to start a new thread
768 static bool _thread_safety_check(Thread* thread) {
769 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) {
770 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat)
771 // Heap is mmap'ed at lower end of memory space. Thread stacks are
772 // allocated (MAP_FIXED) from high address space. Every thread stack
773 // occupies a fixed size slot (usually 2Mbytes, but user can change
774 // it to other values if they rebuild LinuxThreads).
775 //
776 // Problem with MAP_FIXED is that mmap() can still succeed even part of
777 // the memory region has already been mmap'ed. That means if we have too
778 // many threads and/or very large heap, eventually thread stack will
779 // collide with heap.
780 //
781 // Here we try to prevent heap/stack collision by comparing current
782 // stack bottom with the highest address that has been mmap'ed by JVM
783 // plus a safety margin for memory maps created by native code.
784 //
785 // This feature can be disabled by setting ThreadSafetyMargin to 0
786 //
787 if (ThreadSafetyMargin > 0) {
788 address stack_bottom = os::current_stack_base() - os::current_stack_size();
789
790 // not safe if our stack extends below the safety margin
791 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address();
792 } else {
793 return true;
794 }
795 } else {
796 // Floating stack LinuxThreads or NPTL:
797 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When
798 // there's not enough space left, pthread_create() will fail. If we come
799 // here, that means enough space has been reserved for stack.
800 return true;
801 }
802 }
803
804 // Thread start routine for all newly created threads
805 static void *java_start(Thread *thread) {
806 // Try to randomize the cache line index of hot stack frames.
807 // This helps when threads of the same stack traces evict each other's
808 // cache lines. The threads can be either from the same JVM instance, or
809 // from different JVM instances. The benefit is especially true for
810 // processors with hyperthreading technology.
811 static int counter = 0;
812 int pid = os::current_process_id();
813 alloca(((pid ^ counter++) & 7) * 128);
814
815 ThreadLocalStorage::set_thread(thread);
816
817 OSThread* osthread = thread->osthread();
818 Monitor* sync = osthread->startThread_lock();
819
820 // non floating stack LinuxThreads needs extra check, see above
821 if (!_thread_safety_check(thread)) {
822 // notify parent thread
823 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
824 osthread->set_state(ZOMBIE);
825 sync->notify_all();
826 return NULL;
827 }
828
829 // thread_id is kernel thread id (similar to Solaris LWP id)
830 osthread->set_thread_id(os::Linux::gettid());
831
832 if (UseNUMA) {
833 int lgrp_id = os::numa_get_group_id();
834 if (lgrp_id != -1) {
835 thread->set_lgrp_id(lgrp_id);
836 }
837 }
838 // initialize signal mask for this thread
839 os::Linux::hotspot_sigmask(thread);
840
841 // initialize floating point control register
842 os::Linux::init_thread_fpu_state();
843
844 // handshaking with parent thread
845 {
846 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
847
848 // notify parent thread
849 osthread->set_state(INITIALIZED);
850 sync->notify_all();
851
852 // wait until os::start_thread()
853 while (osthread->get_state() == INITIALIZED) {
854 sync->wait(Mutex::_no_safepoint_check_flag);
855 }
856 }
857
858 // call one more level start routine
859 thread->run();
860
861 return 0;
862 }
863
864 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
865 assert(thread->osthread() == NULL, "caller responsible");
866
867 // Allocate the OSThread object
868 OSThread* osthread = new OSThread(NULL, NULL);
869 if (osthread == NULL) {
870 return false;
871 }
872
873 // set the correct thread state
874 osthread->set_thread_type(thr_type);
875
876 // Initial state is ALLOCATED but not INITIALIZED
877 osthread->set_state(ALLOCATED);
878
879 thread->set_osthread(osthread);
880
881 // init thread attributes
882 pthread_attr_t attr;
883 pthread_attr_init(&attr);
884 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
885
886 // stack size
887 if (os::Linux::supports_variable_stack_size()) {
888 // calculate stack size if it's not specified by caller
889 if (stack_size == 0) {
890 stack_size = os::Linux::default_stack_size(thr_type);
891
892 switch (thr_type) {
893 case os::java_thread:
894 // Java threads use ThreadStackSize which default value can be
895 // changed with the flag -Xss
896 assert (JavaThread::stack_size_at_create() > 0, "this should be set");
897 stack_size = JavaThread::stack_size_at_create();
898 break;
899 case os::compiler_thread:
900 if (CompilerThreadStackSize > 0) {
901 stack_size = (size_t)(CompilerThreadStackSize * K);
902 break;
903 } // else fall through:
904 // use VMThreadStackSize if CompilerThreadStackSize is not defined
905 case os::vm_thread:
906 case os::pgc_thread:
907 case os::cgc_thread:
908 case os::watcher_thread:
909 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
910 break;
911 }
912 }
913
914 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
915 pthread_attr_setstacksize(&attr, stack_size);
916 } else {
917 // let pthread_create() pick the default value.
918 }
919
920 // glibc guard page
921 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
922
923 ThreadState state;
924
925 {
926 // Serialize thread creation if we are running with fixed stack LinuxThreads
927 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack();
928 if (lock) {
929 os::Linux::createThread_lock()->lock_without_safepoint_check();
930 }
931
932 pthread_t tid;
933 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
934
935 pthread_attr_destroy(&attr);
936
937 if (ret != 0) {
938 if (PrintMiscellaneous && (Verbose || WizardMode)) {
939 perror("pthread_create()");
940 }
941 // Need to clean up stuff we've allocated so far
942 thread->set_osthread(NULL);
943 delete osthread;
944 if (lock) os::Linux::createThread_lock()->unlock();
945 return false;
946 }
947
948 // Store pthread info into the OSThread
949 osthread->set_pthread_id(tid);
950
951 // Wait until child thread is either initialized or aborted
952 {
953 Monitor* sync_with_child = osthread->startThread_lock();
954 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
955 while ((state = osthread->get_state()) == ALLOCATED) {
956 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
957 }
958 }
959
960 if (lock) {
961 os::Linux::createThread_lock()->unlock();
962 }
963 }
964
965 // Aborted due to thread limit being reached
966 if (state == ZOMBIE) {
967 thread->set_osthread(NULL);
968 delete osthread;
969 return false;
970 }
971
972 // The thread is returned suspended (in state INITIALIZED),
973 // and is started higher up in the call chain
974 assert(state == INITIALIZED, "race condition");
975 return true;
976 }
977
978 /////////////////////////////////////////////////////////////////////////////
979 // attach existing thread
980
981 // bootstrap the main thread
982 bool os::create_main_thread(JavaThread* thread) {
983 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
984 return create_attached_thread(thread);
985 }
986
987 bool os::create_attached_thread(JavaThread* thread) {
988 #ifdef ASSERT
989 thread->verify_not_published();
990 #endif
991
992 // Allocate the OSThread object
993 OSThread* osthread = new OSThread(NULL, NULL);
994
995 if (osthread == NULL) {
996 return false;
997 }
998
999 // Store pthread info into the OSThread
1000 osthread->set_thread_id(os::Linux::gettid());
1001 osthread->set_pthread_id(::pthread_self());
1002
1003 // initialize floating point control register
1004 os::Linux::init_thread_fpu_state();
1005
1006 // Initial thread state is RUNNABLE
1007 osthread->set_state(RUNNABLE);
1008
1009 thread->set_osthread(osthread);
1010
1011 if (UseNUMA) {
1012 int lgrp_id = os::numa_get_group_id();
1013 if (lgrp_id != -1) {
1014 thread->set_lgrp_id(lgrp_id);
1015 }
1016 }
1017
1018 if (os::Linux::is_initial_thread()) {
1019 // If current thread is initial thread, its stack is mapped on demand,
1020 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
1021 // the entire stack region to avoid SEGV in stack banging.
1022 // It is also useful to get around the heap-stack-gap problem on SuSE
1023 // kernel (see 4821821 for details). We first expand stack to the top
1024 // of yellow zone, then enable stack yellow zone (order is significant,
1025 // enabling yellow zone first will crash JVM on SuSE Linux), so there
1026 // is no gap between the last two virtual memory regions.
1027
1028 JavaThread *jt = (JavaThread *)thread;
1029 address addr = jt->stack_yellow_zone_base();
1030 assert(addr != NULL, "initialization problem?");
1031 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
1032
1033 osthread->set_expanding_stack();
1034 os::Linux::manually_expand_stack(jt, addr);
1035 osthread->clear_expanding_stack();
1036 }
1037
1038 // initialize signal mask for this thread
1039 // and save the caller's signal mask
1040 os::Linux::hotspot_sigmask(thread);
1041
1042 return true;
1043 }
1044
1045 void os::pd_start_thread(Thread* thread) {
1046 OSThread * osthread = thread->osthread();
1047 assert(osthread->get_state() != INITIALIZED, "just checking");
1048 Monitor* sync_with_child = osthread->startThread_lock();
1049 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
1050 sync_with_child->notify();
1051 }
1052
1053 // Free Linux resources related to the OSThread
1054 void os::free_thread(OSThread* osthread) {
1055 assert(osthread != NULL, "osthread not set");
1056
1057 if (Thread::current()->osthread() == osthread) {
1058 // Restore caller's signal mask
1059 sigset_t sigmask = osthread->caller_sigmask();
1060 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1061 }
1062
1063 delete osthread;
1064 }
1065
1066 //////////////////////////////////////////////////////////////////////////////
1067 // thread local storage
1068
1069 int os::allocate_thread_local_storage() {
1070 pthread_key_t key;
1071 int rslt = pthread_key_create(&key, NULL);
1072 assert(rslt == 0, "cannot allocate thread local storage");
1073 return (int)key;
1074 }
1075
1076 // Note: This is currently not used by VM, as we don't destroy TLS key
1077 // on VM exit.
1078 void os::free_thread_local_storage(int index) {
1079 int rslt = pthread_key_delete((pthread_key_t)index);
1080 assert(rslt == 0, "invalid index");
1081 }
1082
1083 void os::thread_local_storage_at_put(int index, void* value) {
1084 int rslt = pthread_setspecific((pthread_key_t)index, value);
1085 assert(rslt == 0, "pthread_setspecific failed");
1086 }
1087
1088 extern "C" Thread* get_thread() {
1089 return ThreadLocalStorage::thread();
1090 }
1091
1092 //////////////////////////////////////////////////////////////////////////////
1093 // initial thread
1094
1095 // Check if current thread is the initial thread, similar to Solaris thr_main.
1096 bool os::Linux::is_initial_thread(void) {
1097 char dummy;
1098 // If called before init complete, thread stack bottom will be null.
1099 // Can be called if fatal error occurs before initialization.
1100 if (initial_thread_stack_bottom() == NULL) return false;
1101 assert(initial_thread_stack_bottom() != NULL &&
1102 initial_thread_stack_size() != 0,
1103 "os::init did not locate initial thread's stack region");
1104 if ((address)&dummy >= initial_thread_stack_bottom() &&
1105 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size())
1106 return true;
1107 else return false;
1108 }
1109
1110 // Find the virtual memory area that contains addr
1111 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1112 FILE *fp = fopen("/proc/self/maps", "r");
1113 if (fp) {
1114 address low, high;
1115 while (!feof(fp)) {
1116 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1117 if (low <= addr && addr < high) {
1118 if (vma_low) *vma_low = low;
1119 if (vma_high) *vma_high = high;
1120 fclose (fp);
1121 return true;
1122 }
1123 }
1124 for (;;) {
1125 int ch = fgetc(fp);
1126 if (ch == EOF || ch == (int)'\n') break;
1127 }
1128 }
1129 fclose(fp);
1130 }
1131 return false;
1132 }
1133
1134 // Locate initial thread stack. This special handling of initial thread stack
1135 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1136 // bogus value for initial thread.
1137 void os::Linux::capture_initial_stack(size_t max_size) {
1138 // stack size is the easy part, get it from RLIMIT_STACK
1139 size_t stack_size;
1140 struct rlimit rlim;
1141 getrlimit(RLIMIT_STACK, &rlim);
1142 stack_size = rlim.rlim_cur;
1143
1144 // 6308388: a bug in ld.so will relocate its own .data section to the
1145 // lower end of primordial stack; reduce ulimit -s value a little bit
1146 // so we won't install guard page on ld.so's data section.
1147 stack_size -= 2 * page_size();
1148
1149 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
1150 // 7.1, in both cases we will get 2G in return value.
1151 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
1152 // SuSE 7.2, Debian) can not handle alternate signal stack correctly
1153 // for initial thread if its stack size exceeds 6M. Cap it at 2M,
1154 // in case other parts in glibc still assumes 2M max stack size.
1155 // FIXME: alt signal stack is gone, maybe we can relax this constraint?
1156 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
1157 if (stack_size > 2 * K * K IA64_ONLY(*2))
1158 stack_size = 2 * K * K IA64_ONLY(*2);
1159 // Try to figure out where the stack base (top) is. This is harder.
1160 //
1161 // When an application is started, glibc saves the initial stack pointer in
1162 // a global variable "__libc_stack_end", which is then used by system
1163 // libraries. __libc_stack_end should be pretty close to stack top. The
1164 // variable is available since the very early days. However, because it is
1165 // a private interface, it could disappear in the future.
1166 //
1167 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1168 // to __libc_stack_end, it is very close to stack top, but isn't the real
1169 // stack top. Note that /proc may not exist if VM is running as a chroot
1170 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1171 // /proc/<pid>/stat could change in the future (though unlikely).
1172 //
1173 // We try __libc_stack_end first. If that doesn't work, look for
1174 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1175 // as a hint, which should work well in most cases.
1176
1177 uintptr_t stack_start;
1178
1179 // try __libc_stack_end first
1180 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1181 if (p && *p) {
1182 stack_start = *p;
1183 } else {
1184 // see if we can get the start_stack field from /proc/self/stat
1185 FILE *fp;
1186 int pid;
1187 char state;
1188 int ppid;
1189 int pgrp;
1190 int session;
1191 int nr;
1192 int tpgrp;
1193 unsigned long flags;
1194 unsigned long minflt;
1195 unsigned long cminflt;
1196 unsigned long majflt;
1197 unsigned long cmajflt;
1198 unsigned long utime;
1199 unsigned long stime;
1200 long cutime;
1201 long cstime;
1202 long prio;
1203 long nice;
1204 long junk;
1205 long it_real;
1206 uintptr_t start;
1207 uintptr_t vsize;
1208 intptr_t rss;
1209 uintptr_t rsslim;
1210 uintptr_t scodes;
1211 uintptr_t ecode;
1212 int i;
1213
1214 // Figure what the primordial thread stack base is. Code is inspired
1215 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1216 // followed by command name surrounded by parentheses, state, etc.
1217 char stat[2048];
1218 int statlen;
1219
1220 fp = fopen("/proc/self/stat", "r");
1221 if (fp) {
1222 statlen = fread(stat, 1, 2047, fp);
1223 stat[statlen] = '\0';
1224 fclose(fp);
1225
1226 // Skip pid and the command string. Note that we could be dealing with
1227 // weird command names, e.g. user could decide to rename java launcher
1228 // to "java 1.4.2 :)", then the stat file would look like
1229 // 1234 (java 1.4.2 :)) R ... ...
1230 // We don't really need to know the command string, just find the last
1231 // occurrence of ")" and then start parsing from there. See bug 4726580.
1232 char * s = strrchr(stat, ')');
1233
1234 i = 0;
1235 if (s) {
1236 // Skip blank chars
1237 do s++; while (isspace(*s));
1238
1239 #define _UFM UINTX_FORMAT
1240 #define _DFM INTX_FORMAT
1241
1242 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */
1243 /* 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 */
1244 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,
1245 &state, /* 3 %c */
1246 &ppid, /* 4 %d */
1247 &pgrp, /* 5 %d */
1248 &session, /* 6 %d */
1249 &nr, /* 7 %d */
1250 &tpgrp, /* 8 %d */
1251 &flags, /* 9 %lu */
1252 &minflt, /* 10 %lu */
1253 &cminflt, /* 11 %lu */
1254 &majflt, /* 12 %lu */
1255 &cmajflt, /* 13 %lu */
1256 &utime, /* 14 %lu */
1257 &stime, /* 15 %lu */
1258 &cutime, /* 16 %ld */
1259 &cstime, /* 17 %ld */
1260 &prio, /* 18 %ld */
1261 &nice, /* 19 %ld */
1262 &junk, /* 20 %ld */
1263 &it_real, /* 21 %ld */
1264 &start, /* 22 UINTX_FORMAT */
1265 &vsize, /* 23 UINTX_FORMAT */
1266 &rss, /* 24 INTX_FORMAT */
1267 &rsslim, /* 25 UINTX_FORMAT */
1268 &scodes, /* 26 UINTX_FORMAT */
1269 &ecode, /* 27 UINTX_FORMAT */
1270 &stack_start); /* 28 UINTX_FORMAT */
1271 }
1272
1273 #undef _UFM
1274 #undef _DFM
1275
1276 if (i != 28 - 2) {
1277 assert(false, "Bad conversion from /proc/self/stat");
1278 // product mode - assume we are the initial thread, good luck in the
1279 // embedded case.
1280 warning("Can't detect initial thread stack location - bad conversion");
1281 stack_start = (uintptr_t) &rlim;
1282 }
1283 } else {
1284 // For some reason we can't open /proc/self/stat (for example, running on
1285 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1286 // most cases, so don't abort:
1287 warning("Can't detect initial thread stack location - no /proc/self/stat");
1288 stack_start = (uintptr_t) &rlim;
1289 }
1290 }
1291
1292 // Now we have a pointer (stack_start) very close to the stack top, the
1293 // next thing to do is to figure out the exact location of stack top. We
1294 // can find out the virtual memory area that contains stack_start by
1295 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1296 // and its upper limit is the real stack top. (again, this would fail if
1297 // running inside chroot, because /proc may not exist.)
1298
1299 uintptr_t stack_top;
1300 address low, high;
1301 if (find_vma((address)stack_start, &low, &high)) {
1302 // success, "high" is the true stack top. (ignore "low", because initial
1303 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1304 stack_top = (uintptr_t)high;
1305 } else {
1306 // failed, likely because /proc/self/maps does not exist
1307 warning("Can't detect initial thread stack location - find_vma failed");
1308 // best effort: stack_start is normally within a few pages below the real
1309 // stack top, use it as stack top, and reduce stack size so we won't put
1310 // guard page outside stack.
1311 stack_top = stack_start;
1312 stack_size -= 16 * page_size();
1313 }
1314
1315 // stack_top could be partially down the page so align it
1316 stack_top = align_size_up(stack_top, page_size());
1317
1318 if (max_size && stack_size > max_size) {
1319 _initial_thread_stack_size = max_size;
1320 } else {
1321 _initial_thread_stack_size = stack_size;
1322 }
1323
1324 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1325 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1326 }
1327
1328 ////////////////////////////////////////////////////////////////////////////////
1329 // time support
1330
1331 // Time since start-up in seconds to a fine granularity.
1332 // Used by VMSelfDestructTimer and the MemProfiler.
1333 double os::elapsedTime() {
1334
1335 return (double)(os::elapsed_counter()) * 0.000001;
1336 }
1337
1338 jlong os::elapsed_counter() {
1339 timeval time;
1340 int status = gettimeofday(&time, NULL);
1341 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count;
1342 }
1343
1344 jlong os::elapsed_frequency() {
1345 return (1000 * 1000);
1346 }
1347
1348 bool os::supports_vtime() { return true; }
1349 bool os::enable_vtime() { return false; }
1350 bool os::vtime_enabled() { return false; }
1351
1352 double os::elapsedVTime() {
1353 struct rusage usage;
1354 int retval = getrusage(RUSAGE_THREAD, &usage);
1355 if (retval == 0) {
1356 return (double) (usage.ru_utime.tv_sec + usage.ru_stime.tv_sec) + (double) (usage.ru_utime.tv_usec + usage.ru_stime.tv_usec) / (1000 * 1000);
1357 } else {
1358 // better than nothing, but not much
1359 return elapsedTime();
1360 }
1361 }
1362
1363 jlong os::javaTimeMillis() {
1364 timeval time;
1365 int status = gettimeofday(&time, NULL);
1366 assert(status != -1, "linux error");
1367 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1368 }
1369
1370 #ifndef CLOCK_MONOTONIC
1371 #define CLOCK_MONOTONIC (1)
1372 #endif
1373
1374 void os::Linux::clock_init() {
1375 // we do dlopen's in this particular order due to bug in linux
1376 // dynamical loader (see 6348968) leading to crash on exit
1377 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1378 if (handle == NULL) {
1379 handle = dlopen("librt.so", RTLD_LAZY);
1380 }
1381
1382 if (handle) {
1383 int (*clock_getres_func)(clockid_t, struct timespec*) =
1384 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1385 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1386 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1387 if (clock_getres_func && clock_gettime_func) {
1388 // See if monotonic clock is supported by the kernel. Note that some
1389 // early implementations simply return kernel jiffies (updated every
1390 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1391 // for nano time (though the monotonic property is still nice to have).
1392 // It's fixed in newer kernels, however clock_getres() still returns
1393 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1394 // resolution for now. Hopefully as people move to new kernels, this
1395 // won't be a problem.
1396 struct timespec res;
1397 struct timespec tp;
1398 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1399 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1400 // yes, monotonic clock is supported
1401 _clock_gettime = clock_gettime_func;
1402 } else {
1403 // close librt if there is no monotonic clock
1404 dlclose(handle);
1405 }
1406 }
1407 }
1408 }
1409
1410 #ifndef SYS_clock_getres
1411
1412 #if defined(IA32) || defined(AMD64)
1413 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229)
1414 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1415 #else
1416 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1417 #define sys_clock_getres(x,y) -1
1418 #endif
1419
1420 #else
1421 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1422 #endif
1423
1424 void os::Linux::fast_thread_clock_init() {
1425 if (!UseLinuxPosixThreadCPUClocks) {
1426 return;
1427 }
1428 clockid_t clockid;
1429 struct timespec tp;
1430 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1431 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1432
1433 // Switch to using fast clocks for thread cpu time if
1434 // the sys_clock_getres() returns 0 error code.
