1 /*
2 * Copyright (c) 1999, 2020, 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 "jvm.h"
27 #include "classfile/classLoader.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/icBuffer.hpp"
31 #include "code/vtableStubs.hpp"
32 #include "compiler/compileBroker.hpp"
33 #include "compiler/disassembler.hpp"
34 #include "interpreter/interpreter.hpp"
35 #include "logging/log.hpp"
36 #include "logging/logStream.hpp"
37 #include "memory/allocation.inline.hpp"
38 #include "memory/filemap.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "os_linux.inline.hpp"
41 #include "os_posix.inline.hpp"
42 #include "os_share_linux.hpp"
43 #include "osContainer_linux.hpp"
44 #include "prims/jniFastGetField.hpp"
45 #include "prims/jvm_misc.hpp"
46 #include "runtime/arguments.hpp"
47 #include "runtime/atomic.hpp"
48 #include "runtime/extendedPC.hpp"
49 #include "runtime/globals.hpp"
50 #include "runtime/interfaceSupport.inline.hpp"
51 #include "runtime/init.hpp"
52 #include "runtime/java.hpp"
53 #include "runtime/javaCalls.hpp"
54 #include "runtime/mutexLocker.hpp"
55 #include "runtime/objectMonitor.hpp"
56 #include "runtime/osThread.hpp"
57 #include "runtime/perfMemory.hpp"
58 #include "runtime/sharedRuntime.hpp"
59 #include "runtime/statSampler.hpp"
60 #include "runtime/stubRoutines.hpp"
61 #include "runtime/thread.inline.hpp"
62 #include "runtime/threadCritical.hpp"
63 #include "runtime/threadSMR.hpp"
64 #include "runtime/timer.hpp"
65 #include "runtime/vm_version.hpp"
66 #include "semaphore_posix.hpp"
67 #include "services/attachListener.hpp"
68 #include "services/memTracker.hpp"
69 #include "services/runtimeService.hpp"
70 #include "utilities/align.hpp"
71 #include "utilities/decoder.hpp"
72 #include "utilities/defaultStream.hpp"
73 #include "utilities/events.hpp"
74 #include "utilities/elfFile.hpp"
75 #include "utilities/growableArray.hpp"
76 #include "utilities/macros.hpp"
77 #include "utilities/powerOfTwo.hpp"
78 #include "utilities/vmError.hpp"
79
80 // put OS-includes here
81 # include <sys/types.h>
82 # include <sys/mman.h>
83 # include <sys/stat.h>
84 # include <sys/select.h>
85 # include <pthread.h>
86 # include <signal.h>
87 # include <endian.h>
88 # include <errno.h>
89 # include <dlfcn.h>
90 # include <stdio.h>
91 # include <unistd.h>
92 # include <sys/resource.h>
93 # include <pthread.h>
94 # include <sys/stat.h>
95 # include <sys/time.h>
96 # include <sys/times.h>
97 # include <sys/utsname.h>
98 # include <sys/socket.h>
99 # include <sys/wait.h>
100 # include <pwd.h>
101 # include <poll.h>
102 # include <fcntl.h>
103 # include <string.h>
104 # include <syscall.h>
105 # include <sys/sysinfo.h>
106 # include <gnu/libc-version.h>
107 # include <sys/ipc.h>
108 # include <sys/shm.h>
109 # include <link.h>
110 # include <stdint.h>
111 # include <inttypes.h>
112 # include <sys/ioctl.h>
113
114 #ifndef _GNU_SOURCE
115 #define _GNU_SOURCE
116 #include <sched.h>
117 #undef _GNU_SOURCE
118 #else
119 #include <sched.h>
120 #endif
121
122 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling
123 // getrusage() is prepared to handle the associated failure.
124 #ifndef RUSAGE_THREAD
125 #define RUSAGE_THREAD (1) /* only the calling thread */
126 #endif
127
128 #define MAX_PATH (2 * K)
129
130 #define MAX_SECS 100000000
131
132 // for timer info max values which include all bits
133 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
134
135 enum CoredumpFilterBit {
136 FILE_BACKED_PVT_BIT = 1 << 2,
137 FILE_BACKED_SHARED_BIT = 1 << 3,
138 LARGEPAGES_BIT = 1 << 6,
139 DAX_SHARED_BIT = 1 << 8
140 };
141
142 ////////////////////////////////////////////////////////////////////////////////
143 // global variables
144 julong os::Linux::_physical_memory = 0;
145
146 address os::Linux::_initial_thread_stack_bottom = NULL;
147 uintptr_t os::Linux::_initial_thread_stack_size = 0;
148
149 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
150 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL;
151 pthread_t os::Linux::_main_thread;
152 int os::Linux::_page_size = -1;
153 bool os::Linux::_supports_fast_thread_cpu_time = false;
154 const char * os::Linux::_glibc_version = NULL;
155 const char * os::Linux::_libpthread_version = NULL;
156
157 static jlong initial_time_count=0;
158
159 static int clock_tics_per_sec = 100;
160
161 // If the VM might have been created on the primordial thread, we need to resolve the
162 // primordial thread stack bounds and check if the current thread might be the
163 // primordial thread in places. If we know that the primordial thread is never used,
164 // such as when the VM was created by one of the standard java launchers, we can
165 // avoid this
166 static bool suppress_primordial_thread_resolution = false;
167
168 // For diagnostics to print a message once. see run_periodic_checks
169 static sigset_t check_signal_done;
170 static bool check_signals = true;
171
172 // Signal number used to suspend/resume a thread
173
174 // do not use any signal number less than SIGSEGV, see 4355769
175 static int SR_signum = SIGUSR2;
176 sigset_t SR_sigset;
177
178 // utility functions
179
180 static int SR_initialize();
181
182 julong os::available_memory() {
183 return Linux::available_memory();
184 }
185
186 julong os::Linux::available_memory() {
187 // values in struct sysinfo are "unsigned long"
188 struct sysinfo si;
189 julong avail_mem;
190
191 if (OSContainer::is_containerized()) {
192 jlong mem_limit, mem_usage;
193 if ((mem_limit = OSContainer::memory_limit_in_bytes()) < 1) {
194 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value",
195 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit);
196 }
197 if (mem_limit > 0 && (mem_usage = OSContainer::memory_usage_in_bytes()) < 1) {
198 log_debug(os, container)("container memory usage failed: " JLONG_FORMAT ", using host value", mem_usage);
199 }
200 if (mem_limit > 0 && mem_usage > 0 ) {
201 avail_mem = mem_limit > mem_usage ? (julong)mem_limit - (julong)mem_usage : 0;
202 log_trace(os)("available container memory: " JULONG_FORMAT, avail_mem);
203 return avail_mem;
204 }
205 }
206
207 sysinfo(&si);
208 avail_mem = (julong)si.freeram * si.mem_unit;
209 log_trace(os)("available memory: " JULONG_FORMAT, avail_mem);
210 return avail_mem;
211 }
212
213 julong os::physical_memory() {
214 jlong phys_mem = 0;
215 if (OSContainer::is_containerized()) {
216 jlong mem_limit;
217 if ((mem_limit = OSContainer::memory_limit_in_bytes()) > 0) {
218 log_trace(os)("total container memory: " JLONG_FORMAT, mem_limit);
219 return mem_limit;
220 }
221 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value",
222 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit);
223 }
224
225 phys_mem = Linux::physical_memory();
226 log_trace(os)("total system memory: " JLONG_FORMAT, phys_mem);
227 return phys_mem;
228 }
229
230 static uint64_t initial_total_ticks = 0;
231 static uint64_t initial_steal_ticks = 0;
232 static bool has_initial_tick_info = false;
233
234 static void next_line(FILE *f) {
235 int c;
236 do {
237 c = fgetc(f);
238 } while (c != '\n' && c != EOF);
239 }
240
241 bool os::Linux::get_tick_information(CPUPerfTicks* pticks, int which_logical_cpu) {
242 FILE* fh;
243 uint64_t userTicks, niceTicks, systemTicks, idleTicks;
244 // since at least kernel 2.6 : iowait: time waiting for I/O to complete
245 // irq: time servicing interrupts; softirq: time servicing softirqs
246 uint64_t iowTicks = 0, irqTicks = 0, sirqTicks= 0;
247 // steal (since kernel 2.6.11): time spent in other OS when running in a virtualized environment
248 uint64_t stealTicks = 0;
249 // guest (since kernel 2.6.24): time spent running a virtual CPU for guest OS under the
250 // control of the Linux kernel
251 uint64_t guestNiceTicks = 0;
252 int logical_cpu = -1;
253 const int required_tickinfo_count = (which_logical_cpu == -1) ? 4 : 5;
254 int n;
255
256 memset(pticks, 0, sizeof(CPUPerfTicks));
257
258 if ((fh = fopen("/proc/stat", "r")) == NULL) {
259 return false;
260 }
261
262 if (which_logical_cpu == -1) {
263 n = fscanf(fh, "cpu " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
264 UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
265 UINT64_FORMAT " " UINT64_FORMAT " ",
266 &userTicks, &niceTicks, &systemTicks, &idleTicks,
267 &iowTicks, &irqTicks, &sirqTicks,
268 &stealTicks, &guestNiceTicks);
269 } else {
270 // Move to next line
271 next_line(fh);
272
273 // find the line for requested cpu faster to just iterate linefeeds?
274 for (int i = 0; i < which_logical_cpu; i++) {
275 next_line(fh);
276 }
277
278 n = fscanf(fh, "cpu%u " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
279 UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
280 UINT64_FORMAT " " UINT64_FORMAT " ",
281 &logical_cpu, &userTicks, &niceTicks,
282 &systemTicks, &idleTicks, &iowTicks, &irqTicks, &sirqTicks,
283 &stealTicks, &guestNiceTicks);
284 }
285
286 fclose(fh);
287 if (n < required_tickinfo_count || logical_cpu != which_logical_cpu) {
288 return false;
289 }
290 pticks->used = userTicks + niceTicks;
291 pticks->usedKernel = systemTicks + irqTicks + sirqTicks;
292 pticks->total = userTicks + niceTicks + systemTicks + idleTicks +
293 iowTicks + irqTicks + sirqTicks + stealTicks + guestNiceTicks;
294
295 if (n > required_tickinfo_count + 3) {
296 pticks->steal = stealTicks;
297 pticks->has_steal_ticks = true;
298 } else {
299 pticks->steal = 0;
300 pticks->has_steal_ticks = false;
301 }
302
303 return true;
304 }
305
306 // Return true if user is running as root.
307
308 bool os::have_special_privileges() {
309 static bool init = false;
310 static bool privileges = false;
311 if (!init) {
312 privileges = (getuid() != geteuid()) || (getgid() != getegid());
313 init = true;
314 }
315 return privileges;
316 }
317
318
319 #ifndef SYS_gettid
320 // i386: 224, ia64: 1105, amd64: 186, sparc 143
321 #ifdef __ia64__
322 #define SYS_gettid 1105
323 #else
324 #ifdef __i386__
325 #define SYS_gettid 224
326 #else
327 #ifdef __amd64__
328 #define SYS_gettid 186
329 #else
330 #ifdef __sparc__
331 #define SYS_gettid 143
332 #else
333 #error define gettid for the arch
334 #endif
335 #endif
336 #endif
337 #endif
338 #endif
339
340
341 // pid_t gettid()
342 //
343 // Returns the kernel thread id of the currently running thread. Kernel
344 // thread id is used to access /proc.
345 pid_t os::Linux::gettid() {
346 int rslt = syscall(SYS_gettid);
347 assert(rslt != -1, "must be."); // old linuxthreads implementation?
348 return (pid_t)rslt;
349 }
350
351 // Most versions of linux have a bug where the number of processors are
352 // determined by looking at the /proc file system. In a chroot environment,
353 // the system call returns 1.
354 static bool unsafe_chroot_detected = false;
355 static const char *unstable_chroot_error = "/proc file system not found.\n"
356 "Java may be unstable running multithreaded in a chroot "
357 "environment on Linux when /proc filesystem is not mounted.";
358
359 void os::Linux::initialize_system_info() {
360 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
361 if (processor_count() == 1) {
362 pid_t pid = os::Linux::gettid();
363 char fname[32];
364 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
365 FILE *fp = fopen(fname, "r");
366 if (fp == NULL) {
367 unsafe_chroot_detected = true;
368 } else {
369 fclose(fp);
370 }
371 }
372 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
373 assert(processor_count() > 0, "linux error");
374 }
375
376 void os::init_system_properties_values() {
377 // The next steps are taken in the product version:
378 //
379 // Obtain the JAVA_HOME value from the location of libjvm.so.
380 // This library should be located at:
381 // <JAVA_HOME>/lib/{client|server}/libjvm.so.
382 //
383 // If "/jre/lib/" appears at the right place in the path, then we
384 // assume libjvm.so is installed in a JDK and we use this path.
385 //
386 // Otherwise exit with message: "Could not create the Java virtual machine."
387 //
388 // The following extra steps are taken in the debugging version:
389 //
390 // If "/jre/lib/" does NOT appear at the right place in the path
391 // instead of exit check for $JAVA_HOME environment variable.
392 //
393 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
394 // then we append a fake suffix "hotspot/libjvm.so" to this path so
395 // it looks like libjvm.so is installed there
396 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
397 //
398 // Otherwise exit.
399 //
400 // Important note: if the location of libjvm.so changes this
401 // code needs to be changed accordingly.
402
403 // See ld(1):
404 // The linker uses the following search paths to locate required
405 // shared libraries:
406 // 1: ...
407 // ...
408 // 7: The default directories, normally /lib and /usr/lib.
409 #ifndef OVERRIDE_LIBPATH
410 #if defined(AMD64) || (defined(_LP64) && defined(SPARC)) || defined(PPC64) || defined(S390)
411 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
412 #else
413 #define DEFAULT_LIBPATH "/lib:/usr/lib"
414 #endif
415 #else
416 #define DEFAULT_LIBPATH OVERRIDE_LIBPATH
417 #endif
418
419 // Base path of extensions installed on the system.
420 #define SYS_EXT_DIR "/usr/java/packages"
421 #define EXTENSIONS_DIR "/lib/ext"
422
423 // Buffer that fits several sprintfs.
424 // Note that the space for the colon and the trailing null are provided
425 // by the nulls included by the sizeof operator.
426 const size_t bufsize =
427 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends.
428 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir
429 char *buf = NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
430
431 // sysclasspath, java_home, dll_dir
432 {
433 char *pslash;
434 os::jvm_path(buf, bufsize);
435
436 // Found the full path to libjvm.so.
437 // Now cut the path to <java_home>/jre if we can.
438 pslash = strrchr(buf, '/');
439 if (pslash != NULL) {
440 *pslash = '\0'; // Get rid of /libjvm.so.
441 }
442 pslash = strrchr(buf, '/');
443 if (pslash != NULL) {
444 *pslash = '\0'; // Get rid of /{client|server|hotspot}.
445 }
446 Arguments::set_dll_dir(buf);
447
448 if (pslash != NULL) {
449 pslash = strrchr(buf, '/');
450 if (pslash != NULL) {
451 *pslash = '\0'; // Get rid of /lib.
452 }
453 }
454 Arguments::set_java_home(buf);
455 if (!set_boot_path('/', ':')) {
456 vm_exit_during_initialization("Failed setting boot class path.", NULL);
457 }
458 }
459
460 // Where to look for native libraries.
461 //
462 // Note: Due to a legacy implementation, most of the library path
463 // is set in the launcher. This was to accomodate linking restrictions
464 // on legacy Linux implementations (which are no longer supported).
465 // Eventually, all the library path setting will be done here.
466 //
467 // However, to prevent the proliferation of improperly built native
468 // libraries, the new path component /usr/java/packages is added here.
469 // Eventually, all the library path setting will be done here.
470 {
471 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
472 // should always exist (until the legacy problem cited above is
473 // addressed).
474 const char *v = ::getenv("LD_LIBRARY_PATH");
475 const char *v_colon = ":";
476 if (v == NULL) { v = ""; v_colon = ""; }
477 // That's +1 for the colon and +1 for the trailing '\0'.
478 char *ld_library_path = NEW_C_HEAP_ARRAY(char,
479 strlen(v) + 1 +
480 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1,
481 mtInternal);
482 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon);
483 Arguments::set_library_path(ld_library_path);
484 FREE_C_HEAP_ARRAY(char, ld_library_path);
485 }
486
487 // Extensions directories.
488 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home());
489 Arguments::set_ext_dirs(buf);
490
491 FREE_C_HEAP_ARRAY(char, buf);
492
493 #undef DEFAULT_LIBPATH
494 #undef SYS_EXT_DIR
495 #undef EXTENSIONS_DIR
496 }
497
498 ////////////////////////////////////////////////////////////////////////////////
499 // breakpoint support
500
501 void os::breakpoint() {
502 BREAKPOINT;
503 }
504
505 extern "C" void breakpoint() {
506 // use debugger to set breakpoint here
507 }
508
509 ////////////////////////////////////////////////////////////////////////////////
510 // signal support
511
512 debug_only(static bool signal_sets_initialized = false);
513 static sigset_t unblocked_sigs, vm_sigs;
514
515 void os::Linux::signal_sets_init() {
516 // Should also have an assertion stating we are still single-threaded.
517 assert(!signal_sets_initialized, "Already initialized");
518 // Fill in signals that are necessarily unblocked for all threads in
519 // the VM. Currently, we unblock the following signals:
520 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
521 // by -Xrs (=ReduceSignalUsage));
522 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
523 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
524 // the dispositions or masks wrt these signals.
525 // Programs embedding the VM that want to use the above signals for their
526 // own purposes must, at this time, use the "-Xrs" option to prevent
527 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
528 // (See bug 4345157, and other related bugs).
529 // In reality, though, unblocking these signals is really a nop, since
530 // these signals are not blocked by default.
531 sigemptyset(&unblocked_sigs);
532 sigaddset(&unblocked_sigs, SIGILL);
533 sigaddset(&unblocked_sigs, SIGSEGV);
534 sigaddset(&unblocked_sigs, SIGBUS);
535 sigaddset(&unblocked_sigs, SIGFPE);
536 #if defined(PPC64)
537 sigaddset(&unblocked_sigs, SIGTRAP);
538 #endif
539 sigaddset(&unblocked_sigs, SR_signum);
540
541 if (!ReduceSignalUsage) {
542 if (!os::Posix::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
543 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
544 }
545 if (!os::Posix::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
546 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
547 }
548 if (!os::Posix::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
549 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
550 }
551 }
552 // Fill in signals that are blocked by all but the VM thread.
553 sigemptyset(&vm_sigs);
554 if (!ReduceSignalUsage) {
555 sigaddset(&vm_sigs, BREAK_SIGNAL);
556 }
557 debug_only(signal_sets_initialized = true);
558
559 }
560
561 // These are signals that are unblocked while a thread is running Java.
562 // (For some reason, they get blocked by default.)
563 sigset_t* os::Linux::unblocked_signals() {
564 assert(signal_sets_initialized, "Not initialized");
565 return &unblocked_sigs;
566 }
567
568 // These are the signals that are blocked while a (non-VM) thread is
569 // running Java. Only the VM thread handles these signals.
570 sigset_t* os::Linux::vm_signals() {
571 assert(signal_sets_initialized, "Not initialized");
572 return &vm_sigs;
573 }
574
575 void os::Linux::hotspot_sigmask(Thread* thread) {
576
577 //Save caller's signal mask before setting VM signal mask
578 sigset_t caller_sigmask;
579 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
580
581 OSThread* osthread = thread->osthread();
582 osthread->set_caller_sigmask(caller_sigmask);
583
584 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
585
586 if (!ReduceSignalUsage) {
587 if (thread->is_VM_thread()) {
588 // Only the VM thread handles BREAK_SIGNAL ...
589 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
590 } else {
591 // ... all other threads block BREAK_SIGNAL
592 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
593 }
594 }
595 }
596
597 //////////////////////////////////////////////////////////////////////////////
598 // detecting pthread library
599
600 void os::Linux::libpthread_init() {
601 // Save glibc and pthread version strings.
602 #if !defined(_CS_GNU_LIBC_VERSION) || \
603 !defined(_CS_GNU_LIBPTHREAD_VERSION)
604 #error "glibc too old (< 2.3.2)"
605 #endif
606
607 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
608 assert(n > 0, "cannot retrieve glibc version");
609 char *str = (char *)malloc(n, mtInternal);
610 confstr(_CS_GNU_LIBC_VERSION, str, n);
611 os::Linux::set_glibc_version(str);
612
613 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
614 assert(n > 0, "cannot retrieve pthread version");
615 str = (char *)malloc(n, mtInternal);
616 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
617 os::Linux::set_libpthread_version(str);
618 }
619
620 /////////////////////////////////////////////////////////////////////////////
621 // thread stack expansion
622
623 // os::Linux::manually_expand_stack() takes care of expanding the thread
624 // stack. Note that this is normally not needed: pthread stacks allocate
625 // thread stack using mmap() without MAP_NORESERVE, so the stack is already
626 // committed. Therefore it is not necessary to expand the stack manually.
627 //
628 // Manually expanding the stack was historically needed on LinuxThreads
629 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays
630 // it is kept to deal with very rare corner cases:
631 //
632 // For one, user may run the VM on an own implementation of threads
633 // whose stacks are - like the old LinuxThreads - implemented using
634 // mmap(MAP_GROWSDOWN).
635 //
636 // Also, this coding may be needed if the VM is running on the primordial
637 // thread. Normally we avoid running on the primordial thread; however,
638 // user may still invoke the VM on the primordial thread.
639 //
640 // The following historical comment describes the details about running
641 // on a thread stack allocated with mmap(MAP_GROWSDOWN):
642
643
644 // Force Linux kernel to expand current thread stack. If "bottom" is close
645 // to the stack guard, caller should block all signals.
646 //
647 // MAP_GROWSDOWN:
648 // A special mmap() flag that is used to implement thread stacks. It tells
649 // kernel that the memory region should extend downwards when needed. This
650 // allows early versions of LinuxThreads to only mmap the first few pages
651 // when creating a new thread. Linux kernel will automatically expand thread
652 // stack as needed (on page faults).
653 //
654 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
655 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
656 // region, it's hard to tell if the fault is due to a legitimate stack
657 // access or because of reading/writing non-exist memory (e.g. buffer
658 // overrun). As a rule, if the fault happens below current stack pointer,
659 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
660 // application (see Linux kernel fault.c).
661 //
662 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
663 // stack overflow detection.
664 //
665 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
666 // not use MAP_GROWSDOWN.
667 //
668 // To get around the problem and allow stack banging on Linux, we need to
669 // manually expand thread stack after receiving the SIGSEGV.
670 //
671 // There are two ways to expand thread stack to address "bottom", we used
672 // both of them in JVM before 1.5:
673 // 1. adjust stack pointer first so that it is below "bottom", and then
674 // touch "bottom"
675 // 2. mmap() the page in question
676 //
677 // Now alternate signal stack is gone, it's harder to use 2. For instance,
678 // if current sp is already near the lower end of page 101, and we need to
679 // call mmap() to map page 100, it is possible that part of the mmap() frame
680 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
681 // That will destroy the mmap() frame and cause VM to crash.
682 //
683 // The following code works by adjusting sp first, then accessing the "bottom"
684 // page to force a page fault. Linux kernel will then automatically expand the
685 // stack mapping.
686 //
687 // _expand_stack_to() assumes its frame size is less than page size, which
688 // should always be true if the function is not inlined.
689
690 static void NOINLINE _expand_stack_to(address bottom) {
691 address sp;
692 size_t size;
693 volatile char *p;
694
695 // Adjust bottom to point to the largest address within the same page, it
696 // gives us a one-page buffer if alloca() allocates slightly more memory.
697 bottom = (address)align_down((uintptr_t)bottom, os::Linux::page_size());
698 bottom += os::Linux::page_size() - 1;
699
700 // sp might be slightly above current stack pointer; if that's the case, we
701 // will alloca() a little more space than necessary, which is OK. Don't use
702 // os::current_stack_pointer(), as its result can be slightly below current
703 // stack pointer, causing us to not alloca enough to reach "bottom".
704 sp = (address)&sp;
705
706 if (sp > bottom) {
707 size = sp - bottom;
708 p = (volatile char *)alloca(size);
709 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
710 p[0] = '\0';
711 }
712 }
713
714 void os::Linux::expand_stack_to(address bottom) {
715 _expand_stack_to(bottom);
716 }
717
718 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
719 assert(t!=NULL, "just checking");
720 assert(t->osthread()->expanding_stack(), "expand should be set");
721 assert(t->stack_base() != NULL, "stack_base was not initialized");
722
723 if (t->is_in_usable_stack(addr)) {
724 sigset_t mask_all, old_sigset;
725 sigfillset(&mask_all);
726 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
727 _expand_stack_to(addr);
728 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
729 return true;
730 }
731 return false;
732 }
733
734 //////////////////////////////////////////////////////////////////////////////
735 // create new thread
736
737 // Thread start routine for all newly created threads
738 static void *thread_native_entry(Thread *thread) {
739
740 thread->record_stack_base_and_size();
741
742 // Try to randomize the cache line index of hot stack frames.
743 // This helps when threads of the same stack traces evict each other's
744 // cache lines. The threads can be either from the same JVM instance, or
745 // from different JVM instances. The benefit is especially true for
746 // processors with hyperthreading technology.
747 static int counter = 0;
748 int pid = os::current_process_id();
749 alloca(((pid ^ counter++) & 7) * 128);
750
751 thread->initialize_thread_current();
752
753 OSThread* osthread = thread->osthread();
754 Monitor* sync = osthread->startThread_lock();
755
756 osthread->set_thread_id(os::current_thread_id());
757
758 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
759 os::current_thread_id(), (uintx) pthread_self());
760
761 if (UseNUMA) {
762 int lgrp_id = os::numa_get_group_id();
763 if (lgrp_id != -1) {
764 thread->set_lgrp_id(lgrp_id);
765 }
766 }
767 // initialize signal mask for this thread
768 os::Linux::hotspot_sigmask(thread);
769
770 // initialize floating point control register
771 os::Linux::init_thread_fpu_state();
772
773 // handshaking with parent thread
774 {
775 MutexLocker ml(sync, Mutex::_no_safepoint_check_flag);
776
777 // notify parent thread
778 osthread->set_state(INITIALIZED);
779 sync->notify_all();
780
781 // wait until os::start_thread()
782 while (osthread->get_state() == INITIALIZED) {
783 sync->wait_without_safepoint_check();
784 }
785 }
786
787 assert(osthread->pthread_id() != 0, "pthread_id was not set as expected");
788
789 // call one more level start routine
790 thread->call_run();
791
792 // Note: at this point the thread object may already have deleted itself.
