1 /* 2 * Copyright (c) 1999, 2019, 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_share_linux.hpp" 42 #include "osContainer_linux.hpp" 43 #include "prims/jniFastGetField.hpp" 44 #include "prims/jvm_misc.hpp" 45 #include "runtime/arguments.hpp" 46 #include "runtime/atomic.hpp" 47 #include "runtime/extendedPC.hpp" 48 #include "runtime/globals.hpp" 49 #include "runtime/interfaceSupport.inline.hpp" 50 #include "runtime/init.hpp" 51 #include "runtime/java.hpp" 52 #include "runtime/javaCalls.hpp" 53 #include "runtime/mutexLocker.hpp" 54 #include "runtime/objectMonitor.hpp" 55 #include "runtime/orderAccess.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/vmError.hpp" 78 79 // put OS-includes here 80 # include <sys/types.h> 81 # include <sys/mman.h> 82 # include <sys/stat.h> 83 # include <sys/select.h> 84 # include <pthread.h> 85 # include <signal.h> 86 # include <errno.h> 87 # include <dlfcn.h> 88 # include <stdio.h> 89 # include <unistd.h> 90 # include <sys/resource.h> 91 # include <pthread.h> 92 # include <sys/stat.h> 93 # include <sys/time.h> 94 # include <sys/times.h> 95 # include <sys/utsname.h> 96 # include <sys/socket.h> 97 # include <sys/wait.h> 98 # include <pwd.h> 99 # include <poll.h> 100 # include <fcntl.h> 101 # include <string.h> 102 # include <syscall.h> 103 # include <sys/sysinfo.h> 104 # include <gnu/libc-version.h> 105 # include <sys/ipc.h> 106 # include <sys/shm.h> 107 # include <link.h> 108 # include <stdint.h> 109 # include <inttypes.h> 110 # include <sys/ioctl.h> 111 112 #ifndef _GNU_SOURCE 113 #define _GNU_SOURCE 114 #include <sched.h> 115 #undef _GNU_SOURCE 116 #else 117 #include <sched.h> 118 #endif 119 120 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling 121 // getrusage() is prepared to handle the associated failure. 122 #ifndef RUSAGE_THREAD 123 #define RUSAGE_THREAD (1) /* only the calling thread */ 124 #endif 125 126 #define MAX_PATH (2 * K) 127 128 #define MAX_SECS 100000000 129 130 // for timer info max values which include all bits 131 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 132 133 enum CoredumpFilterBit { 134 FILE_BACKED_PVT_BIT = 1 << 2, 135 FILE_BACKED_SHARED_BIT = 1 << 3, 136 LARGEPAGES_BIT = 1 << 6, 137 DAX_SHARED_BIT = 1 << 8 138 }; 139 140 //////////////////////////////////////////////////////////////////////////////// 141 // global variables 142 julong os::Linux::_physical_memory = 0; 143 144 address os::Linux::_initial_thread_stack_bottom = NULL; 145 uintptr_t os::Linux::_initial_thread_stack_size = 0; 146 147 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL; 148 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 149 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL; 150 Mutex* os::Linux::_createThread_lock = 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 uint32_t os::Linux::_os_version = 0; 155 const char * os::Linux::_glibc_version = NULL; 156 const char * os::Linux::_libpthread_version = NULL; 157 158 static jlong initial_time_count=0; 159 160 static int clock_tics_per_sec = 100; 161 162 // If the VM might have been created on the primordial thread, we need to resolve the 163 // primordial thread stack bounds and check if the current thread might be the 164 // primordial thread in places. If we know that the primordial thread is never used, 165 // such as when the VM was created by one of the standard java launchers, we can 166 // avoid this 167 static bool suppress_primordial_thread_resolution = false; 168 169 // For diagnostics to print a message once. see run_periodic_checks 170 static sigset_t check_signal_done; 171 static bool check_signals = true; 172 173 // Signal number used to suspend/resume a thread 174 175 // do not use any signal number less than SIGSEGV, see 4355769 176 static int SR_signum = SIGUSR2; 177 sigset_t SR_sigset; 178 179 // utility functions 180 181 static int SR_initialize(); 182 183 julong os::available_memory() { 184 return Linux::available_memory(); 185 } 186 187 julong os::Linux::available_memory() { 188 // values in struct sysinfo are "unsigned long" 189 struct sysinfo si; 190 julong