1435 // Note, that some kernels may support the current thread
1436 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1437 // returned by the pthread_getcpuclockid().
1438 // If the fast Posix clocks are supported then the sys_clock_getres()
1439 // must return at least tp.tv_sec == 0 which means a resolution
1440 // better than 1 sec. This is extra check for reliability.
1441
1442 if(pthread_getcpuclockid_func &&
1443 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1444 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1445
1446 _supports_fast_thread_cpu_time = true;
1447 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1448 }
1449 }
1450
1451 jlong os::javaTimeNanos() {
1452 if (Linux::supports_monotonic_clock()) {
1453 struct timespec tp;
1454 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1455 assert(status == 0, "gettime error");
1456 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1457 return result;
1458 } else {
1459 timeval time;
1460 int status = gettimeofday(&time, NULL);
1461 assert(status != -1, "linux error");
1462 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1463 return 1000 * usecs;
1464 }
1465 }
1466
1467 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1468 if (Linux::supports_monotonic_clock()) {
1469 info_ptr->max_value = ALL_64_BITS;
1470
1471 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1472 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1473 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1474 } else {
1475 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1476 info_ptr->max_value = ALL_64_BITS;
1477
1478 // gettimeofday is a real time clock so it skips
1479 info_ptr->may_skip_backward = true;
1480 info_ptr->may_skip_forward = true;
1481 }
1482
1483 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1484 }
1485
1486 // Return the real, user, and system times in seconds from an
1487 // arbitrary fixed point in the past.
1488 bool os::getTimesSecs(double* process_real_time,
1489 double* process_user_time,
1490 double* process_system_time) {
1491 struct tms ticks;
1492 clock_t real_ticks = times(&ticks);
1493
1494 if (real_ticks == (clock_t) (-1)) {
1495 return false;
1496 } else {
1497 double ticks_per_second = (double) clock_tics_per_sec;
1498 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1499 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1500 *process_real_time = ((double) real_ticks) / ticks_per_second;
1501
1502 return true;
1503 }
1504 }
1505
1506
1507 char * os::local_time_string(char *buf, size_t buflen) {
1508 struct tm t;
1509 time_t long_time;
1510 time(&long_time);
1511 localtime_r(&long_time, &t);
1512 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1513 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1514 t.tm_hour, t.tm_min, t.tm_sec);
1515 return buf;
1516 }
1517
1518 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1519 return localtime_r(clock, res);
1520 }
1521
1522 ////////////////////////////////////////////////////////////////////////////////
1523 // runtime exit support
1524
1525 // Note: os::shutdown() might be called very early during initialization, or
1526 // called from signal handler. Before adding something to os::shutdown(), make
1527 // sure it is async-safe and can handle partially initialized VM.
1528 void os::shutdown() {
1529
1530 // allow PerfMemory to attempt cleanup of any persistent resources
1531 perfMemory_exit();
1532
1533 // needs to remove object in file system
1534 AttachListener::abort();
1535
1536 // flush buffered output, finish log files
1537 ostream_abort();
1538
1539 // Check for abort hook
1540 abort_hook_t abort_hook = Arguments::abort_hook();
1541 if (abort_hook != NULL) {
1542 abort_hook();
1543 }
1544
1545 }
1546
1547 // Note: os::abort() might be called very early during initialization, or
1548 // called from signal handler. Before adding something to os::abort(), make
1549 // sure it is async-safe and can handle partially initialized VM.
1550 void os::abort(bool dump_core) {
1551 os::shutdown();
1552 if (dump_core) {
1553 #ifndef PRODUCT
1554 fdStream out(defaultStream::output_fd());
1555 out.print_raw("Current thread is ");
1556 char buf[16];
1557 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1558 out.print_raw_cr(buf);
1559 out.print_raw_cr("Dumping core ...");
1560 #endif
1561 ::abort(); // dump core
1562 }
1563
1564 ::exit(1);
1565 }
1566
1567 // Die immediately, no exit hook, no abort hook, no cleanup.
1568 void os::die() {
1569 // _exit() on LinuxThreads only kills current thread
1570 ::abort();
1571 }
1572
1573 // unused on linux for now.
1574 void os::set_error_file(const char *logfile) {}
1575
1576
1577 // This method is a copy of JDK's sysGetLastErrorString
1578 // from src/solaris/hpi/src/system_md.c
1579
1580 size_t os::lasterror(char *buf, size_t len) {
1581
1582 if (errno == 0) return 0;
1583
1584 const char *s = ::strerror(errno);
1585 size_t n = ::strlen(s);
1586 if (n >= len) {
1587 n = len - 1;
1588 }
1589 ::strncpy(buf, s, n);
1590 buf[n] = '\0';
1591 return n;
1592 }
1593
1594 intx os::current_thread_id() { return (intx)pthread_self(); }
1595 int os::current_process_id() {
1596
1597 // Under the old linux thread library, linux gives each thread
1598 // its own process id. Because of this each thread will return
1599 // a different pid if this method were to return the result
1600 // of getpid(2). Linux provides no api that returns the pid
1601 // of the launcher thread for the vm. This implementation
1602 // returns a unique pid, the pid of the launcher thread
1603 // that starts the vm 'process'.
1604
1605 // Under the NPTL, getpid() returns the same pid as the
1606 // launcher thread rather than a unique pid per thread.
1607 // Use gettid() if you want the old pre NPTL behaviour.
1608
1609 // if you are looking for the result of a call to getpid() that
1610 // returns a unique pid for the calling thread, then look at the
1611 // OSThread::thread_id() method in osThread_linux.hpp file
1612
1613 return (int)(_initial_pid ? _initial_pid : getpid());
1614 }
1615
1616 // DLL functions
1617
1618 const char* os::dll_file_extension() { return ".so"; }
1619
1620 // This must be hard coded because it's the system's temporary
1621 // directory not the java application's temp directory, ala java.io.tmpdir.
1622 const char* os::get_temp_directory() { return "/tmp"; }
1623
1624 static bool file_exists(const char* filename) {
1625 struct stat statbuf;
1626 if (filename == NULL || strlen(filename) == 0) {
1627 return false;
1628 }
1629 return os::stat(filename, &statbuf) == 0;
1630 }
1631
1632 bool os::dll_build_name(char* buffer, size_t buflen,
1633 const char* pname, const char* fname) {
1634 bool retval = false;
1635 // Copied from libhpi
1636 const size_t pnamelen = pname ? strlen(pname) : 0;
1637
1638 // Return error on buffer overflow.
1639 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1640 return retval;
1641 }
1642
1643 if (pnamelen == 0) {
1644 snprintf(buffer, buflen, "lib%s.so", fname);
1645 retval = true;
1646 } else if (strchr(pname, *os::path_separator()) != NULL) {
1647 int n;
1648 char** pelements = split_path(pname, &n);
1649 if (pelements == NULL) {
1650 return false;
1651 }
1652 for (int i = 0 ; i < n ; i++) {
1653 // Really shouldn't be NULL, but check can't hurt
1654 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1655 continue; // skip the empty path values
1656 }
1657 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1658 if (file_exists(buffer)) {
1659 retval = true;
1660 break;
1661 }
1662 }
1663 // release the storage
1664 for (int i = 0 ; i < n ; i++) {
1665 if (pelements[i] != NULL) {
1666 FREE_C_HEAP_ARRAY(char, pelements[i], mtInternal);
1667 }
1668 }
1669 if (pelements != NULL) {
1670 FREE_C_HEAP_ARRAY(char*, pelements, mtInternal);
1671 }
1672 } else {
1673 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1674 retval = true;
1675 }
1676 return retval;
1677 }
1678
1679 // check if addr is inside libjvm.so
1680 bool os::address_is_in_vm(address addr) {
1681 static address libjvm_base_addr;
1682 Dl_info dlinfo;
1683
1684 if (libjvm_base_addr == NULL) {
1685 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1686 libjvm_base_addr = (address)dlinfo.dli_fbase;
1687 }
1688 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1689 }
1690
1691 if (dladdr((void *)addr, &dlinfo) != 0) {
1692 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1693 }
1694
1695 return false;
1696 }
1697
1698 bool os::dll_address_to_function_name(address addr, char *buf,
1699 int buflen, int *offset) {
1700 // buf is not optional, but offset is optional
1701 assert(buf != NULL, "sanity check");
1702
1703 Dl_info dlinfo;
1704
1705 if (dladdr((void*)addr, &dlinfo) != 0) {
1706 // see if we have a matching symbol
1707 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1708 if (!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) {
1709 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1710 }
1711 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1712 return true;
1713 }
1714 // no matching symbol so try for just file info
1715 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1716 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1717 buf, buflen, offset, dlinfo.dli_fname)) {
1718 return true;
1719 }
1720 }
1721 }
1722
1723 buf[0] = '\0';
1724 if (offset != NULL) *offset = -1;
1725 return false;
1726 }
1727
1728 struct _address_to_library_name {
1729 address addr; // input : memory address
1730 size_t buflen; // size of fname
1731 char* fname; // output: library name
1732 address base; // library base addr
1733 };
1734
1735 static int address_to_library_name_callback(struct dl_phdr_info *info,
1736 size_t size, void *data) {
1737 int i;
1738 bool found = false;
1739 address libbase = NULL;
1740 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1741
1742 // iterate through all loadable segments
1743 for (i = 0; i < info->dlpi_phnum; i++) {
1744 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1745 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1746 // base address of a library is the lowest address of its loaded
1747 // segments.
1748 if (libbase == NULL || libbase > segbase) {
1749 libbase = segbase;
1750 }
1751 // see if 'addr' is within current segment
1752 if (segbase <= d->addr &&
1753 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1754 found = true;
1755 }
1756 }
1757 }
1758
1759 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1760 // so dll_address_to_library_name() can fall through to use dladdr() which
1761 // can figure out executable name from argv[0].
1762 if (found && info->dlpi_name && info->dlpi_name[0]) {
1763 d->base = libbase;
1764 if (d->fname) {
1765 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1766 }
1767 return 1;
1768 }
1769 return 0;
1770 }
1771
1772 bool os::dll_address_to_library_name(address addr, char* buf,
1773 int buflen, int* offset) {
1774 // buf is not optional, but offset is optional
1775 assert(buf != NULL, "sanity check");
1776
1777 Dl_info dlinfo;
1778 struct _address_to_library_name data;
1779
1780 // There is a bug in old glibc dladdr() implementation that it could resolve
1781 // to wrong library name if the .so file has a base address != NULL. Here
1782 // we iterate through the program headers of all loaded libraries to find
1783 // out which library 'addr' really belongs to. This workaround can be
1784 // removed once the minimum requirement for glibc is moved to 2.3.x.
1785 data.addr = addr;
1786 data.fname = buf;
1787 data.buflen = buflen;
1788 data.base = NULL;
1789 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1790
1791 if (rslt) {
1792 // buf already contains library name
1793 if (offset) *offset = addr - data.base;
1794 return true;
1795 }
1796 if (dladdr((void*)addr, &dlinfo) != 0) {
1797 if (dlinfo.dli_fname != NULL) {
1798 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1799 }
1800 if (dlinfo.dli_fbase != NULL && offset != NULL) {
1801 *offset = addr - (address)dlinfo.dli_fbase;
1802 }
1803 return true;
1804 }
1805
1806 buf[0] = '\0';
1807 if (offset) *offset = -1;
1808 return false;
1809 }
1810
1811 // Loads .dll/.so and
1812 // in case of error it checks if .dll/.so was built for the
1813 // same architecture as Hotspot is running on
1814
1815
1816 // Remember the stack's state. The Linux dynamic linker will change
1817 // the stack to 'executable' at most once, so we must safepoint only once.
1818 bool os::Linux::_stack_is_executable = false;
1819
1820 // VM operation that loads a library. This is necessary if stack protection
1821 // of the Java stacks can be lost during loading the library. If we
1822 // do not stop the Java threads, they can stack overflow before the stacks
1823 // are protected again.
1824 class VM_LinuxDllLoad: public VM_Operation {
1825 private:
1826 const char *_filename;
1827 char *_ebuf;
1828 int _ebuflen;
1829 void *_lib;
1830 public:
1831 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
1832 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
1833 VMOp_Type type() const { return VMOp_LinuxDllLoad; }
1834 void doit() {
1835 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
1836 os::Linux::_stack_is_executable = true;
1837 }
1838 void* loaded_library() { return _lib; }
1839 };
1840
1841 void * os::dll_load(const char *filename, char *ebuf, int ebuflen)
1842 {
1843 void * result = NULL;
1844 bool load_attempted = false;
1845
1846 // Check whether the library to load might change execution rights
1847 // of the stack. If they are changed, the protection of the stack
1848 // guard pages will be lost. We need a safepoint to fix this.
1849 //
1850 // See Linux man page execstack(8) for more info.
1851 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
1852 ElfFile ef(filename);
1853 if (!ef.specifies_noexecstack()) {
1854 if (!is_init_completed()) {
1855 os::Linux::_stack_is_executable = true;
1856 // This is OK - No Java threads have been created yet, and hence no
1857 // stack guard pages to fix.
1858 //
1859 // This should happen only when you are building JDK7 using a very
1860 // old version of JDK6 (e.g., with JPRT) and running test_gamma.
1861 //
1862 // Dynamic loader will make all stacks executable after
1863 // this function returns, and will not do that again.
1864 assert(Threads::first() == NULL, "no Java threads should exist yet.");
1865 } else {
1866 warning("You have loaded library %s which might have disabled stack guard. "
1867 "The VM will try to fix the stack guard now.\n"
1868 "It's highly recommended that you fix the library with "
1869 "'execstack -c <libfile>', or link it with '-z noexecstack'.",
1870 filename);
1871
1872 assert(Thread::current()->is_Java_thread(), "must be Java thread");
1873 JavaThread *jt = JavaThread::current();
1874 if (jt->thread_state() != _thread_in_native) {
1875 // This happens when a compiler thread tries to load a hsdis-<arch>.so file
1876 // that requires ExecStack. Cannot enter safe point. Let's give up.
1877 warning("Unable to fix stack guard. Giving up.");
1878 } else {
1879 if (!LoadExecStackDllInVMThread) {
1880 // This is for the case where the DLL has an static
1881 // constructor function that executes JNI code. We cannot
1882 // load such DLLs in the VMThread.
1883 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1884 }
1885
1886 ThreadInVMfromNative tiv(jt);
1887 debug_only(VMNativeEntryWrapper vew;)
1888
1889 VM_LinuxDllLoad op(filename, ebuf, ebuflen);
1890 VMThread::execute(&op);
1891 if (LoadExecStackDllInVMThread) {
1892 result = op.loaded_library();
1893 }
1894 load_attempted = true;
1895 }
1896 }
1897 }
1898 }
1899
1900 if (!load_attempted) {
1901 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1902 }
1903
1904 if (result != NULL) {
1905 // Successful loading
1906 return result;
1907 }
1908
1909 Elf32_Ehdr elf_head;
1910 int diag_msg_max_length=ebuflen-strlen(ebuf);
1911 char* diag_msg_buf=ebuf+strlen(ebuf);
1912
1913 if (diag_msg_max_length==0) {
1914 // No more space in ebuf for additional diagnostics message
1915 return NULL;
1916 }
1917
1918
1919 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1920
1921 if (file_descriptor < 0) {
1922 // Can't open library, report dlerror() message
1923 return NULL;
1924 }
1925
1926 bool failed_to_read_elf_head=
1927 (sizeof(elf_head)!=
1928 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ;
1929
1930 ::close(file_descriptor);
1931 if (failed_to_read_elf_head) {
1932 // file i/o error - report dlerror() msg
1933 return NULL;
1934 }
1935
1936 typedef struct {
1937 Elf32_Half code; // Actual value as defined in elf.h
1938 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1939 char elf_class; // 32 or 64 bit
1940 char endianess; // MSB or LSB
1941 char* name; // String representation
1942 } arch_t;
1943
1944 #ifndef EM_486
1945 #define EM_486 6 /* Intel 80486 */
1946 #endif
1947
1948 static const arch_t arch_array[]={
1949 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1950 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1951 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1952 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1953 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1954 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1955 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1956 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1957 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1958 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1959 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1960 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1961 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1962 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1963 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1964 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}
1965 };
1966
1967 #if (defined IA32)
1968 static Elf32_Half running_arch_code=EM_386;
1969 #elif (defined AMD64)
1970 static Elf32_Half running_arch_code=EM_X86_64;
1971 #elif (defined IA64)
1972 static Elf32_Half running_arch_code=EM_IA_64;
1973 #elif (defined __sparc) && (defined _LP64)
1974 static Elf32_Half running_arch_code=EM_SPARCV9;
1975 #elif (defined __sparc) && (!defined _LP64)
1976 static Elf32_Half running_arch_code=EM_SPARC;
1977 #elif (defined __powerpc64__)
1978 static Elf32_Half running_arch_code=EM_PPC64;
1979 #elif (defined __powerpc__)
1980 static Elf32_Half running_arch_code=EM_PPC;
1981 #elif (defined ARM)
1982 static Elf32_Half running_arch_code=EM_ARM;
1983 #elif (defined S390)
1984 static Elf32_Half running_arch_code=EM_S390;
1985 #elif (defined ALPHA)
1986 static Elf32_Half running_arch_code=EM_ALPHA;
1987 #elif (defined MIPSEL)
1988 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1989 #elif (defined PARISC)
1990 static Elf32_Half running_arch_code=EM_PARISC;
1991 #elif (defined MIPS)
1992 static Elf32_Half running_arch_code=EM_MIPS;
1993 #elif (defined M68K)
1994 static Elf32_Half running_arch_code=EM_68K;
1995 #else
1996 #error Method os::dll_load requires that one of following is defined:\
1997 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K
1998 #endif
1999
2000 // Identify compatability class for VM's architecture and library's architecture
2001 // Obtain string descriptions for architectures
2002
2003 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
2004 int running_arch_index=-1;
2005
2006 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) {
2007 if (running_arch_code == arch_array[i].code) {
2008 running_arch_index = i;
2009 }
2010 if (lib_arch.code == arch_array[i].code) {
2011 lib_arch.compat_class = arch_array[i].compat_class;
2012 lib_arch.name = arch_array[i].name;
2013 }
2014 }
2015
2016 assert(running_arch_index != -1,
2017 "Didn't find running architecture code (running_arch_code) in arch_array");
2018 if (running_arch_index == -1) {
2019 // Even though running architecture detection failed
2020 // we may still continue with reporting dlerror() message
2021 return NULL;
2022 }
2023
2024 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
2025 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
2026 return NULL;
2027 }
2028
2029 #ifndef S390
2030 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
2031 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
2032 return NULL;
2033 }
2034 #endif // !S390
2035
2036 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
2037 if ( lib_arch.name!=NULL ) {
2038 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
2039 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
2040 lib_arch.name, arch_array[running_arch_index].name);
2041 } else {
2042 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
2043 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
2044 lib_arch.code,
2045 arch_array[running_arch_index].name);
2046 }
2047 }
2048
2049 return NULL;
2050 }
2051
2052 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, int ebuflen) {
2053 void * result = ::dlopen(filename, RTLD_LAZY);
2054 if (result == NULL) {
2055 ::strncpy(ebuf, ::dlerror(), ebuflen - 1);
2056 ebuf[ebuflen-1] = '\0';
2057 }
2058 return result;
2059 }
2060
2061 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, int ebuflen) {
2062 void * result = NULL;
2063 if (LoadExecStackDllInVMThread) {
2064 result = dlopen_helper(filename, ebuf, ebuflen);
2065 }
2066
2067 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
2068 // library that requires an executable stack, or which does not have this
2069 // stack attribute set, dlopen changes the stack attribute to executable. The
2070 // read protection of the guard pages gets lost.
2071 //
2072 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
2073 // may have been queued at the same time.
2074
2075 if (!_stack_is_executable) {
2076 JavaThread *jt = Threads::first();
2077
2078 while (jt) {
2079 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized
2080 jt->stack_yellow_zone_enabled()) { // No pending stack overflow exceptions
2081 if (!os::guard_memory((char *) jt->stack_red_zone_base() - jt->stack_red_zone_size(),
2082 jt->stack_yellow_zone_size() + jt->stack_red_zone_size())) {
2083 warning("Attempt to reguard stack yellow zone failed.");
2084 }
2085 }
2086 jt = jt->next();
2087 }
2088 }
2089
2090 return result;
2091 }
2092
2093 /*
2094 * glibc-2.0 libdl is not MT safe. If you are building with any glibc,
2095 * chances are you might want to run the generated bits against glibc-2.0
2096 * libdl.so, so always use locking for any version of glibc.