793 // Prevent dereferencing it from here on out.
794 thread = NULL;
795
796 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
797 os::current_thread_id(), (uintx) pthread_self());
798
799 return 0;
800 }
801
802 // On Linux, glibc places static TLS blocks (for __thread variables) on
803 // the thread stack. This decreases the stack size actually available
804 // to threads.
805 //
806 // For large static TLS sizes, this may cause threads to malfunction due
807 // to insufficient stack space. This is a well-known issue in glibc:
808 // http://sourceware.org/bugzilla/show_bug.cgi?id=11787.
809 //
810 // As a workaround, we call a private but assumed-stable glibc function,
811 // __pthread_get_minstack() to obtain the minstack size and derive the
812 // static TLS size from it. We then increase the user requested stack
813 // size by this TLS size.
814 //
815 // Due to compatibility concerns, this size adjustment is opt-in and
816 // controlled via AdjustStackSizeForTLS.
817 typedef size_t (*GetMinStack)(const pthread_attr_t *attr);
818
819 GetMinStack _get_minstack_func = NULL;
820
821 static void get_minstack_init() {
822 _get_minstack_func =
823 (GetMinStack)dlsym(RTLD_DEFAULT, "__pthread_get_minstack");
824 log_info(os, thread)("Lookup of __pthread_get_minstack %s",
825 _get_minstack_func == NULL ? "failed" : "succeeded");
826 }
827
828 // Returns the size of the static TLS area glibc puts on thread stacks.
829 // The value is cached on first use, which occurs when the first thread
830 // is created during VM initialization.
831 static size_t get_static_tls_area_size(const pthread_attr_t *attr) {
832 size_t tls_size = 0;
833 if (_get_minstack_func != NULL) {
834 // Obtain the pthread minstack size by calling __pthread_get_minstack.
835 size_t minstack_size = _get_minstack_func(attr);
836
837 // Remove non-TLS area size included in minstack size returned
838 // by __pthread_get_minstack() to get the static TLS size.
839 // In glibc before 2.27, minstack size includes guard_size.
840 // In glibc 2.27 and later, guard_size is automatically added
841 // to the stack size by pthread_create and is no longer included
842 // in minstack size. In both cases, the guard_size is taken into
843 // account, so there is no need to adjust the result for that.
844 //
845 // Although __pthread_get_minstack() is a private glibc function,
846 // it is expected to have a stable behavior across future glibc
847 // versions while glibc still allocates the static TLS blocks off
848 // the stack. Following is glibc 2.28 __pthread_get_minstack():
849 //
850 // size_t
851 // __pthread_get_minstack (const pthread_attr_t *attr)
852 // {
853 // return GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN;
854 // }
855 //
856 //
857 // The following 'minstack_size > os::vm_page_size() + PTHREAD_STACK_MIN'
858 // if check is done for precaution.
859 if (minstack_size > (size_t)os::vm_page_size() + PTHREAD_STACK_MIN) {
860 tls_size = minstack_size - os::vm_page_size() - PTHREAD_STACK_MIN;
861 }
862 }
863
864 log_info(os, thread)("Stack size adjustment for TLS is " SIZE_FORMAT,
865 tls_size);
866 return tls_size;
867 }
868
869 bool os::create_thread(Thread* thread, ThreadType thr_type,
870 size_t req_stack_size) {
871 assert(thread->osthread() == NULL, "caller responsible");
872
873 // Allocate the OSThread object
874 OSThread* osthread = new OSThread(NULL, NULL);
875 if (osthread == NULL) {
876 return false;
877 }
878
879 // set the correct thread state
880 osthread->set_thread_type(thr_type);
881
882 // Initial state is ALLOCATED but not INITIALIZED
883 osthread->set_state(ALLOCATED);
884
885 thread->set_osthread(osthread);
886
887 // init thread attributes
888 pthread_attr_t attr;
889 pthread_attr_init(&attr);
890 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
891
892 // Calculate stack size if it's not specified by caller.
893 size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size);
894 // In glibc versions prior to 2.7 the guard size mechanism
895 // is not implemented properly. The posix standard requires adding
896 // the size of the guard pages to the stack size, instead Linux
897 // takes the space out of 'stacksize'. Thus we adapt the requested
898 // stack_size by the size of the guard pages to mimick proper
899 // behaviour. However, be careful not to end up with a size
900 // of zero due to overflow. Don't add the guard page in that case.
901 size_t guard_size = os::Linux::default_guard_size(thr_type);
902 // Configure glibc guard page. Must happen before calling
903 // get_static_tls_area_size(), which uses the guard_size.
904 pthread_attr_setguardsize(&attr, guard_size);
905
906 size_t stack_adjust_size = 0;
907 if (AdjustStackSizeForTLS) {
908 // Adjust the stack_size for on-stack TLS - see get_static_tls_area_size().
909 stack_adjust_size += get_static_tls_area_size(&attr);
910 } else {
911 stack_adjust_size += guard_size;
912 }
913
914 stack_adjust_size = align_up(stack_adjust_size, os::vm_page_size());
915 if (stack_size <= SIZE_MAX - stack_adjust_size) {
916 stack_size += stack_adjust_size;
917 }
918 assert(is_aligned(stack_size, os::vm_page_size()), "stack_size not aligned");
919
920 int status = pthread_attr_setstacksize(&attr, stack_size);
921 assert_status(status == 0, status, "pthread_attr_setstacksize");
922
923 ThreadState state;
924
925 {
926 pthread_t tid;
927 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread);
928
929 char buf[64];
930 if (ret == 0) {
931 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ",
932 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
933 } else {
934 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.",
935 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
936 // Log some OS information which might explain why creating the thread failed.
937 log_info(os, thread)("Number of threads approx. running in the VM: %d", Threads::number_of_threads());
938 LogStream st(Log(os, thread)::info());
939 os::Posix::print_rlimit_info(&st);
940 os::print_memory_info(&st);
941 os::Linux::print_proc_sys_info(&st);
942 os::Linux::print_container_info(&st);
943 }
944
945 pthread_attr_destroy(&attr);
946
947 if (ret != 0) {
948 // Need to clean up stuff we've allocated so far
949 thread->set_osthread(NULL);
950 delete osthread;
951 return false;
952 }
953
954 // Store pthread info into the OSThread
955 osthread->set_pthread_id(tid);
956
957 // Wait until child thread is either initialized or aborted
958 {
959 Monitor* sync_with_child = osthread->startThread_lock();
960 MutexLocker ml(sync_with_child, Mutex::_no_safepoint_check_flag);
961 while ((state = osthread->get_state()) == ALLOCATED) {
962 sync_with_child->wait_without_safepoint_check();
963 }
964 }
965 }
966
967 // Aborted due to thread limit being reached
968 if (state == ZOMBIE) {
969 thread->set_osthread(NULL);
970 delete osthread;
971 return false;
972 }
973
974 // The thread is returned suspended (in state INITIALIZED),
975 // and is started higher up in the call chain
976 assert(state == INITIALIZED, "race condition");
977 return true;
978 }
979
980 /////////////////////////////////////////////////////////////////////////////
981 // attach existing thread
982
983 // bootstrap the main thread
984 bool os::create_main_thread(JavaThread* thread) {
985 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
986 return create_attached_thread(thread);
987 }
988
989 bool os::create_attached_thread(JavaThread* thread) {
990 #ifdef ASSERT
991 thread->verify_not_published();
992 #endif
993
994 // Allocate the OSThread object
995 OSThread* osthread = new OSThread(NULL, NULL);
996
997 if (osthread == NULL) {
998 return false;
999 }
1000
1001 // Store pthread info into the OSThread
1002 osthread->set_thread_id(os::Linux::gettid());
1003 osthread->set_pthread_id(::pthread_self());
1004
1005 // initialize floating point control register
1006 os::Linux::init_thread_fpu_state();
1007
1008 // Initial thread state is RUNNABLE
1009 osthread->set_state(RUNNABLE);
1010
1011 thread->set_osthread(osthread);
1012
1013 if (UseNUMA) {
1014 int lgrp_id = os::numa_get_group_id();
1015 if (lgrp_id != -1) {
1016 thread->set_lgrp_id(lgrp_id);
1017 }
1018 }
1019
1020 if (os::is_primordial_thread()) {
1021 // If current thread is primordial thread, its stack is mapped on demand,
1022 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
1023 // the entire stack region to avoid SEGV in stack banging.
1024 // It is also useful to get around the heap-stack-gap problem on SuSE
1025 // kernel (see 4821821 for details). We first expand stack to the top
1026 // of yellow zone, then enable stack yellow zone (order is significant,
1027 // enabling yellow zone first will crash JVM on SuSE Linux), so there
1028 // is no gap between the last two virtual memory regions.
1029
1030 JavaThread *jt = (JavaThread *)thread;
1031 address addr = jt->stack_reserved_zone_base();
1032 assert(addr != NULL, "initialization problem?");
1033 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
1034
1035 osthread->set_expanding_stack();
1036 os::Linux::manually_expand_stack(jt, addr);
1037 osthread->clear_expanding_stack();
1038 }
1039
1040 // initialize signal mask for this thread
1041 // and save the caller's signal mask
1042 os::Linux::hotspot_sigmask(thread);
1043
1044 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
1045 os::current_thread_id(), (uintx) pthread_self());
1046
1047 return true;
1048 }
1049
1050 void os::pd_start_thread(Thread* thread) {
1051 OSThread * osthread = thread->osthread();
1052 assert(osthread->get_state() != INITIALIZED, "just checking");
1053 Monitor* sync_with_child = osthread->startThread_lock();
1054 MutexLocker ml(sync_with_child, Mutex::_no_safepoint_check_flag);
1055 sync_with_child->notify();
1056 }
1057
1058 // Free Linux resources related to the OSThread
1059 void os::free_thread(OSThread* osthread) {
1060 assert(osthread != NULL, "osthread not set");
1061
1062 // We are told to free resources of the argument thread,
1063 // but we can only really operate on the current thread.
1064 assert(Thread::current()->osthread() == osthread,
1065 "os::free_thread but not current thread");
1066
1067 #ifdef ASSERT
1068 sigset_t current;
1069 sigemptyset(¤t);
1070 pthread_sigmask(SIG_SETMASK, NULL, ¤t);
1071 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!");
1072 #endif
1073
1074 // Restore caller's signal mask
1075 sigset_t sigmask = osthread->caller_sigmask();
1076 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1077
1078 delete osthread;
1079 }
1080
1081 //////////////////////////////////////////////////////////////////////////////
1082 // primordial thread
1083
1084 // Check if current thread is the primordial thread, similar to Solaris thr_main.
1085 bool os::is_primordial_thread(void) {
1086 if (suppress_primordial_thread_resolution) {
1087 return false;
1088 }
1089 char dummy;
1090 // If called before init complete, thread stack bottom will be null.
1091 // Can be called if fatal error occurs before initialization.
1092 if (os::Linux::initial_thread_stack_bottom() == NULL) return false;
1093 assert(os::Linux::initial_thread_stack_bottom() != NULL &&
1094 os::Linux::initial_thread_stack_size() != 0,
1095 "os::init did not locate primordial thread's stack region");
1096 if ((address)&dummy >= os::Linux::initial_thread_stack_bottom() &&
1097 (address)&dummy < os::Linux::initial_thread_stack_bottom() +
1098 os::Linux::initial_thread_stack_size()) {
1099 return true;
1100 } else {
1101 return false;
1102 }
1103 }
1104
1105 // Find the virtual memory area that contains addr
1106 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1107 FILE *fp = fopen("/proc/self/maps", "r");
1108 if (fp) {
1109 address low, high;
1110 while (!feof(fp)) {
1111 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1112 if (low <= addr && addr < high) {
1113 if (vma_low) *vma_low = low;
1114 if (vma_high) *vma_high = high;
1115 fclose(fp);
1116 return true;
1117 }
1118 }
1119 for (;;) {
1120 int ch = fgetc(fp);
1121 if (ch == EOF || ch == (int)'\n') break;
1122 }
1123 }
1124 fclose(fp);
1125 }
1126 return false;
1127 }
1128
1129 // Locate primordial thread stack. This special handling of primordial thread stack
1130 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1131 // bogus value for the primordial process thread. While the launcher has created
1132 // the VM in a new thread since JDK 6, we still have to allow for the use of the
1133 // JNI invocation API from a primordial thread.
1134 void os::Linux::capture_initial_stack(size_t max_size) {
1135
1136 // max_size is either 0 (which means accept OS default for thread stacks) or
1137 // a user-specified value known to be at least the minimum needed. If we
1138 // are actually on the primordial thread we can make it appear that we have a
1139 // smaller max_size stack by inserting the guard pages at that location. But we
1140 // cannot do anything to emulate a larger stack than what has been provided by
1141 // the OS or threading library. In fact if we try to use a stack greater than
1142 // what is set by rlimit then we will crash the hosting process.
1143
1144 // Maximum stack size is the easy part, get it from RLIMIT_STACK.
1145 // If this is "unlimited" then it will be a huge value.
1146 struct rlimit rlim;
1147 getrlimit(RLIMIT_STACK, &rlim);
1148 size_t stack_size = rlim.rlim_cur;
1149
1150 // 6308388: a bug in ld.so will relocate its own .data section to the
1151 // lower end of primordial stack; reduce ulimit -s value a little bit
1152 // so we won't install guard page on ld.so's data section.
1153 // But ensure we don't underflow the stack size - allow 1 page spare
1154 if (stack_size >= (size_t)(3 * page_size())) {
1155 stack_size -= 2 * page_size();
1156 }
1157
1158 // Try to figure out where the stack base (top) is. This is harder.
1159 //
1160 // When an application is started, glibc saves the initial stack pointer in
1161 // a global variable "__libc_stack_end", which is then used by system
1162 // libraries. __libc_stack_end should be pretty close to stack top. The
1163 // variable is available since the very early days. However, because it is
1164 // a private interface, it could disappear in the future.
1165 //
1166 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1167 // to __libc_stack_end, it is very close to stack top, but isn't the real
1168 // stack top. Note that /proc may not exist if VM is running as a chroot
1169 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1170 // /proc/<pid>/stat could change in the future (though unlikely).
1171 //
1172 // We try __libc_stack_end first. If that doesn't work, look for
1173 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1174 // as a hint, which should work well in most cases.
1175
1176 uintptr_t stack_start;
1177
1178 // try __libc_stack_end first
1179 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1180 if (p && *p) {
1181 stack_start = *p;
1182 } else {
1183 // see if we can get the start_stack field from /proc/self/stat
1184 FILE *fp;
1185 int pid;
1186 char state;
1187 int ppid;
1188 int pgrp;
1189 int session;
1190 int nr;
1191 int tpgrp;
1192 unsigned long flags;
1193 unsigned long minflt;
1194 unsigned long cminflt;
1195 unsigned long majflt;
1196 unsigned long cmajflt;
1197 unsigned long utime;
1198 unsigned long stime;
1199 long cutime;
1200 long cstime;
1201 long prio;
1202 long nice;
1203 long junk;
1204 long it_real;
1205 uintptr_t start;
1206 uintptr_t vsize;
1207 intptr_t rss;
1208 uintptr_t rsslim;
1209 uintptr_t scodes;
1210 uintptr_t ecode;
1211 int i;
1212
1213 // Figure what the primordial thread stack base is. Code is inspired
1214 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1215 // followed by command name surrounded by parentheses, state, etc.
1216 char stat[2048];
1217 int statlen;
1218
1219 fp = fopen("/proc/self/stat", "r");
1220 if (fp) {
1221 statlen = fread(stat, 1, 2047, fp);
1222 stat[statlen] = '\0';
1223 fclose(fp);
1224
1225 // Skip pid and the command string. Note that we could be dealing with
1226 // weird command names, e.g. user could decide to rename java launcher
1227 // to "java 1.4.2 :)", then the stat file would look like
1228 // 1234 (java 1.4.2 :)) R ... ...
1229 // We don't really need to know the command string, just find the last
1230 // occurrence of ")" and then start parsing from there. See bug 4726580.
1231 char * s = strrchr(stat, ')');
1232
1233 i = 0;
1234 if (s) {
1235 // Skip blank chars
1236 do { s++; } while (s && isspace(*s));
1237
1238 #define _UFM UINTX_FORMAT
1239 #define _DFM INTX_FORMAT
1240
1241 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2
1242 // 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
1243 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,
1244 &state, // 3 %c
1245 &ppid, // 4 %d
1246 &pgrp, // 5 %d
1247 &session, // 6 %d
1248 &nr, // 7 %d
1249 &tpgrp, // 8 %d
1250 &flags, // 9 %lu
1251 &minflt, // 10 %lu
1252 &cminflt, // 11 %lu
1253 &majflt, // 12 %lu
1254 &cmajflt, // 13 %lu
1255 &utime, // 14 %lu
1256 &stime, // 15 %lu
1257 &cutime, // 16 %ld
1258 &cstime, // 17 %ld
1259 &prio, // 18 %ld
1260 &nice, // 19 %ld
1261 &junk, // 20 %ld
1262 &it_real, // 21 %ld
1263 &start, // 22 UINTX_FORMAT
1264 &vsize, // 23 UINTX_FORMAT
1265 &rss, // 24 INTX_FORMAT
1266 &rsslim, // 25 UINTX_FORMAT
1267 &scodes, // 26 UINTX_FORMAT
1268 &ecode, // 27 UINTX_FORMAT
1269 &stack_start); // 28 UINTX_FORMAT
1270 }
1271
1272 #undef _UFM
1273 #undef _DFM
1274
1275 if (i != 28 - 2) {
1276 assert(false, "Bad conversion from /proc/self/stat");
1277 // product mode - assume we are the primordial thread, good luck in the
1278 // embedded case.
1279 warning("Can't detect primordial thread stack location - bad conversion");
1280 stack_start = (uintptr_t) &rlim;
1281 }
1282 } else {
1283 // For some reason we can't open /proc/self/stat (for example, running on
1284 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1285 // most cases, so don't abort:
1286 warning("Can't detect primordial thread stack location - no /proc/self/stat");
1287 stack_start = (uintptr_t) &rlim;
1288 }
1289 }
1290
1291 // Now we have a pointer (stack_start) very close to the stack top, the
1292 // next thing to do is to figure out the exact location of stack top. We
1293 // can find out the virtual memory area that contains stack_start by
1294 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1295 // and its upper limit is the real stack top. (again, this would fail if
1296 // running inside chroot, because /proc may not exist.)
1297
1298 uintptr_t stack_top;
1299 address low, high;
1300 if (find_vma((address)stack_start, &low, &high)) {
1301 // success, "high" is the true stack top. (ignore "low", because initial
1302 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1303 stack_top = (uintptr_t)high;
1304 } else {
1305 // failed, likely because /proc/self/maps does not exist
1306 warning("Can't detect primordial thread stack location - find_vma failed");
1307 // best effort: stack_start is normally within a few pages below the real
1308 // stack top, use it as stack top, and reduce stack size so we won't put
1309 // guard page outside stack.
1310 stack_top = stack_start;
1311 stack_size -= 16 * page_size();
1312 }
1313
1314 // stack_top could be partially down the page so align it
1315 stack_top = align_up(stack_top, page_size());
1316
1317 // Allowed stack value is minimum of max_size and what we derived from rlimit
1318 if (max_size > 0) {
1319 _initial_thread_stack_size = MIN2(max_size, stack_size);
1320 } else {
1321 // Accept the rlimit max, but if stack is unlimited then it will be huge, so
1322 // clamp it at 8MB as we do on Solaris
1323 _initial_thread_stack_size = MIN2(stack_size, 8*M);
1324 }
1325 _initial_thread_stack_size = align_down(_initial_thread_stack_size, page_size());
1326 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1327
1328 assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!");
1329
1330 if (log_is_enabled(Info, os, thread)) {
1331 // See if we seem to be on primordial process thread
1332 bool primordial = uintptr_t(&rlim) > uintptr_t(_initial_thread_stack_bottom) &&
1333 uintptr_t(&rlim) < stack_top;
1334
1335 log_info(os, thread)("Capturing initial stack in %s thread: req. size: " SIZE_FORMAT "K, actual size: "
1336 SIZE_FORMAT "K, top=" INTPTR_FORMAT ", bottom=" INTPTR_FORMAT,
1337 primordial ? "primordial" : "user", max_size / K, _initial_thread_stack_size / K,
1338 stack_top, intptr_t(_initial_thread_stack_bottom));
1339 }
1340 }
1341
1342 ////////////////////////////////////////////////////////////////////////////////
1343 // time support
1344
1345 #ifndef SUPPORTS_CLOCK_MONOTONIC
1346 #error "Build platform doesn't support clock_gettime and related functionality"
1347 #endif
1348
1349 // Time since start-up in seconds to a fine granularity.
1350 // Used by VMSelfDestructTimer and the MemProfiler.
1351 double os::elapsedTime() {
1352
1353 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution
1354 }
1355
1356 jlong os::elapsed_counter() {
1357 return javaTimeNanos() - initial_time_count;
1358 }
1359
1360 jlong os::elapsed_frequency() {
1361 return NANOSECS_PER_SEC; // nanosecond resolution
1362 }
1363
1364 bool os::supports_vtime() { return true; }
1365
1366 double os::elapsedVTime() {
1367 struct rusage usage;
1368 int retval = getrusage(RUSAGE_THREAD, &usage);
1369 if (retval == 0) {
1370 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);
1371 } else {
1372 // better than nothing, but not much
1373 return elapsedTime();
1374 }
1375 }
1376
1377 jlong os::javaTimeMillis() {
1378 timeval time;
1379 int status = gettimeofday(&time, NULL);
1380 assert(status != -1, "linux error");
1381 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1382 }
1383
1384 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) {
1385 timeval time;
1386 int status = gettimeofday(&time, NULL);
1387 assert(status != -1, "linux error");
1388 seconds = jlong(time.tv_sec);
1389 nanos = jlong(time.tv_usec) * 1000;
1390 }
1391
1392 void os::Linux::fast_thread_clock_init() {
1393 if (!UseLinuxPosixThreadCPUClocks) {
1394 return;
1395 }
1396 clockid_t clockid;
1397 struct timespec tp;
1398 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1399 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1400
1401 // Switch to using fast clocks for thread cpu time if
1402 // the clock_getres() returns 0 error code.
1403 // Note, that some kernels may support the current thread
1404 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1405 // returned by the pthread_getcpuclockid().
1406 // If the fast Posix clocks are supported then the clock_getres()
1407 // must return at least tp.tv_sec == 0 which means a resolution
1408 // better than 1 sec. This is extra check for reliability.
1409
1410 if (pthread_getcpuclockid_func &&
1411 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1412 os::Posix::clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1413 _supports_fast_thread_cpu_time = true;
1414 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1415 }
1416 }
1417
1418 jlong os::javaTimeNanos() {
1419 if (os::supports_monotonic_clock()) {
1420 struct timespec tp;
1421 int status = os::Posix::clock_gettime(CLOCK_MONOTONIC, &tp);
1422 assert(status == 0, "gettime error");
1423 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1424 return result;
1425 } else {
1426 timeval time;
1427 int status = gettimeofday(&time, NULL);
1428 assert(status != -1, "linux error");
1429 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1430 return 1000 * usecs;
1431 }
1432 }
1433
1434 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1435 if (os::supports_monotonic_clock()) {
1436 info_ptr->max_value = ALL_64_BITS;
1437
1438 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1439 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1440 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1441 } else {
1442 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1443 info_ptr->max_value = ALL_64_BITS;
1444
1445 // gettimeofday is a real time clock so it skips
1446 info_ptr->may_skip_backward = true;
1447 info_ptr->may_skip_forward = true;
1448 }
1449
1450 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1451 }
1452
1453 // Return the real, user, and system times in seconds from an
1454 // arbitrary fixed point in the past.
1455 bool os::getTimesSecs(double* process_real_time,
1456 double* process_user_time,
1457 double* process_system_time) {
1458 struct tms ticks;
1459 clock_t real_ticks = times(&ticks);
1460
1461 if (real_ticks == (clock_t) (-1)) {
1462 return false;
1463 } else {
1464 double ticks_per_second = (double) clock_tics_per_sec;
1465 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1466 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1467 *process_real_time = ((double) real_ticks) / ticks_per_second;
1468
1469 return true;
1470 }
1471 }
1472
1473
1474 char * os::local_time_string(char *buf, size_t buflen) {
1475 struct tm t;
1476 time_t long_time;
1477 time(&long_time);
1478 localtime_r(&long_time, &t);
1479 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1480 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1481 t.tm_hour, t.tm_min, t.tm_sec);
1482 return buf;
1483 }
1484
1485 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1486 return localtime_r(clock, res);
1487 }
1488
1489 ////////////////////////////////////////////////////////////////////////////////
1490 // runtime exit support
1491
1492 // Note: os::shutdown() might be called very early during initialization, or
1493 // called from signal handler. Before adding something to os::shutdown(), make
1494 // sure it is async-safe and can handle partially initialized VM.
1495 void os::shutdown() {
1496
1497 // allow PerfMemory to attempt cleanup of any persistent resources
1498 perfMemory_exit();
1499
1500 // needs to remove object in file system
1501 AttachListener::abort();
1502
1503 // flush buffered output, finish log files
1504 ostream_abort();
1505
1506 // Check for abort hook
1507 abort_hook_t abort_hook = Arguments::abort_hook();
1508 if (abort_hook != NULL) {
1509 abort_hook();
1510 }
1511
1512 }
1513
1514 // Note: os::abort() might be called very early during initialization, or
1515 // called from signal handler. Before adding something to os::abort(), make
1516 // sure it is async-safe and can handle partially initialized VM.
1517 void os::abort(bool dump_core, void* siginfo, const void* context) {
1518 os::shutdown();
1519 if (dump_core) {
1520 if (DumpPrivateMappingsInCore) {
1521 ClassLoader::close_jrt_image();
1522 }
1523 #ifndef PRODUCT
1524 fdStream out(defaultStream::output_fd());
1525 out.print_raw("Current thread is ");
1526 char buf[16];
1527 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1528 out.print_raw_cr(buf);
1529 out.print_raw_cr("Dumping core ...");
1530 #endif
1531 ::abort(); // dump core
1532 }
1533
1534 ::exit(1);
1535 }
1536
1537 // Die immediately, no exit hook, no abort hook, no cleanup.
1538 // Dump a core file, if possible, for debugging.