avail_mem; 191 192 if (OSContainer::is_containerized()) { 193 jlong mem_limit, mem_usage; 194 if ((mem_limit = OSContainer::memory_limit_in_bytes()) < 1) { 195 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value", 196 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit); 197 } 198 if (mem_limit > 0 && (mem_usage = OSContainer::memory_usage_in_bytes()) < 1) { 199 log_debug(os, container)("container memory usage failed: " JLONG_FORMAT ", using host value", mem_usage); 200 } 201 if (mem_limit > 0 && mem_usage > 0 ) { 202 avail_mem = mem_limit > mem_usage ? (julong)mem_limit - (julong)mem_usage : 0; 203 log_trace(os)("available container memory: " JULONG_FORMAT, avail_mem); 204 return avail_mem; 205 } 206 } 207 208 sysinfo(&si); 209 avail_mem = (julong)si.freeram * si.mem_unit; 210 log_trace(os)("available memory: " JULONG_FORMAT, avail_mem); 211 return avail_mem; 212 } 213 214 julong os::physical_memory() { 215 jlong phys_mem = 0; 216 if (OSContainer::is_containerized()) { 217 jlong mem_limit; 218 if ((mem_limit = OSContainer::memory_limit_in_bytes()) > 0) { 219 log_trace(os)("total container memory: " JLONG_FORMAT, mem_limit); 220 return mem_limit; 221 } 222 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value", 223 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit); 224 } 225 226 phys_mem = Linux::physical_memory(); 227 log_trace(os)("total system memory: " JLONG_FORMAT, phys_mem); 228 return phys_mem; 229 } 230 231 static uint64_t initial_total_ticks = 0; 232 static uint64_t initial_steal_ticks = 0; 233 static bool has_initial_tick_info = false; 234 235 static void next_line(FILE *f) { 236 int c; 237 do { 238 c = fgetc(f); 239 } while (c != '\n' && c != EOF); 240 } 241 242 bool os::Linux::get_tick_information(CPUPerfTicks* pticks, int which_logical_cpu) { 243 FILE* fh; 244 uint64_t userTicks, niceTicks, systemTicks, idleTicks; 245 // since at least kernel 2.6 : iowait: time waiting for I/O to complete 246 // irq: time servicing interrupts; softirq: time servicing softirqs 247 uint64_t iowTicks = 0, irqTicks = 0, sirqTicks= 0; 248 // steal (since kernel 2.6.11): time spent in other OS when running in a virtualized environment 249 uint64_t stealTicks = 0; 250 // guest (since kernel 2.6.24): time spent running a virtual CPU for guest OS under the 251 // control of the Linux kernel 252 uint64_t guestNiceTicks = 0; 253 int logical_cpu = -1; 254 const int required_tickinfo_count = (which_logical_cpu == -1) ? 4 : 5; 255 int n; 256 257 memset(pticks, 0, sizeof(CPUPerfTicks)); 258 259 if ((fh = fopen("/proc/stat", "r")) == NULL) { 260 return false; 261 } 262 263 if (which_logical_cpu == -1) { 264 n = fscanf(fh, "cpu " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " 265 UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " 266 UINT64_FORMAT " " UINT64_FORMAT " ", 267 &userTicks, &niceTicks, &systemTicks, &idleTicks, 268 &iowTicks, &irqTicks, &sirqTicks, 269 &stealTicks, &guestNiceTicks); 270 } else { 271 // Move to next line 272 next_line(fh); 273 274 // find the line for requested cpu faster to just iterate linefeeds? 275 for (int i = 0; i < which_logical_cpu; i++) { 276 next_line(fh); 277 } 278 279 n = fscanf(fh, "cpu%u " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " 280 UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " 281 UINT64_FORMAT " " UINT64_FORMAT " ", 282 &logical_cpu, &userTicks, &niceTicks, 283 &systemTicks, &idleTicks, &iowTicks, &irqTicks, &sirqTicks, 284 &stealTicks, &guestNiceTicks); 285 } 286 287 fclose(fh); 288 if (n < required_tickinfo_count || logical_cpu != which_logical_cpu) { 289 return false; 290 } 291 pticks->used = userTicks + niceTicks; 292 pticks->usedKernel = systemTicks + irqTicks + sirqTicks; 293 pticks->total = userTicks + niceTicks + systemTicks + idleTicks + 294 iowTicks + irqTicks + sirqTicks + stealTicks + guestNiceTicks; 295 296 if (n > required_tickinfo_count + 3) { 297 pticks->steal = stealTicks; 298 pticks->has_steal_ticks = true; 299 } else { 300 pticks->steal = 0; 301 pticks->has_steal_ticks = false; 302 } 303 304 return true; 