2097 */
2098 void* os::dll_lookup(void* handle, const char* name) {
2099 pthread_mutex_lock(&dl_mutex);
2100 void* res = dlsym(handle, name);
2101 pthread_mutex_unlock(&dl_mutex);
2102 return res;
2103 }
2104
2105
2106 static bool _print_ascii_file(const char* filename, outputStream* st) {
2107 int fd = ::open(filename, O_RDONLY);
2108 if (fd == -1) {
2109 return false;
2110 }
2111
2112 char buf[32];
2113 int bytes;
2114 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) {
2115 st->print_raw(buf, bytes);
2116 }
2117
2118 ::close(fd);
2119
2120 return true;
2121 }
2122
2123 void os::print_dll_info(outputStream *st) {
2124 st->print_cr("Dynamic libraries:");
2125
2126 char fname[32];
2127 pid_t pid = os::Linux::gettid();
2128
2129 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
2130
2131 if (!_print_ascii_file(fname, st)) {
2132 st->print("Can not get library information for pid = %d\n", pid);
2133 }
2134 }
2135
2136 void os::print_os_info_brief(outputStream* st) {
2137 os::Linux::print_distro_info(st);
2138
2139 os::Posix::print_uname_info(st);
2140
2141 os::Linux::print_libversion_info(st);
2142
2143 }
2144
2145 void os::print_os_info(outputStream* st) {
2146 st->print("OS:");
2147
2148 os::Linux::print_distro_info(st);
2149
2150 os::Posix::print_uname_info(st);
2151
2152 // Print warning if unsafe chroot environment detected
2153 if (unsafe_chroot_detected) {
2154 st->print("WARNING!! ");
2155 st->print_cr(unstable_chroot_error);
2156 }
2157
2158 os::Linux::print_libversion_info(st);
2159
2160 os::Posix::print_rlimit_info(st);
2161
2162 os::Posix::print_load_average(st);
2163
2164 os::Linux::print_full_memory_info(st);
2165 }
2166
2167 // Try to identify popular distros.
2168 // Most Linux distributions have /etc/XXX-release file, which contains
2169 // the OS version string. Some have more than one /etc/XXX-release file
2170 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.),
2171 // so the order is important.
2172 void os::Linux::print_distro_info(outputStream* st) {
2173 if (!_print_ascii_file("/etc/mandrake-release", st) &&
2174 !_print_ascii_file("/etc/sun-release", st) &&
2175 !_print_ascii_file("/etc/redhat-release", st) &&
2176 !_print_ascii_file("/etc/SuSE-release", st) &&
2177 !_print_ascii_file("/etc/turbolinux-release", st) &&
2178 !_print_ascii_file("/etc/gentoo-release", st) &&
2179 !_print_ascii_file("/etc/debian_version", st) &&
2180 !_print_ascii_file("/etc/ltib-release", st) &&
2181 !_print_ascii_file("/etc/angstrom-version", st)) {
2182 st->print("Linux");
2183 }
2184 st->cr();
2185 }
2186
2187 void os::Linux::print_libversion_info(outputStream* st) {
2188 // libc, pthread
2189 st->print("libc:");
2190 st->print(os::Linux::glibc_version()); st->print(" ");
2191 st->print(os::Linux::libpthread_version()); st->print(" ");
2192 if (os::Linux::is_LinuxThreads()) {
2193 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed");
2194 }
2195 st->cr();
2196 }
2197
2198 void os::Linux::print_full_memory_info(outputStream* st) {
2199 st->print("\n/proc/meminfo:\n");
2200 _print_ascii_file("/proc/meminfo", st);
2201 st->cr();
2202 }
2203
2204 void os::print_memory_info(outputStream* st) {
2205
2206 st->print("Memory:");
2207 st->print(" %dk page", os::vm_page_size()>>10);
2208
2209 // values in struct sysinfo are "unsigned long"
2210 struct sysinfo si;
2211 sysinfo(&si);
2212
2213 st->print(", physical " UINT64_FORMAT "k",
2214 os::physical_memory() >> 10);
2215 st->print("(" UINT64_FORMAT "k free)",
2216 os::available_memory() >> 10);
2217 st->print(", swap " UINT64_FORMAT "k",
2218 ((jlong)si.totalswap * si.mem_unit) >> 10);
2219 st->print("(" UINT64_FORMAT "k free)",
2220 ((jlong)si.freeswap * si.mem_unit) >> 10);
2221 st->cr();
2222 }
2223
2224 void os::pd_print_cpu_info(outputStream* st) {
2225 st->print("\n/proc/cpuinfo:\n");
2226 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2227 st->print(" <Not Available>");
2228 }
2229 st->cr();
2230 }
2231
2232 // Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific
2233 // but they're the same for all the linux arch that we support
2234 // and they're the same for solaris but there's no common place to put this.
2235 const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR",
2236 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG",
2237 "ILL_COPROC", "ILL_BADSTK" };
2238
2239 const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV",
2240 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES",
2241 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" };
2242
2243 const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" };
2244
2245 const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" };
2246
2247 void os::print_siginfo(outputStream* st, void* siginfo) {
2248 st->print("siginfo:");
2249
2250 const int buflen = 100;
2251 char buf[buflen];
2252 siginfo_t *si = (siginfo_t*)siginfo;
2253 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen));
2254 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) {
2255 st->print("si_errno=%s", buf);
2256 } else {
2257 st->print("si_errno=%d", si->si_errno);
2258 }
2259 const int c = si->si_code;
2260 assert(c > 0, "unexpected si_code");
2261 switch (si->si_signo) {
2262 case SIGILL:
2263 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]);
2264 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2265 break;
2266 case SIGFPE:
2267 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]);
2268 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2269 break;
2270 case SIGSEGV:
2271 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]);
2272 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2273 break;
2274 case SIGBUS:
2275 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]);
2276 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2277 break;
2278 default:
2279 st->print(", si_code=%d", si->si_code);
2280 // no si_addr
2281 }
2282
2283 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
2284 UseSharedSpaces) {
2285 FileMapInfo* mapinfo = FileMapInfo::current_info();
2286 if (mapinfo->is_in_shared_space(si->si_addr)) {
2287 st->print("\n\nError accessing class data sharing archive." \
2288 " Mapped file inaccessible during execution, " \
2289 " possible disk/network problem.");
2290 }
2291 }
2292 st->cr();
2293 }
2294
2295
2296 static void print_signal_handler(outputStream* st, int sig,
2297 char* buf, size_t buflen);
2298
2299 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2300 st->print_cr("Signal Handlers:");
2301 print_signal_handler(st, SIGSEGV, buf, buflen);
2302 print_signal_handler(st, SIGBUS , buf, buflen);
2303 print_signal_handler(st, SIGFPE , buf, buflen);
2304 print_signal_handler(st, SIGPIPE, buf, buflen);
2305 print_signal_handler(st, SIGXFSZ, buf, buflen);
2306 print_signal_handler(st, SIGILL , buf, buflen);
2307 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
2308 print_signal_handler(st, SR_signum, buf, buflen);
2309 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2310 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2311 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2312 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2313 }
2314
2315 static char saved_jvm_path[MAXPATHLEN] = {0};
2316
2317 // Find the full path to the current module, libjvm.so
2318 void os::jvm_path(char *buf, jint buflen) {
2319 // Error checking.
2320 if (buflen < MAXPATHLEN) {
2321 assert(false, "must use a large-enough buffer");
2322 buf[0] = '\0';
2323 return;
2324 }
2325 // Lazy resolve the path to current module.
2326 if (saved_jvm_path[0] != 0) {
2327 strcpy(buf, saved_jvm_path);
2328 return;
2329 }
2330
2331 char dli_fname[MAXPATHLEN];
2332 bool ret = dll_address_to_library_name(
2333 CAST_FROM_FN_PTR(address, os::jvm_path),
2334 dli_fname, sizeof(dli_fname), NULL);
2335 assert(ret, "cannot locate libjvm");
2336 char *rp = NULL;
2337 if (ret && dli_fname[0] != '\0') {
2338 rp = realpath(dli_fname, buf);
2339 }
2340 if (rp == NULL)
2341 return;
2342
2343 if (Arguments::created_by_gamma_launcher()) {
2344 // Support for the gamma launcher. Typical value for buf is
2345 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at
2346 // the right place in the string, then assume we are installed in a JDK and
2347 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix
2348 // up the path so it looks like libjvm.so is installed there (append a
2349 // fake suffix hotspot/libjvm.so).
2350 const char *p = buf + strlen(buf) - 1;
2351 for (int count = 0; p > buf && count < 5; ++count) {
2352 for (--p; p > buf && *p != '/'; --p)
2353 /* empty */ ;
2354 }
2355
2356 if (strncmp(p, "/jre/lib/", 9) != 0) {
2357 // Look for JAVA_HOME in the environment.
2358 char* java_home_var = ::getenv("JAVA_HOME");
2359 if (java_home_var != NULL && java_home_var[0] != 0) {
2360 char* jrelib_p;
2361 int len;
2362
2363 // Check the current module name "libjvm.so".
2364 p = strrchr(buf, '/');
2365 assert(strstr(p, "/libjvm") == p, "invalid library name");
2366
2367 rp = realpath(java_home_var, buf);
2368 if (rp == NULL)
2369 return;
2370
2371 // determine if this is a legacy image or modules image
2372 // modules image doesn't have "jre" subdirectory
2373 len = strlen(buf);
2374 jrelib_p = buf + len;
2375 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch);
2376 if (0 != access(buf, F_OK)) {
2377 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch);
2378 }
2379
2380 if (0 == access(buf, F_OK)) {
2381 // Use current module name "libjvm.so"
2382 len = strlen(buf);
2383 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
2384 } else {
2385 // Go back to path of .so
2386 rp = realpath(dli_fname, buf);
2387 if (rp == NULL)
2388 return;
2389 }
2390 }
2391 }
2392 }
2393
2394 strcpy(saved_jvm_path, buf);
2395 }
2396
2397 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2398 // no prefix required, not even "_"
2399 }
2400
2401 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2402 // no suffix required
2403 }
2404
2405 ////////////////////////////////////////////////////////////////////////////////
2406 // sun.misc.Signal support
2407
2408 static volatile jint sigint_count = 0;
2409
2410 static void
2411 UserHandler(int sig, void *siginfo, void *context) {
2412 // 4511530 - sem_post is serialized and handled by the manager thread. When
2413 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2414 // don't want to flood the manager thread with sem_post requests.
2415 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
2416 return;
2417
2418 // Ctrl-C is pressed during error reporting, likely because the error
2419 // handler fails to abort. Let VM die immediately.
2420 if (sig == SIGINT && is_error_reported()) {
2421 os::die();
2422 }
2423
2424 os::signal_notify(sig);
2425 }
2426
2427 void* os::user_handler() {
2428 return CAST_FROM_FN_PTR(void*, UserHandler);
2429 }
2430
2431 class Semaphore : public StackObj {
2432 public:
2433 Semaphore();
2434 ~Semaphore();
2435 void signal();
2436 void wait();
2437 bool trywait();
2438 bool timedwait(unsigned int sec, int nsec);
2439 private:
2440 sem_t _semaphore;
2441 };
2442
2443
2444 Semaphore::Semaphore() {
2445 sem_init(&_semaphore, 0, 0);
2446 }
2447
2448 Semaphore::~Semaphore() {
2449 sem_destroy(&_semaphore);
2450 }
2451
2452 void Semaphore::signal() {
2453 sem_post(&_semaphore);
2454 }
2455
2456 void Semaphore::wait() {
2457 sem_wait(&_semaphore);
2458 }
2459
2460 bool Semaphore::trywait() {
2461 return sem_trywait(&_semaphore) == 0;
2462 }
2463
2464 bool Semaphore::timedwait(unsigned int sec, int nsec) {
2465 struct timespec ts;
2466 unpackTime(&ts, false, (sec * NANOSECS_PER_SEC) + nsec);
2467
2468 while (1) {
2469 int result = sem_timedwait(&_semaphore, &ts);
2470 if (result == 0) {
2471 return true;
2472 } else if (errno == EINTR) {
2473 continue;
2474 } else if (errno == ETIMEDOUT) {
2475 return false;
2476 } else {
2477 return false;
2478 }
2479 }
2480 }
2481
2482 extern "C" {
2483 typedef void (*sa_handler_t)(int);
2484 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2485 }
2486
2487 void* os::signal(int signal_number, void* handler) {
2488 struct sigaction sigAct, oldSigAct;
2489
2490 sigfillset(&(sigAct.sa_mask));
2491 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2492 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2493
2494 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2495 // -1 means registration failed
2496 return (void *)-1;
2497 }
2498
2499 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2500 }
2501
2502 void os::signal_raise(int signal_number) {
2503 ::raise(signal_number);
2504 }
2505
2506 /*
2507 * The following code is moved from os.cpp for making this
2508 * code platform specific, which it is by its very nature.
2509 */
2510
2511 // Will be modified when max signal is changed to be dynamic
2512 int os::sigexitnum_pd() {
2513 return NSIG;
2514 }
2515
2516 // a counter for each possible signal value
2517 static volatile jint pending_signals[NSIG+1] = { 0 };
2518
2519 // Linux(POSIX) specific hand shaking semaphore.
2520 static sem_t sig_sem;
2521 static Semaphore sr_semaphore;
2522
2523 void os::signal_init_pd() {
2524 // Initialize signal structures
2525 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2526
2527 // Initialize signal semaphore
2528 ::sem_init(&sig_sem, 0, 0);
2529 }
2530
2531 void os::signal_notify(int sig) {
2532 Atomic::inc(&pending_signals[sig]);
2533 ::sem_post(&sig_sem);
2534 }
2535
2536 static int check_pending_signals(bool wait) {
2537 Atomic::store(0, &sigint_count);
2538 for (;;) {
2539 for (int i = 0; i < NSIG + 1; i++) {
2540 jint n = pending_signals[i];
2541 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2542 return i;
2543 }
2544 }
2545 if (!wait) {
2546 return -1;
2547 }
2548 JavaThread *thread = JavaThread::current();
2549 ThreadBlockInVM tbivm(thread);
2550
2551 bool threadIsSuspended;
2552 do {
2553 thread->set_suspend_equivalent();
2554 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2555 ::sem_wait(&sig_sem);
2556
2557 // were we externally suspended while we were waiting?
2558 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2559 if (threadIsSuspended) {
2560 //
2561 // The semaphore has been incremented, but while we were waiting
2562 // another thread suspended us. We don't want to continue running
2563 // while suspended because that would surprise the thread that
2564 // suspended us.
2565 //
2566 ::sem_post(&sig_sem);
2567
2568 thread->java_suspend_self();
2569 }
2570 } while (threadIsSuspended);
2571 }
2572 }
2573
2574 int os::signal_lookup() {
2575 return check_pending_signals(false);
2576 }
2577
2578 int os::signal_wait() {
2579 return check_pending_signals(true);
2580 }
2581
2582 ////////////////////////////////////////////////////////////////////////////////
2583 // Virtual Memory
2584
2585 int os::vm_page_size() {
2586 // Seems redundant as all get out
2587 assert(os::Linux::page_size() != -1, "must call os::init");
2588 return os::Linux::page_size();
2589 }
2590
2591 // Solaris allocates memory by pages.
2592 int os::vm_allocation_granularity() {
2593 assert(os::Linux::page_size() != -1, "must call os::init");
2594 return os::Linux::page_size();
2595 }
2596
2597 // Rationale behind this function:
2598 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2599 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2600 // samples for JITted code. Here we create private executable mapping over the code cache
2601 // and then we can use standard (well, almost, as mapping can change) way to provide
2602 // info for the reporting script by storing timestamp and location of symbol
2603 void linux_wrap_code(char* base, size_t size) {
2604 static volatile jint cnt = 0;
2605
2606 if (!UseOprofile) {
2607 return;
2608 }
2609
2610 char buf[PATH_MAX+1];
2611 int num = Atomic::add(1, &cnt);
2612
2613 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2614 os::get_temp_directory(), os::current_process_id(), num);
2615 unlink(buf);
2616
2617 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2618
2619 if (fd != -1) {
2620 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2621 if (rv != (off_t)-1) {
2622 if (::write(fd, "", 1) == 1) {
2623 mmap(base, size,
2624 PROT_READ|PROT_WRITE|PROT_EXEC,
2625 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2626 }
2627 }
2628 ::close(fd);
2629 unlink(buf);
2630 }
2631 }
2632
2633 static bool recoverable_mmap_error(int err) {
2634 // See if the error is one we can let the caller handle. This
2635 // list of errno values comes from JBS-6843484. I can't find a
2636 // Linux man page that documents this specific set of errno
2637 // values so while this list currently matches Solaris, it may
2638 // change as we gain experience with this failure mode.
2639 switch (err) {
2640 case EBADF:
2641 case EINVAL:
2642 case ENOTSUP:
2643 // let the caller deal with these errors
2644 return true;
2645
2646 default:
2647 // Any remaining errors on this OS can cause our reserved mapping
2648 // to be lost. That can cause confusion where different data
2649 // structures think they have the same memory mapped. The worst
2650 // scenario is if both the VM and a library think they have the
2651 // same memory mapped.
2652 return false;
2653 }
2654 }
2655
2656 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2657 int err) {
2658 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2659 ", %d) failed; error='%s' (errno=%d)", addr, size, exec,
2660 strerror(err), err);
2661 }
2662
2663 static void warn_fail_commit_memory(char* addr, size_t size,
2664 size_t alignment_hint, bool exec,
2665 int err) {
2666 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2667 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", addr, size,
2668 alignment_hint, exec, strerror(err), err);
2669 }
2670
2671 // NOTE: Linux kernel does not really reserve the pages for us.
2672 // All it does is to check if there are enough free pages
2673 // left at the time of mmap(). This could be a potential
2674 // problem.
2675 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) {
2676 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2677 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2678 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2679 if (res != (uintptr_t) MAP_FAILED) {
2680 if (UseNUMAInterleaving) {
2681 numa_make_global(addr, size);
2682 }
2683 return 0;
2684 }
2685
2686 int err = errno; // save errno from mmap() call above
2687
2688 if (!recoverable_mmap_error(err)) {
2689 warn_fail_commit_memory(addr, size, exec, err);
2690 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory.");
2691 }
2692
2693 return err;
2694 }
2695
2696 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2697 return os::Linux::commit_memory_impl(addr, size, exec) == 0;
2698 }
2699
2700 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2701 const char* mesg) {
2702 assert(mesg != NULL, "mesg must be specified");
2703 int err = os::Linux::commit_memory_impl(addr, size, exec);
2704 if (err != 0) {
2705 // the caller wants all commit errors to exit with the specified mesg:
2706 warn_fail_commit_memory(addr, size, exec, err);
2707 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, mesg);
2708 }
2709 }
2710
2711 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2712 #ifndef MAP_HUGETLB
2713 #define MAP_HUGETLB 0x40000
2714 #endif
2715
2716 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2717 #ifndef MADV_HUGEPAGE
2718 #define MADV_HUGEPAGE 14
2719 #endif
2720
2721 int os::Linux::commit_memory_impl(char* addr, size_t size,
2722 size_t alignment_hint, bool exec) {
2723 int err = os::Linux::commit_memory_impl(addr, size, exec);
2724 if (err == 0) {
2725 realign_memory(addr, size, alignment_hint);
2726 }
2727 return err;
2728 }
2729
2730 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2731 bool exec) {
2732 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0;
2733 }
2734
2735 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2736 size_t alignment_hint, bool exec,
2737 const char* mesg) {
2738 assert(mesg != NULL, "mesg must be specified");
2739 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec);
2740 if (err != 0) {
2741 // the caller wants all commit errors to exit with the specified mesg:
2742 warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
2743 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, mesg);
2744 }
2745 }
2746
2747 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2748 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
2749 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2750 // be supported or the memory may already be backed by huge pages.
2751 ::madvise(addr, bytes, MADV_HUGEPAGE);
2752 }
2753 }
2754
2755 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2756 // This method works by doing an mmap over an existing mmaping and effectively discarding
2757 // the existing pages. However it won't work for SHM-based large pages that cannot be
2758 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
2759 // small pages on top of the SHM segment. This method always works for small pages, so we
2760 // allow that in any case.
2761 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
2762 commit_memory(addr, bytes, alignment_hint, !ExecMem);
2763 }
2764 }
2765
2766 void os::numa_make_global(char *addr, size_t bytes) {
2767 Linux::numa_interleave_memory(addr, bytes);
2768 }
2769
2770 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the
2771 // bind policy to MPOL_PREFERRED for the current thread.
2772 #define USE_MPOL_PREFERRED 0
2773
2774 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2775 // To make NUMA and large pages more robust when both enabled, we need to ease
2776 // the requirements on where the memory should be allocated. MPOL_BIND is the
2777 // default policy and it will force memory to be allocated on the specified
2778 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on
2779 // the specified node, but will not force it. Using this policy will prevent
2780 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no
2781 // free large pages.
2782 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED);
2783 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2784 }
2785
2786 bool os::numa_topology_changed() { return false; }
2787
2788 size_t os::numa_get_groups_num() {
2789 int max_node = Linux::numa_max_node();
2790 return max_node > 0 ? max_node + 1 : 1;
2791 }
2792
2793 int os::numa_get_group_id() {
2794 int cpu_id = Linux::sched_getcpu();
2795 if (cpu_id != -1) {
2796 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2797 if (lgrp_id != -1) {
2798 return lgrp_id;
2799 }
2800 }
2801 return 0;
2802 }
2803
2804 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2805 for (size_t i = 0; i < size; i++) {
2806 ids[i] = i;
2807 }
2808 return size;
2809 }
2810
2811 bool os::get_page_info(char *start, page_info* info) {
2812 return false;
2813 }
2814
2815 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2816 return end;
2817 }
2818
2819
2820 int os::Linux::sched_getcpu_syscall(void) {
2821 unsigned int cpu;
2822 int retval = -1;
2823
2824 #if defined(IA32)
2825 # ifndef SYS_getcpu
2826 # define SYS_getcpu 318
2827 # endif
2828 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2829 #elif defined(AMD64)
2830 // Unfortunately we have to bring all these macros here from vsyscall.h
2831 // to be able to compile on old linuxes.