1539 void os::die() {
1540 if (TestUnresponsiveErrorHandler && !CreateCoredumpOnCrash) {
1541 // For TimeoutInErrorHandlingTest.java, we just kill the VM
1542 // and don't take the time to generate a core file.
1543 os::signal_raise(SIGKILL);
1544 } else {
1545 ::abort();
1546 }
1547 }
1548
1549 // thread_id is kernel thread id (similar to Solaris LWP id)
1550 intx os::current_thread_id() { return os::Linux::gettid(); }
1551 int os::current_process_id() {
1552 return ::getpid();
1553 }
1554
1555 // DLL functions
1556
1557 const char* os::dll_file_extension() { return ".so"; }
1558
1559 // This must be hard coded because it's the system's temporary
1560 // directory not the java application's temp directory, ala java.io.tmpdir.
1561 const char* os::get_temp_directory() { return "/tmp"; }
1562
1563 static bool file_exists(const char* filename) {
1564 struct stat statbuf;
1565 if (filename == NULL || strlen(filename) == 0) {
1566 return false;
1567 }
1568 return os::stat(filename, &statbuf) == 0;
1569 }
1570
1571 // check if addr is inside libjvm.so
1572 bool os::address_is_in_vm(address addr) {
1573 static address libjvm_base_addr;
1574 Dl_info dlinfo;
1575
1576 if (libjvm_base_addr == NULL) {
1577 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1578 libjvm_base_addr = (address)dlinfo.dli_fbase;
1579 }
1580 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1581 }
1582
1583 if (dladdr((void *)addr, &dlinfo) != 0) {
1584 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1585 }
1586
1587 return false;
1588 }
1589
1590 bool os::dll_address_to_function_name(address addr, char *buf,
1591 int buflen, int *offset,
1592 bool demangle) {
1593 // buf is not optional, but offset is optional
1594 assert(buf != NULL, "sanity check");
1595
1596 Dl_info dlinfo;
1597
1598 if (dladdr((void*)addr, &dlinfo) != 0) {
1599 // see if we have a matching symbol
1600 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1601 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) {
1602 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1603 }
1604 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1605 return true;
1606 }
1607 // no matching symbol so try for just file info
1608 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1609 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1610 buf, buflen, offset, dlinfo.dli_fname, demangle)) {
1611 return true;
1612 }
1613 }
1614 }
1615
1616 buf[0] = '\0';
1617 if (offset != NULL) *offset = -1;
1618 return false;
1619 }
1620
1621 struct _address_to_library_name {
1622 address addr; // input : memory address
1623 size_t buflen; // size of fname
1624 char* fname; // output: library name
1625 address base; // library base addr
1626 };
1627
1628 static int address_to_library_name_callback(struct dl_phdr_info *info,
1629 size_t size, void *data) {
1630 int i;
1631 bool found = false;
1632 address libbase = NULL;
1633 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1634
1635 // iterate through all loadable segments
1636 for (i = 0; i < info->dlpi_phnum; i++) {
1637 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1638 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1639 // base address of a library is the lowest address of its loaded
1640 // segments.
1641 if (libbase == NULL || libbase > segbase) {
1642 libbase = segbase;
1643 }
1644 // see if 'addr' is within current segment
1645 if (segbase <= d->addr &&
1646 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1647 found = true;
1648 }
1649 }
1650 }
1651
1652 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1653 // so dll_address_to_library_name() can fall through to use dladdr() which
1654 // can figure out executable name from argv[0].
1655 if (found && info->dlpi_name && info->dlpi_name[0]) {
1656 d->base = libbase;
1657 if (d->fname) {
1658 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1659 }
1660 return 1;
1661 }
1662 return 0;
1663 }
1664
1665 bool os::dll_address_to_library_name(address addr, char* buf,
1666 int buflen, int* offset) {
1667 // buf is not optional, but offset is optional
1668 assert(buf != NULL, "sanity check");
1669
1670 Dl_info dlinfo;
1671 struct _address_to_library_name data;
1672
1673 // There is a bug in old glibc dladdr() implementation that it could resolve
1674 // to wrong library name if the .so file has a base address != NULL. Here
1675 // we iterate through the program headers of all loaded libraries to find
1676 // out which library 'addr' really belongs to. This workaround can be
1677 // removed once the minimum requirement for glibc is moved to 2.3.x.
1678 data.addr = addr;
1679 data.fname = buf;
1680 data.buflen = buflen;
1681 data.base = NULL;
1682 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1683
1684 if (rslt) {
1685 // buf already contains library name
1686 if (offset) *offset = addr - data.base;
1687 return true;
1688 }
1689 if (dladdr((void*)addr, &dlinfo) != 0) {
1690 if (dlinfo.dli_fname != NULL) {
1691 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1692 }
1693 if (dlinfo.dli_fbase != NULL && offset != NULL) {
1694 *offset = addr - (address)dlinfo.dli_fbase;
1695 }
1696 return true;
1697 }
1698
1699 buf[0] = '\0';
1700 if (offset) *offset = -1;
1701 return false;
1702 }
1703
1704 // Loads .dll/.so and
1705 // in case of error it checks if .dll/.so was built for the
1706 // same architecture as Hotspot is running on
1707
1708
1709 // Remember the stack's state. The Linux dynamic linker will change
1710 // the stack to 'executable' at most once, so we must safepoint only once.
1711 bool os::Linux::_stack_is_executable = false;
1712
1713 // VM operation that loads a library. This is necessary if stack protection
1714 // of the Java stacks can be lost during loading the library. If we
1715 // do not stop the Java threads, they can stack overflow before the stacks
1716 // are protected again.
1717 class VM_LinuxDllLoad: public VM_Operation {
1718 private:
1719 const char *_filename;
1720 char *_ebuf;
1721 int _ebuflen;
1722 void *_lib;
1723 public:
1724 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
1725 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
1726 VMOp_Type type() const { return VMOp_LinuxDllLoad; }
1727 void doit() {
1728 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
1729 os::Linux::_stack_is_executable = true;
1730 }
1731 void* loaded_library() { return _lib; }
1732 };
1733
1734 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1735 void * result = NULL;
1736 bool load_attempted = false;
1737
1738 log_info(os)("attempting shared library load of %s", filename);
1739
1740 // Check whether the library to load might change execution rights
1741 // of the stack. If they are changed, the protection of the stack
1742 // guard pages will be lost. We need a safepoint to fix this.
1743 //
1744 // See Linux man page execstack(8) for more info.
1745 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
1746 if (!ElfFile::specifies_noexecstack(filename)) {
1747 if (!is_init_completed()) {
1748 os::Linux::_stack_is_executable = true;
1749 // This is OK - No Java threads have been created yet, and hence no
1750 // stack guard pages to fix.
1751 //
1752 // Dynamic loader will make all stacks executable after
1753 // this function returns, and will not do that again.
1754 assert(Threads::number_of_threads() == 0, "no Java threads should exist yet.");
1755 } else {
1756 warning("You have loaded library %s which might have disabled stack guard. "
1757 "The VM will try to fix the stack guard now.\n"
1758 "It's highly recommended that you fix the library with "
1759 "'execstack -c <libfile>', or link it with '-z noexecstack'.",
1760 filename);
1761
1762 assert(Thread::current()->is_Java_thread(), "must be Java thread");
1763 JavaThread *jt = JavaThread::current();
1764 if (jt->thread_state() != _thread_in_native) {
1765 // This happens when a compiler thread tries to load a hsdis-<arch>.so file
1766 // that requires ExecStack. Cannot enter safe point. Let's give up.
1767 warning("Unable to fix stack guard. Giving up.");
1768 } else {
1769 if (!LoadExecStackDllInVMThread) {
1770 // This is for the case where the DLL has an static
1771 // constructor function that executes JNI code. We cannot
1772 // load such DLLs in the VMThread.
1773 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1774 }
1775
1776 ThreadInVMfromNative tiv(jt);
1777 debug_only(VMNativeEntryWrapper vew;)
1778
1779 VM_LinuxDllLoad op(filename, ebuf, ebuflen);
1780 VMThread::execute(&op);
1781 if (LoadExecStackDllInVMThread) {
1782 result = op.loaded_library();
1783 }
1784 load_attempted = true;
1785 }
1786 }
1787 }
1788 }
1789
1790 if (!load_attempted) {
1791 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1792 }
1793
1794 if (result != NULL) {
1795 // Successful loading
1796 return result;
1797 }
1798
1799 Elf32_Ehdr elf_head;
1800 int diag_msg_max_length=ebuflen-strlen(ebuf);
1801 char* diag_msg_buf=ebuf+strlen(ebuf);
1802
1803 if (diag_msg_max_length==0) {
1804 // No more space in ebuf for additional diagnostics message
1805 return NULL;
1806 }
1807
1808
1809 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1810
1811 if (file_descriptor < 0) {
1812 // Can't open library, report dlerror() message
1813 return NULL;
1814 }
1815
1816 bool failed_to_read_elf_head=
1817 (sizeof(elf_head)!=
1818 (::read(file_descriptor, &elf_head,sizeof(elf_head))));
1819
1820 ::close(file_descriptor);
1821 if (failed_to_read_elf_head) {
1822 // file i/o error - report dlerror() msg
1823 return NULL;
1824 }
1825
1826 if (elf_head.e_ident[EI_DATA] != LITTLE_ENDIAN_ONLY(ELFDATA2LSB) BIG_ENDIAN_ONLY(ELFDATA2MSB)) {
1827 // handle invalid/out of range endianness values
1828 if (elf_head.e_ident[EI_DATA] == 0 || elf_head.e_ident[EI_DATA] > 2) {
1829 return NULL;
1830 }
1831
1832 #if defined(VM_LITTLE_ENDIAN)
1833 // VM is LE, shared object BE
1834 elf_head.e_machine = be16toh(elf_head.e_machine);
1835 #else
1836 // VM is BE, shared object LE
1837 elf_head.e_machine = le16toh(elf_head.e_machine);
1838 #endif
1839 }
1840
1841 typedef struct {
1842 Elf32_Half code; // Actual value as defined in elf.h
1843 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1844 unsigned char elf_class; // 32 or 64 bit
1845 unsigned char endianness; // MSB or LSB
1846 char* name; // String representation
1847 } arch_t;
1848
1849 #ifndef EM_486
1850 #define EM_486 6 /* Intel 80486 */
1851 #endif
1852 #ifndef EM_AARCH64
1853 #define EM_AARCH64 183 /* ARM AARCH64 */
1854 #endif
1855
1856 static const arch_t arch_array[]={
1857 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1858 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1859 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1860 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1861 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1862 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1863 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1864 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1865 #if defined(VM_LITTLE_ENDIAN)
1866 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64 LE"},
1867 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2LSB, (char*)"SuperH"},
1868 #else
1869 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1870 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2MSB, (char*)"SuperH BE"},
1871 #endif
1872 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1873 // we only support 64 bit z architecture
1874 {EM_S390, EM_S390, ELFCLASS64, ELFDATA2MSB, (char*)"IBM System/390"},
1875 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1876 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1877 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1878 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1879 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"},
1880 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"},
1881 };
1882
1883 #if (defined IA32)
1884 static Elf32_Half running_arch_code=EM_386;
1885 #elif (defined AMD64) || (defined X32)
1886 static Elf32_Half running_arch_code=EM_X86_64;
1887 #elif (defined IA64)
1888 static Elf32_Half running_arch_code=EM_IA_64;
1889 #elif (defined __sparc) && (defined _LP64)
1890 static Elf32_Half running_arch_code=EM_SPARCV9;
1891 #elif (defined __sparc) && (!defined _LP64)
1892 static Elf32_Half running_arch_code=EM_SPARC;
1893 #elif (defined __powerpc64__)
1894 static Elf32_Half running_arch_code=EM_PPC64;
1895 #elif (defined __powerpc__)
1896 static Elf32_Half running_arch_code=EM_PPC;
1897 #elif (defined AARCH64)
1898 static Elf32_Half running_arch_code=EM_AARCH64;
1899 #elif (defined ARM)
1900 static Elf32_Half running_arch_code=EM_ARM;
1901 #elif (defined S390)
1902 static Elf32_Half running_arch_code=EM_S390;
1903 #elif (defined ALPHA)
1904 static Elf32_Half running_arch_code=EM_ALPHA;
1905 #elif (defined MIPSEL)
1906 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1907 #elif (defined PARISC)
1908 static Elf32_Half running_arch_code=EM_PARISC;
1909 #elif (defined MIPS)
1910 static Elf32_Half running_arch_code=EM_MIPS;
1911 #elif (defined M68K)
1912 static Elf32_Half running_arch_code=EM_68K;
1913 #elif (defined SH)
1914 static Elf32_Half running_arch_code=EM_SH;
1915 #else
1916 #error Method os::dll_load requires that one of following is defined:\
1917 AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, S390, SH, __sparc
1918 #endif
1919
1920 // Identify compatibility class for VM's architecture and library's architecture
1921 // Obtain string descriptions for architectures
1922
1923 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1924 int running_arch_index=-1;
1925
1926 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) {
1927 if (running_arch_code == arch_array[i].code) {
1928 running_arch_index = i;
1929 }
1930 if (lib_arch.code == arch_array[i].code) {
1931 lib_arch.compat_class = arch_array[i].compat_class;
1932 lib_arch.name = arch_array[i].name;
1933 }
1934 }
1935
1936 assert(running_arch_index != -1,
1937 "Didn't find running architecture code (running_arch_code) in arch_array");
1938 if (running_arch_index == -1) {
1939 // Even though running architecture detection failed
1940 // we may still continue with reporting dlerror() message
1941 return NULL;
1942 }
1943
1944 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1945 if (lib_arch.name != NULL) {
1946 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1947 " (Possible cause: can't load %s .so on a %s platform)",
1948 lib_arch.name, arch_array[running_arch_index].name);
1949 } else {
1950 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1951 " (Possible cause: can't load this .so (machine code=0x%x) on a %s platform)",
1952 lib_arch.code, arch_array[running_arch_index].name);
1953 }
1954 return NULL;
1955 }
1956
1957 if (lib_arch.endianness != arch_array[running_arch_index].endianness) {
1958 ::snprintf(diag_msg_buf, diag_msg_max_length-1, " (Possible cause: endianness mismatch)");
1959 return NULL;
1960 }
1961
1962 // ELF file class/capacity : 0 - invalid, 1 - 32bit, 2 - 64bit
1963 if (lib_arch.elf_class > 2 || lib_arch.elf_class < 1) {
1964 ::snprintf(diag_msg_buf, diag_msg_max_length-1, " (Possible cause: invalid ELF file class)");
1965 return NULL;
1966 }
1967
1968 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1969 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1970 " (Possible cause: architecture word width mismatch, can't load %d-bit .so on a %d-bit platform)",
1971 (int) lib_arch.elf_class * 32, arch_array[running_arch_index].elf_class * 32);
1972 return NULL;
1973 }
1974
1975 return NULL;
1976 }
1977
1978 void * os::Linux::dlopen_helper(const char *filename, char *ebuf,
1979 int ebuflen) {
1980 void * result = ::dlopen(filename, RTLD_LAZY);
1981 if (result == NULL) {
1982 const char* error_report = ::dlerror();
1983 if (error_report == NULL) {
1984 error_report = "dlerror returned no error description";
1985 }
1986 if (ebuf != NULL && ebuflen > 0) {
1987 ::strncpy(ebuf, error_report, ebuflen-1);
1988 ebuf[ebuflen-1]='\0';
1989 }
1990 Events::log(NULL, "Loading shared library %s failed, %s", filename, error_report);
1991 log_info(os)("shared library load of %s failed, %s", filename, error_report);
1992 } else {
1993 Events::log(NULL, "Loaded shared library %s", filename);
1994 log_info(os)("shared library load of %s was successful", filename);
1995 }
1996 return result;
1997 }
1998
1999 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf,
2000 int ebuflen) {
2001 void * result = NULL;
2002 if (LoadExecStackDllInVMThread) {
2003 result = dlopen_helper(filename, ebuf, ebuflen);
2004 }
2005
2006 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
2007 // library that requires an executable stack, or which does not have this
2008 // stack attribute set, dlopen changes the stack attribute to executable. The
2009 // read protection of the guard pages gets lost.
2010 //
2011 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
2012 // may have been queued at the same time.
2013
2014 if (!_stack_is_executable) {
2015 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) {
2016 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized
2017 jt->stack_guards_enabled()) { // No pending stack overflow exceptions
2018 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) {
2019 warning("Attempt to reguard stack yellow zone failed.");
2020 }
2021 }
2022 }
2023 }
2024
2025 return result;
2026 }
2027
2028 void* os::dll_lookup(void* handle, const char* name) {
2029 void* res = dlsym(handle, name);
2030 return res;
2031 }
2032
2033 void* os::get_default_process_handle() {
2034 return (void*)::dlopen(NULL, RTLD_LAZY);
2035 }
2036
2037 static bool _print_ascii_file(const char* filename, outputStream* st, const char* hdr = NULL) {
2038 int fd = ::open(filename, O_RDONLY);
2039 if (fd == -1) {
2040 return false;
2041 }
2042
2043 if (hdr != NULL) {
2044 st->print_cr("%s", hdr);
2045 }
2046
2047 char buf[33];
2048 int bytes;
2049 buf[32] = '\0';
2050 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) {
2051 st->print_raw(buf, bytes);
2052 }
2053
2054 ::close(fd);
2055
2056 return true;
2057 }
2058
2059 void os::print_dll_info(outputStream *st) {
2060 st->print_cr("Dynamic libraries:");
2061
2062 char fname[32];
2063 pid_t pid = os::Linux::gettid();
2064
2065 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
2066
2067 if (!_print_ascii_file(fname, st)) {
2068 st->print("Can not get library information for pid = %d\n", pid);
2069 }
2070 }
2071
2072 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) {
2073 FILE *procmapsFile = NULL;
2074
2075 // Open the procfs maps file for the current process
2076 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) {
2077 // Allocate PATH_MAX for file name plus a reasonable size for other fields.
2078 char line[PATH_MAX + 100];
2079
2080 // Read line by line from 'file'
2081 while (fgets(line, sizeof(line), procmapsFile) != NULL) {
2082 u8 base, top, offset, inode;
2083 char permissions[5];
2084 char device[6];
2085 char name[sizeof(line)];
2086
2087 // Parse fields from line
2088 int matches = sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %5s " INT64_FORMAT " %s",
2089 &base, &top, permissions, &offset, device, &inode, name);
2090 // the last entry 'name' is empty for some entries, so we might have 6 matches instead of 7 for some lines
2091 if (matches < 6) continue;
2092 if (matches == 6) name[0] = '\0';
2093
2094 // Filter by device id '00:00' so that we only get file system mapped files.
2095 if (strcmp(device, "00:00") != 0) {
2096
2097 // Call callback with the fields of interest
2098 if(callback(name, (address)base, (address)top, param)) {
2099 // Oops abort, callback aborted
2100 fclose(procmapsFile);
2101 return 1;
2102 }
2103 }
2104 }
2105 fclose(procmapsFile);
2106 }
2107 return 0;
2108 }
2109
2110 void os::print_os_info_brief(outputStream* st) {
2111 os::Linux::print_distro_info(st);
2112
2113 os::Posix::print_uname_info(st);
2114
2115 os::Linux::print_libversion_info(st);
2116
2117 }
2118
2119 void os::print_os_info(outputStream* st) {
2120 st->print("OS:");
2121
2122 os::Linux::print_distro_info(st);
2123
2124 os::Posix::print_uname_info(st);
2125
2126 os::Linux::print_uptime_info(st);
2127
2128 // Print warning if unsafe chroot environment detected
2129 if (unsafe_chroot_detected) {
2130 st->print("WARNING!! ");
2131 st->print_cr("%s", unstable_chroot_error);
2132 }
2133
2134 os::Linux::print_libversion_info(st);
2135
2136 os::Posix::print_rlimit_info(st);
2137
2138 os::Posix::print_load_average(st);
2139
2140 os::Linux::print_full_memory_info(st);
2141
2142 os::Linux::print_proc_sys_info(st);
2143
2144 os::Linux::print_ld_preload_file(st);
2145
2146 os::Linux::print_container_info(st);
2147
2148 VM_Version::print_platform_virtualization_info(st);
2149
2150 os::Linux::print_steal_info(st);
2151 }
2152
2153 // Try to identify popular distros.
2154 // Most Linux distributions have a /etc/XXX-release file, which contains
2155 // the OS version string. Newer Linux distributions have a /etc/lsb-release
2156 // file that also contains the OS version string. Some have more than one
2157 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and
2158 // /etc/redhat-release.), so the order is important.
2159 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have
2160 // their own specific XXX-release file as well as a redhat-release file.
2161 // Because of this the XXX-release file needs to be searched for before the
2162 // redhat-release file.
2163 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the
2164 // search for redhat-release / SuSE-release needs to be before lsb-release.
2165 // Since the lsb-release file is the new standard it needs to be searched
2166 // before the older style release files.
2167 // Searching system-release (Red Hat) and os-release (other Linuxes) are a
2168 // next to last resort. The os-release file is a new standard that contains
2169 // distribution information and the system-release file seems to be an old
2170 // standard that has been replaced by the lsb-release and os-release files.
2171 // Searching for the debian_version file is the last resort. It contains
2172 // an informative string like "6.0.6" or "wheezy/sid". Because of this
2173 // "Debian " is printed before the contents of the debian_version file.
2174
2175 const char* distro_files[] = {
2176 "/etc/oracle-release",
2177 "/etc/mandriva-release",
2178 "/etc/mandrake-release",
2179 "/etc/sun-release",
2180 "/etc/redhat-release",
2181 "/etc/SuSE-release",
2182 "/etc/lsb-release",
2183 "/etc/turbolinux-release",
2184 "/etc/gentoo-release",
2185 "/etc/ltib-release",
2186 "/etc/angstrom-version",
2187 "/etc/system-release",
2188 "/etc/os-release",
2189 NULL };
2190
2191 void os::Linux::print_distro_info(outputStream* st) {
2192 for (int i = 0;; i++) {
2193 const char* file = distro_files[i];
2194 if (file == NULL) {
2195 break; // done
2196 }
2197 // If file prints, we found it.