305 } 306 307 // Return true if user is running as root. 308 309 bool os::have_special_privileges() { 310 static bool init = false; 311 static bool privileges = false; 312 if (!init) { 313 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 314 init = true; 315 } 316 return privileges; 317 } 318 319 320 #ifndef SYS_gettid 321 // i386: 224, ia64: 1105, amd64: 186, sparc 143 322 #ifdef __ia64__ 323 #define SYS_gettid 1105 324 #else 325 #ifdef __i386__ 326 #define SYS_gettid 224 327 #else 328 #ifdef __amd64__ 329 #define SYS_gettid 186 330 #else 331 #ifdef __sparc__ 332 #define SYS_gettid 143 333 #else 334 #error define gettid for the arch 335 #endif 336 #endif 337 #endif 338 #endif 339 #endif 340 341 342 // pid_t gettid() 343 // 344 // Returns the kernel thread id of the currently running thread. Kernel 345 // thread id is used to access /proc. 346 pid_t os::Linux::gettid() { 347 int rslt = syscall(SYS_gettid); 348 assert(rslt != -1, "must be."); // old linuxthreads implementation? 349 return (pid_t)rslt; 350 } 351 352 // Most versions of linux have a bug where the number of processors are 353 // determined by looking at the /proc file system. In a chroot environment, 354 // the system call returns 1. This causes the VM to act as if it is 355 // a single processor and elide locking (see is_MP() call). 356 static bool unsafe_chroot_detected = false; 357 static const char *unstable_chroot_error = "/proc file system not found.\n" 358 "Java may be unstable running multithreaded in a chroot " 359 "environment on Linux when /proc filesystem is not mounted."; 360 361 void os::Linux::initialize_system_info() { 362 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 363 if (processor_count() == 1) { 364 pid_t pid = os::Linux::gettid(); 365 char fname[32]; 366 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 367 FILE *fp = fopen(fname, "r"); 368 if (fp == NULL) { 369 unsafe_chroot_detected = true; 370 } else { 371 fclose(fp); 372 } 373 } 374 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 375 assert(processor_count() > 0, "linux error"); 376 } 377 378 void os::init_system_properties_values() { 379 // The next steps are taken in the product version: 380 // 381 // Obtain the JAVA_HOME value from the location of libjvm.so. 382 // This library should be located at: 383 // <JAVA_HOME>/lib/{client|server}/libjvm.so. 384 // 385 // If "/jre/lib/" appears at the right place in the path, then we 386 // assume libjvm.so is installed in a JDK and we use this path. 387 // 388 // Otherwise exit with message: "Could not create the Java virtual machine." 389 // 390 // The following extra steps are taken in the debugging version: 391 // 392 // If "/jre/lib/" does NOT appear at the right place in the path 393 // instead of exit check for $JAVA_HOME environment variable. 394 // 395 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 396 // then we append a fake suffix "hotspot/libjvm.so" to this path so 397 // it looks like libjvm.so is installed there 398 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so. 399 // 400 // Otherwise exit. 401 // 402 // Important note: if the location of libjvm.so changes this 403 // code needs to be changed accordingly. 404 405 // See ld(1): 406 // The linker uses the following search paths to locate required 407 // shared libraries: 408 // 1: ... 409 // ... 410 // 7: The default directories, normally /lib and /usr/lib. 411 #if defined(AMD64) || (defined(_LP64) && defined(SPARC)) || defined(PPC64) || defined(S390) 412 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 413 #else 414 #define DEFAULT_LIBPATH "/lib:/usr/lib" 415 #endif 416 417 // Base path of extensions installed on the system. 418 #define SYS_EXT_DIR "/usr/java/packages" 419 #define EXTENSIONS_DIR "/lib/ext" 420 421 // Buffer that fits several sprintfs. 422 // Note that the space for the colon and the trailing null are provided 423 // by the nulls included by the sizeof operator. 