2832 # define __NR_vgetcpu 2
2833 # define VSYSCALL_START (-10UL << 20)
2834 # define VSYSCALL_SIZE 1024
2835 # define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2836 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2837 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2838 retval = vgetcpu(&cpu, NULL, NULL);
2839 #endif
2840
2841 return (retval == -1) ? retval : cpu;
2842 }
2843
2844 // Something to do with the numa-aware allocator needs these symbols
2845 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2846 extern "C" JNIEXPORT void numa_error(char *where) { }
2847 extern "C" JNIEXPORT int fork1() { return fork(); }
2848
2849
2850 // If we are running with libnuma version > 2, then we should
2851 // be trying to use symbols with versions 1.1
2852 // If we are running with earlier version, which did not have symbol versions,
2853 // we should use the base version.
2854 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2855 void *f = dlvsym(handle, name, "libnuma_1.1");
2856 if (f == NULL) {
2857 f = dlsym(handle, name);
2858 }
2859 return f;
2860 }
2861
2862 bool os::Linux::libnuma_init() {
2863 // sched_getcpu() should be in libc.
2864 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2865 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2866
2867 // If it's not, try a direct syscall.
2868 if (sched_getcpu() == -1)
2869 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, (void*)&sched_getcpu_syscall));
2870
2871 if (sched_getcpu() != -1) { // Does it work?
2872 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2873 if (handle != NULL) {
2874 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2875 libnuma_dlsym(handle, "numa_node_to_cpus")));
2876 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2877 libnuma_dlsym(handle, "numa_max_node")));
2878 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2879 libnuma_dlsym(handle, "numa_available")));
2880 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2881 libnuma_dlsym(handle, "numa_tonode_memory")));
2882 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2883 libnuma_dlsym(handle, "numa_interleave_memory")));
2884 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t,
2885 libnuma_dlsym(handle, "numa_set_bind_policy")));
2886
2887
2888 if (numa_available() != -1) {
2889 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2890 // Create a cpu -> node mapping
2891 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
2892 rebuild_cpu_to_node_map();
2893 return true;
2894 }
2895 }
2896 }
2897 return false;
2898 }
2899
2900 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2901 // The table is later used in get_node_by_cpu().
2902 void os::Linux::rebuild_cpu_to_node_map() {
2903 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2904 // in libnuma (possible values are starting from 16,
2905 // and continuing up with every other power of 2, but less
2906 // than the maximum number of CPUs supported by kernel), and
2907 // is a subject to change (in libnuma version 2 the requirements
2908 // are more reasonable) we'll just hardcode the number they use
2909 // in the library.
2910 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2911
2912 size_t cpu_num = os::active_processor_count();
2913 size_t cpu_map_size = NCPUS / BitsPerCLong;
2914 size_t cpu_map_valid_size =
2915 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2916
2917 cpu_to_node()->clear();
2918 cpu_to_node()->at_grow(cpu_num - 1);
2919 size_t node_num = numa_get_groups_num();
2920
2921 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
2922 for (size_t i = 0; i < node_num; i++) {
2923 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2924 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2925 if (cpu_map[j] != 0) {
2926 for (size_t k = 0; k < BitsPerCLong; k++) {
2927 if (cpu_map[j] & (1UL << k)) {
2928 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
2929 }
2930 }
2931 }
2932 }
2933 }
2934 }
2935 FREE_C_HEAP_ARRAY(unsigned long, cpu_map, mtInternal);
2936 }
2937
2938 int os::Linux::get_node_by_cpu(int cpu_id) {
2939 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2940 return cpu_to_node()->at(cpu_id);
2941 }
2942 return -1;
2943 }
2944
2945 GrowableArray<int>* os::Linux::_cpu_to_node;
2946 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2947 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2948 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2949 os::Linux::numa_available_func_t os::Linux::_numa_available;
2950 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2951 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2952 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy;
2953 unsigned long* os::Linux::_numa_all_nodes;
2954
2955 bool os::pd_uncommit_memory(char* addr, size_t size) {
2956 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2957 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2958 return res != (uintptr_t) MAP_FAILED;
2959 }
2960
2961 // Linux uses a growable mapping for the stack, and if the mapping for
2962 // the stack guard pages is not removed when we detach a thread the
2963 // stack cannot grow beyond the pages where the stack guard was
2964 // mapped. If at some point later in the process the stack expands to
2965 // that point, the Linux kernel cannot expand the stack any further
2966 // because the guard pages are in the way, and a segfault occurs.
2967 //
2968 // However, it's essential not to split the stack region by unmapping
2969 // a region (leaving a hole) that's already part of the stack mapping,
2970 // so if the stack mapping has already grown beyond the guard pages at
2971 // the time we create them, we have to truncate the stack mapping.
2972 // So, we need to know the extent of the stack mapping when
2973 // create_stack_guard_pages() is called.
2974
2975 // Find the bounds of the stack mapping. Return true for success.
2976 //
2977 // We only need this for stacks that are growable: at the time of
2978 // writing thread stacks don't use growable mappings (i.e. those
2979 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
2980 // only applies to the main thread.
2981
2982 static
2983 bool get_stack_bounds(uintptr_t *bottom, uintptr_t *top) {
2984
2985 char buf[128];
2986 int fd, sz;
2987
2988 if ((fd = ::open("/proc/self/maps", O_RDONLY)) < 0) {
2989 return false;
2990 }
2991
2992 const char kw[] = "[stack]";
2993 const int kwlen = sizeof(kw)-1;
2994
2995 // Address part of /proc/self/maps couldn't be more than 128 bytes
2996 while ((sz = os::get_line_chars(fd, buf, sizeof(buf))) > 0) {
2997 if (sz > kwlen && ::memcmp(buf+sz-kwlen, kw, kwlen) == 0) {
2998 // Extract addresses
2999 if (sscanf(buf, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) {
3000 uintptr_t sp = (uintptr_t) __builtin_frame_address(0);
3001 if (sp >= *bottom && sp <= *top) {
3002 ::close(fd);
3003 return true;
3004 }
3005 }
3006 }
3007 }
3008
3009 ::close(fd);
3010 return false;
3011 }
3012
3013
3014 // If the (growable) stack mapping already extends beyond the point
3015 // where we're going to put our guard pages, truncate the mapping at
3016 // that point by munmap()ping it. This ensures that when we later
3017 // munmap() the guard pages we don't leave a hole in the stack
3018 // mapping. This only affects the main/initial thread, but guard
3019 // against future OS changes
3020 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
3021 uintptr_t stack_extent, stack_base;
3022 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true);
3023 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) {
3024 assert(os::Linux::is_initial_thread(),
3025 "growable stack in non-initial thread");
3026 if (stack_extent < (uintptr_t)addr)
3027 ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent);
3028 }
3029
3030 return os::commit_memory(addr, size, !ExecMem);
3031 }
3032
3033 // If this is a growable mapping, remove the guard pages entirely by
3034 // munmap()ping them. If not, just call uncommit_memory(). This only
3035 // affects the main/initial thread, but guard against future OS changes
3036 bool os::remove_stack_guard_pages(char* addr, size_t size) {
3037 uintptr_t stack_extent, stack_base;
3038 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true);
3039 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) {
3040 assert(os::Linux::is_initial_thread(),
3041 "growable stack in non-initial thread");
3042
3043 return ::munmap(addr, size) == 0;
3044 }
3045
3046 return os::uncommit_memory(addr, size);
3047 }
3048
3049 static address _highest_vm_reserved_address = NULL;
3050
3051 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
3052 // at 'requested_addr'. If there are existing memory mappings at the same
3053 // location, however, they will be overwritten. If 'fixed' is false,
3054 // 'requested_addr' is only treated as a hint, the return value may or
3055 // may not start from the requested address. Unlike Linux mmap(), this
3056 // function returns NULL to indicate failure.
3057 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
3058 char * addr;
3059 int flags;
3060
3061 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
3062 if (fixed) {
3063 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
3064 flags |= MAP_FIXED;
3065 }
3066
3067 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
3068 // touch an uncommitted page. Otherwise, the read/write might
3069 // succeed if we have enough swap space to back the physical page.
3070 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
3071 flags, -1, 0);
3072
3073 if (addr != MAP_FAILED) {
3074 // anon_mmap() should only get called during VM initialization,
3075 // don't need lock (actually we can skip locking even it can be called
3076 // from multiple threads, because _highest_vm_reserved_address is just a
3077 // hint about the upper limit of non-stack memory regions.)
3078 if ((address)addr + bytes > _highest_vm_reserved_address) {
3079 _highest_vm_reserved_address = (address)addr + bytes;
3080 }
3081 }
3082
3083 return addr == MAP_FAILED ? NULL : addr;
3084 }
3085
3086 // Don't update _highest_vm_reserved_address, because there might be memory
3087 // regions above addr + size. If so, releasing a memory region only creates
3088 // a hole in the address space, it doesn't help prevent heap-stack collision.
3089 //
3090 static int anon_munmap(char * addr, size_t size) {
3091 return ::munmap(addr, size) == 0;
3092 }
3093
3094 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
3095 size_t alignment_hint) {
3096 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
3097 }
3098
3099 bool os::pd_release_memory(char* addr, size_t size) {
3100 return anon_munmap(addr, size);
3101 }
3102
3103 static address highest_vm_reserved_address() {
3104 return _highest_vm_reserved_address;
3105 }
3106
3107 static bool linux_mprotect(char* addr, size_t size, int prot) {
3108 // Linux wants the mprotect address argument to be page aligned.
3109 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
3110
3111 // According to SUSv3, mprotect() should only be used with mappings
3112 // established by mmap(), and mmap() always maps whole pages. Unaligned
3113 // 'addr' likely indicates problem in the VM (e.g. trying to change
3114 // protection of malloc'ed or statically allocated memory). Check the
3115 // caller if you hit this assert.
3116 assert(addr == bottom, "sanity check");
3117
3118 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
3119 return ::mprotect(bottom, size, prot) == 0;
3120 }
3121
3122 // Set protections specified
3123 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
3124 bool is_committed) {
3125 unsigned int p = 0;
3126 switch (prot) {
3127 case MEM_PROT_NONE: p = PROT_NONE; break;
3128 case MEM_PROT_READ: p = PROT_READ; break;
3129 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
3130 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
3131 default:
3132 ShouldNotReachHere();
3133 }
3134 // is_committed is unused.
3135 return linux_mprotect(addr, bytes, p);
3136 }
3137
3138 bool os::guard_memory(char* addr, size_t size) {
3139 return linux_mprotect(addr, size, PROT_NONE);
3140 }
3141
3142 bool os::unguard_memory(char* addr, size_t size) {
3143 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
3144 }
3145
3146 bool os::Linux::transparent_huge_pages_sanity_check(bool warn, size_t page_size) {
3147 bool result = false;
3148 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
3149 MAP_ANONYMOUS|MAP_PRIVATE,
3150 -1, 0);
3151 if (p != MAP_FAILED) {
3152 void *aligned_p = align_ptr_up(p, page_size);
3153
3154 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
3155
3156 munmap(p, page_size * 2);
3157 }
3158
3159 if (warn && !result) {
3160 warning("TransparentHugePages is not supported by the operating system.");
3161 }
3162
3163 return result;
3164 }
3165
3166 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
3167 bool result = false;
3168 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
3169 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
3170 -1, 0);
3171
3172 if (p != MAP_FAILED) {
3173 // We don't know if this really is a huge page or not.
3174 FILE *fp = fopen("/proc/self/maps", "r");
3175 if (fp) {
3176 while (!feof(fp)) {
3177 char chars[257];
3178 long x = 0;
3179 if (fgets(chars, sizeof(chars), fp)) {
3180 if (sscanf(chars, "%lx-%*x", &x) == 1
3181 && x == (long)p) {
3182 if (strstr (chars, "hugepage")) {
3183 result = true;
3184 break;
3185 }
3186 }
3187 }
3188 }
3189 fclose(fp);
3190 }
3191 munmap(p, page_size);
3192 }
3193
3194 if (warn && !result) {
3195 warning("HugeTLBFS is not supported by the operating system.");
3196 }
3197
3198 return result;
3199 }
3200
3201 /*
3202 * Set the coredump_filter bits to include largepages in core dump (bit 6)
3203 *
3204 * From the coredump_filter documentation:
3205 *
3206 * - (bit 0) anonymous private memory
3207 * - (bit 1) anonymous shared memory
3208 * - (bit 2) file-backed private memory
3209 * - (bit 3) file-backed shared memory
3210 * - (bit 4) ELF header pages in file-backed private memory areas (it is
3211 * effective only if the bit 2 is cleared)
3212 * - (bit 5) hugetlb private memory
3213 * - (bit 6) hugetlb shared memory
3214 */
3215 static void set_coredump_filter(void) {
3216 FILE *f;
3217 long cdm;
3218
3219 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
3220 return;
3221 }
3222
3223 if (fscanf(f, "%lx", &cdm) != 1) {
3224 fclose(f);
3225 return;
3226 }
3227
3228 rewind(f);
3229
3230 if ((cdm & LARGEPAGES_BIT) == 0) {
3231 cdm |= LARGEPAGES_BIT;
3232 fprintf(f, "%#lx", cdm);
3233 }
3234
3235 fclose(f);
3236 }
3237
3238 // Large page support
3239
3240 static size_t _large_page_size = 0;
3241
3242 size_t os::Linux::find_large_page_size() {
3243 size_t large_page_size = 0;
3244
3245 // large_page_size on Linux is used to round up heap size. x86 uses either
3246 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3247 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3248 // page as large as 256M.
3249 //
3250 // Here we try to figure out page size by parsing /proc/meminfo and looking
3251 // for a line with the following format:
3252 // Hugepagesize: 2048 kB
3253 //
3254 // If we can't determine the value (e.g. /proc is not mounted, or the text
3255 // format has been changed), we'll use the largest page size supported by
3256 // the processor.
3257
3258 #ifndef ZERO
3259 large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M)
3260 ARM_ONLY(2 * M) PPC_ONLY(4 * M);
3261 #endif // ZERO
3262
3263 FILE *fp = fopen("/proc/meminfo", "r");
3264 if (fp) {
3265 while (!feof(fp)) {
3266 int x = 0;
3267 char buf[16];
3268 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3269 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3270 large_page_size = x * K;
3271 break;
3272 }
3273 } else {
3274 // skip to next line
3275 for (;;) {
3276 int ch = fgetc(fp);
3277 if (ch == EOF || ch == (int)'\n') break;
3278 }
3279 }
3280 }
3281 fclose(fp);
3282 }
3283
3284 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) {
3285 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is "
3286 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size),
3287 proper_unit_for_byte_size(large_page_size));
3288 }
3289
3290 return large_page_size;
3291 }
3292
3293 size_t os::Linux::setup_large_page_size() {
3294 _large_page_size = Linux::find_large_page_size();
3295 const size_t default_page_size = (size_t)Linux::page_size();
3296 if (_large_page_size > default_page_size) {
3297 _page_sizes[0] = _large_page_size;
3298 _page_sizes[1] = default_page_size;
3299 _page_sizes[2] = 0;
3300 }
3301
3302 return _large_page_size;
3303 }
3304
3305 bool os::Linux::setup_large_page_type(size_t page_size) {
3306 if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
3307 FLAG_IS_DEFAULT(UseSHM) &&
3308 FLAG_IS_DEFAULT(UseTransparentHugePages)) {
3309 // If UseLargePages is specified on the command line try all methods,
3310 // if it's default, then try only UseTransparentHugePages.
3311 if (FLAG_IS_DEFAULT(UseLargePages)) {
3312 UseTransparentHugePages = true;
3313 } else {
3314 UseHugeTLBFS = UseTransparentHugePages = UseSHM = true;
3315 }
3316 }
3317
3318 if (UseTransparentHugePages) {
3319 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
3320 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
3321 UseHugeTLBFS = false;
3322 UseSHM = false;
3323 return true;
3324 }
3325 UseTransparentHugePages = false;
3326 }
3327
3328 if (UseHugeTLBFS) {
3329 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3330 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3331 UseSHM = false;
3332 return true;
3333 }
3334 UseHugeTLBFS = false;
3335 }
3336
3337 return UseSHM;
3338 }
3339
3340 void os::large_page_init() {
3341 if (!UseLargePages) {
3342 UseHugeTLBFS = false;
3343 UseTransparentHugePages = false;
3344 UseSHM = false;
3345 return;
3346 }
3347
3348 size_t large_page_size = Linux::setup_large_page_size();
3349 UseLargePages = Linux::setup_large_page_type(large_page_size);
3350
3351 set_coredump_filter();
3352 }
3353
3354 #ifndef SHM_HUGETLB
3355 #define SHM_HUGETLB 04000
3356 #endif
3357
3358 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3359 // "exec" is passed in but not used. Creating the shared image for
3360 // the code cache doesn't have an SHM_X executable permission to check.
3361 assert(UseLargePages && UseSHM, "only for SHM large pages");
3362 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3363
3364 if (!is_size_aligned(bytes, os::large_page_size()) || alignment > os::large_page_size()) {
3365 return NULL; // Fallback to small pages.
3366 }
3367
3368 key_t key = IPC_PRIVATE;
3369 char *addr;
3370
3371 bool warn_on_failure = UseLargePages &&
3372 (!FLAG_IS_DEFAULT(UseLargePages) ||
3373 !FLAG_IS_DEFAULT(UseSHM) ||
3374 !FLAG_IS_DEFAULT(LargePageSizeInBytes)
3375 );
3376 char msg[128];
3377
3378 // Create a large shared memory region to attach to based on size.
3379 // Currently, size is the total size of the heap
3380 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3381 if (shmid == -1) {
3382 // Possible reasons for shmget failure:
3383 // 1. shmmax is too small for Java heap.
3384 // > check shmmax value: cat /proc/sys/kernel/shmmax
3385 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3386 // 2. not enough large page memory.
3387 // > check available large pages: cat /proc/meminfo
3388 // > increase amount of large pages:
3389 // echo new_value > /proc/sys/vm/nr_hugepages
3390 // Note 1: different Linux may use different name for this property,
3391 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3392 // Note 2: it's possible there's enough physical memory available but
3393 // they are so fragmented after a long run that they can't
3394 // coalesce into large pages. Try to reserve large pages when
3395 // the system is still "fresh".
3396 if (warn_on_failure) {
3397 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno);
3398 warning(msg);
3399 }
3400 return NULL;
3401 }
3402
3403 // attach to the region
3404 addr = (char*)shmat(shmid, req_addr, 0);
3405 int err = errno;
3406
3407 // Remove shmid. If shmat() is successful, the actual shared memory segment
3408 // will be deleted when it's detached by shmdt() or when the process
3409 // terminates. If shmat() is not successful this will remove the shared
3410 // segment immediately.
3411 shmctl(shmid, IPC_RMID, NULL);
3412
3413 if ((intptr_t)addr == -1) {
3414 if (warn_on_failure) {
3415 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err);
3416 warning(msg);
3417 }
3418 return NULL;
3419 }
3420
3421 return addr;
3422 }
3423
3424 static void warn_on_large_pages_failure(char* req_addr, size_t bytes, int error) {
3425 assert(error == ENOMEM, "Only expect to fail if no memory is available");
3426
3427 bool warn_on_failure = UseLargePages &&
3428 (!FLAG_IS_DEFAULT(UseLargePages) ||
3429 !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
3430 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
3431
3432 if (warn_on_failure) {
3433 char msg[128];
3434 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
3435 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
3436 warning(msg);
3437 }
3438 }
3439
3440 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, char* req_addr, bool exec) {
3441 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3442 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size");
3443 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3444
3445 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3446 char* addr = (char*)::mmap(req_addr, bytes, prot,
3447 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB,
3448 -1, 0);
3449
3450 if (addr == MAP_FAILED) {
3451 warn_on_large_pages_failure(req_addr, bytes, errno);
3452 return NULL;
3453 }
3454
3455 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be");
3456
3457 return addr;
3458 }
3459
3460 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3461 size_t large_page_size = os::large_page_size();
3462
3463 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
3464
3465 // Allocate small pages.
3466
3467 char* start;
3468 if (req_addr != NULL) {
3469 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3470 assert(is_size_aligned(bytes, alignment), "Must be");
3471 start = os::reserve_memory(bytes, req_addr);
3472 assert(start == NULL || start == req_addr, "Must be");
3473 } else {
3474 start = os::reserve_memory_aligned(bytes, alignment);
3475 }
3476
3477 if (start == NULL) {
3478 return NULL;
3479 }
3480
3481 assert(is_ptr_aligned(start, alignment), "Must be");
3482
3483 // os::reserve_memory_special will record this memory area.
3484 // Need to release it here to prevent overlapping reservations.
3485 MemTracker::record_virtual_memory_release((address)start, bytes);
3486
3487 char* end = start + bytes;
3488
3489 // Find the regions of the allocated chunk that can be promoted to large pages.
3490 char* lp_start = (char*)align_ptr_up(start, large_page_size);
3491 char* lp_end = (char*)align_ptr_down(end, large_page_size);
3492
3493 size_t lp_bytes = lp_end - lp_start;
3494
3495 assert(is_size_aligned(lp_bytes, large_page_size), "Must be");
3496
3497 if (lp_bytes == 0) {
3498 // The mapped region doesn't even span the start and the end of a large page.
3499 // Fall back to allocate a non-special area.
3500 ::munmap(start, end - start);
3501 return NULL;
3502 }
3503
3504 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3505
3506
3507 void* result;
3508
3509 if (start != lp_start) {
3510 result = ::mmap(start, lp_start - start, prot,
3511 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3512 -1, 0);
3513 if (result == MAP_FAILED) {
3514 ::munmap(lp_start, end - lp_start);
3515 return NULL;
3516 }
3517 }
3518
3519 result = ::mmap(lp_start, lp_bytes, prot,
3520 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB,
3521 -1, 0);
3522 if (result == MAP_FAILED) {
3523 warn_on_large_pages_failure(req_addr, bytes, errno);
3524 // If the mmap above fails, the large pages region will be unmapped and we
3525 // have regions before and after with small pages. Release these regions.