2198 if (_print_ascii_file(file, st)) {
2199 return;
2200 }
2201 }
2202
2203 if (file_exists("/etc/debian_version")) {
2204 st->print("Debian ");
2205 _print_ascii_file("/etc/debian_version", st);
2206 } else {
2207 st->print("Linux");
2208 }
2209 st->cr();
2210 }
2211
2212 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) {
2213 char buf[256];
2214 while (fgets(buf, sizeof(buf), fp)) {
2215 // Edit out extra stuff in expected format
2216 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) {
2217 char* ptr = strstr(buf, "\""); // the name is in quotes
2218 if (ptr != NULL) {
2219 ptr++; // go beyond first quote
2220 char* nl = strchr(ptr, '\"');
2221 if (nl != NULL) *nl = '\0';
2222 strncpy(distro, ptr, length);
2223 } else {
2224 ptr = strstr(buf, "=");
2225 ptr++; // go beyond equals then
2226 char* nl = strchr(ptr, '\n');
2227 if (nl != NULL) *nl = '\0';
2228 strncpy(distro, ptr, length);
2229 }
2230 return;
2231 } else if (get_first_line) {
2232 char* nl = strchr(buf, '\n');
2233 if (nl != NULL) *nl = '\0';
2234 strncpy(distro, buf, length);
2235 return;
2236 }
2237 }
2238 // print last line and close
2239 char* nl = strchr(buf, '\n');
2240 if (nl != NULL) *nl = '\0';
2241 strncpy(distro, buf, length);
2242 }
2243
2244 static void parse_os_info(char* distro, size_t length, const char* file) {
2245 FILE* fp = fopen(file, "r");
2246 if (fp != NULL) {
2247 // if suse format, print out first line
2248 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0);
2249 parse_os_info_helper(fp, distro, length, get_first_line);
2250 fclose(fp);
2251 }
2252 }
2253
2254 void os::get_summary_os_info(char* buf, size_t buflen) {
2255 for (int i = 0;; i++) {
2256 const char* file = distro_files[i];
2257 if (file == NULL) {
2258 break; // ran out of distro_files
2259 }
2260 if (file_exists(file)) {
2261 parse_os_info(buf, buflen, file);
2262 return;
2263 }
2264 }
2265 // special case for debian
2266 if (file_exists("/etc/debian_version")) {
2267 strncpy(buf, "Debian ", buflen);
2268 if (buflen > 7) {
2269 parse_os_info(&buf[7], buflen-7, "/etc/debian_version");
2270 }
2271 } else {
2272 strncpy(buf, "Linux", buflen);
2273 }
2274 }
2275
2276 void os::Linux::print_libversion_info(outputStream* st) {
2277 // libc, pthread
2278 st->print("libc:");
2279 st->print("%s ", os::Linux::glibc_version());
2280 st->print("%s ", os::Linux::libpthread_version());
2281 st->cr();
2282 }
2283
2284 void os::Linux::print_proc_sys_info(outputStream* st) {
2285 st->cr();
2286 st->print_cr("/proc/sys/kernel/threads-max (system-wide limit on the number of threads):");
2287 _print_ascii_file("/proc/sys/kernel/threads-max", st);
2288 st->cr();
2289 st->cr();
2290
2291 st->print_cr("/proc/sys/vm/max_map_count (maximum number of memory map areas a process may have):");
2292 _print_ascii_file("/proc/sys/vm/max_map_count", st);
2293 st->cr();
2294 st->cr();
2295
2296 st->print_cr("/proc/sys/kernel/pid_max (system-wide limit on number of process identifiers):");
2297 _print_ascii_file("/proc/sys/kernel/pid_max", st);
2298 st->cr();
2299 st->cr();
2300 }
2301
2302 void os::Linux::print_full_memory_info(outputStream* st) {
2303 st->print("\n/proc/meminfo:\n");
2304 _print_ascii_file("/proc/meminfo", st);
2305 st->cr();
2306 }
2307
2308 void os::Linux::print_ld_preload_file(outputStream* st) {
2309 _print_ascii_file("/etc/ld.so.preload", st, "\n/etc/ld.so.preload:");
2310 st->cr();
2311 }
2312
2313 void os::Linux::print_uptime_info(outputStream* st) {
2314 struct sysinfo sinfo;
2315 int ret = sysinfo(&sinfo);
2316 if (ret == 0) {
2317 os::print_dhm(st, "OS uptime:", (long) sinfo.uptime);
2318 }
2319 }
2320
2321
2322 void os::Linux::print_container_info(outputStream* st) {
2323 if (!OSContainer::is_containerized()) {
2324 return;
2325 }
2326
2327 st->print("container (cgroup) information:\n");
2328
2329 const char *p_ct = OSContainer::container_type();
2330 st->print("container_type: %s\n", p_ct != NULL ? p_ct : "not supported");
2331
2332 char *p = OSContainer::cpu_cpuset_cpus();
2333 st->print("cpu_cpuset_cpus: %s\n", p != NULL ? p : "not supported");
2334 free(p);
2335
2336 p = OSContainer::cpu_cpuset_memory_nodes();
2337 st->print("cpu_memory_nodes: %s\n", p != NULL ? p : "not supported");
2338 free(p);
2339
2340 int i = OSContainer::active_processor_count();
2341 st->print("active_processor_count: ");
2342 if (i > 0) {
2343 st->print("%d\n", i);
2344 } else {
2345 st->print("not supported\n");
2346 }
2347
2348 i = OSContainer::cpu_quota();
2349 st->print("cpu_quota: ");
2350 if (i > 0) {
2351 st->print("%d\n", i);
2352 } else {
2353 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no quota");
2354 }
2355
2356 i = OSContainer::cpu_period();
2357 st->print("cpu_period: ");
2358 if (i > 0) {
2359 st->print("%d\n", i);
2360 } else {
2361 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no period");
2362 }
2363
2364 i = OSContainer::cpu_shares();
2365 st->print("cpu_shares: ");
2366 if (i > 0) {
2367 st->print("%d\n", i);
2368 } else {
2369 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no shares");
2370 }
2371
2372 jlong j = OSContainer::memory_limit_in_bytes();
2373 st->print("memory_limit_in_bytes: ");
2374 if (j > 0) {
2375 st->print(JLONG_FORMAT "\n", j);
2376 } else {
2377 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2378 }
2379
2380 j = OSContainer::memory_and_swap_limit_in_bytes();
2381 st->print("memory_and_swap_limit_in_bytes: ");
2382 if (j > 0) {
2383 st->print(JLONG_FORMAT "\n", j);
2384 } else {
2385 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2386 }
2387
2388 j = OSContainer::memory_soft_limit_in_bytes();
2389 st->print("memory_soft_limit_in_bytes: ");
2390 if (j > 0) {
2391 st->print(JLONG_FORMAT "\n", j);
2392 } else {
2393 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2394 }
2395
2396 j = OSContainer::OSContainer::memory_usage_in_bytes();
2397 st->print("memory_usage_in_bytes: ");
2398 if (j > 0) {
2399 st->print(JLONG_FORMAT "\n", j);
2400 } else {
2401 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2402 }
2403
2404 j = OSContainer::OSContainer::memory_max_usage_in_bytes();
2405 st->print("memory_max_usage_in_bytes: ");
2406 if (j > 0) {
2407 st->print(JLONG_FORMAT "\n", j);
2408 } else {
2409 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2410 }
2411 st->cr();
2412 }
2413
2414 void os::Linux::print_steal_info(outputStream* st) {
2415 if (has_initial_tick_info) {
2416 CPUPerfTicks pticks;
2417 bool res = os::Linux::get_tick_information(&pticks, -1);
2418
2419 if (res && pticks.has_steal_ticks) {
2420 uint64_t steal_ticks_difference = pticks.steal - initial_steal_ticks;
2421 uint64_t total_ticks_difference = pticks.total - initial_total_ticks;
2422 double steal_ticks_perc = 0.0;
2423 if (total_ticks_difference != 0) {
2424 steal_ticks_perc = (double) steal_ticks_difference / total_ticks_difference;
2425 }
2426 st->print_cr("Steal ticks since vm start: " UINT64_FORMAT, steal_ticks_difference);
2427 st->print_cr("Steal ticks percentage since vm start:%7.3f", steal_ticks_perc);
2428 }
2429 }
2430 }
2431
2432 void os::print_memory_info(outputStream* st) {
2433
2434 st->print("Memory:");
2435 st->print(" %dk page", os::vm_page_size()>>10);
2436
2437 // values in struct sysinfo are "unsigned long"
2438 struct sysinfo si;
2439 sysinfo(&si);
2440
2441 st->print(", physical " UINT64_FORMAT "k",
2442 os::physical_memory() >> 10);
2443 st->print("(" UINT64_FORMAT "k free)",
2444 os::available_memory() >> 10);
2445 st->print(", swap " UINT64_FORMAT "k",
2446 ((jlong)si.totalswap * si.mem_unit) >> 10);
2447 st->print("(" UINT64_FORMAT "k free)",
2448 ((jlong)si.freeswap * si.mem_unit) >> 10);
2449 st->cr();
2450 }
2451
2452 // Print the first "model name" line and the first "flags" line
2453 // that we find and nothing more. We assume "model name" comes
2454 // before "flags" so if we find a second "model name", then the
2455 // "flags" field is considered missing.
2456 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) {
2457 #if defined(IA32) || defined(AMD64)
2458 // Other platforms have less repetitive cpuinfo files
2459 FILE *fp = fopen("/proc/cpuinfo", "r");
2460 if (fp) {
2461 while (!feof(fp)) {
2462 if (fgets(buf, buflen, fp)) {
2463 // Assume model name comes before flags
2464 bool model_name_printed = false;
2465 if (strstr(buf, "model name") != NULL) {
2466 if (!model_name_printed) {
2467 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n");
2468 st->print_raw(buf);
2469 model_name_printed = true;
2470 } else {
2471 // model name printed but not flags? Odd, just return
2472 fclose(fp);
2473 return true;
2474 }
2475 }
2476 // print the flags line too
2477 if (strstr(buf, "flags") != NULL) {
2478 st->print_raw(buf);
2479 fclose(fp);
2480 return true;
2481 }
2482 }
2483 }
2484 fclose(fp);
2485 }
2486 #endif // x86 platforms
2487 return false;
2488 }
2489
2490 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
2491 // Only print the model name if the platform provides this as a summary
2492 if (!print_model_name_and_flags(st, buf, buflen)) {
2493 st->print("\n/proc/cpuinfo:\n");
2494 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2495 st->print_cr(" <Not Available>");
2496 }
2497 }
2498 }
2499
2500 #if defined(AMD64) || defined(IA32) || defined(X32)
2501 const char* search_string = "model name";
2502 #elif defined(M68K)
2503 const char* search_string = "CPU";
2504 #elif defined(PPC64)
2505 const char* search_string = "cpu";
2506 #elif defined(S390)
2507 const char* search_string = "machine =";
2508 #elif defined(SPARC)
2509 const char* search_string = "cpu";
2510 #else
2511 const char* search_string = "Processor";
2512 #endif
2513
2514 // Parses the cpuinfo file for string representing the model name.
2515 void os::get_summary_cpu_info(char* cpuinfo, size_t length) {
2516 FILE* fp = fopen("/proc/cpuinfo", "r");
2517 if (fp != NULL) {
2518 while (!feof(fp)) {
2519 char buf[256];
2520 if (fgets(buf, sizeof(buf), fp)) {
2521 char* start = strstr(buf, search_string);
2522 if (start != NULL) {
2523 char *ptr = start + strlen(search_string);
2524 char *end = buf + strlen(buf);
2525 while (ptr != end) {
2526 // skip whitespace and colon for the rest of the name.
2527 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') {
2528 break;
2529 }
2530 ptr++;
2531 }
2532 if (ptr != end) {
2533 // reasonable string, get rid of newline and keep the rest
2534 char* nl = strchr(buf, '\n');
2535 if (nl != NULL) *nl = '\0';
2536 strncpy(cpuinfo, ptr, length);
2537 fclose(fp);
2538 return;
2539 }
2540 }
2541 }
2542 }
2543 fclose(fp);
2544 }
2545 // cpuinfo not found or parsing failed, just print generic string. The entire
2546 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86)
2547 #if defined(AARCH64)
2548 strncpy(cpuinfo, "AArch64", length);
2549 #elif defined(AMD64)
2550 strncpy(cpuinfo, "x86_64", length);
2551 #elif defined(ARM) // Order wrt. AARCH64 is relevant!
2552 strncpy(cpuinfo, "ARM", length);
2553 #elif defined(IA32)
2554 strncpy(cpuinfo, "x86_32", length);
2555 #elif defined(IA64)
2556 strncpy(cpuinfo, "IA64", length);
2557 #elif defined(PPC)
2558 strncpy(cpuinfo, "PPC64", length);
2559 #elif defined(S390)
2560 strncpy(cpuinfo, "S390", length);
2561 #elif defined(SPARC)
2562 strncpy(cpuinfo, "sparcv9", length);
2563 #elif defined(ZERO_LIBARCH)
2564 strncpy(cpuinfo, ZERO_LIBARCH, length);
2565 #else
2566 strncpy(cpuinfo, "unknown", length);
2567 #endif
2568 }
2569
2570 static void print_signal_handler(outputStream* st, int sig,
2571 char* buf, size_t buflen);
2572
2573 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2574 st->print_cr("Signal Handlers:");
2575 print_signal_handler(st, SIGSEGV, buf, buflen);
2576 print_signal_handler(st, SIGBUS , buf, buflen);
2577 print_signal_handler(st, SIGFPE , buf, buflen);
2578 print_signal_handler(st, SIGPIPE, buf, buflen);
2579 print_signal_handler(st, SIGXFSZ, buf, buflen);
2580 print_signal_handler(st, SIGILL , buf, buflen);
2581 print_signal_handler(st, SR_signum, buf, buflen);
2582 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2583 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2584 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2585 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2586 #if defined(PPC64)
2587 print_signal_handler(st, SIGTRAP, buf, buflen);
2588 #endif
2589 }
2590
2591 static char saved_jvm_path[MAXPATHLEN] = {0};
2592
2593 // Find the full path to the current module, libjvm.so
2594 void os::jvm_path(char *buf, jint buflen) {
2595 // Error checking.
2596 if (buflen < MAXPATHLEN) {
2597 assert(false, "must use a large-enough buffer");
2598 buf[0] = '\0';
2599 return;
2600 }
2601 // Lazy resolve the path to current module.
2602 if (saved_jvm_path[0] != 0) {
2603 strcpy(buf, saved_jvm_path);
2604 return;
2605 }
2606
2607 char dli_fname[MAXPATHLEN];
2608 bool ret = dll_address_to_library_name(
2609 CAST_FROM_FN_PTR(address, os::jvm_path),
2610 dli_fname, sizeof(dli_fname), NULL);
2611 assert(ret, "cannot locate libjvm");
2612 char *rp = NULL;
2613 if (ret && dli_fname[0] != '\0') {
2614 rp = os::Posix::realpath(dli_fname, buf, buflen);
2615 }
2616 if (rp == NULL) {
2617 return;
2618 }
2619
2620 if (Arguments::sun_java_launcher_is_altjvm()) {
2621 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
2622 // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so".
2623 // If "/jre/lib/" appears at the right place in the string, then
2624 // assume we are installed in a JDK and we're done. Otherwise, check
2625 // for a JAVA_HOME environment variable and fix up the path so it
2626 // looks like libjvm.so is installed there (append a fake suffix
2627 // hotspot/libjvm.so).
2628 const char *p = buf + strlen(buf) - 1;
2629 for (int count = 0; p > buf && count < 5; ++count) {
2630 for (--p; p > buf && *p != '/'; --p)
2631 /* empty */ ;
2632 }
2633
2634 if (strncmp(p, "/jre/lib/", 9) != 0) {
2635 // Look for JAVA_HOME in the environment.
2636 char* java_home_var = ::getenv("JAVA_HOME");
2637 if (java_home_var != NULL && java_home_var[0] != 0) {
2638 char* jrelib_p;
2639 int len;
2640
2641 // Check the current module name "libjvm.so".
2642 p = strrchr(buf, '/');
2643 if (p == NULL) {
2644 return;
2645 }
2646 assert(strstr(p, "/libjvm") == p, "invalid library name");
2647
2648 rp = os::Posix::realpath(java_home_var, buf, buflen);
2649 if (rp == NULL) {
2650 return;
2651 }
2652
2653 // determine if this is a legacy image or modules image
2654 // modules image doesn't have "jre" subdirectory
2655 len = strlen(buf);
2656 assert(len < buflen, "Ran out of buffer room");
2657 jrelib_p = buf + len;
2658 snprintf(jrelib_p, buflen-len, "/jre/lib");
2659 if (0 != access(buf, F_OK)) {
2660 snprintf(jrelib_p, buflen-len, "/lib");
2661 }
2662
2663 if (0 == access(buf, F_OK)) {
2664 // Use current module name "libjvm.so"
2665 len = strlen(buf);
2666 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
2667 } else {
2668 // Go back to path of .so
2669 rp = os::Posix::realpath(dli_fname, buf, buflen);
2670 if (rp == NULL) {
2671 return;
2672 }
2673 }
2674 }
2675 }
2676 }
2677
2678 strncpy(saved_jvm_path, buf, MAXPATHLEN);
2679 saved_jvm_path[MAXPATHLEN - 1] = '\0';
2680 }
2681
2682 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2683 // no prefix required, not even "_"
2684 }
2685
2686 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2687 // no suffix required
2688 }
2689
2690 ////////////////////////////////////////////////////////////////////////////////
2691 // sun.misc.Signal support
2692
2693 static void UserHandler(int sig, void *siginfo, void *context) {
2694 // Ctrl-C is pressed during error reporting, likely because the error
2695 // handler fails to abort. Let VM die immediately.
2696 if (sig == SIGINT && VMError::is_error_reported()) {
2697 os::die();
2698 }
2699
2700 os::signal_notify(sig);
2701 }
2702
2703 void* os::user_handler() {
2704 return CAST_FROM_FN_PTR(void*, UserHandler);
2705 }
2706
2707 extern "C" {
2708 typedef void (*sa_handler_t)(int);
2709 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2710 }
2711
2712 void* os::signal(int signal_number, void* handler) {
2713 struct sigaction sigAct, oldSigAct;
2714
2715 sigfillset(&(sigAct.sa_mask));
2716 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2717 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2718
2719 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2720 // -1 means registration failed
2721 return (void *)-1;
2722 }
2723
2724 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2725 }
2726
2727 void os::signal_raise(int signal_number) {
2728 ::raise(signal_number);
2729 }
2730
2731 // The following code is moved from os.cpp for making this
2732 // code platform specific, which it is by its very nature.
2733
2734 // Will be modified when max signal is changed to be dynamic
2735 int os::sigexitnum_pd() {
2736 return NSIG;
2737 }
2738
2739 // a counter for each possible signal value
2740 static volatile jint pending_signals[NSIG+1] = { 0 };
2741
2742 // Linux(POSIX) specific hand shaking semaphore.
2743 static Semaphore* sig_sem = NULL;
2744 static PosixSemaphore sr_semaphore;
2745
2746 static void jdk_misc_signal_init() {
2747 // Initialize signal structures
2748 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2749
2750 // Initialize signal semaphore
2751 sig_sem = new Semaphore();
2752 }
2753
2754 void os::signal_notify(int sig) {
2755 if (sig_sem != NULL) {
2756 Atomic::inc(&pending_signals[sig]);
2757 sig_sem->signal();
2758 } else {
2759 // Signal thread is not created with ReduceSignalUsage and jdk_misc_signal_init
2760 // initialization isn't called.
2761 assert(ReduceSignalUsage, "signal semaphore should be created");
2762 }
2763 }
2764
2765 static int check_pending_signals() {
2766 for (;;) {
2767 for (int i = 0; i < NSIG + 1; i++) {
2768 jint n = pending_signals[i];
2769 if (n > 0 && n == Atomic::cmpxchg(&pending_signals[i], n, n - 1)) {
2770 return i;
2771 }
2772 }
2773 JavaThread *thread = JavaThread::current();
2774 ThreadBlockInVM tbivm(thread);
2775
2776 bool threadIsSuspended;
2777 do {
2778 thread->set_suspend_equivalent();
2779 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2780 sig_sem->wait();
2781
2782 // were we externally suspended while we were waiting?
2783 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2784 if (threadIsSuspended) {
2785 // The semaphore has been incremented, but while we were waiting
2786 // another thread suspended us. We don't want to continue running
2787 // while suspended because that would surprise the thread that
2788 // suspended us.
2789 sig_sem->signal();
2790
2791 thread->java_suspend_self();
2792 }
2793 } while (threadIsSuspended);
2794 }
2795 }
2796
2797 int os::signal_wait() {
2798 return check_pending_signals();
2799 }
2800
2801 ////////////////////////////////////////////////////////////////////////////////
2802 // Virtual Memory
2803
2804 int os::vm_page_size() {
2805 // Seems redundant as all get out
2806 assert(os::Linux::page_size() != -1, "must call os::init");
2807 return os::Linux::page_size();
2808 }
2809
2810 // Solaris allocates memory by pages.
2811 int os::vm_allocation_granularity() {
2812 assert(os::Linux::page_size() != -1, "must call os::init");
2813 return os::Linux::page_size();
2814 }
2815
2816 // Rationale behind this function:
2817 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2818 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2819 // samples for JITted code. Here we create private executable mapping over the code cache
2820 // and then we can use standard (well, almost, as mapping can change) way to provide
2821 // info for the reporting script by storing timestamp and location of symbol
2822 void linux_wrap_code(char* base, size_t size) {
2823 static volatile jint cnt = 0;
2824
2825 if (!UseOprofile) {
2826 return;
2827 }
2828
2829 char buf[PATH_MAX+1];
2830 int num = Atomic::add(&cnt, 1);
2831
2832 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2833 os::get_temp_directory(), os::current_process_id(), num);
2834 unlink(buf);
2835
2836 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2837
2838 if (fd != -1) {
2839 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2840 if (rv != (off_t)-1) {
2841 if (::write(fd, "", 1) == 1) {
2842 mmap(base, size,
2843 PROT_READ|PROT_WRITE|PROT_EXEC,
2844 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2845 }
2846 }
2847 ::close(fd);
2848 unlink(buf);
2849 }
2850 }
2851
2852 static bool recoverable_mmap_error(int err) {
2853 // See if the error is one we can let the caller handle. This
2854 // list of errno values comes from JBS-6843484. I can't find a
2855 // Linux man page that documents this specific set of errno
2856 // values so while this list currently matches Solaris, it may
2857 // change as we gain experience with this failure mode.
2858 switch (err) {
2859 case EBADF:
2860 case EINVAL:
2861 case ENOTSUP:
2862 // let the caller deal with these errors
2863 return true;
2864
2865 default:
2866 // Any remaining errors on this OS can cause our reserved mapping
2867 // to be lost. That can cause confusion where different data
2868 // structures think they have the same memory mapped. The worst
2869 // scenario is if both the VM and a library think they have the
2870 // same memory mapped.
2871 return false;
2872 }
2873 }
2874
2875 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2876 int err) {
2877 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2878 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec,
2879 os::strerror(err), err);
2880 }
2881
2882 static void warn_fail_commit_memory(char* addr, size_t size,
2883 size_t alignment_hint, bool exec,
2884 int err) {
2885 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2886 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size,
2887 alignment_hint, exec, os::strerror(err), err);
2888 }
2889
2890 // NOTE: Linux kernel does not really reserve the pages for us.
2891 // All it does is to check if there are enough free pages
2892 // left at the time of mmap(). This could be a potential
2893 // problem.
2894 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) {
2895 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2896 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2897 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2898 if (res != (uintptr_t) MAP_FAILED) {
2899 if (UseNUMAInterleaving) {
2900 numa_make_global(addr, size);
2901 }
2902 return 0;
2903 }
2904
2905 int err = errno; // save errno from mmap() call above
2906
2907 if (!recoverable_mmap_error(err)) {
2908 warn_fail_commit_memory(addr, size, exec, err);
2909 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory.");
2910 }
2911
2912 return err;
2913 }
2914
2915 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2916 return os::Linux::commit_memory_impl(addr, size, exec) == 0;
2917 }
2918
2919 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2920 const char* mesg) {
2921 assert(mesg != NULL, "mesg must be specified");
2922 int err = os::Linux::commit_memory_impl(addr, size, exec);
2923 if (err != 0) {
2924 // the caller wants all commit errors to exit with the specified mesg:
2925 warn_fail_commit_memory(addr, size, exec, err);
2926 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2927 }
2928 }
2929
2930 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2931 #ifndef MAP_HUGETLB
2932 #define MAP_HUGETLB 0x40000
2933 #endif
2934
2935 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2936 #ifndef MADV_HUGEPAGE
2937 #define MADV_HUGEPAGE 14
2938 #endif
2939
2940 int os::Linux::commit_memory_impl(char* addr, size_t size,
2941 size_t alignment_hint, bool exec) {
2942 int err = os::Linux::commit_memory_impl(addr, size, exec);
2943 if (err == 0) {
2944 realign_memory(addr, size, alignment_hint);
2945 }
2946 return err;
2947 }
2948
2949 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2950 bool exec) {
2951 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0;
2952 }
2953
2954 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2955 size_t alignment_hint, bool exec,
2956 const char* mesg) {
2957 assert(mesg != NULL, "mesg must be specified");
2958 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec);
2959 if (err != 0) {
2960 // the caller wants all commit errors to exit with the specified mesg:
2961 warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
2962 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2963 }
2964 }
2965
2966 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2967 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
2968 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2969 // be supported or the memory may already be backed by huge pages.
2970 ::madvise(addr, bytes, MADV_HUGEPAGE);
2971 }
2972 }
2973
2974 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2975 // This method works by doing an mmap over an existing mmaping and effectively discarding
2976 // the existing pages. However it won't work for SHM-based large pages that cannot be
2977 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
2978 // small pages on top of the SHM segment. This method always works for small pages, so we
2979 // allow that in any case.
2980 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
2981 commit_memory(addr, bytes, alignment_hint, !ExecMem);
2982 }
2983 }
2984
2985 void os::numa_make_global(char *addr, size_t bytes) {
2986 Linux::numa_interleave_memory(addr, bytes);
2987 }
2988
2989 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the
2990 // bind policy to MPOL_PREFERRED for the current thread.
2991 #define USE_MPOL_PREFERRED 0
2992
2993 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2994 // To make NUMA and large pages more robust when both enabled, we need to ease
2995 // the requirements on where the memory should be allocated. MPOL_BIND is the
2996 // default policy and it will force memory to be allocated on the specified
2997 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on
2998 // the specified node, but will not force it. Using this policy will prevent
2999 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no
3000 // free large pages.
3001 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED);
3002 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
3003 }
3004
3005 bool os::numa_topology_changed() { return false; }
3006
3007 size_t os::numa_get_groups_num() {
3008 // Return just the number of nodes in which it's possible to allocate memory
3009 // (in numa terminology, configured nodes).
3010 return Linux::numa_num_configured_nodes();
3011 }
3012
3013 int os::numa_get_group_id() {
3014 int cpu_id = Linux::sched_getcpu();
3015 if (cpu_id != -1) {
3016 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
3017 if (lgrp_id != -1) {
3018 return lgrp_id;
3019 }
3020 }
3021 return 0;
3022 }
3023
3024 int os::numa_get_group_id_for_address(const void* address) {
3025 void** pages = const_cast<void**>(&address);
3026 int id = -1;
3027
3028 if (os::Linux::numa_move_pages(0, 1, pages, NULL, &id, 0) == -1) {
3029 return -1;
3030 }
3031 if (id < 0) {
3032 return -1;
3033 }
3034 return id;
3035 }
3036
3037 int os::Linux::get_existing_num_nodes() {
3038 int node;
3039 int highest_node_number = Linux::numa_max_node();
3040 int num_nodes = 0;
3041
3042 // Get the total number of nodes in the system including nodes without memory.
3043 for (node = 0; node <= highest_node_number; node++) {
3044 if (is_node_in_existing_nodes(node)) {
3045 num_nodes++;
3046 }
3047 }
3048 return num_nodes;
3049 }
3050
3051 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
3052 int highest_node_number = Linux::numa_max_node();
3053 size_t i = 0;
3054
3055 // Map all node ids in which it is possible to allocate memory. Also nodes are
3056 // not always consecutively available, i.e. available from 0 to the highest
3057 // node number. If the nodes have been bound explicitly using numactl membind,
3058 // then allocate memory from those nodes only.
3059 for (int node = 0; node <= highest_node_number; node++) {
3060 if (Linux::is_node_in_bound_nodes((unsigned int)node)) {
3061 ids[i++] = node;
3062 }
3063 }
3064 return i;
3065 }
3066
3067 bool os::get_page_info(char *start, page_info* info) {
3068 return false;
3069 }
3070
3071 char *os::scan_pages(char *start, char* end, page_info* page_expected,
3072 page_info* page_found) {
3073 return end;
3074 }
3075
3076
3077 int os::Linux::sched_getcpu_syscall(void) {
3078 unsigned int cpu = 0;
3079 int retval = -1;
3080
3081 #if defined(IA32)
3082 #ifndef SYS_getcpu
3083 #define SYS_getcpu 318
3084 #endif
3085 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
3086 #elif defined(AMD64)
3087 // Unfortunately we have to bring all these macros here from vsyscall.h
3088 // to be able to compile on old linuxes.
3089 #define __NR_vgetcpu 2
3090 #define VSYSCALL_START (-10UL << 20)
3091 #define VSYSCALL_SIZE 1024
3092 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
3093 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
3094 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
3095 retval = vgetcpu(&cpu, NULL, NULL);
3096 #endif
3097
3098 return (retval == -1) ? retval : cpu;
3099 }
3100
3101 void os::Linux::sched_getcpu_init() {
3102 // sched_getcpu() should be in libc.
3103 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
3104 dlsym(RTLD_DEFAULT, "sched_getcpu")));
3105
3106 // If it's not, try a direct syscall.
3107 if (sched_getcpu() == -1) {
3108 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
3109 (void*)&sched_getcpu_syscall));
3110 }
3111
3112 if (sched_getcpu() == -1) {
3113 vm_exit_during_initialization("getcpu(2) system call not supported by kernel");
3114 }
3115 }
3116
3117 // Something to do with the numa-aware allocator needs these symbols
3118 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
3119 extern "C" JNIEXPORT void numa_error(char *where) { }
3120
3121 // Handle request to load libnuma symbol version 1.1 (API v1). If it fails
3122 // load symbol from base version instead.
3123 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
3124 void *f = dlvsym(handle, name, "libnuma_1.1");
3125 if (f == NULL) {
3126 f = dlsym(handle, name);
3127 }
3128 return f;
3129 }
3130
3131 // Handle request to load libnuma symbol version 1.2 (API v2) only.
3132 // Return NULL if the symbol is not defined in this particular version.