424 const size_t bufsize = 425 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends. 426 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir 427 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal); 428 429 // sysclasspath, java_home, dll_dir 430 { 431 char *pslash; 432 os::jvm_path(buf, bufsize); 433 434 // Found the full path to libjvm.so. 435 // Now cut the path to <java_home>/jre if we can. 436 pslash = strrchr(buf, '/'); 437 if (pslash != NULL) { 438 *pslash = '\0'; // Get rid of /libjvm.so. 439 } 440 pslash = strrchr(buf, '/'); 441 if (pslash != NULL) { 442 *pslash = '\0'; // Get rid of /{client|server|hotspot}. 443 } 444 Arguments::set_dll_dir(buf); 445 446 if (pslash != NULL) { 447 pslash = strrchr(buf, '/'); 448 if (pslash != NULL) { 449 *pslash = '\0'; // Get rid of /lib. 450 } 451 } 452 Arguments::set_java_home(buf); 453 set_boot_path('/', ':'); 454 } 455 456 // Where to look for native libraries. 457 // 458 // Note: Due to a legacy implementation, most of the library path 459 // is set in the launcher. This was to accomodate linking restrictions 460 // on legacy Linux implementations (which are no longer supported). 461 // Eventually, all the library path setting will be done here. 462 // 463 // However, to prevent the proliferation of improperly built native 464 // libraries, the new path component /usr/java/packages is added here. 465 // Eventually, all the library path setting will be done here. 466 { 467 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It 468 // should always exist (until the legacy problem cited above is 469 // addressed). 470 const char *v = ::getenv("LD_LIBRARY_PATH"); 471 const char *v_colon = ":"; 472 if (v == NULL) { v = ""; v_colon = ""; } 473 // That's +1 for the colon and +1 for the trailing '\0'. 474 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char, 475 strlen(v) + 1 + 476 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1, 477 mtInternal); 478 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon); 479 Arguments::set_library_path(ld_library_path); 480 FREE_C_HEAP_ARRAY(char, ld_library_path); 481 } 482 483 // Extensions directories. 484 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home()); 485 Arguments::set_ext_dirs(buf); 486 487 FREE_C_HEAP_ARRAY(char, buf); 488 489 #undef DEFAULT_LIBPATH 490 #undef SYS_EXT_DIR 491 #undef EXTENSIONS_DIR 492 } 493 494 //////////////////////////////////////////////////////////////////////////////// 495 // breakpoint support 496 497 void os::breakpoint() { 498 BREAKPOINT; 499 } 500 501 extern "C" void breakpoint() { 502 // use debugger to set breakpoint here 503 } 504 505 //////////////////////////////////////////////////////////////////////////////// 506 // signal support 507 508 debug_only(static bool signal_sets_initialized = false); 509 static sigset_t unblocked_sigs, vm_sigs; 510 511 void os::Linux::signal_sets_init() { 512 // Should also have an assertion stating we are still single-threaded. 513 assert(!signal_sets_initialized, "Already initialized"); 514 // Fill in signals that are necessarily unblocked for all threads in 515 // the VM. Currently, we unblock the following signals: 516 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 517 // by -Xrs (=ReduceSignalUsage)); 518 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 519 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 520 // the dispositions or masks wrt these signals. 521 // Programs embedding the VM that want to use the above signals for their 522 // own purposes must, at this time, use the "-Xrs" option to prevent 523 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 524 // (See bug 4345157, and other related bugs). 525 // In reality, though, unblocking these signals is really a nop, since 526 // these signals are not blocked by default. 