3526 //
3527 // | mapped | unmapped | mapped |
3528 // ^ ^ ^ ^
3529 // start lp_start lp_end end
3530 //
3531 ::munmap(start, lp_start - start);
3532 ::munmap(lp_end, end - lp_end);
3533 return NULL;
3534 }
3535
3536 if (lp_end != end) {
3537 result = ::mmap(lp_end, end - lp_end, prot,
3538 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3539 -1, 0);
3540 if (result == MAP_FAILED) {
3541 ::munmap(start, lp_end - start);
3542 return NULL;
3543 }
3544 }
3545
3546 return start;
3547 }
3548
3549 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3550 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3551 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3552 assert(is_power_of_2(alignment), "Must be");
3553 assert(is_power_of_2(os::large_page_size()), "Must be");
3554 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
3555
3556 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
3557 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
3558 } else {
3559 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
3560 }
3561 }
3562
3563 char* os::reserve_memory_special(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3564 assert(UseLargePages, "only for large pages");
3565
3566 char* addr;
3567 if (UseSHM) {
3568 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
3569 } else {
3570 assert(UseHugeTLBFS, "must be");
3571 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
3572 }
3573
3574 if (addr != NULL) {
3575 if (UseNUMAInterleaving) {
3576 numa_make_global(addr, bytes);
3577 }
3578
3579 // The memory is committed
3580 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, mtNone, CALLER_PC);
3581 }
3582
3583 return addr;
3584 }
3585
3586 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
3587 // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
3588 return shmdt(base) == 0;
3589 }
3590
3591 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
3592 return pd_release_memory(base, bytes);
3593 }
3594
3595 bool os::release_memory_special(char* base, size_t bytes) {
3596 assert(UseLargePages, "only for large pages");
3597
3598 MemTracker::Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
3599
3600 bool res;
3601 if (UseSHM) {
3602 res = os::Linux::release_memory_special_shm(base, bytes);
3603 } else {
3604 assert(UseHugeTLBFS, "must be");
3605 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
3606 }
3607
3608 if (res) {
3609 tkr.record((address)base, bytes);
3610 } else {
3611 tkr.discard();
3612 }
3613
3614 return res;
3615 }
3616
3617 size_t os::large_page_size() {
3618 return _large_page_size;
3619 }
3620
3621 // With SysV SHM the entire memory region must be allocated as shared
3622 // memory.
3623 // HugeTLBFS allows application to commit large page memory on demand.
3624 // However, when committing memory with HugeTLBFS fails, the region
3625 // that was supposed to be committed will lose the old reservation
3626 // and allow other threads to steal that memory region. Because of this
3627 // behavior we can't commit HugeTLBFS memory.
3628 bool os::can_commit_large_page_memory() {
3629 return UseTransparentHugePages;
3630 }
3631
3632 bool os::can_execute_large_page_memory() {
3633 return UseTransparentHugePages || UseHugeTLBFS;
3634 }
3635
3636 // Reserve memory at an arbitrary address, only if that area is
3637 // available (and not reserved for something else).
3638
3639 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3640 const int max_tries = 10;
3641 char* base[max_tries];
3642 size_t size[max_tries];
3643 const size_t gap = 0x000000;
3644
3645 // Assert only that the size is a multiple of the page size, since
3646 // that's all that mmap requires, and since that's all we really know
3647 // about at this low abstraction level. If we need higher alignment,
3648 // we can either pass an alignment to this method or verify alignment
3649 // in one of the methods further up the call chain. See bug 5044738.
3650 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3651
3652 // Repeatedly allocate blocks until the block is allocated at the
3653 // right spot. Give up after max_tries. Note that reserve_memory() will
3654 // automatically update _highest_vm_reserved_address if the call is
3655 // successful. The variable tracks the highest memory address every reserved
3656 // by JVM. It is used to detect heap-stack collision if running with
3657 // fixed-stack LinuxThreads. Because here we may attempt to reserve more
3658 // space than needed, it could confuse the collision detecting code. To
3659 // solve the problem, save current _highest_vm_reserved_address and
3660 // calculate the correct value before return.
3661 address old_highest = _highest_vm_reserved_address;
3662
3663 // Linux mmap allows caller to pass an address as hint; give it a try first,
3664 // if kernel honors the hint then we can return immediately.
3665 char * addr = anon_mmap(requested_addr, bytes, false);
3666 if (addr == requested_addr) {
3667 return requested_addr;
3668 }
3669
3670 if (addr != NULL) {
3671 // mmap() is successful but it fails to reserve at the requested address
3672 anon_munmap(addr, bytes);
3673 }
3674
3675 int i;
3676 for (i = 0; i < max_tries; ++i) {
3677 base[i] = reserve_memory(bytes);
3678
3679 if (base[i] != NULL) {
3680 // Is this the block we wanted?
3681 if (base[i] == requested_addr) {
3682 size[i] = bytes;
3683 break;
3684 }
3685
3686 // Does this overlap the block we wanted? Give back the overlapped
3687 // parts and try again.
3688
3689 size_t top_overlap = requested_addr + (bytes + gap) - base[i];
3690 if (top_overlap >= 0 && top_overlap < bytes) {
3691 unmap_memory(base[i], top_overlap);
3692 base[i] += top_overlap;
3693 size[i] = bytes - top_overlap;
3694 } else {
3695 size_t bottom_overlap = base[i] + bytes - requested_addr;
3696 if (bottom_overlap >= 0 && bottom_overlap < bytes) {
3697 unmap_memory(requested_addr, bottom_overlap);
3698 size[i] = bytes - bottom_overlap;
3699 } else {
3700 size[i] = bytes;
3701 }
3702 }
3703 }
3704 }
3705
3706 // Give back the unused reserved pieces.
3707
3708 for (int j = 0; j < i; ++j) {
3709 if (base[j] != NULL) {
3710 unmap_memory(base[j], size[j]);
3711 }
3712 }
3713
3714 if (i < max_tries) {
3715 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes);
3716 return requested_addr;
3717 } else {
3718 _highest_vm_reserved_address = old_highest;
3719 return NULL;
3720 }
3721 }
3722
3723 size_t os::read(int fd, void *buf, unsigned int nBytes) {
3724 return ::read(fd, buf, nBytes);
3725 }
3726
3727 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation.
3728 // Solaris uses poll(), linux uses park().
3729 // Poll() is likely a better choice, assuming that Thread.interrupt()
3730 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with
3731 // SIGSEGV, see 4355769.
3732
3733 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
3734 assert(thread == Thread::current(), "thread consistency check");
3735
3736 ParkEvent * const slp = thread->_SleepEvent ;
3737 slp->reset() ;
3738 OrderAccess::fence() ;
3739
3740 if (interruptible) {
3741 jlong prevtime = javaTimeNanos();
3742
3743 for (;;) {
3744 if (os::is_interrupted(thread, true)) {
3745 return OS_INTRPT;
3746 }
3747
3748 jlong newtime = javaTimeNanos();
3749
3750 if (newtime - prevtime < 0) {
3751 // time moving backwards, should only happen if no monotonic clock
3752 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3753 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3754 } else {
3755 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
3756 }
3757
3758 if(millis <= 0) {
3759 return OS_OK;
3760 }
3761
3762 prevtime = newtime;
3763
3764 {
3765 assert(thread->is_Java_thread(), "sanity check");
3766 JavaThread *jt = (JavaThread *) thread;
3767 ThreadBlockInVM tbivm(jt);
3768 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
3769
3770 jt->set_suspend_equivalent();
3771 // cleared by handle_special_suspend_equivalent_condition() or
3772 // java_suspend_self() via check_and_wait_while_suspended()
3773
3774 slp->park(millis);
3775
3776 // were we externally suspended while we were waiting?
3777 jt->check_and_wait_while_suspended();
3778 }
3779 }
3780 } else {
3781 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
3782 jlong prevtime = javaTimeNanos();
3783
3784 for (;;) {
3785 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
3786 // the 1st iteration ...
3787 jlong newtime = javaTimeNanos();
3788
3789 if (newtime - prevtime < 0) {
3790 // time moving backwards, should only happen if no monotonic clock
3791 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3792 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3793 } else {
3794 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
3795 }
3796
3797 if(millis <= 0) break ;
3798
3799 prevtime = newtime;
3800 slp->park(millis);
3801 }
3802 return OS_OK ;
3803 }
3804 }
3805
3806 int os::naked_sleep() {
3807 // %% make the sleep time an integer flag. for now use 1 millisec.
3808 return os::sleep(Thread::current(), 1, false);
3809 }
3810
3811 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3812 void os::infinite_sleep() {
3813 while (true) { // sleep forever ...
3814 ::sleep(100); // ... 100 seconds at a time
3815 }
3816 }
3817
3818 // Used to convert frequent JVM_Yield() to nops
3819 bool os::dont_yield() {
3820 return DontYieldALot;
3821 }
3822
3823 void os::yield() {
3824 sched_yield();
3825 }
3826
3827 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;}
3828
3829 void os::yield_all(int attempts) {
3830 // Yields to all threads, including threads with lower priorities
3831 // Threads on Linux are all with same priority. The Solaris style
3832 // os::yield_all() with nanosleep(1ms) is not necessary.
3833 sched_yield();
3834 }
3835
3836 // Called from the tight loops to possibly influence time-sharing heuristics
3837 void os::loop_breaker(int attempts) {
3838 os::yield_all(attempts);
3839 }
3840
3841 ////////////////////////////////////////////////////////////////////////////////
3842 // thread priority support
3843
3844 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
3845 // only supports dynamic priority, static priority must be zero. For real-time
3846 // applications, Linux supports SCHED_RR which allows static priority (1-99).
3847 // However, for large multi-threaded applications, SCHED_RR is not only slower
3848 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
3849 // of 5 runs - Sep 2005).
3850 //
3851 // The following code actually changes the niceness of kernel-thread/LWP. It
3852 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
3853 // not the entire user process, and user level threads are 1:1 mapped to kernel
3854 // threads. It has always been the case, but could change in the future. For
3855 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
3856 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
3857
3858 int os::java_to_os_priority[CriticalPriority + 1] = {
3859 19, // 0 Entry should never be used
3860
3861 4, // 1 MinPriority
3862 3, // 2
3863 2, // 3
3864
3865 1, // 4
3866 0, // 5 NormPriority
3867 -1, // 6
3868
3869 -2, // 7
3870 -3, // 8
3871 -4, // 9 NearMaxPriority
3872
3873 -5, // 10 MaxPriority
3874
3875 -5 // 11 CriticalPriority
3876 };
3877
3878 static int prio_init() {
3879 if (ThreadPriorityPolicy == 1) {
3880 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
3881 // if effective uid is not root. Perhaps, a more elegant way of doing
3882 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
3883 if (geteuid() != 0) {
3884 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
3885 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
3886 }
3887 ThreadPriorityPolicy = 0;
3888 }
3889 }
3890 if (UseCriticalJavaThreadPriority) {
3891 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
3892 }
3893 return 0;
3894 }
3895
3896 OSReturn os::set_native_priority(Thread* thread, int newpri) {
3897 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK;
3898
3899 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
3900 return (ret == 0) ? OS_OK : OS_ERR;
3901 }
3902
3903 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
3904 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) {
3905 *priority_ptr = java_to_os_priority[NormPriority];
3906 return OS_OK;
3907 }
3908
3909 errno = 0;
3910 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
3911 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
3912 }
3913
3914 // Hint to the underlying OS that a task switch would not be good.
3915 // Void return because it's a hint and can fail.
3916 void os::hint_no_preempt() {}
3917
3918 ////////////////////////////////////////////////////////////////////////////////
3919 // suspend/resume support
3920
3921 // the low-level signal-based suspend/resume support is a remnant from the
3922 // old VM-suspension that used to be for java-suspension, safepoints etc,
3923 // within hotspot. Now there is a single use-case for this:
3924 // - calling get_thread_pc() on the VMThread by the flat-profiler task
3925 // that runs in the watcher thread.
3926 // The remaining code is greatly simplified from the more general suspension
3927 // code that used to be used.
3928 //
3929 // The protocol is quite simple:
3930 // - suspend:
3931 // - sends a signal to the target thread
3932 // - polls the suspend state of the osthread using a yield loop
3933 // - target thread signal handler (SR_handler) sets suspend state
3934 // and blocks in sigsuspend until continued
3935 // - resume:
3936 // - sets target osthread state to continue
3937 // - sends signal to end the sigsuspend loop in the SR_handler
3938 //
3939 // Note that the SR_lock plays no role in this suspend/resume protocol.
3940 //
3941
3942 static void resume_clear_context(OSThread *osthread) {
3943 osthread->set_ucontext(NULL);
3944 osthread->set_siginfo(NULL);
3945 }
3946
3947 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
3948 osthread->set_ucontext(context);
3949 osthread->set_siginfo(siginfo);
3950 }
3951
3952 //
3953 // Handler function invoked when a thread's execution is suspended or
3954 // resumed. We have to be careful that only async-safe functions are
3955 // called here (Note: most pthread functions are not async safe and
3956 // should be avoided.)
3957 //
3958 // Note: sigwait() is a more natural fit than sigsuspend() from an
3959 // interface point of view, but sigwait() prevents the signal hander
3960 // from being run. libpthread would get very confused by not having
3961 // its signal handlers run and prevents sigwait()'s use with the
3962 // mutex granting granting signal.
3963 //
3964 // Currently only ever called on the VMThread and JavaThreads (PC sampling)
3965 //
3966 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
3967 // Save and restore errno to avoid confusing native code with EINTR
3968 // after sigsuspend.
3969 int old_errno = errno;
3970
3971 Thread* thread = Thread::current();
3972 OSThread* osthread = thread->osthread();
3973 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
3974
3975 os::SuspendResume::State current = osthread->sr.state();
3976 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
3977 suspend_save_context(osthread, siginfo, context);
3978
3979 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
3980 os::SuspendResume::State state = osthread->sr.suspended();
3981 if (state == os::SuspendResume::SR_SUSPENDED) {
3982 sigset_t suspend_set; // signals for sigsuspend()
3983
3984 // get current set of blocked signals and unblock resume signal
3985 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
3986 sigdelset(&suspend_set, SR_signum);
3987
3988 sr_semaphore.signal();
3989 // wait here until we are resumed
3990 while (1) {
3991 sigsuspend(&suspend_set);
3992
3993 os::SuspendResume::State result = osthread->sr.running();
3994 if (result == os::SuspendResume::SR_RUNNING) {
3995 sr_semaphore.signal();
3996 break;
3997 }
3998 }
3999
4000 } else if (state == os::SuspendResume::SR_RUNNING) {
4001 // request was cancelled, continue
4002 } else {
4003 ShouldNotReachHere();
4004 }
4005
4006 resume_clear_context(osthread);
4007 } else if (current == os::SuspendResume::SR_RUNNING) {
4008 // request was cancelled, continue
4009 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
4010 // ignore
4011 } else {
4012 // ignore
4013 }
4014
4015 errno = old_errno;
4016 }
4017
4018
4019 static int SR_initialize() {
4020 struct sigaction act;
4021 char *s;
4022 /* Get signal number to use for suspend/resume */
4023 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
4024 int sig = ::strtol(s, 0, 10);
4025 if (sig > 0 || sig < _NSIG) {
4026 SR_signum = sig;
4027 }
4028 }
4029
4030 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
4031 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
4032
4033 sigemptyset(&SR_sigset);
4034 sigaddset(&SR_sigset, SR_signum);
4035
4036 /* Set up signal handler for suspend/resume */
4037 act.sa_flags = SA_RESTART|SA_SIGINFO;
4038 act.sa_handler = (void (*)(int)) SR_handler;
4039
4040 // SR_signum is blocked by default.
4041 // 4528190 - We also need to block pthread restart signal (32 on all
4042 // supported Linux platforms). Note that LinuxThreads need to block
4043 // this signal for all threads to work properly. So we don't have
4044 // to use hard-coded signal number when setting up the mask.
4045 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
4046
4047 if (sigaction(SR_signum, &act, 0) == -1) {
4048 return -1;
4049 }
4050
4051 // Save signal flag
4052 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
4053 return 0;
4054 }
4055
4056 static int sr_notify(OSThread* osthread) {
4057 int status = pthread_kill(osthread->pthread_id(), SR_signum);
4058 assert_status(status == 0, status, "pthread_kill");
4059 return status;
4060 }
4061
4062 // "Randomly" selected value for how long we want to spin
4063 // before bailing out on suspending a thread, also how often
4064 // we send a signal to a thread we want to resume
4065 static const int RANDOMLY_LARGE_INTEGER = 1000000;
4066 static const int RANDOMLY_LARGE_INTEGER2 = 100;
4067
4068 // returns true on success and false on error - really an error is fatal
4069 // but this seems the normal response to library errors
4070 static bool do_suspend(OSThread* osthread) {
4071 assert(osthread->sr.is_running(), "thread should be running");
4072 assert(!sr_semaphore.trywait(), "semaphore has invalid state");
4073
4074 // mark as suspended and send signal
4075 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
4076 // failed to switch, state wasn't running?
4077 ShouldNotReachHere();
4078 return false;
4079 }
4080
4081 if (sr_notify(osthread) != 0) {
4082 ShouldNotReachHere();
4083 }
4084
4085 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
4086 while (true) {
4087 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4088 break;
4089 } else {
4090 // timeout
4091 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
4092 if (cancelled == os::SuspendResume::SR_RUNNING) {
4093 return false;
4094 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
4095 // make sure that we consume the signal on the semaphore as well
4096 sr_semaphore.wait();
4097 break;
4098 } else {
4099 ShouldNotReachHere();
4100 return false;
4101 }
4102 }
4103 }
4104
4105 guarantee(osthread->sr.is_suspended(), "Must be suspended");
4106 return true;
4107 }
4108
4109 static void do_resume(OSThread* osthread) {
4110 assert(osthread->sr.is_suspended(), "thread should be suspended");
4111 assert(!sr_semaphore.trywait(), "invalid semaphore state");
4112
4113 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
4114 // failed to switch to WAKEUP_REQUEST
4115 ShouldNotReachHere();
4116 return;
4117 }
4118
4119 while (true) {
4120 if (sr_notify(osthread) == 0) {
4121 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4122 if (osthread->sr.is_running()) {
4123 return;
4124 }
4125 }
4126 } else {
4127 ShouldNotReachHere();
4128 }
4129 }
4130
4131 guarantee(osthread->sr.is_running(), "Must be running!");
4132 }
4133
4134 ////////////////////////////////////////////////////////////////////////////////
4135 // interrupt support
4136
4137 void os::interrupt(Thread* thread) {
4138 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
4139 "possibility of dangling Thread pointer");
4140
4141 OSThread* osthread = thread->osthread();
4142
4143 if (!osthread->interrupted()) {
4144 osthread->set_interrupted(true);
4145 // More than one thread can get here with the same value of osthread,
4146 // resulting in multiple notifications. We do, however, want the store
4147 // to interrupted() to be visible to other threads before we execute unpark().
4148 OrderAccess::fence();
4149 ParkEvent * const slp = thread->_SleepEvent ;
4150 if (slp != NULL) slp->unpark() ;
4151 }
4152
4153 // For JSR166. Unpark even if interrupt status already was set
4154 if (thread->is_Java_thread())
4155 ((JavaThread*)thread)->parker()->unpark();
4156
4157 ParkEvent * ev = thread->_ParkEvent ;
4158 if (ev != NULL) ev->unpark() ;
4159
4160 }
4161
4162 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
4163 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
4164 "possibility of dangling Thread pointer");
4165
4166 OSThread* osthread = thread->osthread();
4167
4168 bool interrupted = osthread->interrupted();
4169
4170 if (interrupted && clear_interrupted) {
4171 osthread->set_interrupted(false);
4172 // consider thread->_SleepEvent->reset() ... optional optimization
4173 }
4174
4175 return interrupted;
4176 }
4177
4178 ///////////////////////////////////////////////////////////////////////////////////
4179 // signal handling (except suspend/resume)
4180
4181 // This routine may be used by user applications as a "hook" to catch signals.
4182 // The user-defined signal handler must pass unrecognized signals to this
4183 // routine, and if it returns true (non-zero), then the signal handler must
4184 // return immediately. If the flag "abort_if_unrecognized" is true, then this
4185 // routine will never retun false (zero), but instead will execute a VM panic
4186 // routine kill the process.
4187 //
4188 // If this routine returns false, it is OK to call it again. This allows
4189 // the user-defined signal handler to perform checks either before or after
4190 // the VM performs its own checks. Naturally, the user code would be making
4191 // a serious error if it tried to handle an exception (such as a null check
4192 // or breakpoint) that the VM was generating for its own correct operation.
4193 //
4194 // This routine may recognize any of the following kinds of signals:
4195 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
4196 // It should be consulted by handlers for any of those signals.
4197 //
4198 // The caller of this routine must pass in the three arguments supplied
4199 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
4200 // field of the structure passed to sigaction(). This routine assumes that
4201 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
4202 //
4203 // Note that the VM will print warnings if it detects conflicting signal
4204 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
4205 //
4206 extern "C" JNIEXPORT int
4207 JVM_handle_linux_signal(int signo, siginfo_t* siginfo,
4208 void* ucontext, int abort_if_unrecognized);
4209
4210 void signalHandler(int sig, siginfo_t* info, void* uc) {
4211 assert(info != NULL && uc != NULL, "it must be old kernel");
4212 int orig_errno = errno; // Preserve errno value over signal handler.