3133 void* os::Linux::libnuma_v2_dlsym(void* handle, const char* name) {
3134 return dlvsym(handle, name, "libnuma_1.2");
3135 }
3136
3137 bool os::Linux::libnuma_init() {
3138 if (sched_getcpu() != -1) { // Requires sched_getcpu() support
3139 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
3140 if (handle != NULL) {
3141 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
3142 libnuma_dlsym(handle, "numa_node_to_cpus")));
3143 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
3144 libnuma_dlsym(handle, "numa_max_node")));
3145 set_numa_num_configured_nodes(CAST_TO_FN_PTR(numa_num_configured_nodes_func_t,
3146 libnuma_dlsym(handle, "numa_num_configured_nodes")));
3147 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
3148 libnuma_dlsym(handle, "numa_available")));
3149 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
3150 libnuma_dlsym(handle, "numa_tonode_memory")));
3151 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
3152 libnuma_dlsym(handle, "numa_interleave_memory")));
3153 set_numa_interleave_memory_v2(CAST_TO_FN_PTR(numa_interleave_memory_v2_func_t,
3154 libnuma_v2_dlsym(handle, "numa_interleave_memory")));
3155 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t,
3156 libnuma_dlsym(handle, "numa_set_bind_policy")));
3157 set_numa_bitmask_isbitset(CAST_TO_FN_PTR(numa_bitmask_isbitset_func_t,
3158 libnuma_dlsym(handle, "numa_bitmask_isbitset")));
3159 set_numa_distance(CAST_TO_FN_PTR(numa_distance_func_t,
3160 libnuma_dlsym(handle, "numa_distance")));
3161 set_numa_get_membind(CAST_TO_FN_PTR(numa_get_membind_func_t,
3162 libnuma_v2_dlsym(handle, "numa_get_membind")));
3163 set_numa_get_interleave_mask(CAST_TO_FN_PTR(numa_get_interleave_mask_func_t,
3164 libnuma_v2_dlsym(handle, "numa_get_interleave_mask")));
3165 set_numa_move_pages(CAST_TO_FN_PTR(numa_move_pages_func_t,
3166 libnuma_dlsym(handle, "numa_move_pages")));
3167 set_numa_set_preferred(CAST_TO_FN_PTR(numa_set_preferred_func_t,
3168 libnuma_dlsym(handle, "numa_set_preferred")));
3169
3170 if (numa_available() != -1) {
3171 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
3172 set_numa_all_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_all_nodes_ptr"));
3173 set_numa_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_nodes_ptr"));
3174 set_numa_interleave_bitmask(_numa_get_interleave_mask());
3175 set_numa_membind_bitmask(_numa_get_membind());
3176 // Create an index -> node mapping, since nodes are not always consecutive
3177 _nindex_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
3178 rebuild_nindex_to_node_map();
3179 // Create a cpu -> node mapping
3180 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
3181 rebuild_cpu_to_node_map();
3182 return true;
3183 }
3184 }
3185 }
3186 return false;
3187 }
3188
3189 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
3190 // Creating guard page is very expensive. Java thread has HotSpot
3191 // guard pages, only enable glibc guard page for non-Java threads.
3192 // (Remember: compiler thread is a Java thread, too!)
3193 return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size());
3194 }
3195
3196 void os::Linux::rebuild_nindex_to_node_map() {
3197 int highest_node_number = Linux::numa_max_node();
3198
3199 nindex_to_node()->clear();
3200 for (int node = 0; node <= highest_node_number; node++) {
3201 if (Linux::is_node_in_existing_nodes(node)) {
3202 nindex_to_node()->append(node);
3203 }
3204 }
3205 }
3206
3207 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
3208 // The table is later used in get_node_by_cpu().
3209 void os::Linux::rebuild_cpu_to_node_map() {
3210 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
3211 // in libnuma (possible values are starting from 16,
3212 // and continuing up with every other power of 2, but less
3213 // than the maximum number of CPUs supported by kernel), and
3214 // is a subject to change (in libnuma version 2 the requirements
3215 // are more reasonable) we'll just hardcode the number they use
3216 // in the library.
3217 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
3218
3219 size_t cpu_num = processor_count();
3220 size_t cpu_map_size = NCPUS / BitsPerCLong;
3221 size_t cpu_map_valid_size =
3222 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
3223
3224 cpu_to_node()->clear();
3225 cpu_to_node()->at_grow(cpu_num - 1);
3226
3227 size_t node_num = get_existing_num_nodes();
3228
3229 int distance = 0;
3230 int closest_distance = INT_MAX;
3231 int closest_node = 0;
3232 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
3233 for (size_t i = 0; i < node_num; i++) {
3234 // Check if node is configured (not a memory-less node). If it is not, find
3235 // the closest configured node. Check also if node is bound, i.e. it's allowed
3236 // to allocate memory from the node. If it's not allowed, map cpus in that node
3237 // to the closest node from which memory allocation is allowed.
3238 if (!is_node_in_configured_nodes(nindex_to_node()->at(i)) ||
3239 !is_node_in_bound_nodes(nindex_to_node()->at(i))) {
3240 closest_distance = INT_MAX;
3241 // Check distance from all remaining nodes in the system. Ignore distance
3242 // from itself, from another non-configured node, and from another non-bound
3243 // node.
3244 for (size_t m = 0; m < node_num; m++) {
3245 if (m != i &&
3246 is_node_in_configured_nodes(nindex_to_node()->at(m)) &&
3247 is_node_in_bound_nodes(nindex_to_node()->at(m))) {
3248 distance = numa_distance(nindex_to_node()->at(i), nindex_to_node()->at(m));
3249 // If a closest node is found, update. There is always at least one
3250 // configured and bound node in the system so there is always at least
3251 // one node close.
3252 if (distance != 0 && distance < closest_distance) {
3253 closest_distance = distance;
3254 closest_node = nindex_to_node()->at(m);
3255 }
3256 }
3257 }
3258 } else {
3259 // Current node is already a configured node.
3260 closest_node = nindex_to_node()->at(i);
3261 }
3262
3263 // Get cpus from the original node and map them to the closest node. If node
3264 // is a configured node (not a memory-less node), then original node and
3265 // closest node are the same.
3266 if (numa_node_to_cpus(nindex_to_node()->at(i), cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
3267 for (size_t j = 0; j < cpu_map_valid_size; j++) {
3268 if (cpu_map[j] != 0) {
3269 for (size_t k = 0; k < BitsPerCLong; k++) {
3270 if (cpu_map[j] & (1UL << k)) {
3271 cpu_to_node()->at_put(j * BitsPerCLong + k, closest_node);
3272 }
3273 }
3274 }
3275 }
3276 }
3277 }
3278 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
3279 }
3280
3281 int os::Linux::get_node_by_cpu(int cpu_id) {
3282 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
3283 return cpu_to_node()->at(cpu_id);
3284 }
3285 return -1;
3286 }
3287
3288 GrowableArray<int>* os::Linux::_cpu_to_node;
3289 GrowableArray<int>* os::Linux::_nindex_to_node;
3290 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
3291 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
3292 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
3293 os::Linux::numa_num_configured_nodes_func_t os::Linux::_numa_num_configured_nodes;
3294 os::Linux::numa_available_func_t os::Linux::_numa_available;
3295 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
3296 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
3297 os::Linux::numa_interleave_memory_v2_func_t os::Linux::_numa_interleave_memory_v2;
3298 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy;
3299 os::Linux::numa_bitmask_isbitset_func_t os::Linux::_numa_bitmask_isbitset;
3300 os::Linux::numa_distance_func_t os::Linux::_numa_distance;
3301 os::Linux::numa_get_membind_func_t os::Linux::_numa_get_membind;
3302 os::Linux::numa_get_interleave_mask_func_t os::Linux::_numa_get_interleave_mask;
3303 os::Linux::numa_move_pages_func_t os::Linux::_numa_move_pages;
3304 os::Linux::numa_set_preferred_func_t os::Linux::_numa_set_preferred;
3305 os::Linux::NumaAllocationPolicy os::Linux::_current_numa_policy;
3306 unsigned long* os::Linux::_numa_all_nodes;
3307 struct bitmask* os::Linux::_numa_all_nodes_ptr;
3308 struct bitmask* os::Linux::_numa_nodes_ptr;
3309 struct bitmask* os::Linux::_numa_interleave_bitmask;
3310 struct bitmask* os::Linux::_numa_membind_bitmask;
3311
3312 bool os::pd_uncommit_memory(char* addr, size_t size) {
3313 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
3314 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
3315 return res != (uintptr_t) MAP_FAILED;
3316 }
3317
3318 static address get_stack_commited_bottom(address bottom, size_t size) {
3319 address nbot = bottom;
3320 address ntop = bottom + size;
3321
3322 size_t page_sz = os::vm_page_size();
3323 unsigned pages = size / page_sz;
3324
3325 unsigned char vec[1];
3326 unsigned imin = 1, imax = pages + 1, imid;
3327 int mincore_return_value = 0;
3328
3329 assert(imin <= imax, "Unexpected page size");
3330
3331 while (imin < imax) {
3332 imid = (imax + imin) / 2;
3333 nbot = ntop - (imid * page_sz);
3334
3335 // Use a trick with mincore to check whether the page is mapped or not.
3336 // mincore sets vec to 1 if page resides in memory and to 0 if page
3337 // is swapped output but if page we are asking for is unmapped
3338 // it returns -1,ENOMEM
3339 mincore_return_value = mincore(nbot, page_sz, vec);
3340
3341 if (mincore_return_value == -1) {
3342 // Page is not mapped go up
3343 // to find first mapped page
3344 if (errno != EAGAIN) {
3345 assert(errno == ENOMEM, "Unexpected mincore errno");
3346 imax = imid;
3347 }
3348 } else {
3349 // Page is mapped go down
3350 // to find first not mapped page
3351 imin = imid + 1;
3352 }
3353 }
3354
3355 nbot = nbot + page_sz;
3356
3357 // Adjust stack bottom one page up if last checked page is not mapped
3358 if (mincore_return_value == -1) {
3359 nbot = nbot + page_sz;
3360 }
3361
3362 return nbot;
3363 }
3364
3365 bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) {
3366 int mincore_return_value;
3367 const size_t stripe = 1024; // query this many pages each time
3368 unsigned char vec[stripe + 1];
3369 // set a guard
3370 vec[stripe] = 'X';
3371
3372 const size_t page_sz = os::vm_page_size();
3373 size_t pages = size / page_sz;
3374
3375 assert(is_aligned(start, page_sz), "Start address must be page aligned");
3376 assert(is_aligned(size, page_sz), "Size must be page aligned");
3377
3378 committed_start = NULL;
3379
3380 int loops = (pages + stripe - 1) / stripe;
3381 int committed_pages = 0;
3382 address loop_base = start;
3383 bool found_range = false;
3384
3385 for (int index = 0; index < loops && !found_range; index ++) {
3386 assert(pages > 0, "Nothing to do");
3387 int pages_to_query = (pages >= stripe) ? stripe : pages;
3388 pages -= pages_to_query;
3389
3390 // Get stable read
3391 while ((mincore_return_value = mincore(loop_base, pages_to_query * page_sz, vec)) == -1 && errno == EAGAIN);
3392
3393 // During shutdown, some memory goes away without properly notifying NMT,
3394 // E.g. ConcurrentGCThread/WatcherThread can exit without deleting thread object.
3395 // Bailout and return as not committed for now.
3396 if (mincore_return_value == -1 && errno == ENOMEM) {
3397 return false;
3398 }
3399
3400 assert(vec[stripe] == 'X', "overflow guard");
3401 assert(mincore_return_value == 0, "Range must be valid");
3402 // Process this stripe
3403 for (int vecIdx = 0; vecIdx < pages_to_query; vecIdx ++) {
3404 if ((vec[vecIdx] & 0x01) == 0) { // not committed
3405 // End of current contiguous region
3406 if (committed_start != NULL) {
3407 found_range = true;
3408 break;
3409 }
3410 } else { // committed
3411 // Start of region
3412 if (committed_start == NULL) {
3413 committed_start = loop_base + page_sz * vecIdx;
3414 }
3415 committed_pages ++;
3416 }
3417 }
3418
3419 loop_base += pages_to_query * page_sz;
3420 }
3421
3422 if (committed_start != NULL) {
3423 assert(committed_pages > 0, "Must have committed region");
3424 assert(committed_pages <= int(size / page_sz), "Can not commit more than it has");
3425 assert(committed_start >= start && committed_start < start + size, "Out of range");
3426 committed_size = page_sz * committed_pages;
3427 return true;
3428 } else {
3429 assert(committed_pages == 0, "Should not have committed region");
3430 return false;
3431 }
3432 }
3433
3434
3435 // Linux uses a growable mapping for the stack, and if the mapping for
3436 // the stack guard pages is not removed when we detach a thread the
3437 // stack cannot grow beyond the pages where the stack guard was
3438 // mapped. If at some point later in the process the stack expands to
3439 // that point, the Linux kernel cannot expand the stack any further
3440 // because the guard pages are in the way, and a segfault occurs.
3441 //
3442 // However, it's essential not to split the stack region by unmapping
3443 // a region (leaving a hole) that's already part of the stack mapping,
3444 // so if the stack mapping has already grown beyond the guard pages at
3445 // the time we create them, we have to truncate the stack mapping.
3446 // So, we need to know the extent of the stack mapping when
3447 // create_stack_guard_pages() is called.
3448
3449 // We only need this for stacks that are growable: at the time of
3450 // writing thread stacks don't use growable mappings (i.e. those
3451 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
3452 // only applies to the main thread.
3453
3454 // If the (growable) stack mapping already extends beyond the point
3455 // where we're going to put our guard pages, truncate the mapping at
3456 // that point by munmap()ping it. This ensures that when we later
3457 // munmap() the guard pages we don't leave a hole in the stack
3458 // mapping. This only affects the main/primordial thread
3459
3460 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
3461 if (os::is_primordial_thread()) {
3462 // As we manually grow stack up to bottom inside create_attached_thread(),
3463 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and
3464 // we don't need to do anything special.
3465 // Check it first, before calling heavy function.
3466 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom();
3467 unsigned char vec[1];
3468
3469 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) {
3470 // Fallback to slow path on all errors, including EAGAIN
3471 stack_extent = (uintptr_t) get_stack_commited_bottom(
3472 os::Linux::initial_thread_stack_bottom(),
3473 (size_t)addr - stack_extent);
3474 }
3475
3476 if (stack_extent < (uintptr_t)addr) {
3477 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent));
3478 }
3479 }
3480
3481 return os::commit_memory(addr, size, !ExecMem);
3482 }
3483
3484 // If this is a growable mapping, remove the guard pages entirely by
3485 // munmap()ping them. If not, just call uncommit_memory(). This only
3486 // affects the main/primordial thread, but guard against future OS changes.
3487 // It's safe to always unmap guard pages for primordial thread because we
3488 // always place it right after end of the mapped region.
3489
3490 bool os::remove_stack_guard_pages(char* addr, size_t size) {
3491 uintptr_t stack_extent, stack_base;
3492
3493 if (os::is_primordial_thread()) {
3494 return ::munmap(addr, size) == 0;
3495 }
3496
3497 return os::uncommit_memory(addr, size);
3498 }
3499
3500 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
3501 // at 'requested_addr'. If there are existing memory mappings at the same
3502 // location, however, they will be overwritten. If 'fixed' is false,
3503 // 'requested_addr' is only treated as a hint, the return value may or
3504 // may not start from the requested address. Unlike Linux mmap(), this
3505 // function returns NULL to indicate failure.
3506 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
3507 char * addr;
3508 int flags;
3509
3510 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
3511 if (fixed) {
3512 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
3513 flags |= MAP_FIXED;
3514 }
3515
3516 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
3517 // touch an uncommitted page. Otherwise, the read/write might
3518 // succeed if we have enough swap space to back the physical page.
3519 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
3520 flags, -1, 0);
3521
3522 return addr == MAP_FAILED ? NULL : addr;
3523 }
3524
3525 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address
3526 // (req_addr != NULL) or with a given alignment.
3527 // - bytes shall be a multiple of alignment.
3528 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3529 // - alignment sets the alignment at which memory shall be allocated.
3530 // It must be a multiple of allocation granularity.
3531 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3532 // req_addr or NULL.
3533 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) {
3534
3535 size_t extra_size = bytes;
3536 if (req_addr == NULL && alignment > 0) {
3537 extra_size += alignment;
3538 }
3539
3540 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE,
3541 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
3542 -1, 0);
3543 if (start == MAP_FAILED) {
3544 start = NULL;
3545 } else {
3546 if (req_addr != NULL) {
3547 if (start != req_addr) {
3548 ::munmap(start, extra_size);
3549 start = NULL;
3550 }
3551 } else {
3552 char* const start_aligned = align_up(start, alignment);
3553 char* const end_aligned = start_aligned + bytes;
3554 char* const end = start + extra_size;
3555 if (start_aligned > start) {
3556 ::munmap(start, start_aligned - start);
3557 }
3558 if (end_aligned < end) {
3559 ::munmap(end_aligned, end - end_aligned);
3560 }
3561 start = start_aligned;
3562 }
3563 }
3564 return start;
3565 }
3566
3567 static int anon_munmap(char * addr, size_t size) {
3568 return ::munmap(addr, size) == 0;
3569 }
3570
3571 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
3572 size_t alignment_hint) {
3573 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
3574 }
3575
3576 bool os::pd_release_memory(char* addr, size_t size) {
3577 return anon_munmap(addr, size);
3578 }
3579
3580 static bool linux_mprotect(char* addr, size_t size, int prot) {
3581 // Linux wants the mprotect address argument to be page aligned.
3582 char* bottom = (char*)align_down((intptr_t)addr, os::Linux::page_size());
3583
3584 // According to SUSv3, mprotect() should only be used with mappings
3585 // established by mmap(), and mmap() always maps whole pages. Unaligned
3586 // 'addr' likely indicates problem in the VM (e.g. trying to change
3587 // protection of malloc'ed or statically allocated memory). Check the
3588 // caller if you hit this assert.
3589 assert(addr == bottom, "sanity check");
3590
3591 size = align_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
3592 Events::log(NULL, "Protecting memory [" INTPTR_FORMAT "," INTPTR_FORMAT "] with protection modes %x", p2i(bottom), p2i(bottom+size), prot);
3593 return ::mprotect(bottom, size, prot) == 0;
3594 }
3595
3596 // Set protections specified
3597 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
3598 bool is_committed) {
3599 unsigned int p = 0;
3600 switch (prot) {
3601 case MEM_PROT_NONE: p = PROT_NONE; break;
3602 case MEM_PROT_READ: p = PROT_READ; break;
3603 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
3604 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
3605 default:
3606 ShouldNotReachHere();
3607 }
3608 // is_committed is unused.
3609 return linux_mprotect(addr, bytes, p);
3610 }
3611
3612 bool os::guard_memory(char* addr, size_t size) {
3613 return linux_mprotect(addr, size, PROT_NONE);
3614 }
3615
3616 bool os::unguard_memory(char* addr, size_t size) {
3617 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
3618 }
3619
3620 bool os::Linux::transparent_huge_pages_sanity_check(bool warn,
3621 size_t page_size) {
3622 bool result = false;
3623 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
3624 MAP_ANONYMOUS|MAP_PRIVATE,
3625 -1, 0);
3626 if (p != MAP_FAILED) {
3627 void *aligned_p = align_up(p, page_size);
3628
3629 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
3630
3631 munmap(p, page_size * 2);
3632 }
3633
3634 if (warn && !result) {
3635 warning("TransparentHugePages is not supported by the operating system.");
3636 }
3637
3638 return result;
3639 }
3640
3641 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
3642 bool result = false;
3643 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
3644 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
3645 -1, 0);
3646
3647 if (p != MAP_FAILED) {
3648 // We don't know if this really is a huge page or not.
3649 FILE *fp = fopen("/proc/self/maps", "r");
3650 if (fp) {
3651 while (!feof(fp)) {
3652 char chars[257];
3653 long x = 0;
3654 if (fgets(chars, sizeof(chars), fp)) {
3655 if (sscanf(chars, "%lx-%*x", &x) == 1
3656 && x == (long)p) {
3657 if (strstr (chars, "hugepage")) {
3658 result = true;
3659 break;
3660 }
3661 }
3662 }
3663 }
3664 fclose(fp);
3665 }
3666 munmap(p, page_size);
3667 }
3668
3669 if (warn && !result) {
3670 warning("HugeTLBFS is not supported by the operating system.");
3671 }
3672
3673 return result;
3674 }
3675
3676 // From the coredump_filter documentation:
3677 //
3678 // - (bit 0) anonymous private memory
3679 // - (bit 1) anonymous shared memory
3680 // - (bit 2) file-backed private memory
3681 // - (bit 3) file-backed shared memory
3682 // - (bit 4) ELF header pages in file-backed private memory areas (it is
3683 // effective only if the bit 2 is cleared)
3684 // - (bit 5) hugetlb private memory
3685 // - (bit 6) hugetlb shared memory
3686 // - (bit 7) dax private memory
3687 // - (bit 8) dax shared memory
3688 //
3689 static void set_coredump_filter(CoredumpFilterBit bit) {
3690 FILE *f;
3691 long cdm;
3692
3693 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
3694 return;
3695 }
3696
3697 if (fscanf(f, "%lx", &cdm) != 1) {
3698 fclose(f);
3699 return;
3700 }
3701
3702 long saved_cdm = cdm;
3703 rewind(f);
3704 cdm |= bit;
3705
3706 if (cdm != saved_cdm) {
3707 fprintf(f, "%#lx", cdm);
3708 }
3709
3710 fclose(f);
3711 }
3712
3713 // Large page support
3714
3715 static size_t _large_page_size = 0;
3716
3717 size_t os::Linux::find_large_page_size() {
3718 size_t large_page_size = 0;
3719
3720 // large_page_size on Linux is used to round up heap size. x86 uses either
3721 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3722 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3723 // page as large as 256M.
3724 //
3725 // Here we try to figure out page size by parsing /proc/meminfo and looking
3726 // for a line with the following format:
3727 // Hugepagesize: 2048 kB
3728 //
3729 // If we can't determine the value (e.g. /proc is not mounted, or the text
3730 // format has been changed), we'll use the largest page size supported by
3731 // the processor.
3732
3733 #ifndef ZERO
3734 large_page_size =
3735 AARCH64_ONLY(2 * M)
3736 AMD64_ONLY(2 * M)
3737 ARM32_ONLY(2 * M)
3738 IA32_ONLY(4 * M)
3739 IA64_ONLY(256 * M)
3740 PPC_ONLY(4 * M)
3741 S390_ONLY(1 * M)
3742 SPARC_ONLY(4 * M);
3743 #endif // ZERO
3744
3745 FILE *fp = fopen("/proc/meminfo", "r");
3746 if (fp) {
3747 while (!feof(fp)) {
3748 int x = 0;
3749 char buf[16];
3750 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3751 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3752 large_page_size = x * K;
3753 break;
3754 }
3755 } else {
3756 // skip to next line
3757 for (;;) {
3758 int ch = fgetc(fp);
3759 if (ch == EOF || ch == (int)'\n') break;
3760 }
3761 }
3762 }
3763 fclose(fp);
3764 }
3765
3766 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) {
3767 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is "
3768 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size),
3769 proper_unit_for_byte_size(large_page_size));
3770 }
3771
3772 return large_page_size;
3773 }
3774
3775 size_t os::Linux::setup_large_page_size() {
3776 _large_page_size = Linux::find_large_page_size();
3777 const size_t default_page_size = (size_t)Linux::page_size();
3778 if (_large_page_size > default_page_size) {
3779 _page_sizes[0] = _large_page_size;
3780 _page_sizes[1] = default_page_size;
3781 _page_sizes[2] = 0;
3782 }
3783
3784 return _large_page_size;
3785 }
3786
3787 bool os::Linux::setup_large_page_type(size_t page_size) {
3788 if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
3789 FLAG_IS_DEFAULT(UseSHM) &&
3790 FLAG_IS_DEFAULT(UseTransparentHugePages)) {
3791
3792 // The type of large pages has not been specified by the user.
3793
3794 // Try UseHugeTLBFS and then UseSHM.
3795 UseHugeTLBFS = UseSHM = true;
3796
3797 // Don't try UseTransparentHugePages since there are known
3798 // performance issues with it turned on. This might change in the future.
3799 UseTransparentHugePages = false;
3800 }
3801
3802 if (UseTransparentHugePages) {
3803 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
3804 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
3805 UseHugeTLBFS = false;
3806 UseSHM = false;
3807 return true;
3808 }
3809 UseTransparentHugePages = false;
3810 }
3811
3812 if (UseHugeTLBFS) {
3813 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3814 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3815 UseSHM = false;
3816 return true;
3817 }
3818 UseHugeTLBFS = false;
3819 }
3820
3821 return UseSHM;
3822 }
3823
3824 void os::large_page_init() {
3825 if (!UseLargePages &&
3826 !UseTransparentHugePages &&
3827 !UseHugeTLBFS &&
3828 !UseSHM) {
3829 // Not using large pages.
3830 return;
3831 }
3832
3833 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
3834 // The user explicitly turned off large pages.
3835 // Ignore the rest of the large pages flags.
3836 UseTransparentHugePages = false;
3837 UseHugeTLBFS = false;
3838 UseSHM = false;
3839 return;
3840 }
3841
3842 size_t large_page_size = Linux::setup_large_page_size();
3843 UseLargePages = Linux::setup_large_page_type(large_page_size);
3844
3845 set_coredump_filter(LARGEPAGES_BIT);
3846 }
3847
3848 #ifndef SHM_HUGETLB
3849 #define SHM_HUGETLB 04000
3850 #endif
3851
3852 #define shm_warning_format(format, ...) \
3853 do { \
3854 if (UseLargePages && \
3855 (!FLAG_IS_DEFAULT(UseLargePages) || \
3856 !FLAG_IS_DEFAULT(UseSHM) || \
3857 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \
3858 warning(format, __VA_ARGS__); \
3859 } \
3860 } while (0)
3861
3862 #define shm_warning(str) shm_warning_format("%s", str)
3863
3864 #define shm_warning_with_errno(str) \
3865 do { \
3866 int err = errno; \
3867 shm_warning_format(str " (error = %d)", err); \
3868 } while (0)
3869
3870 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) {
3871 assert(is_aligned(bytes, alignment), "Must be divisible by the alignment");
3872
3873 if (!is_aligned(alignment, SHMLBA)) {
3874 assert(false, "Code below assumes that alignment is at least SHMLBA aligned");
3875 return NULL;
3876 }
3877
3878 // To ensure that we get 'alignment' aligned memory from shmat,
3879 // we pre-reserve aligned virtual memory and then attach to that.