527 sigemptyset(&unblocked_sigs); 528 sigaddset(&unblocked_sigs, SIGILL); 529 sigaddset(&unblocked_sigs, SIGSEGV); 530 sigaddset(&unblocked_sigs, SIGBUS); 531 sigaddset(&unblocked_sigs, SIGFPE); 532 #if defined(PPC64) 533 sigaddset(&unblocked_sigs, SIGTRAP); 534 #endif 535 sigaddset(&unblocked_sigs, SR_signum); 536 537 if (!ReduceSignalUsage) { 538 if (!os::Posix::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 539 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 540 } 541 if (!os::Posix::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 542 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 543 } 544 if (!os::Posix::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 545 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 546 } 547 } 548 // Fill in signals that are blocked by all but the VM thread. 549 sigemptyset(&vm_sigs); 550 if (!ReduceSignalUsage) { 551 sigaddset(&vm_sigs, BREAK_SIGNAL); 552 } 553 debug_only(signal_sets_initialized = true); 554 555 } 556 557 // These are signals that are unblocked while a thread is running Java. 558 // (For some reason, they get blocked by default.) 559 sigset_t* os::Linux::unblocked_signals() { 560 assert(signal_sets_initialized, "Not initialized"); 561 return &unblocked_sigs; 562 } 563 564 // These are the signals that are blocked while a (non-VM) thread is 565 // running Java. Only the VM thread handles these signals. 566 sigset_t* os::Linux::vm_signals() { 567 assert(signal_sets_initialized, "Not initialized"); 568 return &vm_sigs; 569 } 570 571 void os::Linux::hotspot_sigmask(Thread* thread) { 572 573 //Save caller's signal mask before setting VM signal mask 574 sigset_t caller_sigmask; 575 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 576 577 OSThread* osthread = thread->osthread(); 578 osthread->set_caller_sigmask(caller_sigmask); 579 580 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 581 582 if (!ReduceSignalUsage) { 583 if (thread->is_VM_thread()) { 584 // Only the VM thread handles BREAK_SIGNAL ... 585 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 586 } else { 587 // ... all other threads block BREAK_SIGNAL 588 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 589 } 590 } 591 } 592 593 ////////////////////////////////////////////////////////////////////////////// 594 // detecting pthread library 595 596 void os::Linux::libpthread_init() { 597 // Save glibc and pthread version strings. 598 #if !defined(_CS_GNU_LIBC_VERSION) || \ 599 !defined(_CS_GNU_LIBPTHREAD_VERSION) 600 #error "glibc too old (< 2.3.2)" 601 #endif 602 603 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 604 assert(n > 0, "cannot retrieve glibc version"); 605 char *str = (char *)malloc(n, mtInternal); 606 confstr(_CS_GNU_LIBC_VERSION, str, n); 607 os::Linux::set_glibc_version(str); 608 609 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 610 assert(n > 0, "cannot retrieve pthread version"); 611 str = (char *)malloc(n, mtInternal); 612 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 613 os::Linux::set_libpthread_version(str); 614 } 615 616 ///////////////////////////////////////////////////////////////////////////// 617 // thread stack expansion 618 619 // os::Linux::manually_expand_stack() takes care of expanding the thread 620 // stack. Note that this is normally not needed: pthread stacks allocate 621 // thread stack using mmap() without MAP_NORESERVE, so the stack is already 622 // committed. Therefore it is not necessary to expand the stack manually. 623 // 624 // Manually expanding the stack was historically needed on LinuxThreads 625 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays 626 // it is kept to deal with very rare corner cases: 627 // 628 // For one, user may run the VM on an own implementation of threads 629 // whose stacks are - like the old LinuxThreads - implemented using 630 // mmap(MAP_GROWSDOWN). 631 // 632 // Also, this coding may be needed if the VM is running on the primordial 633 // thread. Normally we avoid running on the primordial thread; however, 634 // user may still invoke the VM on the primordial thread. 635 // 636 // The following historical comment describes the details about running 637 // on a thread stack allocated with mmap(MAP_GROWSDOWN): 638 639 640 // Force Linux kernel to expand current thread stack. If "bottom" is close 641 // to the stack guard, caller should block all signals. 