4213 JVM_handle_linux_signal(sig, info, uc, true);
4214 errno = orig_errno;
4215 }
4216
4217
4218 // This boolean allows users to forward their own non-matching signals
4219 // to JVM_handle_linux_signal, harmlessly.
4220 bool os::Linux::signal_handlers_are_installed = false;
4221
4222 // For signal-chaining
4223 struct sigaction os::Linux::sigact[MAXSIGNUM];
4224 unsigned int os::Linux::sigs = 0;
4225 bool os::Linux::libjsig_is_loaded = false;
4226 typedef struct sigaction *(*get_signal_t)(int);
4227 get_signal_t os::Linux::get_signal_action = NULL;
4228
4229 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
4230 struct sigaction *actp = NULL;
4231
4232 if (libjsig_is_loaded) {
4233 // Retrieve the old signal handler from libjsig
4234 actp = (*get_signal_action)(sig);
4235 }
4236 if (actp == NULL) {
4237 // Retrieve the preinstalled signal handler from jvm
4238 actp = get_preinstalled_handler(sig);
4239 }
4240
4241 return actp;
4242 }
4243
4244 static bool call_chained_handler(struct sigaction *actp, int sig,
4245 siginfo_t *siginfo, void *context) {
4246 // Call the old signal handler
4247 if (actp->sa_handler == SIG_DFL) {
4248 // It's more reasonable to let jvm treat it as an unexpected exception
4249 // instead of taking the default action.
4250 return false;
4251 } else if (actp->sa_handler != SIG_IGN) {
4252 if ((actp->sa_flags & SA_NODEFER) == 0) {
4253 // automaticlly block the signal
4254 sigaddset(&(actp->sa_mask), sig);
4255 }
4256
4257 sa_handler_t hand;
4258 sa_sigaction_t sa;
4259 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
4260 // retrieve the chained handler
4261 if (siginfo_flag_set) {
4262 sa = actp->sa_sigaction;
4263 } else {
4264 hand = actp->sa_handler;
4265 }
4266
4267 if ((actp->sa_flags & SA_RESETHAND) != 0) {
4268 actp->sa_handler = SIG_DFL;
4269 }
4270
4271 // try to honor the signal mask
4272 sigset_t oset;
4273 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
4274
4275 // call into the chained handler
4276 if (siginfo_flag_set) {
4277 (*sa)(sig, siginfo, context);
4278 } else {
4279 (*hand)(sig);
4280 }
4281
4282 // restore the signal mask
4283 pthread_sigmask(SIG_SETMASK, &oset, 0);
4284 }
4285 // Tell jvm's signal handler the signal is taken care of.
4286 return true;
4287 }
4288
4289 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
4290 bool chained = false;
4291 // signal-chaining
4292 if (UseSignalChaining) {
4293 struct sigaction *actp = get_chained_signal_action(sig);
4294 if (actp != NULL) {
4295 chained = call_chained_handler(actp, sig, siginfo, context);
4296 }
4297 }
4298 return chained;
4299 }
4300
4301 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
4302 if ((( (unsigned int)1 << sig ) & sigs) != 0) {
4303 return &sigact[sig];
4304 }
4305 return NULL;
4306 }
4307
4308 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
4309 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4310 sigact[sig] = oldAct;
4311 sigs |= (unsigned int)1 << sig;
4312 }
4313
4314 // for diagnostic
4315 int os::Linux::sigflags[MAXSIGNUM];
4316
4317 int os::Linux::get_our_sigflags(int sig) {
4318 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4319 return sigflags[sig];
4320 }
4321
4322 void os::Linux::set_our_sigflags(int sig, int flags) {
4323 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4324 sigflags[sig] = flags;
4325 }
4326
4327 void os::Linux::set_signal_handler(int sig, bool set_installed) {
4328 // Check for overwrite.
4329 struct sigaction oldAct;
4330 sigaction(sig, (struct sigaction*)NULL, &oldAct);
4331
4332 void* oldhand = oldAct.sa_sigaction
4333 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4334 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4335 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
4336 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
4337 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
4338 if (AllowUserSignalHandlers || !set_installed) {
4339 // Do not overwrite; user takes responsibility to forward to us.
4340 return;
4341 } else if (UseSignalChaining) {
4342 // save the old handler in jvm
4343 save_preinstalled_handler(sig, oldAct);
4344 // libjsig also interposes the sigaction() call below and saves the
4345 // old sigaction on it own.
4346 } else {
4347 fatal(err_msg("Encountered unexpected pre-existing sigaction handler "
4348 "%#lx for signal %d.", (long)oldhand, sig));
4349 }
4350 }
4351
4352 struct sigaction sigAct;
4353 sigfillset(&(sigAct.sa_mask));
4354 sigAct.sa_handler = SIG_DFL;
4355 if (!set_installed) {
4356 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4357 } else {
4358 sigAct.sa_sigaction = signalHandler;
4359 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4360 }
4361 // Save flags, which are set by ours
4362 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4363 sigflags[sig] = sigAct.sa_flags;
4364
4365 int ret = sigaction(sig, &sigAct, &oldAct);
4366 assert(ret == 0, "check");
4367
4368 void* oldhand2 = oldAct.sa_sigaction
4369 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4370 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4371 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
4372 }
4373
4374 // install signal handlers for signals that HotSpot needs to
4375 // handle in order to support Java-level exception handling.
4376
4377 void os::Linux::install_signal_handlers() {
4378 if (!signal_handlers_are_installed) {
4379 signal_handlers_are_installed = true;
4380
4381 // signal-chaining
4382 typedef void (*signal_setting_t)();
4383 signal_setting_t begin_signal_setting = NULL;
4384 signal_setting_t end_signal_setting = NULL;
4385 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4386 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
4387 if (begin_signal_setting != NULL) {
4388 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4389 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
4390 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
4391 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
4392 libjsig_is_loaded = true;
4393 assert(UseSignalChaining, "should enable signal-chaining");
4394 }
4395 if (libjsig_is_loaded) {
4396 // Tell libjsig jvm is setting signal handlers
4397 (*begin_signal_setting)();
4398 }
4399
4400 set_signal_handler(SIGSEGV, true);
4401 set_signal_handler(SIGPIPE, true);
4402 set_signal_handler(SIGBUS, true);
4403 set_signal_handler(SIGILL, true);
4404 set_signal_handler(SIGFPE, true);
4405 set_signal_handler(SIGXFSZ, true);
4406
4407 if (libjsig_is_loaded) {
4408 // Tell libjsig jvm finishes setting signal handlers
4409 (*end_signal_setting)();
4410 }
4411
4412 // We don't activate signal checker if libjsig is in place, we trust ourselves
4413 // and if UserSignalHandler is installed all bets are off.
4414 // Log that signal checking is off only if -verbose:jni is specified.
4415 if (CheckJNICalls) {
4416 if (libjsig_is_loaded) {
4417 if (PrintJNIResolving) {
4418 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
4419 }
4420 check_signals = false;
4421 }
4422 if (AllowUserSignalHandlers) {
4423 if (PrintJNIResolving) {
4424 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
4425 }
4426 check_signals = false;
4427 }
4428 }
4429 }
4430 }
4431
4432 // This is the fastest way to get thread cpu time on Linux.
4433 // Returns cpu time (user+sys) for any thread, not only for current.
4434 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
4435 // It might work on 2.6.10+ with a special kernel/glibc patch.
4436 // For reference, please, see IEEE Std 1003.1-2004:
4437 // http://www.unix.org/single_unix_specification
4438
4439 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
4440 struct timespec tp;
4441 int rc = os::Linux::clock_gettime(clockid, &tp);
4442 assert(rc == 0, "clock_gettime is expected to return 0 code");
4443
4444 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
4445 }
4446
4447 /////
4448 // glibc on Linux platform uses non-documented flag
4449 // to indicate, that some special sort of signal
4450 // trampoline is used.
4451 // We will never set this flag, and we should
4452 // ignore this flag in our diagnostic
4453 #ifdef SIGNIFICANT_SIGNAL_MASK
4454 #undef SIGNIFICANT_SIGNAL_MASK
4455 #endif
4456 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
4457
4458 static const char* get_signal_handler_name(address handler,
4459 char* buf, int buflen) {
4460 int offset;
4461 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
4462 if (found) {
4463 // skip directory names
4464 const char *p1, *p2;
4465 p1 = buf;
4466 size_t len = strlen(os::file_separator());
4467 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
4468 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
4469 } else {
4470 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
4471 }
4472 return buf;
4473 }
4474
4475 static void print_signal_handler(outputStream* st, int sig,
4476 char* buf, size_t buflen) {
4477 struct sigaction sa;
4478
4479 sigaction(sig, NULL, &sa);
4480
4481 // See comment for SIGNIFICANT_SIGNAL_MASK define
4482 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4483
4484 st->print("%s: ", os::exception_name(sig, buf, buflen));
4485
4486 address handler = (sa.sa_flags & SA_SIGINFO)
4487 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
4488 : CAST_FROM_FN_PTR(address, sa.sa_handler);
4489
4490 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
4491 st->print("SIG_DFL");
4492 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
4493 st->print("SIG_IGN");
4494 } else {
4495 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
4496 }
4497
4498 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask);
4499
4500 address rh = VMError::get_resetted_sighandler(sig);
4501 // May be, handler was resetted by VMError?
4502 if(rh != NULL) {
4503 handler = rh;
4504 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
4505 }
4506
4507 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags);
4508
4509 // Check: is it our handler?
4510 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
4511 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
4512 // It is our signal handler
4513 // check for flags, reset system-used one!
4514 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
4515 st->print(
4516 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
4517 os::Linux::get_our_sigflags(sig));
4518 }
4519 }
4520 st->cr();
4521 }
4522
4523
4524 #define DO_SIGNAL_CHECK(sig) \
4525 if (!sigismember(&check_signal_done, sig)) \
4526 os::Linux::check_signal_handler(sig)
4527
4528 // This method is a periodic task to check for misbehaving JNI applications
4529 // under CheckJNI, we can add any periodic checks here
4530
4531 void os::run_periodic_checks() {
4532
4533 if (check_signals == false) return;
4534
4535 // SEGV and BUS if overridden could potentially prevent
4536 // generation of hs*.log in the event of a crash, debugging
4537 // such a case can be very challenging, so we absolutely
4538 // check the following for a good measure:
4539 DO_SIGNAL_CHECK(SIGSEGV);
4540 DO_SIGNAL_CHECK(SIGILL);
4541 DO_SIGNAL_CHECK(SIGFPE);
4542 DO_SIGNAL_CHECK(SIGBUS);
4543 DO_SIGNAL_CHECK(SIGPIPE);
4544 DO_SIGNAL_CHECK(SIGXFSZ);
4545
4546
4547 // ReduceSignalUsage allows the user to override these handlers
4548 // see comments at the very top and jvm_solaris.h
4549 if (!ReduceSignalUsage) {
4550 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4551 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4552 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4553 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4554 }
4555
4556 DO_SIGNAL_CHECK(SR_signum);
4557 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
4558 }
4559
4560 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4561
4562 static os_sigaction_t os_sigaction = NULL;
4563
4564 void os::Linux::check_signal_handler(int sig) {
4565 char buf[O_BUFLEN];
4566 address jvmHandler = NULL;
4567
4568
4569 struct sigaction act;
4570 if (os_sigaction == NULL) {
4571 // only trust the default sigaction, in case it has been interposed
4572 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4573 if (os_sigaction == NULL) return;
4574 }
4575
4576 os_sigaction(sig, (struct sigaction*)NULL, &act);
4577
4578
4579 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4580
4581 address thisHandler = (act.sa_flags & SA_SIGINFO)
4582 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4583 : CAST_FROM_FN_PTR(address, act.sa_handler) ;
4584
4585
4586 switch(sig) {
4587 case SIGSEGV:
4588 case SIGBUS:
4589 case SIGFPE:
4590 case SIGPIPE:
4591 case SIGILL:
4592 case SIGXFSZ:
4593 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4594 break;
4595
4596 case SHUTDOWN1_SIGNAL:
4597 case SHUTDOWN2_SIGNAL:
4598 case SHUTDOWN3_SIGNAL:
4599 case BREAK_SIGNAL:
4600 jvmHandler = (address)user_handler();
4601 break;
4602
4603 case INTERRUPT_SIGNAL:
4604 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
4605 break;
4606
4607 default:
4608 if (sig == SR_signum) {
4609 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4610 } else {
4611 return;
4612 }
4613 break;
4614 }
4615
4616 if (thisHandler != jvmHandler) {
4617 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4618 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4619 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4620 // No need to check this sig any longer
4621 sigaddset(&check_signal_done, sig);
4622 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4623 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4624 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig));
4625 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags);
4626 // No need to check this sig any longer
4627 sigaddset(&check_signal_done, sig);
4628 }
4629
4630 // Dump all the signal
4631 if (sigismember(&check_signal_done, sig)) {
4632 print_signal_handlers(tty, buf, O_BUFLEN);
4633 }
4634 }
4635
4636 extern void report_error(char* file_name, int line_no, char* title, char* format, ...);
4637
4638 extern bool signal_name(int signo, char* buf, size_t len);
4639
4640 const char* os::exception_name(int exception_code, char* buf, size_t size) {
4641 if (0 < exception_code && exception_code <= SIGRTMAX) {
4642 // signal
4643 if (!signal_name(exception_code, buf, size)) {
4644 jio_snprintf(buf, size, "SIG%d", exception_code);
4645 }
4646 return buf;
4647 } else {
4648 return NULL;
4649 }
4650 }
4651
4652 // this is called _before_ the most of global arguments have been parsed
4653 void os::init(void) {
4654 char dummy; /* used to get a guess on initial stack address */
4655 // first_hrtime = gethrtime();
4656
4657 // With LinuxThreads the JavaMain thread pid (primordial thread)
4658 // is different than the pid of the java launcher thread.
4659 // So, on Linux, the launcher thread pid is passed to the VM
4660 // via the sun.java.launcher.pid property.
4661 // Use this property instead of getpid() if it was correctly passed.
4662 // See bug 6351349.
4663 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
4664
4665 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
4666
4667 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4668
4669 init_random(1234567);
4670
4671 ThreadCritical::initialize();
4672
4673 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4674 if (Linux::page_size() == -1) {
4675 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)",
4676 strerror(errno)));
4677 }
4678 init_page_sizes((size_t) Linux::page_size());
4679
4680 Linux::initialize_system_info();
4681
4682 // main_thread points to the aboriginal thread
4683 Linux::_main_thread = pthread_self();
4684
4685 Linux::clock_init();
4686 initial_time_count = os::elapsed_counter();
4687 pthread_mutex_init(&dl_mutex, NULL);
4688
4689 // If the pagesize of the VM is greater than 8K determine the appropriate
4690 // number of initial guard pages. The user can change this with the
4691 // command line arguments, if needed.
4692 if (vm_page_size() > (int)Linux::vm_default_page_size()) {
4693 StackYellowPages = 1;
4694 StackRedPages = 1;
4695 StackShadowPages = round_to((StackShadowPages*Linux::vm_default_page_size()), vm_page_size()) / vm_page_size();
4696 }
4697 }
4698
4699 // To install functions for atexit system call
4700 extern "C" {
4701 static void perfMemory_exit_helper() {
4702 perfMemory_exit();
4703 }
4704 }
4705
4706 // this is called _after_ the global arguments have been parsed
4707 jint os::init_2(void)
4708 {
4709 Linux::fast_thread_clock_init();
4710
4711 // Allocate a single page and mark it as readable for safepoint polling
4712 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4713 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" );
4714
4715 os::set_polling_page( polling_page );
4716
4717 #ifndef PRODUCT
4718 if(Verbose && PrintMiscellaneous)
4719 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
4720 #endif
4721
4722 if (!UseMembar) {
4723 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4724 guarantee( mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page");
4725 os::set_memory_serialize_page( mem_serialize_page );
4726
4727 #ifndef PRODUCT
4728 if(Verbose && PrintMiscellaneous)
4729 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
4730 #endif
4731 }
4732
4733 os::large_page_init();
4734
4735 // initialize suspend/resume support - must do this before signal_sets_init()
4736 if (SR_initialize() != 0) {
4737 perror("SR_initialize failed");
4738 return JNI_ERR;
4739 }
4740
4741 Linux::signal_sets_init();
4742 Linux::install_signal_handlers();
4743
4744 // Check minimum allowable stack size for thread creation and to initialize
4745 // the java system classes, including StackOverflowError - depends on page
4746 // size. Add a page for compiler2 recursion in main thread.
4747 // Add in 2*BytesPerWord times page size to account for VM stack during
4748 // class initialization depending on 32 or 64 bit VM.
4749 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed,
4750 (size_t)(StackYellowPages+StackRedPages+StackShadowPages) * Linux::page_size() +
4751 (2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::vm_default_page_size());
4752
4753 size_t threadStackSizeInBytes = ThreadStackSize * K;
4754 if (threadStackSizeInBytes != 0 &&
4755 threadStackSizeInBytes < os::Linux::min_stack_allowed) {
4756 tty->print_cr("\nThe stack size specified is too small, "
4757 "Specify at least %dk",
4758 os::Linux::min_stack_allowed/ K);
4759 return JNI_ERR;
4760 }
4761
4762 // Make the stack size a multiple of the page size so that
4763 // the yellow/red zones can be guarded.
4764 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
4765 vm_page_size()));
4766
4767 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4768
4769 Linux::libpthread_init();
4770 if (PrintMiscellaneous && (Verbose || WizardMode)) {
4771 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n",
4772 Linux::glibc_version(), Linux::libpthread_version(),
4773 Linux::is_floating_stack() ? "floating stack" : "fixed stack");
4774 }
4775
4776 if (UseNUMA) {
4777 if (!Linux::libnuma_init()) {
4778 UseNUMA = false;
4779 } else {
4780 if ((Linux::numa_max_node() < 1)) {
4781 // There's only one node(they start from 0), disable NUMA.
4782 UseNUMA = false;
4783 }
4784 }
4785 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
4786 // we can make the adaptive lgrp chunk resizing work. If the user specified
4787 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and
4788 // disable adaptive resizing.
4789 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
4790 if (FLAG_IS_DEFAULT(UseNUMA)) {
4791 UseNUMA = false;
4792 } else {
4793 if (FLAG_IS_DEFAULT(UseLargePages) &&
4794 FLAG_IS_DEFAULT(UseSHM) &&
4795 FLAG_IS_DEFAULT(UseHugeTLBFS)) {
4796 UseLargePages = false;
4797 } else {
4798 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing");
4799 UseAdaptiveSizePolicy = false;
4800 UseAdaptiveNUMAChunkSizing = false;
4801 }
4802 }
4803 }
4804 if (!UseNUMA && ForceNUMA) {
4805 UseNUMA = true;
4806 }
4807 }
4808
4809 if (MaxFDLimit) {
4810 // set the number of file descriptors to max. print out error
4811 // if getrlimit/setrlimit fails but continue regardless.
4812 struct rlimit nbr_files;
4813 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
4814 if (status != 0) {
4815 if (PrintMiscellaneous && (Verbose || WizardMode))
4816 perror("os::init_2 getrlimit failed");
4817 } else {
4818 nbr_files.rlim_cur = nbr_files.rlim_max;
4819 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
4820 if (status != 0) {
4821 if (PrintMiscellaneous && (Verbose || WizardMode))
4822 perror("os::init_2 setrlimit failed");
4823 }
4824 }
4825 }
4826
4827 // Initialize lock used to serialize thread creation (see os::create_thread)
4828 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
4829
4830 // at-exit methods are called in the reverse order of their registration.
4831 // atexit functions are called on return from main or as a result of a
4832 // call to exit(3C). There can be only 32 of these functions registered
4833 // and atexit() does not set errno.
4834
4835 if (PerfAllowAtExitRegistration) {
4836 // only register atexit functions if PerfAllowAtExitRegistration is set.
4837 // atexit functions can be delayed until process exit time, which
4838 // can be problematic for embedded VM situations. Embedded VMs should
4839 // call DestroyJavaVM() to assure that VM resources are released.
4840
4841 // note: perfMemory_exit_helper atexit function may be removed in
4842 // the future if the appropriate cleanup code can be added to the
4843 // VM_Exit VMOperation's doit method.
4844 if (atexit(perfMemory_exit_helper) != 0) {
4845 warning("os::init2 atexit(perfMemory_exit_helper) failed");
4846 }
4847 }
4848
4849 // initialize thread priority policy
4850 prio_init();
4851
4852 return JNI_OK;
4853 }
4854
4855 // this is called at the end of vm_initialization
4856 void os::init_3(void)
4857 {
4858 #ifdef JAVASE_EMBEDDED
4859 // Start the MemNotifyThread
4860 if (LowMemoryProtection) {
4861 MemNotifyThread::start();
4862 }
4863 return;
4864 #endif
4865 }
4866
4867 // Mark the polling page as unreadable
4868 void os::make_polling_page_unreadable(void) {
4869 if( !guard_memory((char*)_polling_page, Linux::page_size()) )
4870 fatal("Could not disable polling page");
4871 };
4872
4873 // Mark the polling page as readable
4874 void os::make_polling_page_readable(void) {
4875 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
4876 fatal("Could not enable polling page");
4877 }
4878 };
4879
4880 int os::active_processor_count() {
4881 // Linux doesn't yet have a (official) notion of processor sets,
4882 // so just return the number of online processors.
4883 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
4884 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
4885 return online_cpus;
4886 }
4887
4888 void os::set_native_thread_name(const char *name) {
4889 // Not yet implemented.
4890 return;
4891 }
4892
4893 bool os::distribute_processes(uint length, uint* distribution) {
4894 // Not yet implemented.
4895 return false;
4896 }
4897
4898 bool os::bind_to_processor(uint processor_id) {
4899 // Not yet implemented.