3880
3881 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL);
3882 if (pre_reserved_addr == NULL) {
3883 // Couldn't pre-reserve aligned memory.
3884 shm_warning("Failed to pre-reserve aligned memory for shmat.");
3885 return NULL;
3886 }
3887
3888 // SHM_REMAP is needed to allow shmat to map over an existing mapping.
3889 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP);
3890
3891 if ((intptr_t)addr == -1) {
3892 int err = errno;
3893 shm_warning_with_errno("Failed to attach shared memory.");
3894
3895 assert(err != EACCES, "Unexpected error");
3896 assert(err != EIDRM, "Unexpected error");
3897 assert(err != EINVAL, "Unexpected error");
3898
3899 // Since we don't know if the kernel unmapped the pre-reserved memory area
3900 // we can't unmap it, since that would potentially unmap memory that was
3901 // mapped from other threads.
3902 return NULL;
3903 }
3904
3905 return addr;
3906 }
3907
3908 static char* shmat_at_address(int shmid, char* req_addr) {
3909 if (!is_aligned(req_addr, SHMLBA)) {
3910 assert(false, "Requested address needs to be SHMLBA aligned");
3911 return NULL;
3912 }
3913
3914 char* addr = (char*)shmat(shmid, req_addr, 0);
3915
3916 if ((intptr_t)addr == -1) {
3917 shm_warning_with_errno("Failed to attach shared memory.");
3918 return NULL;
3919 }
3920
3921 return addr;
3922 }
3923
3924 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) {
3925 // If a req_addr has been provided, we assume that the caller has already aligned the address.
3926 if (req_addr != NULL) {
3927 assert(is_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size");
3928 assert(is_aligned(req_addr, alignment), "Must be divisible by given alignment");
3929 return shmat_at_address(shmid, req_addr);
3930 }
3931
3932 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically
3933 // return large page size aligned memory addresses when req_addr == NULL.
3934 // However, if the alignment is larger than the large page size, we have
3935 // to manually ensure that the memory returned is 'alignment' aligned.
3936 if (alignment > os::large_page_size()) {
3937 assert(is_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size");
3938 return shmat_with_alignment(shmid, bytes, alignment);
3939 } else {
3940 return shmat_at_address(shmid, NULL);
3941 }
3942 }
3943
3944 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment,
3945 char* req_addr, bool exec) {
3946 // "exec" is passed in but not used. Creating the shared image for
3947 // the code cache doesn't have an SHM_X executable permission to check.
3948 assert(UseLargePages && UseSHM, "only for SHM large pages");
3949 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address");
3950 assert(is_aligned(req_addr, alignment), "Unaligned address");
3951
3952 if (!is_aligned(bytes, os::large_page_size())) {
3953 return NULL; // Fallback to small pages.
3954 }
3955
3956 // Create a large shared memory region to attach to based on size.
3957 // Currently, size is the total size of the heap.
3958 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3959 if (shmid == -1) {
3960 // Possible reasons for shmget failure:
3961 // 1. shmmax is too small for Java heap.
3962 // > check shmmax value: cat /proc/sys/kernel/shmmax
3963 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3964 // 2. not enough large page memory.
3965 // > check available large pages: cat /proc/meminfo
3966 // > increase amount of large pages:
3967 // echo new_value > /proc/sys/vm/nr_hugepages
3968 // Note 1: different Linux may use different name for this property,
3969 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3970 // Note 2: it's possible there's enough physical memory available but
3971 // they are so fragmented after a long run that they can't
3972 // coalesce into large pages. Try to reserve large pages when
3973 // the system is still "fresh".
3974 shm_warning_with_errno("Failed to reserve shared memory.");
3975 return NULL;
3976 }
3977
3978 // Attach to the region.
3979 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr);
3980
3981 // Remove shmid. If shmat() is successful, the actual shared memory segment
3982 // will be deleted when it's detached by shmdt() or when the process
3983 // terminates. If shmat() is not successful this will remove the shared
3984 // segment immediately.
3985 shmctl(shmid, IPC_RMID, NULL);
3986
3987 return addr;
3988 }
3989
3990 static void warn_on_large_pages_failure(char* req_addr, size_t bytes,
3991 int error) {
3992 assert(error == ENOMEM, "Only expect to fail if no memory is available");
3993
3994 bool warn_on_failure = UseLargePages &&
3995 (!FLAG_IS_DEFAULT(UseLargePages) ||
3996 !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
3997 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
3998
3999 if (warn_on_failure) {
4000 char msg[128];
4001 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
4002 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
4003 warning("%s", msg);
4004 }
4005 }
4006
4007 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes,
4008 char* req_addr,
4009 bool exec) {
4010 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
4011 assert(is_aligned(bytes, os::large_page_size()), "Unaligned size");
4012 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address");
4013
4014 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
4015 char* addr = (char*)::mmap(req_addr, bytes, prot,
4016 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB,
4017 -1, 0);
4018
4019 if (addr == MAP_FAILED) {
4020 warn_on_large_pages_failure(req_addr, bytes, errno);
4021 return NULL;
4022 }
4023
4024 assert(is_aligned(addr, os::large_page_size()), "Must be");
4025
4026 return addr;
4027 }
4028
4029 // Reserve memory using mmap(MAP_HUGETLB).
4030 // - bytes shall be a multiple of alignment.
4031 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
4032 // - alignment sets the alignment at which memory shall be allocated.
4033 // It must be a multiple of allocation granularity.
4034 // Returns address of memory or NULL. If req_addr was not NULL, will only return
4035 // req_addr or NULL.
4036 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes,
4037 size_t alignment,
4038 char* req_addr,
4039 bool exec) {
4040 size_t large_page_size = os::large_page_size();
4041 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
4042
4043 assert(is_aligned(req_addr, alignment), "Must be");
4044 assert(is_aligned(bytes, alignment), "Must be");
4045
4046 // First reserve - but not commit - the address range in small pages.
4047 char* const start = anon_mmap_aligned(bytes, alignment, req_addr);
4048
4049 if (start == NULL) {
4050 return NULL;
4051 }
4052
4053 assert(is_aligned(start, alignment), "Must be");
4054
4055 char* end = start + bytes;
4056
4057 // Find the regions of the allocated chunk that can be promoted to large pages.
4058 char* lp_start = align_up(start, large_page_size);
4059 char* lp_end = align_down(end, large_page_size);
4060
4061 size_t lp_bytes = lp_end - lp_start;
4062
4063 assert(is_aligned(lp_bytes, large_page_size), "Must be");
4064
4065 if (lp_bytes == 0) {
4066 // The mapped region doesn't even span the start and the end of a large page.
4067 // Fall back to allocate a non-special area.
4068 ::munmap(start, end - start);
4069 return NULL;
4070 }
4071
4072 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
4073
4074 void* result;
4075
4076 // Commit small-paged leading area.
4077 if (start != lp_start) {
4078 result = ::mmap(start, lp_start - start, prot,
4079 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
4080 -1, 0);
4081 if (result == MAP_FAILED) {
4082 ::munmap(lp_start, end - lp_start);
4083 return NULL;
4084 }
4085 }
4086
4087 // Commit large-paged area.
4088 result = ::mmap(lp_start, lp_bytes, prot,
4089 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB,
4090 -1, 0);
4091 if (result == MAP_FAILED) {
4092 warn_on_large_pages_failure(lp_start, lp_bytes, errno);
4093 // If the mmap above fails, the large pages region will be unmapped and we
4094 // have regions before and after with small pages. Release these regions.
4095 //
4096 // | mapped | unmapped | mapped |
4097 // ^ ^ ^ ^
4098 // start lp_start lp_end end
4099 //
4100 ::munmap(start, lp_start - start);
4101 ::munmap(lp_end, end - lp_end);
4102 return NULL;
4103 }
4104
4105 // Commit small-paged trailing area.
4106 if (lp_end != end) {
4107 result = ::mmap(lp_end, end - lp_end, prot,
4108 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
4109 -1, 0);
4110 if (result == MAP_FAILED) {
4111 ::munmap(start, lp_end - start);
4112 return NULL;
4113 }
4114 }
4115
4116 return start;
4117 }
4118
4119 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes,
4120 size_t alignment,
4121 char* req_addr,
4122 bool exec) {
4123 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
4124 assert(is_aligned(req_addr, alignment), "Must be");
4125 assert(is_aligned(alignment, os::vm_allocation_granularity()), "Must be");
4126 assert(is_power_of_2(os::large_page_size()), "Must be");
4127 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
4128
4129 if (is_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
4130 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
4131 } else {
4132 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
4133 }
4134 }
4135
4136 char* os::reserve_memory_special(size_t bytes, size_t alignment,
4137 char* req_addr, bool exec) {
4138 assert(UseLargePages, "only for large pages");
4139
4140 char* addr;
4141 if (UseSHM) {
4142 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
4143 } else {
4144 assert(UseHugeTLBFS, "must be");
4145 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
4146 }
4147
4148 if (addr != NULL) {
4149 if (UseNUMAInterleaving) {
4150 numa_make_global(addr, bytes);
4151 }
4152
4153 // The memory is committed
4154 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC);
4155 }
4156
4157 return addr;
4158 }
4159
4160 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
4161 // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
4162 return shmdt(base) == 0;
4163 }
4164
4165 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
4166 return pd_release_memory(base, bytes);
4167 }
4168
4169 bool os::release_memory_special(char* base, size_t bytes) {
4170 bool res;
4171 if (MemTracker::tracking_level() > NMT_minimal) {
4172 Tracker tkr(Tracker::release);
4173 res = os::Linux::release_memory_special_impl(base, bytes);
4174 if (res) {
4175 tkr.record((address)base, bytes);
4176 }
4177
4178 } else {
4179 res = os::Linux::release_memory_special_impl(base, bytes);
4180 }
4181 return res;
4182 }
4183
4184 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) {
4185 assert(UseLargePages, "only for large pages");
4186 bool res;
4187
4188 if (UseSHM) {
4189 res = os::Linux::release_memory_special_shm(base, bytes);
4190 } else {
4191 assert(UseHugeTLBFS, "must be");
4192 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
4193 }
4194 return res;
4195 }
4196
4197 size_t os::large_page_size() {
4198 return _large_page_size;
4199 }
4200
4201 // With SysV SHM the entire memory region must be allocated as shared
4202 // memory.
4203 // HugeTLBFS allows application to commit large page memory on demand.
4204 // However, when committing memory with HugeTLBFS fails, the region
4205 // that was supposed to be committed will lose the old reservation
4206 // and allow other threads to steal that memory region. Because of this
4207 // behavior we can't commit HugeTLBFS memory.
4208 bool os::can_commit_large_page_memory() {
4209 return UseTransparentHugePages;
4210 }
4211
4212 bool os::can_execute_large_page_memory() {
4213 return UseTransparentHugePages || UseHugeTLBFS;
4214 }
4215
4216 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr, int file_desc) {
4217 assert(file_desc >= 0, "file_desc is not valid");
4218 char* result = pd_attempt_reserve_memory_at(bytes, requested_addr);
4219 if (result != NULL) {
4220 if (replace_existing_mapping_with_file_mapping(result, bytes, file_desc) == NULL) {
4221 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory"));
4222 }
4223 }
4224 return result;
4225 }
4226
4227 // Reserve memory at an arbitrary address, only if that area is
4228 // available (and not reserved for something else).
4229
4230 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
4231 // Assert only that the size is a multiple of the page size, since
4232 // that's all that mmap requires, and since that's all we really know
4233 // about at this low abstraction level. If we need higher alignment,
4234 // we can either pass an alignment to this method or verify alignment
4235 // in one of the methods further up the call chain. See bug 5044738.
4236 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
4237
4238 // Repeatedly allocate blocks until the block is allocated at the
4239 // right spot.
4240
4241 // Linux mmap allows caller to pass an address as hint; give it a try first,
4242 // if kernel honors the hint then we can return immediately.
4243 char * addr = anon_mmap(requested_addr, bytes, false);
4244 if (addr == requested_addr) {
4245 return requested_addr;
4246 }
4247
4248 if (addr != NULL) {
4249 // mmap() is successful but it fails to reserve at the requested address
4250 anon_munmap(addr, bytes);
4251 }
4252
4253 return NULL;
4254 }
4255
4256 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
4257 void os::infinite_sleep() {
4258 while (true) { // sleep forever ...
4259 ::sleep(100); // ... 100 seconds at a time
4260 }
4261 }
4262
4263 // Used to convert frequent JVM_Yield() to nops
4264 bool os::dont_yield() {
4265 return DontYieldALot;
4266 }
4267
4268 // Linux CFS scheduler (since 2.6.23) does not guarantee sched_yield(2) will
4269 // actually give up the CPU. Since skip buddy (v2.6.28):
4270 //
4271 // * Sets the yielding task as skip buddy for current CPU's run queue.
4272 // * Picks next from run queue, if empty, picks a skip buddy (can be the yielding task).
4273 // * Clears skip buddies for this run queue (yielding task no longer a skip buddy).
4274 //
4275 // An alternative is calling os::naked_short_nanosleep with a small number to avoid
4276 // getting re-scheduled immediately.
4277 //
4278 void os::naked_yield() {
4279 sched_yield();
4280 }
4281
4282 ////////////////////////////////////////////////////////////////////////////////
4283 // thread priority support
4284
4285 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
4286 // only supports dynamic priority, static priority must be zero. For real-time
4287 // applications, Linux supports SCHED_RR which allows static priority (1-99).
4288 // However, for large multi-threaded applications, SCHED_RR is not only slower
4289 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
4290 // of 5 runs - Sep 2005).
4291 //
4292 // The following code actually changes the niceness of kernel-thread/LWP. It
4293 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
4294 // not the entire user process, and user level threads are 1:1 mapped to kernel
4295 // threads. It has always been the case, but could change in the future. For
4296 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
4297 // It is only used when ThreadPriorityPolicy=1 and may require system level permission
4298 // (e.g., root privilege or CAP_SYS_NICE capability).
4299
4300 int os::java_to_os_priority[CriticalPriority + 1] = {
4301 19, // 0 Entry should never be used
4302
4303 4, // 1 MinPriority
4304 3, // 2
4305 2, // 3
4306
4307 1, // 4
4308 0, // 5 NormPriority
4309 -1, // 6
4310
4311 -2, // 7
4312 -3, // 8
4313 -4, // 9 NearMaxPriority
4314
4315 -5, // 10 MaxPriority
4316
4317 -5 // 11 CriticalPriority
4318 };
4319
4320 static int prio_init() {
4321 if (ThreadPriorityPolicy == 1) {
4322 if (geteuid() != 0) {
4323 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
4324 warning("-XX:ThreadPriorityPolicy=1 may require system level permission, " \
4325 "e.g., being the root user. If the necessary permission is not " \
4326 "possessed, changes to priority will be silently ignored.");
4327 }
4328 }
4329 }
4330 if (UseCriticalJavaThreadPriority) {
4331 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
4332 }
4333 return 0;
4334 }
4335
4336 OSReturn os::set_native_priority(Thread* thread, int newpri) {
4337 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK;
4338
4339 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
4340 return (ret == 0) ? OS_OK : OS_ERR;
4341 }
4342
4343 OSReturn os::get_native_priority(const Thread* const thread,
4344 int *priority_ptr) {
4345 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) {
4346 *priority_ptr = java_to_os_priority[NormPriority];
4347 return OS_OK;
4348 }
4349
4350 errno = 0;
4351 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
4352 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
4353 }
4354
4355 ////////////////////////////////////////////////////////////////////////////////
4356 // suspend/resume support
4357
4358 // The low-level signal-based suspend/resume support is a remnant from the
4359 // old VM-suspension that used to be for java-suspension, safepoints etc,
4360 // within hotspot. Currently used by JFR's OSThreadSampler
4361 //
4362 // The remaining code is greatly simplified from the more general suspension
4363 // code that used to be used.
4364 //
4365 // The protocol is quite simple:
4366 // - suspend:
4367 // - sends a signal to the target thread
4368 // - polls the suspend state of the osthread using a yield loop
4369 // - target thread signal handler (SR_handler) sets suspend state
4370 // and blocks in sigsuspend until continued
4371 // - resume:
4372 // - sets target osthread state to continue
4373 // - sends signal to end the sigsuspend loop in the SR_handler
4374 //
4375 // Note that the SR_lock plays no role in this suspend/resume protocol,
4376 // but is checked for NULL in SR_handler as a thread termination indicator.
4377 // The SR_lock is, however, used by JavaThread::java_suspend()/java_resume() APIs.
4378 //
4379 // Note that resume_clear_context() and suspend_save_context() are needed
4380 // by SR_handler(), so that fetch_frame_from_ucontext() works,
4381 // which in part is used by:
4382 // - Forte Analyzer: AsyncGetCallTrace()
4383 // - StackBanging: get_frame_at_stack_banging_point()
4384
4385 static void resume_clear_context(OSThread *osthread) {
4386 osthread->set_ucontext(NULL);
4387 osthread->set_siginfo(NULL);
4388 }
4389
4390 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo,
4391 ucontext_t* context) {
4392 osthread->set_ucontext(context);
4393 osthread->set_siginfo(siginfo);
4394 }
4395
4396 // Handler function invoked when a thread's execution is suspended or
4397 // resumed. We have to be careful that only async-safe functions are
4398 // called here (Note: most pthread functions are not async safe and
4399 // should be avoided.)
4400 //
4401 // Note: sigwait() is a more natural fit than sigsuspend() from an
4402 // interface point of view, but sigwait() prevents the signal hander
4403 // from being run. libpthread would get very confused by not having
4404 // its signal handlers run and prevents sigwait()'s use with the
4405 // mutex granting granting signal.
4406 //
4407 // Currently only ever called on the VMThread and JavaThreads (PC sampling)
4408 //
4409 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
4410 // Save and restore errno to avoid confusing native code with EINTR
4411 // after sigsuspend.
4412 int old_errno = errno;
4413
4414 Thread* thread = Thread::current_or_null_safe();
4415 assert(thread != NULL, "Missing current thread in SR_handler");
4416
4417 // On some systems we have seen signal delivery get "stuck" until the signal
4418 // mask is changed as part of thread termination. Check that the current thread
4419 // has not already terminated (via SR_lock()) - else the following assertion
4420 // will fail because the thread is no longer a JavaThread as the ~JavaThread
4421 // destructor has completed.
4422
4423 if (thread->SR_lock() == NULL) {
4424 return;
4425 }
4426
4427 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
4428
4429 OSThread* osthread = thread->osthread();
4430
4431 os::SuspendResume::State current = osthread->sr.state();
4432 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
4433 suspend_save_context(osthread, siginfo, context);
4434
4435 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
4436 os::SuspendResume::State state = osthread->sr.suspended();
4437 if (state == os::SuspendResume::SR_SUSPENDED) {
4438 sigset_t suspend_set; // signals for sigsuspend()
4439 sigemptyset(&suspend_set);
4440 // get current set of blocked signals and unblock resume signal
4441 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
4442 sigdelset(&suspend_set, SR_signum);
4443
4444 sr_semaphore.signal();
4445 // wait here until we are resumed
4446 while (1) {
4447 sigsuspend(&suspend_set);
4448
4449 os::SuspendResume::State result = osthread->sr.running();
4450 if (result == os::SuspendResume::SR_RUNNING) {
4451 sr_semaphore.signal();
4452 break;
4453 }
4454 }
4455
4456 } else if (state == os::SuspendResume::SR_RUNNING) {
4457 // request was cancelled, continue
4458 } else {
4459 ShouldNotReachHere();
4460 }
4461
4462 resume_clear_context(osthread);
4463 } else if (current == os::SuspendResume::SR_RUNNING) {
4464 // request was cancelled, continue
4465 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
4466 // ignore
4467 } else {
4468 // ignore
4469 }
4470
4471 errno = old_errno;
4472 }
4473
4474 static int SR_initialize() {
4475 struct sigaction act;
4476 char *s;
4477
4478 // Get signal number to use for suspend/resume
4479 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
4480 int sig = ::strtol(s, 0, 10);
4481 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769.
4482 sig < NSIG) { // Must be legal signal and fit into sigflags[].
4483 SR_signum = sig;
4484 } else {
4485 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.",
4486 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum);
4487 }
4488 }
4489
4490 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
4491 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
4492
4493 sigemptyset(&SR_sigset);
4494 sigaddset(&SR_sigset, SR_signum);
4495
4496 // Set up signal handler for suspend/resume
4497 act.sa_flags = SA_RESTART|SA_SIGINFO;
4498 act.sa_handler = (void (*)(int)) SR_handler;
4499
4500 // SR_signum is blocked by default.
4501 // 4528190 - We also need to block pthread restart signal (32 on all
4502 // supported Linux platforms). Note that LinuxThreads need to block
4503 // this signal for all threads to work properly. So we don't have
4504 // to use hard-coded signal number when setting up the mask.
4505 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
4506
4507 if (sigaction(SR_signum, &act, 0) == -1) {
4508 return -1;
4509 }
4510
4511 // Save signal flag
4512 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
4513 return 0;
4514 }
4515
4516 static int sr_notify(OSThread* osthread) {
4517 int status = pthread_kill(osthread->pthread_id(), SR_signum);
4518 assert_status(status == 0, status, "pthread_kill");
4519 return status;
4520 }
4521
4522 // "Randomly" selected value for how long we want to spin
4523 // before bailing out on suspending a thread, also how often
4524 // we send a signal to a thread we want to resume
4525 static const int RANDOMLY_LARGE_INTEGER = 1000000;
4526 static const int RANDOMLY_LARGE_INTEGER2 = 100;
4527
4528 // returns true on success and false on error - really an error is fatal
4529 // but this seems the normal response to library errors
4530 static bool do_suspend(OSThread* osthread) {
4531 assert(osthread->sr.is_running(), "thread should be running");
4532 assert(!sr_semaphore.trywait(), "semaphore has invalid state");
4533
4534 // mark as suspended and send signal
4535 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
4536 // failed to switch, state wasn't running?
4537 ShouldNotReachHere();
4538 return false;
4539 }
4540
4541 if (sr_notify(osthread) != 0) {
4542 ShouldNotReachHere();
4543 }
4544
4545 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
4546 while (true) {
4547 if (sr_semaphore.timedwait(2)) {
4548 break;
4549 } else {
4550 // timeout
4551 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
4552 if (cancelled == os::SuspendResume::SR_RUNNING) {
4553 return false;
4554 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
4555 // make sure that we consume the signal on the semaphore as well
4556 sr_semaphore.wait();
4557 break;
4558 } else {
4559 ShouldNotReachHere();
4560 return false;
4561 }
4562 }
4563 }
4564
4565 guarantee(osthread->sr.is_suspended(), "Must be suspended");
4566 return true;
4567 }
4568
4569 static void do_resume(OSThread* osthread) {
4570 assert(osthread->sr.is_suspended(), "thread should be suspended");
4571 assert(!sr_semaphore.trywait(), "invalid semaphore state");
4572
4573 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
4574 // failed to switch to WAKEUP_REQUEST
4575 ShouldNotReachHere();
4576 return;
4577 }
4578
4579 while (true) {
4580 if (sr_notify(osthread) == 0) {
4581 if (sr_semaphore.timedwait(2)) {
4582 if (osthread->sr.is_running()) {
4583 return;
4584 }
4585 }
4586 } else {
4587 ShouldNotReachHere();
4588 }
4589 }
4590
4591 guarantee(osthread->sr.is_running(), "Must be running!");
4592 }
4593
4594 ///////////////////////////////////////////////////////////////////////////////////
4595 // signal handling (except suspend/resume)
4596
4597 // This routine may be used by user applications as a "hook" to catch signals.
4598 // The user-defined signal handler must pass unrecognized signals to this
4599 // routine, and if it returns true (non-zero), then the signal handler must
4600 // return immediately. If the flag "abort_if_unrecognized" is true, then this
4601 // routine will never retun false (zero), but instead will execute a VM panic
4602 // routine kill the process.
4603 //
4604 // If this routine returns false, it is OK to call it again. This allows
4605 // the user-defined signal handler to perform checks either before or after
4606 // the VM performs its own checks. Naturally, the user code would be making
4607 // a serious error if it tried to handle an exception (such as a null check
4608 // or breakpoint) that the VM was generating for its own correct operation.
4609 //
4610 // This routine may recognize any of the following kinds of signals:
4611 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
4612 // It should be consulted by handlers for any of those signals.
4613 //
4614 // The caller of this routine must pass in the three arguments supplied
4615 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
4616 // field of the structure passed to sigaction(). This routine assumes that
4617 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
4618 //
4619 // Note that the VM will print warnings if it detects conflicting signal
4620 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
4621 //
4622 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo,
4623 siginfo_t* siginfo,
4624 void* ucontext,
4625 int abort_if_unrecognized);
4626
4627 static void signalHandler(int sig, siginfo_t* info, void* uc) {
4628 assert(info != NULL && uc != NULL, "it must be old kernel");
4629 int orig_errno = errno; // Preserve errno value over signal handler.
4630 JVM_handle_linux_signal(sig, info, uc, true);
4631 errno = orig_errno;
4632 }
4633
4634
4635 // This boolean allows users to forward their own non-matching signals
4636 // to JVM_handle_linux_signal, harmlessly.
4637 bool os::Linux::signal_handlers_are_installed = false;
4638
4639 // For signal-chaining
4640 bool os::Linux::libjsig_is_loaded = false;
4641 typedef struct sigaction *(*get_signal_t)(int);
4642 get_signal_t os::Linux::get_signal_action = NULL;
4643
4644 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
4645 struct sigaction *actp = NULL;
4646
4647 if (libjsig_is_loaded) {
4648 // Retrieve the old signal handler from libjsig
4649 actp = (*get_signal_action)(sig);
4650 }
4651 if (actp == NULL) {
4652 // Retrieve the preinstalled signal handler from jvm
4653 actp = os::Posix::get_preinstalled_handler(sig);
4654 }
4655
4656 return actp;
4657 }
4658
4659 static bool call_chained_handler(struct sigaction *actp, int sig,
4660 siginfo_t *siginfo, void *context) {
4661 // Call the old signal handler
4662 if (actp->sa_handler == SIG_DFL) {
4663 // It's more reasonable to let jvm treat it as an unexpected exception
4664 // instead of taking the default action.