642 // 643 // MAP_GROWSDOWN: 644 // A special mmap() flag that is used to implement thread stacks. It tells 645 // kernel that the memory region should extend downwards when needed. This 646 // allows early versions of LinuxThreads to only mmap the first few pages 647 // when creating a new thread. Linux kernel will automatically expand thread 648 // stack as needed (on page faults). 649 // 650 // However, because the memory region of a MAP_GROWSDOWN stack can grow on 651 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 652 // region, it's hard to tell if the fault is due to a legitimate stack 653 // access or because of reading/writing non-exist memory (e.g. buffer 654 // overrun). As a rule, if the fault happens below current stack pointer, 655 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the 656 // application (see Linux kernel fault.c). 657 // 658 // This Linux feature can cause SIGSEGV when VM bangs thread stack for 659 // stack overflow detection. 660 // 661 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 662 // not use MAP_GROWSDOWN. 663 // 664 // To get around the problem and allow stack banging on Linux, we need to 665 // manually expand thread stack after receiving the SIGSEGV. 666 // 667 // There are two ways to expand thread stack to address "bottom", we used 668 // both of them in JVM before 1.5: 669 // 1. adjust stack pointer first so that it is below "bottom", and then 670 // touch "bottom" 671 // 2. mmap() the page in question 672 // 673 // Now alternate signal stack is gone, it's harder to use 2. For instance, 674 // if current sp is already near the lower end of page 101, and we need to 675 // call mmap() to map page 100, it is possible that part of the mmap() frame 676 // will be placed in page 100. When page 100 is mapped, it is zero-filled. 677 // That will destroy the mmap() frame and cause VM to crash. 678 // 679 // The following code works by adjusting sp first, then accessing the "bottom" 680 // page to force a page fault. Linux kernel will then automatically expand the 681 // stack mapping. 682 // 683 // _expand_stack_to() assumes its frame size is less than page size, which 684 // should always be true if the function is not inlined. 685 686 static void NOINLINE _expand_stack_to(address bottom) { 687 address sp; 688 size_t size; 689 volatile char *p; 690 691 // Adjust bottom to point to the largest address within the same page, it 692 // gives us a one-page buffer if alloca() allocates slightly more memory. 693 bottom = (address)align_down((uintptr_t)bottom, os::Linux::page_size()); 694 bottom += os::Linux::page_size() - 1; 695 696 // sp might be slightly above current stack pointer; if that's the case, we 697 // will alloca() a little more space than necessary, which is OK. Don't use 698 // os::current_stack_pointer(), as its result can be slightly below current 699 // stack pointer, causing us to not alloca enough to reach "bottom". 700 sp = (address)&sp; 701 702 if (sp > bottom) { 703 size = sp - bottom; 704 p = (volatile char *)alloca(size); 705 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 706 p[0] = '\0'; 707 } 708 } 709 710 void os::Linux::expand_stack_to(address bottom) { 711 _expand_stack_to(bottom); 712 } 713 714 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 715 assert(t!=NULL, "just checking"); 716 assert(t->osthread()->expanding_stack(), "expand should be set"); 717 assert(t->stack_base() != NULL, "stack_base was not initialized"); 718 719 if (addr < t->stack_base() && addr >= t->stack_reserved_zone_base()) { 720 sigset_t mask_all, old_sigset; 721 sigfillset(&mask_all); 722 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 723 _expand_stack_to(addr); 724 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 725 return true; 726 } 727 return false; 728 } 729 730 ////////////////////////////////////////////////////////////////////////////// 731 // create new thread 732 733 // Thread start routine for all newly created threads 734 static void *thread_native_entry(Thread *thread) { 735 736 thread->record_stack_base_and_size(); 737 738 // Try to randomize the cache line index of hot stack frames. 