4900 return false;
4901 }
4902
4903 ///
4904
4905 void os::SuspendedThreadTask::internal_do_task() {
4906 if (do_suspend(_thread->osthread())) {
4907 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
4908 do_task(context);
4909 do_resume(_thread->osthread());
4910 }
4911 }
4912
4913 class PcFetcher : public os::SuspendedThreadTask {
4914 public:
4915 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {}
4916 ExtendedPC result();
4917 protected:
4918 void do_task(const os::SuspendedThreadTaskContext& context);
4919 private:
4920 ExtendedPC _epc;
4921 };
4922
4923 ExtendedPC PcFetcher::result() {
4924 guarantee(is_done(), "task is not done yet.");
4925 return _epc;
4926 }
4927
4928 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) {
4929 Thread* thread = context.thread();
4930 OSThread* osthread = thread->osthread();
4931 if (osthread->ucontext() != NULL) {
4932 _epc = os::Linux::ucontext_get_pc((ucontext_t *) context.ucontext());
4933 } else {
4934 // NULL context is unexpected, double-check this is the VMThread
4935 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
4936 }
4937 }
4938
4939 // Suspends the target using the signal mechanism and then grabs the PC before
4940 // resuming the target. Used by the flat-profiler only
4941 ExtendedPC os::get_thread_pc(Thread* thread) {
4942 // Make sure that it is called by the watcher for the VMThread
4943 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
4944 assert(thread->is_VM_thread(), "Can only be called for VMThread");
4945
4946 PcFetcher fetcher(thread);
4947 fetcher.run();
4948 return fetcher.result();
4949 }
4950
4951 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime)
4952 {
4953 if (is_NPTL()) {
4954 return pthread_cond_timedwait(_cond, _mutex, _abstime);
4955 } else {
4956 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control
4957 // word back to default 64bit precision if condvar is signaled. Java
4958 // wants 53bit precision. Save and restore current value.
4959 int fpu = get_fpu_control_word();
4960 int status = pthread_cond_timedwait(_cond, _mutex, _abstime);
4961 set_fpu_control_word(fpu);
4962 return status;
4963 }
4964 }
4965
4966 ////////////////////////////////////////////////////////////////////////////////
4967 // debug support
4968
4969 bool os::find(address addr, outputStream* st) {
4970 Dl_info dlinfo;
4971 memset(&dlinfo, 0, sizeof(dlinfo));
4972 if (dladdr(addr, &dlinfo) != 0) {
4973 st->print(PTR_FORMAT ": ", addr);
4974 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
4975 st->print("%s+%#x", dlinfo.dli_sname,
4976 addr - (intptr_t)dlinfo.dli_saddr);
4977 } else if (dlinfo.dli_fbase != NULL) {
4978 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
4979 } else {
4980 st->print("<absolute address>");
4981 }
4982 if (dlinfo.dli_fname != NULL) {
4983 st->print(" in %s", dlinfo.dli_fname);
4984 }
4985 if (dlinfo.dli_fbase != NULL) {
4986 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
4987 }
4988 st->cr();
4989
4990 if (Verbose) {
4991 // decode some bytes around the PC
4992 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
4993 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size());
4994 address lowest = (address) dlinfo.dli_sname;
4995 if (!lowest) lowest = (address) dlinfo.dli_fbase;
4996 if (begin < lowest) begin = lowest;
4997 Dl_info dlinfo2;
4998 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
4999 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin)
5000 end = (address) dlinfo2.dli_saddr;
5001 Disassembler::decode(begin, end, st);
5002 }
5003 return true;
5004 }
5005 return false;
5006 }
5007
5008 ////////////////////////////////////////////////////////////////////////////////
5009 // misc
5010
5011 // This does not do anything on Linux. This is basically a hook for being
5012 // able to use structured exception handling (thread-local exception filters)
5013 // on, e.g., Win32.
5014 void
5015 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method,
5016 JavaCallArguments* args, Thread* thread) {
5017 f(value, method, args, thread);
5018 }
5019
5020 void os::print_statistics() {
5021 }
5022
5023 int os::message_box(const char* title, const char* message) {
5024 int i;
5025 fdStream err(defaultStream::error_fd());
5026 for (i = 0; i < 78; i++) err.print_raw("=");
5027 err.cr();
5028 err.print_raw_cr(title);
5029 for (i = 0; i < 78; i++) err.print_raw("-");
5030 err.cr();
5031 err.print_raw_cr(message);
5032 for (i = 0; i < 78; i++) err.print_raw("=");
5033 err.cr();
5034
5035 char buf[16];
5036 // Prevent process from exiting upon "read error" without consuming all CPU
5037 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
5038
5039 return buf[0] == 'y' || buf[0] == 'Y';
5040 }
5041
5042 int os::stat(const char *path, struct stat *sbuf) {
5043 char pathbuf[MAX_PATH];
5044 if (strlen(path) > MAX_PATH - 1) {
5045 errno = ENAMETOOLONG;
5046 return -1;
5047 }
5048 os::native_path(strcpy(pathbuf, path));
5049 return ::stat(pathbuf, sbuf);
5050 }
5051
5052 bool os::check_heap(bool force) {
5053 return true;
5054 }
5055
5056 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
5057 return ::vsnprintf(buf, count, format, args);
5058 }
5059
5060 // Is a (classpath) directory empty?
5061 bool os::dir_is_empty(const char* path) {
5062 DIR *dir = NULL;
5063 struct dirent *ptr;
5064
5065 dir = opendir(path);
5066 if (dir == NULL) return true;
5067
5068 /* Scan the directory */
5069 bool result = true;
5070 char buf[sizeof(struct dirent) + MAX_PATH];
5071 while (result && (ptr = ::readdir(dir)) != NULL) {
5072 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
5073 result = false;
5074 }
5075 }
5076 closedir(dir);
5077 return result;
5078 }
5079
5080 // This code originates from JDK's sysOpen and open64_w
5081 // from src/solaris/hpi/src/system_md.c
5082
5083 #ifndef O_DELETE
5084 #define O_DELETE 0x10000
5085 #endif
5086
5087 // Open a file. Unlink the file immediately after open returns
5088 // if the specified oflag has the O_DELETE flag set.
5089 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c
5090
5091 int os::open(const char *path, int oflag, int mode) {
5092
5093 if (strlen(path) > MAX_PATH - 1) {
5094 errno = ENAMETOOLONG;
5095 return -1;
5096 }
5097 int fd;
5098 int o_delete = (oflag & O_DELETE);
5099 oflag = oflag & ~O_DELETE;
5100
5101 fd = ::open64(path, oflag, mode);
5102 if (fd == -1) return -1;
5103
5104 //If the open succeeded, the file might still be a directory
5105 {
5106 struct stat64 buf64;
5107 int ret = ::fstat64(fd, &buf64);
5108 int st_mode = buf64.st_mode;
5109
5110 if (ret != -1) {
5111 if ((st_mode & S_IFMT) == S_IFDIR) {
5112 errno = EISDIR;
5113 ::close(fd);
5114 return -1;
5115 }
5116 } else {
5117 ::close(fd);
5118 return -1;
5119 }
5120 }
5121
5122 /*
5123 * All file descriptors that are opened in the JVM and not
5124 * specifically destined for a subprocess should have the
5125 * close-on-exec flag set. If we don't set it, then careless 3rd
5126 * party native code might fork and exec without closing all
5127 * appropriate file descriptors (e.g. as we do in closeDescriptors in
5128 * UNIXProcess.c), and this in turn might:
5129 *
5130 * - cause end-of-file to fail to be detected on some file
5131 * descriptors, resulting in mysterious hangs, or
5132 *
5133 * - might cause an fopen in the subprocess to fail on a system
5134 * suffering from bug 1085341.
5135 *
5136 * (Yes, the default setting of the close-on-exec flag is a Unix
5137 * design flaw)
5138 *
5139 * See:
5140 * 1085341: 32-bit stdio routines should support file descriptors >255
5141 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed
5142 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
5143 */
5144 #ifdef FD_CLOEXEC
5145 {
5146 int flags = ::fcntl(fd, F_GETFD);
5147 if (flags != -1)
5148 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
5149 }
5150 #endif
5151
5152 if (o_delete != 0) {
5153 ::unlink(path);
5154 }
5155 return fd;
5156 }
5157
5158
5159 // create binary file, rewriting existing file if required
5160 int os::create_binary_file(const char* path, bool rewrite_existing) {
5161 int oflags = O_WRONLY | O_CREAT;
5162 if (!rewrite_existing) {
5163 oflags |= O_EXCL;
5164 }
5165 return ::open64(path, oflags, S_IREAD | S_IWRITE);
5166 }
5167
5168 // return current position of file pointer
5169 jlong os::current_file_offset(int fd) {
5170 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
5171 }
5172
5173 // move file pointer to the specified offset
5174 jlong os::seek_to_file_offset(int fd, jlong offset) {
5175 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
5176 }
5177
5178 // This code originates from JDK's sysAvailable
5179 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
5180
5181 int os::available(int fd, jlong *bytes) {
5182 jlong cur, end;
5183 int mode;
5184 struct stat64 buf64;
5185
5186 if (::fstat64(fd, &buf64) >= 0) {
5187 mode = buf64.st_mode;
5188 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
5189 /*
5190 * XXX: is the following call interruptible? If so, this might
5191 * need to go through the INTERRUPT_IO() wrapper as for other
5192 * blocking, interruptible calls in this file.
5193 */
5194 int n;
5195 if (::ioctl(fd, FIONREAD, &n) >= 0) {
5196 *bytes = n;
5197 return 1;
5198 }
5199 }
5200 }
5201 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
5202 return 0;
5203 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
5204 return 0;
5205 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
5206 return 0;
5207 }
5208 *bytes = end - cur;
5209 return 1;
5210 }
5211
5212 int os::socket_available(int fd, jint *pbytes) {
5213 // Linux doc says EINTR not returned, unlike Solaris
5214 int ret = ::ioctl(fd, FIONREAD, pbytes);
5215
5216 //%% note ioctl can return 0 when successful, JVM_SocketAvailable
5217 // is expected to return 0 on failure and 1 on success to the jdk.
5218 return (ret < 0) ? 0 : 1;
5219 }
5220
5221 // Map a block of memory.
5222 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
5223 char *addr, size_t bytes, bool read_only,
5224 bool allow_exec) {
5225 int prot;
5226 int flags = MAP_PRIVATE;
5227
5228 if (read_only) {
5229 prot = PROT_READ;
5230 } else {
5231 prot = PROT_READ | PROT_WRITE;
5232 }
5233
5234 if (allow_exec) {
5235 prot |= PROT_EXEC;
5236 }
5237
5238 if (addr != NULL) {
5239 flags |= MAP_FIXED;
5240 }
5241
5242 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
5243 fd, file_offset);
5244 if (mapped_address == MAP_FAILED) {
5245 return NULL;
5246 }
5247 return mapped_address;
5248 }
5249
5250
5251 // Remap a block of memory.
5252 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
5253 char *addr, size_t bytes, bool read_only,
5254 bool allow_exec) {
5255 // same as map_memory() on this OS
5256 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
5257 allow_exec);
5258 }
5259
5260
5261 // Unmap a block of memory.
5262 bool os::pd_unmap_memory(char* addr, size_t bytes) {
5263 return munmap(addr, bytes) == 0;
5264 }
5265
5266 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
5267
5268 static clockid_t thread_cpu_clockid(Thread* thread) {
5269 pthread_t tid = thread->osthread()->pthread_id();
5270 clockid_t clockid;
5271
5272 // Get thread clockid
5273 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
5274 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
5275 return clockid;
5276 }
5277
5278 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
5279 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
5280 // of a thread.
5281 //
5282 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
5283 // the fast estimate available on the platform.
5284
5285 jlong os::current_thread_cpu_time() {
5286 if (os::Linux::supports_fast_thread_cpu_time()) {
5287 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5288 } else {
5289 // return user + sys since the cost is the same
5290 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
5291 }
5292 }
5293
5294 jlong os::thread_cpu_time(Thread* thread) {
5295 // consistent with what current_thread_cpu_time() returns
5296 if (os::Linux::supports_fast_thread_cpu_time()) {
5297 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5298 } else {
5299 return slow_thread_cpu_time(thread, true /* user + sys */);
5300 }
5301 }
5302
5303 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
5304 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5305 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5306 } else {
5307 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
5308 }
5309 }
5310
5311 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5312 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5313 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5314 } else {
5315 return slow_thread_cpu_time(thread, user_sys_cpu_time);
5316 }
5317 }
5318
5319 //
5320 // -1 on error.
5321 //
5322
5323 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5324 static bool proc_task_unchecked = true;
5325 static const char *proc_stat_path = "/proc/%d/stat";
5326 pid_t tid = thread->osthread()->thread_id();
5327 char *s;
5328 char stat[2048];
5329 int statlen;
5330 char proc_name[64];
5331 int count;
5332 long sys_time, user_time;
5333 char cdummy;
5334 int idummy;
5335 long ldummy;
5336 FILE *fp;
5337
5338 // The /proc/<tid>/stat aggregates per-process usage on
5339 // new Linux kernels 2.6+ where NPTL is supported.
5340 // The /proc/self/task/<tid>/stat still has the per-thread usage.
5341 // See bug 6328462.
5342 // There possibly can be cases where there is no directory
5343 // /proc/self/task, so we check its availability.
5344 if (proc_task_unchecked && os::Linux::is_NPTL()) {
5345 // This is executed only once
5346 proc_task_unchecked = false;
5347 fp = fopen("/proc/self/task", "r");
5348 if (fp != NULL) {
5349 proc_stat_path = "/proc/self/task/%d/stat";
5350 fclose(fp);
5351 }
5352 }
5353
5354 sprintf(proc_name, proc_stat_path, tid);
5355 fp = fopen(proc_name, "r");
5356 if ( fp == NULL ) return -1;
5357 statlen = fread(stat, 1, 2047, fp);
5358 stat[statlen] = '\0';
5359 fclose(fp);
5360
5361 // Skip pid and the command string. Note that we could be dealing with
5362 // weird command names, e.g. user could decide to rename java launcher
5363 // to "java 1.4.2 :)", then the stat file would look like
5364 // 1234 (java 1.4.2 :)) R ... ...
5365 // We don't really need to know the command string, just find the last
5366 // occurrence of ")" and then start parsing from there. See bug 4726580.
5367 s = strrchr(stat, ')');
5368 if (s == NULL ) return -1;
5369
5370 // Skip blank chars
5371 do s++; while (isspace(*s));
5372
5373 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
5374 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
5375 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
5376 &user_time, &sys_time);
5377 if ( count != 13 ) return -1;
5378 if (user_sys_cpu_time) {
5379 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5380 } else {
5381 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5382 }
5383 }
5384
5385 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5386 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5387 info_ptr->may_skip_backward = false; // elapsed time not wall time
5388 info_ptr->may_skip_forward = false; // elapsed time not wall time
5389 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5390 }
5391
5392 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5393 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5394 info_ptr->may_skip_backward = false; // elapsed time not wall time
5395 info_ptr->may_skip_forward = false; // elapsed time not wall time
5396 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5397 }
5398
5399 bool os::is_thread_cpu_time_supported() {
5400 return true;
5401 }
5402
5403 // System loadavg support. Returns -1 if load average cannot be obtained.
5404 // Linux doesn't yet have a (official) notion of processor sets,
5405 // so just return the system wide load average.
5406 int os::loadavg(double loadavg[], int nelem) {
5407 return ::getloadavg(loadavg, nelem);
5408 }
5409
5410 void os::pause() {
5411 char filename[MAX_PATH];
5412 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
5413 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
5414 } else {
5415 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
5416 }
5417
5418 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
5419 if (fd != -1) {
5420 struct stat buf;
5421 ::close(fd);
5422 while (::stat(filename, &buf) == 0) {
5423 (void)::poll(NULL, 0, 100);
5424 }
5425 } else {
5426 jio_fprintf(stderr,
5427 "Could not open pause file '%s', continuing immediately.\n", filename);
5428 }
5429 }
5430
5431
5432 // Refer to the comments in os_solaris.cpp park-unpark.
5433 //
5434 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
5435 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
5436 // For specifics regarding the bug see GLIBC BUGID 261237 :
5437 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
5438 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
5439 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
5440 // is used. (The simple C test-case provided in the GLIBC bug report manifests the
5441 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
5442 // and monitorenter when we're using 1-0 locking. All those operations may result in
5443 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version
5444 // of libpthread avoids the problem, but isn't practical.
5445 //
5446 // Possible remedies:
5447 //
5448 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work.
5449 // This is palliative and probabilistic, however. If the thread is preempted
5450 // between the call to compute_abstime() and pthread_cond_timedwait(), more
5451 // than the minimum period may have passed, and the abstime may be stale (in the
5452 // past) resultin in a hang. Using this technique reduces the odds of a hang
5453 // but the JVM is still vulnerable, particularly on heavily loaded systems.
5454 //
5455 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
5456 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set
5457 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
5458 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant
5459 // thread.
5460 //
5461 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread
5462 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing
5463 // a timeout request to the chron thread and then blocking via pthread_cond_wait().
5464 // This also works well. In fact it avoids kernel-level scalability impediments
5465 // on certain platforms that don't handle lots of active pthread_cond_timedwait()
5466 // timers in a graceful fashion.
5467 //
5468 // 4. When the abstime value is in the past it appears that control returns
5469 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
5470 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we
5471 // can avoid the problem by reinitializing the condvar -- by cond_destroy()
5472 // followed by cond_init() -- after all calls to pthread_cond_timedwait().
5473 // It may be possible to avoid reinitialization by checking the return
5474 // value from pthread_cond_timedwait(). In addition to reinitializing the
5475 // condvar we must establish the invariant that cond_signal() is only called
5476 // within critical sections protected by the adjunct mutex. This prevents
5477 // cond_signal() from "seeing" a condvar that's in the midst of being
5478 // reinitialized or that is corrupt. Sadly, this invariant obviates the
5479 // desirable signal-after-unlock optimization that avoids futile context switching.
5480 //
5481 // I'm also concerned that some versions of NTPL might allocate an auxilliary
5482 // structure when a condvar is used or initialized. cond_destroy() would
5483 // release the helper structure. Our reinitialize-after-timedwait fix
5484 // put excessive stress on malloc/free and locks protecting the c-heap.
5485 //
5486 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag.
5487 // It may be possible to refine (4) by checking the kernel and NTPL verisons
5488 // and only enabling the work-around for vulnerable environments.
5489
5490 // utility to compute the abstime argument to timedwait:
5491 // millis is the relative timeout time
5492 // abstime will be the absolute timeout time
5493 // TODO: replace compute_abstime() with unpackTime()
5494
5495 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
5496 if (millis < 0) millis = 0;
5497 struct timeval now;
5498 int status = gettimeofday(&now, NULL);
5499 assert(status == 0, "gettimeofday");
5500 jlong seconds = millis / 1000;
5501 millis %= 1000;
5502 if (seconds > 50000000) { // see man cond_timedwait(3T)
5503 seconds = 50000000;
5504 }
5505 abstime->tv_sec = now.tv_sec + seconds;
5506 long usec = now.tv_usec + millis * 1000;
5507 if (usec >= 1000000) {
5508 abstime->tv_sec += 1;
5509 usec -= 1000000;
5510 }
5511 abstime->tv_nsec = usec * 1000;
5512 return abstime;
5513 }
5514
5515
5516 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately.
5517 // Conceptually TryPark() should be equivalent to park(0).
5518
5519 int os::PlatformEvent::TryPark() {
5520 for (;;) {
5521 const int v = _Event ;
5522 guarantee ((v == 0) || (v == 1), "invariant") ;
5523 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ;
5524 }
5525 }
5526
5527 void os::PlatformEvent::park() { // AKA "down()"
5528 // Invariant: Only the thread associated with the Event/PlatformEvent
5529 // may call park().
5530 // TODO: assert that _Assoc != NULL or _Assoc == Self
5531 int v ;
5532 for (;;) {
5533 v = _Event ;
5534 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5535 }
5536 guarantee (v >= 0, "invariant") ;
5537 if (v == 0) {
5538 // Do this the hard way by blocking ...
5539 int status = pthread_mutex_lock(_mutex);
5540 assert_status(status == 0, status, "mutex_lock");
5541 guarantee (_nParked == 0, "invariant") ;
5542 ++ _nParked ;
5543 while (_Event < 0) {
5544 status = pthread_cond_wait(_cond, _mutex);
5545 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
5546 // Treat this the same as if the wait was interrupted
5547 if (status == ETIME) { status = EINTR; }
5548 assert_status(status == 0 || status == EINTR, status, "cond_wait");
5549 }
5550 -- _nParked ;
5551
5552 _Event = 0 ;
5553 status = pthread_mutex_unlock(_mutex);
5554 assert_status(status == 0, status, "mutex_unlock");
5555 // Paranoia to ensure our locked and lock-free paths interact
5556 // correctly with each other.
5557 OrderAccess::fence();
5558 }
5559 guarantee (_Event >= 0, "invariant") ;
5560 }
5561
5562 int os::PlatformEvent::park(jlong millis) {
5563 guarantee (_nParked == 0, "invariant") ;
5564
5565 int v ;
5566 for (;;) {
5567 v = _Event ;
5568 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5569 }
5570 guarantee (v >= 0, "invariant") ;
5571 if (v != 0) return OS_OK ;
5572
5573 // We do this the hard way, by blocking the thread.
5574 // Consider enforcing a minimum timeout value.