4665 return false;
4666 } else if (actp->sa_handler != SIG_IGN) {
4667 if ((actp->sa_flags & SA_NODEFER) == 0) {
4668 // automaticlly block the signal
4669 sigaddset(&(actp->sa_mask), sig);
4670 }
4671
4672 sa_handler_t hand = NULL;
4673 sa_sigaction_t sa = NULL;
4674 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
4675 // retrieve the chained handler
4676 if (siginfo_flag_set) {
4677 sa = actp->sa_sigaction;
4678 } else {
4679 hand = actp->sa_handler;
4680 }
4681
4682 if ((actp->sa_flags & SA_RESETHAND) != 0) {
4683 actp->sa_handler = SIG_DFL;
4684 }
4685
4686 // try to honor the signal mask
4687 sigset_t oset;
4688 sigemptyset(&oset);
4689 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
4690
4691 // call into the chained handler
4692 if (siginfo_flag_set) {
4693 (*sa)(sig, siginfo, context);
4694 } else {
4695 (*hand)(sig);
4696 }
4697
4698 // restore the signal mask
4699 pthread_sigmask(SIG_SETMASK, &oset, NULL);
4700 }
4701 // Tell jvm's signal handler the signal is taken care of.
4702 return true;
4703 }
4704
4705 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
4706 bool chained = false;
4707 // signal-chaining
4708 if (UseSignalChaining) {
4709 struct sigaction *actp = get_chained_signal_action(sig);
4710 if (actp != NULL) {
4711 chained = call_chained_handler(actp, sig, siginfo, context);
4712 }
4713 }
4714 return chained;
4715 }
4716
4717 // for diagnostic
4718 int sigflags[NSIG];
4719
4720 int os::Linux::get_our_sigflags(int sig) {
4721 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4722 return sigflags[sig];
4723 }
4724
4725 void os::Linux::set_our_sigflags(int sig, int flags) {
4726 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4727 if (sig > 0 && sig < NSIG) {
4728 sigflags[sig] = flags;
4729 }
4730 }
4731
4732 void os::Linux::set_signal_handler(int sig, bool set_installed) {
4733 // Check for overwrite.
4734 struct sigaction oldAct;
4735 sigaction(sig, (struct sigaction*)NULL, &oldAct);
4736
4737 void* oldhand = oldAct.sa_sigaction
4738 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4739 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4740 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
4741 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
4742 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
4743 if (AllowUserSignalHandlers || !set_installed) {
4744 // Do not overwrite; user takes responsibility to forward to us.
4745 return;
4746 } else if (UseSignalChaining) {
4747 // save the old handler in jvm
4748 os::Posix::save_preinstalled_handler(sig, oldAct);
4749 // libjsig also interposes the sigaction() call below and saves the
4750 // old sigaction on it own.
4751 } else {
4752 fatal("Encountered unexpected pre-existing sigaction handler "
4753 "%#lx for signal %d.", (long)oldhand, sig);
4754 }
4755 }
4756
4757 struct sigaction sigAct;
4758 sigfillset(&(sigAct.sa_mask));
4759 sigAct.sa_handler = SIG_DFL;
4760 if (!set_installed) {
4761 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4762 } else {
4763 sigAct.sa_sigaction = signalHandler;
4764 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4765 }
4766 // Save flags, which are set by ours
4767 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4768 sigflags[sig] = sigAct.sa_flags;
4769
4770 int ret = sigaction(sig, &sigAct, &oldAct);
4771 assert(ret == 0, "check");
4772
4773 void* oldhand2 = oldAct.sa_sigaction
4774 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4775 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4776 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
4777 }
4778
4779 // install signal handlers for signals that HotSpot needs to
4780 // handle in order to support Java-level exception handling.
4781
4782 void os::Linux::install_signal_handlers() {
4783 if (!signal_handlers_are_installed) {
4784 signal_handlers_are_installed = true;
4785
4786 // signal-chaining
4787 typedef void (*signal_setting_t)();
4788 signal_setting_t begin_signal_setting = NULL;
4789 signal_setting_t end_signal_setting = NULL;
4790 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4791 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
4792 if (begin_signal_setting != NULL) {
4793 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4794 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
4795 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
4796 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
4797 libjsig_is_loaded = true;
4798 assert(UseSignalChaining, "should enable signal-chaining");
4799 }
4800 if (libjsig_is_loaded) {
4801 // Tell libjsig jvm is setting signal handlers
4802 (*begin_signal_setting)();
4803 }
4804
4805 set_signal_handler(SIGSEGV, true);
4806 set_signal_handler(SIGPIPE, true);
4807 set_signal_handler(SIGBUS, true);
4808 set_signal_handler(SIGILL, true);
4809 set_signal_handler(SIGFPE, true);
4810 #if defined(PPC64)
4811 set_signal_handler(SIGTRAP, true);
4812 #endif
4813 set_signal_handler(SIGXFSZ, true);
4814
4815 if (libjsig_is_loaded) {
4816 // Tell libjsig jvm finishes setting signal handlers
4817 (*end_signal_setting)();
4818 }
4819
4820 // We don't activate signal checker if libjsig is in place, we trust ourselves
4821 // and if UserSignalHandler is installed all bets are off.
4822 // Log that signal checking is off only if -verbose:jni is specified.
4823 if (CheckJNICalls) {
4824 if (libjsig_is_loaded) {
4825 log_debug(jni, resolve)("Info: libjsig is activated, all active signal checking is disabled");
4826 check_signals = false;
4827 }
4828 if (AllowUserSignalHandlers) {
4829 log_debug(jni, resolve)("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
4830 check_signals = false;
4831 }
4832 }
4833 }
4834 }
4835
4836 // This is the fastest way to get thread cpu time on Linux.
4837 // Returns cpu time (user+sys) for any thread, not only for current.
4838 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
4839 // It might work on 2.6.10+ with a special kernel/glibc patch.
4840 // For reference, please, see IEEE Std 1003.1-2004:
4841 // http://www.unix.org/single_unix_specification
4842
4843 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
4844 struct timespec tp;
4845 int rc = os::Posix::clock_gettime(clockid, &tp);
4846 assert(rc == 0, "clock_gettime is expected to return 0 code");
4847
4848 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
4849 }
4850
4851 /////
4852 // glibc on Linux platform uses non-documented flag
4853 // to indicate, that some special sort of signal
4854 // trampoline is used.
4855 // We will never set this flag, and we should
4856 // ignore this flag in our diagnostic
4857 #ifdef SIGNIFICANT_SIGNAL_MASK
4858 #undef SIGNIFICANT_SIGNAL_MASK
4859 #endif
4860 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
4861
4862 static const char* get_signal_handler_name(address handler,
4863 char* buf, int buflen) {
4864 int offset = 0;
4865 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
4866 if (found) {
4867 // skip directory names
4868 const char *p1, *p2;
4869 p1 = buf;
4870 size_t len = strlen(os::file_separator());
4871 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
4872 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
4873 } else {
4874 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
4875 }
4876 return buf;
4877 }
4878
4879 static void print_signal_handler(outputStream* st, int sig,
4880 char* buf, size_t buflen) {
4881 struct sigaction sa;
4882
4883 sigaction(sig, NULL, &sa);
4884
4885 // See comment for SIGNIFICANT_SIGNAL_MASK define
4886 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4887
4888 st->print("%s: ", os::exception_name(sig, buf, buflen));
4889
4890 address handler = (sa.sa_flags & SA_SIGINFO)
4891 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
4892 : CAST_FROM_FN_PTR(address, sa.sa_handler);
4893
4894 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
4895 st->print("SIG_DFL");
4896 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
4897 st->print("SIG_IGN");
4898 } else {
4899 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
4900 }
4901
4902 st->print(", sa_mask[0]=");
4903 os::Posix::print_signal_set_short(st, &sa.sa_mask);
4904
4905 address rh = VMError::get_resetted_sighandler(sig);
4906 // May be, handler was resetted by VMError?
4907 if (rh != NULL) {
4908 handler = rh;
4909 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
4910 }
4911
4912 st->print(", sa_flags=");
4913 os::Posix::print_sa_flags(st, sa.sa_flags);
4914
4915 // Check: is it our handler?
4916 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
4917 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
4918 // It is our signal handler
4919 // check for flags, reset system-used one!
4920 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
4921 st->print(
4922 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
4923 os::Linux::get_our_sigflags(sig));
4924 }
4925 }
4926 st->cr();
4927 }
4928
4929
4930 #define DO_SIGNAL_CHECK(sig) \
4931 do { \
4932 if (!sigismember(&check_signal_done, sig)) { \
4933 os::Linux::check_signal_handler(sig); \
4934 } \
4935 } while (0)
4936
4937 // This method is a periodic task to check for misbehaving JNI applications
4938 // under CheckJNI, we can add any periodic checks here
4939
4940 void os::run_periodic_checks() {
4941 if (check_signals == false) return;
4942
4943 // SEGV and BUS if overridden could potentially prevent
4944 // generation of hs*.log in the event of a crash, debugging
4945 // such a case can be very challenging, so we absolutely
4946 // check the following for a good measure:
4947 DO_SIGNAL_CHECK(SIGSEGV);
4948 DO_SIGNAL_CHECK(SIGILL);
4949 DO_SIGNAL_CHECK(SIGFPE);
4950 DO_SIGNAL_CHECK(SIGBUS);
4951 DO_SIGNAL_CHECK(SIGPIPE);
4952 DO_SIGNAL_CHECK(SIGXFSZ);
4953 #if defined(PPC64)
4954 DO_SIGNAL_CHECK(SIGTRAP);
4955 #endif
4956
4957 // ReduceSignalUsage allows the user to override these handlers
4958 // see comments at the very top and jvm_md.h
4959 if (!ReduceSignalUsage) {
4960 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4961 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4962 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4963 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4964 }
4965
4966 DO_SIGNAL_CHECK(SR_signum);
4967 }
4968
4969 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4970
4971 static os_sigaction_t os_sigaction = NULL;
4972
4973 void os::Linux::check_signal_handler(int sig) {
4974 char buf[O_BUFLEN];
4975 address jvmHandler = NULL;
4976
4977
4978 struct sigaction act;
4979 if (os_sigaction == NULL) {
4980 // only trust the default sigaction, in case it has been interposed
4981 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4982 if (os_sigaction == NULL) return;
4983 }
4984
4985 os_sigaction(sig, (struct sigaction*)NULL, &act);
4986
4987
4988 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4989
4990 address thisHandler = (act.sa_flags & SA_SIGINFO)
4991 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4992 : CAST_FROM_FN_PTR(address, act.sa_handler);
4993
4994
4995 switch (sig) {
4996 case SIGSEGV:
4997 case SIGBUS:
4998 case SIGFPE:
4999 case SIGPIPE:
5000 case SIGILL:
5001 case SIGXFSZ:
5002 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
5003 break;
5004
5005 case SHUTDOWN1_SIGNAL:
5006 case SHUTDOWN2_SIGNAL:
5007 case SHUTDOWN3_SIGNAL:
5008 case BREAK_SIGNAL:
5009 jvmHandler = (address)user_handler();
5010 break;
5011
5012 default:
5013 if (sig == SR_signum) {
5014 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
5015 } else {
5016 return;
5017 }
5018 break;
5019 }
5020
5021 if (thisHandler != jvmHandler) {
5022 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
5023 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
5024 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
5025 // No need to check this sig any longer
5026 sigaddset(&check_signal_done, sig);
5027 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
5028 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
5029 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
5030 exception_name(sig, buf, O_BUFLEN));
5031 }
5032 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
5033 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
5034 tty->print("expected:");
5035 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig));
5036 tty->cr();
5037 tty->print(" found:");
5038 os::Posix::print_sa_flags(tty, act.sa_flags);
5039 tty->cr();
5040 // No need to check this sig any longer
5041 sigaddset(&check_signal_done, sig);
5042 }
5043
5044 // Dump all the signal
5045 if (sigismember(&check_signal_done, sig)) {
5046 print_signal_handlers(tty, buf, O_BUFLEN);
5047 }
5048 }
5049
5050 extern void report_error(char* file_name, int line_no, char* title,
5051 char* format, ...);
5052
5053 // this is called _before_ most of the global arguments have been parsed
5054 void os::init(void) {
5055 char dummy; // used to get a guess on initial stack address
5056
5057 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
5058
5059 init_random(1234567);
5060
5061 Linux::set_page_size(sysconf(_SC_PAGESIZE));
5062 if (Linux::page_size() == -1) {
5063 fatal("os_linux.cpp: os::init: sysconf failed (%s)",
5064 os::strerror(errno));
5065 }
5066 init_page_sizes((size_t) Linux::page_size());
5067
5068 Linux::initialize_system_info();
5069
5070 os::Linux::CPUPerfTicks pticks;
5071 bool res = os::Linux::get_tick_information(&pticks, -1);
5072
5073 if (res && pticks.has_steal_ticks) {
5074 has_initial_tick_info = true;
5075 initial_total_ticks = pticks.total;
5076 initial_steal_ticks = pticks.steal;
5077 }
5078
5079 // _main_thread points to the thread that created/loaded the JVM.
5080 Linux::_main_thread = pthread_self();
5081
5082 // retrieve entry point for pthread_setname_np
5083 Linux::_pthread_setname_np =
5084 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np");
5085
5086 os::Posix::init();
5087
5088 initial_time_count = javaTimeNanos();
5089
5090 // Always warn if no monotonic clock available
5091 if (!os::Posix::supports_monotonic_clock()) {
5092 warning("No monotonic clock was available - timed services may " \
5093 "be adversely affected if the time-of-day clock changes");
5094 }
5095 }
5096
5097 // To install functions for atexit system call
5098 extern "C" {
5099 static void perfMemory_exit_helper() {
5100 perfMemory_exit();
5101 }
5102 }
5103
5104 void os::pd_init_container_support() {
5105 OSContainer::init();
5106 }
5107
5108 void os::Linux::numa_init() {
5109
5110 // Java can be invoked as
5111 // 1. Without numactl and heap will be allocated/configured on all nodes as
5112 // per the system policy.
5113 // 2. With numactl --interleave:
5114 // Use numa_get_interleave_mask(v2) API to get nodes bitmask. The same
5115 // API for membind case bitmask is reset.
5116 // Interleave is only hint and Kernel can fallback to other nodes if
5117 // no memory is available on the target nodes.
5118 // 3. With numactl --membind:
5119 // Use numa_get_membind(v2) API to get nodes bitmask. The same API for
5120 // interleave case returns bitmask of all nodes.
5121 // numa_all_nodes_ptr holds bitmask of all nodes.
5122 // numa_get_interleave_mask(v2) and numa_get_membind(v2) APIs returns correct
5123 // bitmask when externally configured to run on all or fewer nodes.
5124
5125 if (!Linux::libnuma_init()) {
5126 UseNUMA = false;
5127 } else {
5128 if ((Linux::numa_max_node() < 1) || Linux::is_bound_to_single_node()) {
5129 // If there's only one node (they start from 0) or if the process
5130 // is bound explicitly to a single node using membind, disable NUMA unless
5131 // user explicilty forces NUMA optimizations on single-node/UMA systems
5132 UseNUMA = ForceNUMA;
5133 } else {
5134
5135 LogTarget(Info,os) log;
5136 LogStream ls(log);
5137
5138 Linux::set_configured_numa_policy(Linux::identify_numa_policy());
5139
5140 struct bitmask* bmp = Linux::_numa_membind_bitmask;
5141 const char* numa_mode = "membind";
5142
5143 if (Linux::is_running_in_interleave_mode()) {
5144 bmp = Linux::_numa_interleave_bitmask;
5145 numa_mode = "interleave";
5146 }
5147
5148 ls.print("UseNUMA is enabled and invoked in '%s' mode."
5149 " Heap will be configured using NUMA memory nodes:", numa_mode);
5150
5151 for (int node = 0; node <= Linux::numa_max_node(); node++) {
5152 if (Linux::_numa_bitmask_isbitset(bmp, node)) {
5153 ls.print(" %d", node);
5154 }
5155 }
5156 }
5157 }
5158
5159 if (UseParallelGC && UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
5160 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
5161 // we can make the adaptive lgrp chunk resizing work. If the user specified both
5162 // UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn
5163 // and disable adaptive resizing.
5164 if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) {
5165 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, "
5166 "disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)");
5167 UseAdaptiveSizePolicy = false;
5168 UseAdaptiveNUMAChunkSizing = false;
5169 }
5170 }
5171 }
5172
5173 // this is called _after_ the global arguments have been parsed
5174 jint os::init_2(void) {
5175
5176 // This could be set after os::Posix::init() but all platforms
5177 // have to set it the same so we have to mirror Solaris.
5178 DEBUG_ONLY(os::set_mutex_init_done();)
5179
5180 os::Posix::init_2();
5181
5182 Linux::fast_thread_clock_init();
5183
5184 // initialize suspend/resume support - must do this before signal_sets_init()
5185 if (SR_initialize() != 0) {
5186 perror("SR_initialize failed");
5187 return JNI_ERR;
5188 }
5189
5190 Linux::signal_sets_init();
5191 Linux::install_signal_handlers();
5192 // Initialize data for jdk.internal.misc.Signal
5193 if (!ReduceSignalUsage) {
5194 jdk_misc_signal_init();
5195 }
5196
5197 if (AdjustStackSizeForTLS) {
5198 get_minstack_init();
5199 }
5200
5201 // Check and sets minimum stack sizes against command line options
5202 if (Posix::set_minimum_stack_sizes() == JNI_ERR) {
5203 return JNI_ERR;
5204 }
5205
5206 #if defined(IA32)
5207 // Need to ensure we've determined the process's initial stack to
5208 // perform the workaround
5209 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
5210 workaround_expand_exec_shield_cs_limit();
5211 #else
5212 suppress_primordial_thread_resolution = Arguments::created_by_java_launcher();
5213 if (!suppress_primordial_thread_resolution) {
5214 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
5215 }
5216 #endif
5217
5218 Linux::libpthread_init();
5219 Linux::sched_getcpu_init();
5220 log_info(os)("HotSpot is running with %s, %s",
5221 Linux::glibc_version(), Linux::libpthread_version());
5222
5223 if (UseNUMA) {
5224 Linux::numa_init();
5225 }
5226
5227 if (MaxFDLimit) {
5228 // set the number of file descriptors to max. print out error
5229 // if getrlimit/setrlimit fails but continue regardless.
5230 struct rlimit nbr_files;
5231 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
5232 if (status != 0) {
5233 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno));
5234 } else {
5235 nbr_files.rlim_cur = nbr_files.rlim_max;
5236 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
5237 if (status != 0) {
5238 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno));
5239 }
5240 }
5241 }
5242
5243 // at-exit methods are called in the reverse order of their registration.
5244 // atexit functions are called on return from main or as a result of a
5245 // call to exit(3C). There can be only 32 of these functions registered
5246 // and atexit() does not set errno.
5247
5248 if (PerfAllowAtExitRegistration) {
5249 // only register atexit functions if PerfAllowAtExitRegistration is set.
5250 // atexit functions can be delayed until process exit time, which
5251 // can be problematic for embedded VM situations. Embedded VMs should
5252 // call DestroyJavaVM() to assure that VM resources are released.
5253
5254 // note: perfMemory_exit_helper atexit function may be removed in
5255 // the future if the appropriate cleanup code can be added to the
5256 // VM_Exit VMOperation's doit method.
5257 if (atexit(perfMemory_exit_helper) != 0) {
5258 warning("os::init_2 atexit(perfMemory_exit_helper) failed");
5259 }
5260 }
5261
5262 // initialize thread priority policy
5263 prio_init();
5264
5265 if (!FLAG_IS_DEFAULT(AllocateHeapAt) || !FLAG_IS_DEFAULT(AllocateOldGenAt)) {
5266 set_coredump_filter(DAX_SHARED_BIT);
5267 }
5268
5269 if (DumpPrivateMappingsInCore) {
5270 set_coredump_filter(FILE_BACKED_PVT_BIT);
5271 }
5272
5273 if (DumpSharedMappingsInCore) {
5274 set_coredump_filter(FILE_BACKED_SHARED_BIT);
5275 }
5276
5277 return JNI_OK;
5278 }
5279
5280 // Mark the polling page as unreadable
5281 void os::make_polling_page_unreadable(void) {
5282 if (!guard_memory((char*)_polling_page, Linux::page_size())) {
5283 fatal("Could not disable polling page");
5284 }
5285 }
5286
5287 // Mark the polling page as readable
5288 void os::make_polling_page_readable(void) {
5289 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
5290 fatal("Could not enable polling page");
5291 }
5292 }
5293
5294 // older glibc versions don't have this macro (which expands to
5295 // an optimized bit-counting function) so we have to roll our own
5296 #ifndef CPU_COUNT
5297
5298 static int _cpu_count(const cpu_set_t* cpus) {
5299 int count = 0;
5300 // only look up to the number of configured processors
5301 for (int i = 0; i < os::processor_count(); i++) {
5302 if (CPU_ISSET(i, cpus)) {
5303 count++;
5304 }
5305 }
5306 return count;
5307 }
5308
5309 #define CPU_COUNT(cpus) _cpu_count(cpus)
5310
5311 #endif // CPU_COUNT
5312
5313 // Get the current number of available processors for this process.
5314 // This value can change at any time during a process's lifetime.
5315 // sched_getaffinity gives an accurate answer as it accounts for cpusets.
5316 // If it appears there may be more than 1024 processors then we do a
5317 // dynamic check - see 6515172 for details.
5318 // If anything goes wrong we fallback to returning the number of online
5319 // processors - which can be greater than the number available to the process.
5320 int os::Linux::active_processor_count() {
5321 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors
5322 cpu_set_t* cpus_p = &cpus;
5323 int cpus_size = sizeof(cpu_set_t);
5324
5325 int configured_cpus = os::processor_count(); // upper bound on available cpus
5326 int cpu_count = 0;
5327
5328 // old build platforms may not support dynamic cpu sets
5329 #ifdef CPU_ALLOC
5330
5331 // To enable easy testing of the dynamic path on different platforms we
5332 // introduce a diagnostic flag: UseCpuAllocPath
5333 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) {
5334 // kernel may use a mask bigger than cpu_set_t
5335 log_trace(os)("active_processor_count: using dynamic path %s"
5336 "- configured processors: %d",
5337 UseCpuAllocPath ? "(forced) " : "",
5338 configured_cpus);
5339 cpus_p = CPU_ALLOC(configured_cpus);
5340 if (cpus_p != NULL) {
5341 cpus_size = CPU_ALLOC_SIZE(configured_cpus);
5342 // zero it just to be safe
5343 CPU_ZERO_S(cpus_size, cpus_p);
5344 }
5345 else {
5346 // failed to allocate so fallback to online cpus
5347 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
5348 log_trace(os)("active_processor_count: "
5349 "CPU_ALLOC failed (%s) - using "
5350 "online processor count: %d",
5351 os::strerror(errno), online_cpus);
5352 return online_cpus;
5353 }
5354 }
5355 else {
5356 log_trace(os)("active_processor_count: using static path - configured processors: %d",
5357 configured_cpus);
5358 }
5359 #else // CPU_ALLOC
5360 // these stubs won't be executed
5361 #define CPU_COUNT_S(size, cpus) -1
5362 #define CPU_FREE(cpus)
5363
5364 log_trace(os)("active_processor_count: only static path available - configured processors: %d",
5365 configured_cpus);
5366 #endif // CPU_ALLOC
5367
5368 // pid 0 means the current thread - which we have to assume represents the process
5369 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) {
5370 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
5371 cpu_count = CPU_COUNT_S(cpus_size, cpus_p);
5372 }
5373 else {
5374 cpu_count = CPU_COUNT(cpus_p);
5375 }
5376 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count);
5377 }
5378 else {
5379 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN);
5380 warning("sched_getaffinity failed (%s)- using online processor count (%d) "
5381 "which may exceed available processors", os::strerror(errno), cpu_count);
5382 }
5383
5384 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
5385 CPU_FREE(cpus_p);
5386 }
5387
5388 assert(cpu_count > 0 && cpu_count <= os::processor_count(), "sanity check");
5389 return cpu_count;
5390 }
5391
5392 // Determine the active processor count from one of
5393 // three different sources:
5394 //
5395 // 1. User option -XX:ActiveProcessorCount
5396 // 2. kernel os calls (sched_getaffinity or sysconf(_SC_NPROCESSORS_ONLN)
5397 // 3. extracted from cgroup cpu subsystem (shares and quotas)
5398 //
5399 // Option 1, if specified, will always override.
5400 // If the cgroup subsystem is active and configured, we
5401 // will return the min of the cgroup and option 2 results.
5402 // This is required since tools, such as numactl, that
5403 // alter cpu affinity do not update cgroup subsystem
5404 // cpuset configuration files.
5405 int os::active_processor_count() {
5406 // User has overridden the number of active processors
5407 if (ActiveProcessorCount > 0) {
5408 log_trace(os)("active_processor_count: "
5409 "active processor count set by user : %d",
5410 ActiveProcessorCount);
5411 return ActiveProcessorCount;
5412 }
5413
5414 int active_cpus;
5415 if (OSContainer::is_containerized()) {
5416 active_cpus = OSContainer::active_processor_count();
5417 log_trace(os)("active_processor_count: determined by OSContainer: %d",
5418 active_cpus);
5419 } else {
5420 active_cpus = os::Linux::active_processor_count();
5421 }
5422
5423 return active_cpus;
5424 }
5425
5426 uint os::processor_id() {
5427 const int id = Linux::sched_getcpu();
5428 assert(id >= 0 && id < _processor_count, "Invalid processor id");
5429 return (uint)id;
5430 }
5431
5432 void os::set_native_thread_name(const char *name) {
5433 if (Linux::_pthread_setname_np) {
5434 char buf [16]; // according to glibc manpage, 16 chars incl. '/0'
5435 snprintf(buf, sizeof(buf), "%s", name);
5436 buf[sizeof(buf) - 1] = '\0';
5437 const int rc = Linux::_pthread_setname_np(pthread_self(), buf);
5438 // ERANGE should not happen; all other errors should just be ignored.
5439 assert(rc != ERANGE, "pthread_setname_np failed");
5440 }
5441 }
5442
5443 bool os::bind_to_processor(uint processor_id) {
5444 // Not yet implemented.
5445 return false;
5446 }
5447
5448 ///
5449
5450 void os::SuspendedThreadTask::internal_do_task() {
5451 if (do_suspend(_thread->osthread())) {
5452 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
5453 do_task(context);
5454 do_resume(_thread->osthread());
5455 }
5456 }
5457
5458 ////////////////////////////////////////////////////////////////////////////////
5459 // debug support
5460
5461 bool os::find(address addr, outputStream* st) {
5462 Dl_info dlinfo;
5463 memset(&dlinfo, 0, sizeof(dlinfo));
5464 if (dladdr(addr, &dlinfo) != 0) {
5465 st->print(PTR_FORMAT ": ", p2i(addr));
5466 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
5467 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname,
5468 p2i(addr) - p2i(dlinfo.dli_saddr));
5469 } else if (dlinfo.dli_fbase != NULL) {
5470 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase));
5471 } else {
5472 st->print("<absolute address>");
5473 }
5474 if (dlinfo.dli_fname != NULL) {
5475 st->print(" in %s", dlinfo.dli_fname);
5476 }
5477 if (dlinfo.dli_fbase != NULL) {
5478 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase));
5479 }
5480 st->cr();
5481
5482 if (Verbose) {
5483 // decode some bytes around the PC
5484 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
5485 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size());
5486 address lowest = (address) dlinfo.dli_sname;
5487 if (!lowest) lowest = (address) dlinfo.dli_fbase;
5488 if (begin < lowest) begin = lowest;
5489 Dl_info dlinfo2;
5490 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
5491 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) {
5492 end = (address) dlinfo2.dli_saddr;
5493 }
5494 Disassembler::decode(begin, end, st);
5495 }
5496 return true;
5497 }
5498 return false;
5499 }
5500
5501 ////////////////////////////////////////////////////////////////////////////////
5502 // misc
5503
5504 // This does not do anything on Linux. This is basically a hook for being
5505 // able to use structured exception handling (thread-local exception filters)
5506 // on, e.g., Win32.
5507 void
5508 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method,
5509 JavaCallArguments* args, Thread* thread) {
5510 f(value, method, args, thread);
5511 }
5512
5513 void os::print_statistics() {
5514 }
5515
5516 bool os::message_box(const char* title, const char* message) {
5517 int i;
5518 fdStream err(defaultStream::error_fd());
5519 for (i = 0; i < 78; i++) err.print_raw("=");
5520 err.cr();
5521 err.print_raw_cr(title);
5522 for (i = 0; i < 78; i++) err.print_raw("-");
5523 err.cr();
5524 err.print_raw_cr(message);
5525 for (i = 0; i < 78; i++) err.print_raw("=");
5526 err.cr();
5527
5528 char buf[16];
5529 // Prevent process from exiting upon "read error" without consuming all CPU
5530 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
5531
5532 return buf[0] == 'y' || buf[0] == 'Y';
5533 }
5534
5535 // Is a (classpath) directory empty?
5536 bool os::dir_is_empty(const char* path) {
5537 DIR *dir = NULL;
5538 struct dirent *ptr;
5539
5540 dir = opendir(path);
5541 if (dir == NULL) return true;
5542
5543 // Scan the directory
5544 bool result = true;
5545 while (result && (ptr = readdir(dir)) != NULL) {
5546 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
5547 result = false;
5548 }
5549 }
5550 closedir(dir);
5551 return result;
5552 }
5553
5554 // This code originates from JDK's sysOpen and open64_w
5555 // from src/solaris/hpi/src/system_md.c
5556
5557 int os::open(const char *path, int oflag, int mode) {
5558 if (strlen(path) > MAX_PATH - 1) {
5559 errno = ENAMETOOLONG;
5560 return -1;
5561 }
5562
5563 // All file descriptors that are opened in the Java process and not
5564 // specifically destined for a subprocess should have the close-on-exec
5565 // flag set. If we don't set it, then careless 3rd party native code
5566 // might fork and exec without closing all appropriate file descriptors
5567 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in
5568 // turn might:
5569 //
5570 // - cause end-of-file to fail to be detected on some file
5571 // descriptors, resulting in mysterious hangs, or
5572 //
5573 // - might cause an fopen in the subprocess to fail on a system
5574 // suffering from bug 1085341.
5575 //
5576 // (Yes, the default setting of the close-on-exec flag is a Unix
5577 // design flaw)
5578 //
5579 // See:
5580 // 1085341: 32-bit stdio routines should support file descriptors >255
5581 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed
5582 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
5583 //
5584 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open().
5585 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor
5586 // because it saves a system call and removes a small window where the flag
5587 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored
5588 // and we fall back to using FD_CLOEXEC (see below).
5589 #ifdef O_CLOEXEC
5590 oflag |= O_CLOEXEC;
5591 #endif
5592
5593 int fd = ::open64(path, oflag, mode);
5594 if (fd == -1) return -1;
5595
5596 //If the open succeeded, the file might still be a directory
5597 {
5598 struct stat64 buf64;
5599 int ret = ::fstat64(fd, &buf64);
5600 int st_mode = buf64.st_mode;
5601
5602 if (ret != -1) {
5603 if ((st_mode & S_IFMT) == S_IFDIR) {
5604 errno = EISDIR;
5605 ::close(fd);
5606 return -1;
5607 }
5608 } else {
5609 ::close(fd);
5610 return -1;
5611 }
5612 }
5613
5614 #ifdef FD_CLOEXEC
5615 // Validate that the use of the O_CLOEXEC flag on open above worked.
5616 // With recent kernels, we will perform this check exactly once.
5617 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0;
5618 if (!O_CLOEXEC_is_known_to_work) {
5619 int flags = ::fcntl(fd, F_GETFD);
5620 if (flags != -1) {
5621 if ((flags & FD_CLOEXEC) != 0)
5622 O_CLOEXEC_is_known_to_work = 1;
5623 else
5624 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
5625 }
5626 }
5627 #endif
5628
5629 return fd;
5630 }
5631
5632
5633 // create binary file, rewriting existing file if required
5634 int os::create_binary_file(const char* path, bool rewrite_existing) {
5635 int oflags = O_WRONLY | O_CREAT;
5636 if (!rewrite_existing) {
5637 oflags |= O_EXCL;
5638 }
5639 return ::open64(path, oflags, S_IREAD | S_IWRITE);
5640 }
5641
5642 // return current position of file pointer
5643 jlong os::current_file_offset(int fd) {
5644 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
5645 }
5646
5647 // move file pointer to the specified offset
5648 jlong os::seek_to_file_offset(int fd, jlong offset) {
5649 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
5650 }
5651
5652 // This code originates from JDK's sysAvailable
5653 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
5654
5655 int os::available(int fd, jlong *bytes) {
5656 jlong cur, end;
5657 int mode;
5658 struct stat64 buf64;
5659
5660 if (::fstat64(fd, &buf64) >= 0) {
5661 mode = buf64.st_mode;
5662 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
5663 int n;
5664 if (::ioctl(fd, FIONREAD, &n) >= 0) {
5665 *bytes = n;
5666 return 1;
5667 }
5668 }
5669 }
5670 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
5671 return 0;
5672 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
5673 return 0;
5674 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
5675 return 0;
5676 }
5677 *bytes = end - cur;
5678 return 1;
5679 }
5680
5681 // Map a block of memory.
5682 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
5683 char *addr, size_t bytes, bool read_only,
5684 bool allow_exec) {
5685 int prot;
5686 int flags = MAP_PRIVATE;
5687
5688 if (read_only) {
5689 prot = PROT_READ;
5690 } else {
5691 prot = PROT_READ | PROT_WRITE;
5692 }
5693
5694 if (allow_exec) {
5695 prot |= PROT_EXEC;
5696 }
5697
5698 if (addr != NULL) {
5699 flags |= MAP_FIXED;
5700 }
5701
5702 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
5703 fd, file_offset);
5704 if (mapped_address == MAP_FAILED) {
5705 return NULL;
5706 }
5707 return mapped_address;
5708 }
5709
5710
5711 // Remap a block of memory.
5712 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
5713 char *addr, size_t bytes, bool read_only,
5714 bool allow_exec) {
5715 // same as map_memory() on this OS
5716 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
5717 allow_exec);
5718 }
5719
5720
5721 // Unmap a block of memory.
5722 bool os::pd_unmap_memory(char* addr, size_t bytes) {
5723 return munmap(addr, bytes) == 0;
5724 }
5725
5726 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
5727
5728 static jlong fast_cpu_time(Thread *thread) {
5729 clockid_t clockid;
5730 int rc = os::Linux::pthread_getcpuclockid(thread->osthread()->pthread_id(),
5731 &clockid);
5732 if (rc == 0) {
5733 return os::Linux::fast_thread_cpu_time(clockid);
5734 } else {
5735 // It's possible to encounter a terminated native thread that failed
5736 // to detach itself from the VM - which should result in ESRCH.
5737 assert_status(rc == ESRCH, rc, "pthread_getcpuclockid failed");
5738 return -1;
5739 }
5740 }
5741
5742 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
5743 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
5744 // of a thread.
5745 //
5746 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
5747 // the fast estimate available on the platform.
5748
5749 jlong os::current_thread_cpu_time() {
5750 if (os::Linux::supports_fast_thread_cpu_time()) {
5751 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5752 } else {
5753 // return user + sys since the cost is the same
5754 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
5755 }
5756 }
5757
5758 jlong os::thread_cpu_time(Thread* thread) {
5759 // consistent with what current_thread_cpu_time() returns
5760 if (os::Linux::supports_fast_thread_cpu_time()) {
5761 return fast_cpu_time(thread);
5762 } else {
5763 return slow_thread_cpu_time(thread, true /* user + sys */);
5764 }
5765 }
5766
5767 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
5768 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5769 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5770 } else {
5771 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
5772 }
5773 }
5774
5775 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5776 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5777 return fast_cpu_time(thread);
5778 } else {
5779 return slow_thread_cpu_time(thread, user_sys_cpu_time);
5780 }
5781 }
5782
5783 // -1 on error.
5784 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5785 pid_t tid = thread->osthread()->thread_id();
5786 char *s;
5787 char stat[2048];
5788 int statlen;
5789 char proc_name[64];
5790 int count;
5791 long sys_time, user_time;
5792 char cdummy;
5793 int idummy;
5794 long ldummy;
5795 FILE *fp;
5796
5797 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid);
5798 fp = fopen(proc_name, "r");
5799 if (fp == NULL) return -1;
5800 statlen = fread(stat, 1, 2047, fp);
5801 stat[statlen] = '\0';
5802 fclose(fp);
5803
5804 // Skip pid and the command string. Note that we could be dealing with
5805 // weird command names, e.g. user could decide to rename java launcher
5806 // to "java 1.4.2 :)", then the stat file would look like
5807 // 1234 (java 1.4.2 :)) R ... ...
5808 // We don't really need to know the command string, just find the last
5809 // occurrence of ")" and then start parsing from there. See bug 4726580.
5810 s = strrchr(stat, ')');
5811 if (s == NULL) return -1;
5812
5813 // Skip blank chars
5814 do { s++; } while (s && isspace(*s));
5815
5816 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
5817 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
5818 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
5819 &user_time, &sys_time);
5820 if (count != 13) return -1;
5821 if (user_sys_cpu_time) {
5822 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5823 } else {
5824 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5825 }
5826 }
5827
5828 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5829 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5830 info_ptr->may_skip_backward = false; // elapsed time not wall time
5831 info_ptr->may_skip_forward = false; // elapsed time not wall time
5832 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5833 }
5834
5835 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5836 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5837 info_ptr->may_skip_backward = false; // elapsed time not wall time
5838 info_ptr->may_skip_forward = false; // elapsed time not wall time
5839 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5840 }
5841
5842 bool os::is_thread_cpu_time_supported() {
5843 return true;
5844 }
5845
5846 // System loadavg support. Returns -1 if load average cannot be obtained.
5847 // Linux doesn't yet have a (official) notion of processor sets,
5848 // so just return the system wide load average.
5849 int os::loadavg(double loadavg[], int nelem) {
5850 return ::getloadavg(loadavg, nelem);
5851 }
5852
5853 void os::pause() {
5854 char filename[MAX_PATH];
5855 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
5856 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile);
5857 } else {
5858 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
5859 }
5860
5861 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
5862 if (fd != -1) {
5863 struct stat buf;
5864 ::close(fd);
5865 while (::stat(filename, &buf) == 0) {
5866 (void)::poll(NULL, 0, 100);
5867 }
5868 } else {
5869 jio_fprintf(stderr,
5870 "Could not open pause file '%s', continuing immediately.\n", filename);
5871 }
5872 }
5873
5874 extern char** environ;
5875
5876 // Run the specified command in a separate process. Return its exit value,
5877 // or -1 on failure (e.g. can't fork a new process).
5878 // Unlike system(), this function can be called from signal handler. It
5879 // doesn't block SIGINT et al.
5880 int os::fork_and_exec(char* cmd, bool use_vfork_if_available) {
5881 const char * argv[4] = {"sh", "-c", cmd, NULL};
5882
5883 pid_t pid ;
5884
5885 if (use_vfork_if_available) {
5886 pid = vfork();
5887 } else {
5888 pid = fork();
5889 }
5890
5891 if (pid < 0) {
5892 // fork failed
5893 return -1;
5894
5895 } else if (pid == 0) {
5896 // child process
5897
5898 execve("/bin/sh", (char* const*)argv, environ);
5899
5900 // execve failed
5901 _exit(-1);
5902
5903 } else {
5904 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5905 // care about the actual exit code, for now.
5906
5907 int status;
5908
5909 // Wait for the child process to exit. This returns immediately if
5910 // the child has already exited. */
5911 while (waitpid(pid, &status, 0) < 0) {
5912 switch (errno) {
5913 case ECHILD: return 0;
5914 case EINTR: break;
5915 default: return -1;
5916 }
5917 }
5918
5919 if (WIFEXITED(status)) {
5920 // The child exited normally; get its exit code.
5921 return WEXITSTATUS(status);
5922 } else if (WIFSIGNALED(status)) {
5923 // The child exited because of a signal
5924 // The best value to return is 0x80 + signal number,
5925 // because that is what all Unix shells do, and because
5926 // it allows callers to distinguish between process exit and
5927 // process death by signal.
5928 return 0x80 + WTERMSIG(status);
5929 } else {
5930 // Unknown exit code; pass it through
5931 return status;
5932 }
5933 }
5934 }
5935
5936 // Get the default path to the core file
5937 // Returns the length of the string
5938 int os::get_core_path(char* buffer, size_t bufferSize) {
5939 /*
5940 * Max length of /proc/sys/kernel/core_pattern is 128 characters.
5941 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt
5942 */
5943 const int core_pattern_len = 129;
5944 char core_pattern[core_pattern_len] = {0};
5945
5946 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY);
5947 if (core_pattern_file == -1) {
5948 return -1;
5949 }
5950
5951 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len);
5952 ::close(core_pattern_file);
5953 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') {
5954 return -1;
5955 }
5956 if (core_pattern[ret-1] == '\n') {
5957 core_pattern[ret-1] = '\0';
5958 } else {
5959 core_pattern[ret] = '\0';
5960 }
5961
5962 // Replace the %p in the core pattern with the process id. NOTE: we do this
5963 // only if the pattern doesn't start with "|", and we support only one %p in
5964 // the pattern.
5965 char *pid_pos = strstr(core_pattern, "%p");
5966 const char* tail = (pid_pos != NULL) ? (pid_pos + 2) : ""; // skip over the "%p"
5967 int written;
5968
5969 if (core_pattern[0] == '/') {
5970 if (pid_pos != NULL) {
5971 *pid_pos = '\0';
5972 written = jio_snprintf(buffer, bufferSize, "%s%d%s", core_pattern,
5973 current_process_id(), tail);
5974 } else {
5975 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern);
5976 }
5977 } else {
5978 char cwd[PATH_MAX];
5979
5980 const char* p = get_current_directory(cwd, PATH_MAX);
5981 if (p == NULL) {
5982 return -1;
5983 }
5984
5985 if (core_pattern[0] == '|') {
5986 written = jio_snprintf(buffer, bufferSize,
5987 "\"%s\" (or dumping to %s/core.%d)",
5988 &core_pattern[1], p, current_process_id());
5989 } else if (pid_pos != NULL) {
5990 *pid_pos = '\0';
5991 written = jio_snprintf(buffer, bufferSize, "%s/%s%d%s", p, core_pattern,
5992 current_process_id(), tail);
5993 } else {
5994 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern);
5995 }
5996 }
5997
5998 if (written < 0) {
5999 return -1;
6000 }
6001
6002 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) {
6003 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY);
6004
6005 if (core_uses_pid_file != -1) {
6006 char core_uses_pid = 0;
6007 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1);
6008 ::close(core_uses_pid_file);
6009
6010 if (core_uses_pid == '1') {
6011 jio_snprintf(buffer + written, bufferSize - written,
6012 ".%d", current_process_id());
6013 }
6014 }
6015 }
6016
6017 return strlen(buffer);
6018 }
6019
6020 bool os::start_debugging(char *buf, int buflen) {
6021 int len = (int)strlen(buf);
6022 char *p = &buf[len];
6023
6024 jio_snprintf(p, buflen-len,
6025 "\n\n"
6026 "Do you want to debug the problem?\n\n"
6027 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n"
6028 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n"
6029 "Otherwise, press RETURN to abort...",
6030 os::current_process_id(), os::current_process_id(),
6031 os::current_thread_id(), os::current_thread_id());
6032
6033 bool yes = os::message_box("Unexpected Error", buf);
6034
6035 if (yes) {
6036 // yes, user asked VM to launch debugger
6037 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d",
6038 os::current_process_id(), os::current_process_id());
6039
6040 os::fork_and_exec(buf);
6041 yes = false;
6042 }
6043 return yes;
6044 }
6045
6046
6047 // Java/Compiler thread:
6048 //
6049 // Low memory addresses
6050 // P0 +------------------------+
6051 // | |\ Java thread created by VM does not have glibc
6052 // | glibc guard page | - guard page, attached Java thread usually has
6053 // | |/ 1 glibc guard page.
6054 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
6055 // | |\
6056 // | HotSpot Guard Pages | - red, yellow and reserved pages
6057 // | |/
6058 // +------------------------+ JavaThread::stack_reserved_zone_base()
6059 // | |\
6060 // | Normal Stack | -
6061 // | |/
6062 // P2 +------------------------+ Thread::stack_base()
6063 //
6064 // Non-Java thread:
6065 //
6066 // Low memory addresses
6067 // P0 +------------------------+
6068 // | |\
6069 // | glibc guard page | - usually 1 page
6070 // | |/
6071 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
6072 // | |\
6073 // | Normal Stack | -
6074 // | |/
6075 // P2 +------------------------+ Thread::stack_base()
6076 //
6077 // ** P1 (aka bottom) and size (P2 = P1 - size) are the address and stack size
6078 // returned from pthread_attr_getstack().
6079 // ** Due to NPTL implementation error, linux takes the glibc guard page out
6080 // of the stack size given in pthread_attr. We work around this for
6081 // threads created by the VM. (We adapt bottom to be P1 and size accordingly.)
6082 //
6083 #ifndef ZERO
6084 static void current_stack_region(address * bottom, size_t * size) {
6085 if (os::is_primordial_thread()) {
6086 // primordial thread needs special handling because pthread_getattr_np()
6087 // may return bogus value.
6088 *bottom = os::Linux::initial_thread_stack_bottom();
6089 *size = os::Linux::initial_thread_stack_size();
6090 } else {
6091 pthread_attr_t attr;
6092
6093 int rslt = pthread_getattr_np(pthread_self(), &attr);
6094
6095 // JVM needs to know exact stack location, abort if it fails
6096 if (rslt != 0) {
6097 if (rslt == ENOMEM) {
6098 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
6099 } else {
6100 fatal("pthread_getattr_np failed with error = %d", rslt);
6101 }
6102 }
6103
6104 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
6105 fatal("Cannot locate current stack attributes!");
6106 }
6107
6108 // Work around NPTL stack guard error.
6109 size_t guard_size = 0;
6110 rslt = pthread_attr_getguardsize(&attr, &guard_size);
6111 if (rslt != 0) {
6112 fatal("pthread_attr_getguardsize failed with error = %d", rslt);
6113 }
6114 *bottom += guard_size;
6115 *size -= guard_size;
6116
6117 pthread_attr_destroy(&attr);
6118
6119 }
6120 assert(os::current_stack_pointer() >= *bottom &&
6121 os::current_stack_pointer() < *bottom + *size, "just checking");
6122 }
6123
6124 address os::current_stack_base() {
6125 address bottom;
6126 size_t size;
6127 current_stack_region(&bottom, &size);
6128 return (bottom + size);
6129 }
6130
6131 size_t os::current_stack_size() {
6132 // This stack size includes the usable stack and HotSpot guard pages
6133 // (for the threads that have Hotspot guard pages).
6134 address bottom;
6135 size_t size;
6136 current_stack_region(&bottom, &size);
6137 return size;
6138 }
6139 #endif
6140
6141 static inline struct timespec get_mtime(const char* filename) {
6142 struct stat st;
6143 int ret = os::stat(filename, &st);
6144 assert(ret == 0, "failed to stat() file '%s': %s", filename, os::strerror(errno));
6145 return st.st_mtim;
6146 }
6147
6148 int os::compare_file_modified_times(const char* file1, const char* file2) {
6149 struct timespec filetime1 = get_mtime(file1);
6150 struct timespec filetime2 = get_mtime(file2);
6151 int diff = filetime1.tv_sec - filetime2.tv_sec;
6152 if (diff == 0) {
6153 return filetime1.tv_nsec - filetime2.tv_nsec;
6154 }
6155 return diff;
6156 }
6157
6158 bool os::supports_map_sync() {
6159 return true;
6160 }
6161
6162 /////////////// Unit tests ///////////////
6163
6164 #ifndef PRODUCT
6165
6166 class TestReserveMemorySpecial : AllStatic {
6167 public:
6168 static void small_page_write(void* addr, size_t size) {
6169 size_t page_size = os::vm_page_size();
6170
6171 char* end = (char*)addr + size;
6172 for (char* p = (char*)addr; p < end; p += page_size) {
6173 *p = 1;
6174 }
6175 }
6176
6177 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) {
6178 if (!UseHugeTLBFS) {
6179 return;
6180 }
6181
6182 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false);
6183
6184 if (addr != NULL) {
6185 small_page_write(addr, size);
6186
6187 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6188 }
6189 }
6190
6191 static void test_reserve_memory_special_huge_tlbfs_only() {
6192 if (!UseHugeTLBFS) {
6193 return;
6194 }
6195
6196 size_t lp = os::large_page_size();
6197
6198 for (size_t size = lp; size <= lp * 10; size += lp) {
6199 test_reserve_memory_special_huge_tlbfs_only(size);
6200 }
6201 }
6202
6203 static void test_reserve_memory_special_huge_tlbfs_mixed() {
6204 size_t lp = os::large_page_size();
6205 size_t ag = os::vm_allocation_granularity();
6206
6207 // sizes to test
6208 const size_t sizes[] = {
6209 lp, lp + ag, lp + lp / 2, lp * 2,
6210 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2,
6211 lp * 10, lp * 10 + lp / 2
6212 };
6213 const int num_sizes = sizeof(sizes) / sizeof(size_t);
6214
6215 // For each size/alignment combination, we test three scenarios:
6216 // 1) with req_addr == NULL
6217 // 2) with a non-null req_addr at which we expect to successfully allocate
6218 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we
6219 // expect the allocation to either fail or to ignore req_addr
6220
6221 // Pre-allocate two areas; they shall be as large as the largest allocation
6222 // and aligned to the largest alignment we will be testing.
6223 const size_t mapping_size = sizes[num_sizes - 1] * 2;
6224 char* const mapping1 = (char*) ::mmap(NULL, mapping_size,
6225 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6226 -1, 0);
6227 assert(mapping1 != MAP_FAILED, "should work");
6228
6229 char* const mapping2 = (char*) ::mmap(NULL, mapping_size,
6230 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6231 -1, 0);
6232 assert(mapping2 != MAP_FAILED, "should work");
6233
6234 // Unmap the first mapping, but leave the second mapping intact: the first
6235 // mapping will serve as a value for a "good" req_addr (case 2). The second
6236 // mapping, still intact, as "bad" req_addr (case 3).
6237 ::munmap(mapping1, mapping_size);
6238
6239 // Case 1
6240 for (int i = 0; i < num_sizes; i++) {
6241 const size_t size = sizes[i];
6242 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6243 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false);
6244 if (p != NULL) {
6245 assert(is_aligned(p, alignment), "must be");
6246 small_page_write(p, size);
6247 os::Linux::release_memory_special_huge_tlbfs(p, size);
6248 }
6249 }
6250 }
6251
6252 // Case 2
6253 for (int i = 0; i < num_sizes; i++) {
6254 const size_t size = sizes[i];
6255 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6256 char* const req_addr = align_up(mapping1, alignment);
6257 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6258 if (p != NULL) {
6259 assert(p == req_addr, "must be");
6260 small_page_write(p, size);
6261 os::Linux::release_memory_special_huge_tlbfs(p, size);
6262 }
6263 }
6264 }
6265
6266 // Case 3
6267 for (int i = 0; i < num_sizes; i++) {
6268 const size_t size = sizes[i];
6269 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6270 char* const req_addr = align_up(mapping2, alignment);
6271 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6272 // as the area around req_addr contains already existing mappings, the API should always
6273 // return NULL (as per contract, it cannot return another address)
6274 assert(p == NULL, "must be");
6275 }
6276 }
6277
6278 ::munmap(mapping2, mapping_size);
6279
6280 }
6281
6282 static void test_reserve_memory_special_huge_tlbfs() {
6283 if (!UseHugeTLBFS) {
6284 return;
6285 }
6286
6287 test_reserve_memory_special_huge_tlbfs_only();
6288 test_reserve_memory_special_huge_tlbfs_mixed();
6289 }
6290
6291 static void test_reserve_memory_special_shm(size_t size, size_t alignment) {
6292 if (!UseSHM) {
6293 return;
6294 }
6295
6296 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false);
6297
6298 if (addr != NULL) {
6299 assert(is_aligned(addr, alignment), "Check");
6300 assert(is_aligned(addr, os::large_page_size()), "Check");
6301
6302 small_page_write(addr, size);
6303
6304 os::Linux::release_memory_special_shm(addr, size);
6305 }
6306 }
6307
6308 static void test_reserve_memory_special_shm() {
6309 size_t lp = os::large_page_size();
6310 size_t ag = os::vm_allocation_granularity();
6311
6312 for (size_t size = ag; size < lp * 3; size += ag) {
6313 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6314 test_reserve_memory_special_shm(size, alignment);
6315 }
6316 }
6317 }
6318
6319 static void test() {
6320 test_reserve_memory_special_huge_tlbfs();
6321 test_reserve_memory_special_shm();
6322 }
6323 };
6324
6325 void TestReserveMemorySpecial_test() {
6326 TestReserveMemorySpecial::test();
6327 }
6328
6329 #endif