5575 struct timespec abst;
5576 compute_abstime(&abst, millis);
5577
5578 int ret = OS_TIMEOUT;
5579 int status = pthread_mutex_lock(_mutex);
5580 assert_status(status == 0, status, "mutex_lock");
5581 guarantee (_nParked == 0, "invariant") ;
5582 ++_nParked ;
5583
5584 // Object.wait(timo) will return because of
5585 // (a) notification
5586 // (b) timeout
5587 // (c) thread.interrupt
5588 //
5589 // Thread.interrupt and object.notify{All} both call Event::set.
5590 // That is, we treat thread.interrupt as a special case of notification.
5591 // The underlying Solaris implementation, cond_timedwait, admits
5592 // spurious/premature wakeups, but the JLS/JVM spec prevents the
5593 // JVM from making those visible to Java code. As such, we must
5594 // filter out spurious wakeups. We assume all ETIME returns are valid.
5595 //
5596 // TODO: properly differentiate simultaneous notify+interrupt.
5597 // In that case, we should propagate the notify to another waiter.
5598
5599 while (_Event < 0) {
5600 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst);
5601 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5602 pthread_cond_destroy (_cond);
5603 pthread_cond_init (_cond, NULL) ;
5604 }
5605 assert_status(status == 0 || status == EINTR ||
5606 status == ETIME || status == ETIMEDOUT,
5607 status, "cond_timedwait");
5608 if (!FilterSpuriousWakeups) break ; // previous semantics
5609 if (status == ETIME || status == ETIMEDOUT) break ;
5610 // We consume and ignore EINTR and spurious wakeups.
5611 }
5612 --_nParked ;
5613 if (_Event >= 0) {
5614 ret = OS_OK;
5615 }
5616 _Event = 0 ;
5617 status = pthread_mutex_unlock(_mutex);
5618 assert_status(status == 0, status, "mutex_unlock");
5619 assert (_nParked == 0, "invariant") ;
5620 // Paranoia to ensure our locked and lock-free paths interact
5621 // correctly with each other.
5622 OrderAccess::fence();
5623 return ret;
5624 }
5625
5626 void os::PlatformEvent::unpark() {
5627 // Transitions for _Event:
5628 // 0 :=> 1
5629 // 1 :=> 1
5630 // -1 :=> either 0 or 1; must signal target thread
5631 // That is, we can safely transition _Event from -1 to either
5632 // 0 or 1. Forcing 1 is slightly more efficient for back-to-back
5633 // unpark() calls.
5634 // See also: "Semaphores in Plan 9" by Mullender & Cox
5635 //
5636 // Note: Forcing a transition from "-1" to "1" on an unpark() means
5637 // that it will take two back-to-back park() calls for the owning
5638 // thread to block. This has the benefit of forcing a spurious return
5639 // from the first park() call after an unpark() call which will help
5640 // shake out uses of park() and unpark() without condition variables.
5641
5642 if (Atomic::xchg(1, &_Event) >= 0) return;
5643
5644 // Wait for the thread associated with the event to vacate
5645 int status = pthread_mutex_lock(_mutex);
5646 assert_status(status == 0, status, "mutex_lock");
5647 int AnyWaiters = _nParked;
5648 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant");
5649 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
5650 AnyWaiters = 0;
5651 pthread_cond_signal(_cond);
5652 }
5653 status = pthread_mutex_unlock(_mutex);
5654 assert_status(status == 0, status, "mutex_unlock");
5655 if (AnyWaiters != 0) {
5656 status = pthread_cond_signal(_cond);
5657 assert_status(status == 0, status, "cond_signal");
5658 }
5659
5660 // Note that we signal() _after dropping the lock for "immortal" Events.
5661 // This is safe and avoids a common class of futile wakeups. In rare
5662 // circumstances this can cause a thread to return prematurely from
5663 // cond_{timed}wait() but the spurious wakeup is benign and the victim will
5664 // simply re-test the condition and re-park itself.
5665 }
5666
5667
5668 // JSR166
5669 // -------------------------------------------------------
5670
5671 /*
5672 * The solaris and linux implementations of park/unpark are fairly
5673 * conservative for now, but can be improved. They currently use a
5674 * mutex/condvar pair, plus a a count.
5675 * Park decrements count if > 0, else does a condvar wait. Unpark
5676 * sets count to 1 and signals condvar. Only one thread ever waits
5677 * on the condvar. Contention seen when trying to park implies that someone
5678 * is unparking you, so don't wait. And spurious returns are fine, so there
5679 * is no need to track notifications.
5680 */
5681
5682 #define MAX_SECS 100000000
5683 /*
5684 * This code is common to linux and solaris and will be moved to a
5685 * common place in dolphin.
5686 *
5687 * The passed in time value is either a relative time in nanoseconds
5688 * or an absolute time in milliseconds. Either way it has to be unpacked
5689 * into suitable seconds and nanoseconds components and stored in the
5690 * given timespec structure.
5691 * Given time is a 64-bit value and the time_t used in the timespec is only
5692 * a signed-32-bit value (except on 64-bit Linux) we have to watch for
5693 * overflow if times way in the future are given. Further on Solaris versions
5694 * prior to 10 there is a restriction (see cond_timedwait) that the specified
5695 * number of seconds, in abstime, is less than current_time + 100,000,000.
5696 * As it will be 28 years before "now + 100000000" will overflow we can
5697 * ignore overflow and just impose a hard-limit on seconds using the value
5698 * of "now + 100,000,000". This places a limit on the timeout of about 3.17
5699 * years from "now".
5700 */
5701
5702 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
5703 assert (time > 0, "convertTime");
5704
5705 struct timeval now;
5706 int status = gettimeofday(&now, NULL);
5707 assert(status == 0, "gettimeofday");
5708
5709 time_t max_secs = now.tv_sec + MAX_SECS;
5710
5711 if (isAbsolute) {
5712 jlong secs = time / 1000;
5713 if (secs > max_secs) {
5714 absTime->tv_sec = max_secs;
5715 }
5716 else {
5717 absTime->tv_sec = secs;
5718 }
5719 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
5720 }
5721 else {
5722 jlong secs = time / NANOSECS_PER_SEC;
5723 if (secs >= MAX_SECS) {
5724 absTime->tv_sec = max_secs;
5725 absTime->tv_nsec = 0;
5726 }
5727 else {
5728 absTime->tv_sec = now.tv_sec + secs;
5729 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
5730 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5731 absTime->tv_nsec -= NANOSECS_PER_SEC;
5732 ++absTime->tv_sec; // note: this must be <= max_secs
5733 }
5734 }
5735 }
5736 assert(absTime->tv_sec >= 0, "tv_sec < 0");
5737 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
5738 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
5739 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
5740 }
5741
5742 void Parker::park(bool isAbsolute, jlong time) {
5743 // Ideally we'd do something useful while spinning, such
5744 // as calling unpackTime().
5745
5746 // Optional fast-path check:
5747 // Return immediately if a permit is available.
5748 // We depend on Atomic::xchg() having full barrier semantics
5749 // since we are doing a lock-free update to _counter.
5750 if (Atomic::xchg(0, &_counter) > 0) return;
5751
5752 Thread* thread = Thread::current();
5753 assert(thread->is_Java_thread(), "Must be JavaThread");
5754 JavaThread *jt = (JavaThread *)thread;
5755
5756 // Optional optimization -- avoid state transitions if there's an interrupt pending.
5757 // Check interrupt before trying to wait
5758 if (Thread::is_interrupted(thread, false)) {
5759 return;
5760 }
5761
5762 // Next, demultiplex/decode time arguments
5763 timespec absTime;
5764 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all
5765 return;
5766 }
5767 if (time > 0) {
5768 unpackTime(&absTime, isAbsolute, time);
5769 }
5770
5771
5772 // Enter safepoint region
5773 // Beware of deadlocks such as 6317397.
5774 // The per-thread Parker:: mutex is a classic leaf-lock.
5775 // In particular a thread must never block on the Threads_lock while
5776 // holding the Parker:: mutex. If safepoints are pending both the
5777 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
5778 ThreadBlockInVM tbivm(jt);
5779
5780 // Don't wait if cannot get lock since interference arises from
5781 // unblocking. Also. check interrupt before trying wait
5782 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
5783 return;
5784 }
5785
5786 int status ;
5787 if (_counter > 0) { // no wait needed
5788 _counter = 0;
5789 status = pthread_mutex_unlock(_mutex);
5790 assert (status == 0, "invariant") ;
5791 // Paranoia to ensure our locked and lock-free paths interact
5792 // correctly with each other and Java-level accesses.
5793 OrderAccess::fence();
5794 return;
5795 }
5796
5797 #ifdef ASSERT
5798 // Don't catch signals while blocked; let the running threads have the signals.
5799 // (This allows a debugger to break into the running thread.)
5800 sigset_t oldsigs;
5801 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
5802 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
5803 #endif
5804
5805 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
5806 jt->set_suspend_equivalent();
5807 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
5808
5809 if (time == 0) {
5810 status = pthread_cond_wait (_cond, _mutex) ;
5811 } else {
5812 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ;
5813 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5814 pthread_cond_destroy (_cond) ;
5815 pthread_cond_init (_cond, NULL);
5816 }
5817 }
5818 assert_status(status == 0 || status == EINTR ||
5819 status == ETIME || status == ETIMEDOUT,
5820 status, "cond_timedwait");
5821
5822 #ifdef ASSERT
5823 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
5824 #endif
5825
5826 _counter = 0 ;
5827 status = pthread_mutex_unlock(_mutex) ;
5828 assert_status(status == 0, status, "invariant") ;
5829 // Paranoia to ensure our locked and lock-free paths interact
5830 // correctly with each other and Java-level accesses.
5831 OrderAccess::fence();
5832
5833 // If externally suspended while waiting, re-suspend
5834 if (jt->handle_special_suspend_equivalent_condition()) {
5835 jt->java_suspend_self();
5836 }
5837 }
5838
5839 void Parker::unpark() {
5840 int s, status ;
5841 status = pthread_mutex_lock(_mutex);
5842 assert (status == 0, "invariant") ;
5843 s = _counter;
5844 _counter = 1;
5845 if (s < 1) {
5846 if (WorkAroundNPTLTimedWaitHang) {
5847 status = pthread_cond_signal (_cond) ;
5848 assert (status == 0, "invariant") ;
5849 status = pthread_mutex_unlock(_mutex);
5850 assert (status == 0, "invariant") ;
5851 } else {
5852 status = pthread_mutex_unlock(_mutex);
5853 assert (status == 0, "invariant") ;
5854 status = pthread_cond_signal (_cond) ;
5855 assert (status == 0, "invariant") ;
5856 }
5857 } else {
5858 pthread_mutex_unlock(_mutex);
5859 assert (status == 0, "invariant") ;
5860 }
5861 }
5862
5863
5864 extern char** environ;
5865
5866 #ifndef __NR_fork
5867 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57)
5868 #endif
5869
5870 #ifndef __NR_execve
5871 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59)
5872 #endif
5873
5874 // Run the specified command in a separate process. Return its exit value,
5875 // or -1 on failure (e.g. can't fork a new process).
5876 // Unlike system(), this function can be called from signal handler. It
5877 // doesn't block SIGINT et al.
5878 int os::fork_and_exec(char* cmd) {
5879 const char * argv[4] = {"sh", "-c", cmd, NULL};
5880
5881 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run
5882 // pthread_atfork handlers and reset pthread library. All we need is a
5883 // separate process to execve. Make a direct syscall to fork process.
5884 // On IA64 there's no fork syscall, we have to use fork() and hope for
5885 // the best...
5886 pid_t pid = NOT_IA64(syscall(__NR_fork);)
5887 IA64_ONLY(fork();)
5888
5889 if (pid < 0) {
5890 // fork failed
5891 return -1;
5892
5893 } else if (pid == 0) {
5894 // child process
5895
5896 // execve() in LinuxThreads will call pthread_kill_other_threads_np()
5897 // first to kill every thread on the thread list. Because this list is
5898 // not reset by fork() (see notes above), execve() will instead kill
5899 // every thread in the parent process. We know this is the only thread
5900 // in the new process, so make a system call directly.
5901 // IA64 should use normal execve() from glibc to match the glibc fork()
5902 // above.
5903 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);)
5904 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);)
5905
5906 // execve failed
5907 _exit(-1);
5908
5909 } else {
5910 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5911 // care about the actual exit code, for now.
5912
5913 int status;
5914
5915 // Wait for the child process to exit. This returns immediately if
5916 // the child has already exited. */
5917 while (waitpid(pid, &status, 0) < 0) {
5918 switch (errno) {
5919 case ECHILD: return 0;
5920 case EINTR: break;
5921 default: return -1;
5922 }
5923 }
5924
5925 if (WIFEXITED(status)) {
5926 // The child exited normally; get its exit code.
5927 return WEXITSTATUS(status);
5928 } else if (WIFSIGNALED(status)) {
5929 // The child exited because of a signal
5930 // The best value to return is 0x80 + signal number,
5931 // because that is what all Unix shells do, and because
5932 // it allows callers to distinguish between process exit and
5933 // process death by signal.
5934 return 0x80 + WTERMSIG(status);
5935 } else {
5936 // Unknown exit code; pass it through
5937 return status;
5938 }
5939 }
5940 }
5941
5942 // is_headless_jre()
5943 //
5944 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
5945 // in order to report if we are running in a headless jre
5946 //
5947 // Since JDK8 xawt/libmawt.so was moved into the same directory
5948 // as libawt.so, and renamed libawt_xawt.so
5949 //
5950 bool os::is_headless_jre() {
5951 struct stat statbuf;
5952 char buf[MAXPATHLEN];
5953 char libmawtpath[MAXPATHLEN];
5954 const char *xawtstr = "/xawt/libmawt.so";
5955 const char *new_xawtstr = "/libawt_xawt.so";
5956 char *p;
5957
5958 // Get path to libjvm.so
5959 os::jvm_path(buf, sizeof(buf));
5960
5961 // Get rid of libjvm.so
5962 p = strrchr(buf, '/');
5963 if (p == NULL) return false;
5964 else *p = '\0';
5965
5966 // Get rid of client or server
5967 p = strrchr(buf, '/');
5968 if (p == NULL) return false;
5969 else *p = '\0';
5970
5971 // check xawt/libmawt.so
5972 strcpy(libmawtpath, buf);
5973 strcat(libmawtpath, xawtstr);
5974 if (::stat(libmawtpath, &statbuf) == 0) return false;
5975
5976 // check libawt_xawt.so
5977 strcpy(libmawtpath, buf);
5978 strcat(libmawtpath, new_xawtstr);
5979 if (::stat(libmawtpath, &statbuf) == 0) return false;
5980
5981 return true;
5982 }
5983
5984 // Get the default path to the core file
5985 // Returns the length of the string
5986 int os::get_core_path(char* buffer, size_t bufferSize) {
5987 const char* p = get_current_directory(buffer, bufferSize);
5988
5989 if (p == NULL) {
5990 assert(p != NULL, "failed to get current directory");
5991 return 0;
5992 }
5993
5994 return strlen(buffer);
5995 }
5996
5997 #ifdef JAVASE_EMBEDDED
5998 //
5999 // A thread to watch the '/dev/mem_notify' device, which will tell us when the OS is running low on memory.
6000 //
6001 MemNotifyThread* MemNotifyThread::_memnotify_thread = NULL;
6002
6003 // ctor
6004 //
6005 MemNotifyThread::MemNotifyThread(int fd): Thread() {
6006 assert(memnotify_thread() == NULL, "we can only allocate one MemNotifyThread");
6007 _fd = fd;
6008
6009 if (os::create_thread(this, os::os_thread)) {
6010 _memnotify_thread = this;
6011 os::set_priority(this, NearMaxPriority);
6012 os::start_thread(this);
6013 }
6014 }
6015
6016 // Where all the work gets done
6017 //
6018 void MemNotifyThread::run() {
6019 assert(this == memnotify_thread(), "expected the singleton MemNotifyThread");
6020
6021 // Set up the select arguments
6022 fd_set rfds;
6023 if (_fd != -1) {
6024 FD_ZERO(&rfds);
6025 FD_SET(_fd, &rfds);
6026 }
6027
6028 // Now wait for the mem_notify device to wake up
6029 while (1) {
6030 // Wait for the mem_notify device to signal us..
6031 int rc = select(_fd+1, _fd != -1 ? &rfds : NULL, NULL, NULL, NULL);
6032 if (rc == -1) {
6033 perror("select!\n");
6034 break;
6035 } else if (rc) {
6036 //ssize_t free_before = os::available_memory();
6037 //tty->print ("Notified: Free: %dK \n",os::available_memory()/1024);
6038
6039 // The kernel is telling us there is not much memory left...
6040 // try to do something about that
6041
6042 // If we are not already in a GC, try one.
6043 if (!Universe::heap()->is_gc_active()) {
6044 Universe::heap()->collect(GCCause::_allocation_failure);
6045
6046 //ssize_t free_after = os::available_memory();
6047 //tty->print ("Post-Notify: Free: %dK\n",free_after/1024);
6048 //tty->print ("GC freed: %dK\n", (free_after - free_before)/1024);
6049 }
6050 // We might want to do something like the following if we find the GC's are not helping...
6051 // Universe::heap()->size_policy()->set_gc_time_limit_exceeded(true);
6052 }
6053 }
6054 }
6055
6056 //
6057 // See if the /dev/mem_notify device exists, and if so, start a thread to monitor it.
6058 //
6059 void MemNotifyThread::start() {
6060 int fd;
6061 fd = open ("/dev/mem_notify", O_RDONLY, 0);
6062 if (fd < 0) {
6063 return;
6064 }
6065
6066 if (memnotify_thread() == NULL) {
6067 new MemNotifyThread(fd);
6068 }
6069 }
6070
6071 #endif // JAVASE_EMBEDDED
6072
6073
6074 /////////////// Unit tests ///////////////
6075
6076 #ifndef PRODUCT
6077
6078 #define test_log(...) \
6079 do {\
6080 if (VerboseInternalVMTests) { \
6081 tty->print_cr(__VA_ARGS__); \
6082 tty->flush(); \
6083 }\
6084 } while (false)
6085
6086 class TestReserveMemorySpecial : AllStatic {
6087 public:
6088 static void small_page_write(void* addr, size_t size) {
6089 size_t page_size = os::vm_page_size();
6090
6091 char* end = (char*)addr + size;
6092 for (char* p = (char*)addr; p < end; p += page_size) {
6093 *p = 1;
6094 }
6095 }
6096
6097 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) {
6098 if (!UseHugeTLBFS) {
6099 return;
6100 }
6101
6102 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size);
6103
6104 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false);
6105
6106 if (addr != NULL) {
6107 small_page_write(addr, size);
6108
6109 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6110 }
6111 }
6112
6113 static void test_reserve_memory_special_huge_tlbfs_only() {
6114 if (!UseHugeTLBFS) {
6115 return;
6116 }
6117
6118 size_t lp = os::large_page_size();
6119
6120 for (size_t size = lp; size <= lp * 10; size += lp) {
6121 test_reserve_memory_special_huge_tlbfs_only(size);
6122 }
6123 }
6124
6125 static void test_reserve_memory_special_huge_tlbfs_mixed(size_t size, size_t alignment) {
6126 if (!UseHugeTLBFS) {
6127 return;
6128 }
6129
6130 test_log("test_reserve_memory_special_huge_tlbfs_mixed(" SIZE_FORMAT ", " SIZE_FORMAT ")",
6131 size, alignment);
6132
6133 assert(size >= os::large_page_size(), "Incorrect input to test");
6134
6135 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false);
6136
6137 if (addr != NULL) {
6138 small_page_write(addr, size);
6139
6140 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6141 }
6142 }
6143
6144 static void test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(size_t size) {
6145 size_t lp = os::large_page_size();
6146 size_t ag = os::vm_allocation_granularity();
6147
6148 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6149 test_reserve_memory_special_huge_tlbfs_mixed(size, alignment);
6150 }
6151 }
6152
6153 static void test_reserve_memory_special_huge_tlbfs_mixed() {
6154 size_t lp = os::large_page_size();
6155 size_t ag = os::vm_allocation_granularity();
6156
6157 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp);
6158 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp + ag);
6159 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp + lp / 2);
6160 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2);
6161 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 + ag);
6162 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 - ag);
6163 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 + lp / 2);
6164 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 10);
6165 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 10 + lp / 2);
6166 }
6167
6168 static void test_reserve_memory_special_huge_tlbfs() {
6169 if (!UseHugeTLBFS) {
6170 return;
6171 }
6172
6173 test_reserve_memory_special_huge_tlbfs_only();
6174 test_reserve_memory_special_huge_tlbfs_mixed();
6175 }
6176
6177 static void test_reserve_memory_special_shm(size_t size, size_t alignment) {
6178 if (!UseSHM) {
6179 return;
6180 }
6181
6182 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment);
6183
6184 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false);
6185
6186 if (addr != NULL) {
6187 assert(is_ptr_aligned(addr, alignment), "Check");
6188 assert(is_ptr_aligned(addr, os::large_page_size()), "Check");
6189
6190 small_page_write(addr, size);
6191
6192 os::Linux::release_memory_special_shm(addr, size);
6193 }
6194 }
6195
6196 static void test_reserve_memory_special_shm() {
6197 size_t lp = os::large_page_size();
6198 size_t ag = os::vm_allocation_granularity();
6199
6200 for (size_t size = ag; size < lp * 3; size += ag) {
6201 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6202 test_reserve_memory_special_shm(size, alignment);
6203 }
6204 }
6205 }
6206
6207 static void test() {
6208 test_reserve_memory_special_huge_tlbfs();
6209 test_reserve_memory_special_shm();
6210 }
6211 };
6212
6213 void TestReserveMemorySpecial_test() {
6214 TestReserveMemorySpecial::test();
6215 }
6216
6217 #endif