739 // This helps when threads of the same stack traces evict each other's 740 // cache lines. The threads can be either from the same JVM instance, or 741 // from different JVM instances. The benefit is especially true for 742 // processors with hyperthreading technology. 743 static int counter = 0; 744 int pid = os::current_process_id(); 745 alloca(((pid ^ counter++) & 7) * 128); 746 747 thread->initialize_thread_current(); 748 749 OSThread* osthread = thread->osthread(); 750 Monitor* sync = osthread->startThread_lock(); 751 752 osthread->set_thread_id(os::current_thread_id()); 753 754 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 755 os::current_thread_id(), (uintx) pthread_self()); 756 757 if (UseNUMA) { 758 int lgrp_id = os::numa_get_group_id(); 759 if (lgrp_id != -1) { 760 thread->set_lgrp_id(lgrp_id); 761 } 762 } 763 // initialize signal mask for this thread 764 os::Linux::hotspot_sigmask(thread); 765 766 // initialize floating point control register 767 os::Linux::init_thread_fpu_state(); 768 769 // handshaking with parent thread 770 { 771 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 772 773 // notify parent thread 774 osthread->set_state(INITIALIZED); 775 sync->notify_all(); 776 777 // wait until os::start_thread() 778 while (osthread->get_state() == INITIALIZED) { 779 sync->wait(Mutex::_no_safepoint_check_flag); 780 } 781 } 782 783 // call one more level start routine 784 thread->call_run(); 785 786 // Note: at this point the thread object may already have deleted itself. 787 // Prevent dereferencing it from here on out. 788 thread = NULL; 789 790 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 791 os::current_thread_id(), (uintx) pthread_self()); 792 793 return 0; 794 } 795 796 bool os::create_thread(Thread* thread, ThreadType thr_type, 797 size_t req_stack_size) { 798 assert(thread->osthread() == NULL, "caller responsible"); 799 800 // Allocate the OSThread object 801 OSThread* osthread = new OSThread(NULL, NULL); 802 if (osthread == NULL) { 803 return false; 804 } 805 806 // set the correct thread state 807 osthread->set_thread_type(thr_type); 808 809 // Initial state is ALLOCATED but not INITIALIZED 810 osthread->set_state(ALLOCATED); 811 812 thread->set_osthread(osthread); 813 814 // init thread attributes 815 pthread_attr_t attr; 816 pthread_attr_init(&attr); 817 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 818 819 // Calculate stack size if it's not specified by caller. 820 size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size); 821 // In the Linux NPTL pthread implementation the guard size mechanism 822 // is not implemented properly. The posix standard requires adding 823 // the size of the guard pages to the stack size, instead Linux 824 // takes the space out of 'stacksize'. Thus we adapt the requested 825 // stack_size by the size of the guard pages to mimick proper 826 // behaviour. However, be careful not to end up with a size 827 // of zero due to overflow. Don't add the guard page in that case. 828 size_t guard_size = os::Linux::default_guard_size(thr_type); 829 if (stack_size <= SIZE_MAX - guard_size) { 830 stack_size += guard_size; 831 } 832 assert(is_aligned(stack_size, os::vm_page_size()), "stack_size not aligned"); 833 834 int status = pthread_attr_setstacksize(&attr, stack_size); 835 assert_status(status == 0, status, "pthread_attr_setstacksize"); 836 837 // Configure glibc guard page. 838 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 839 840 ThreadState state; 841 842 { 843 pthread_t tid; 844 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread); 845 846 char buf[64]; 847 if (ret == 0) { 848 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ", 849 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 850 } else { 851 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.", 852 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 853 // Log some OS information which might explain why creating the thread failed. 854 log_info(os, thread)("Number of threads approx. running in the VM: %d", Threads::number_of_threads()); 855 LogStream st(Log(os, thread)::info()); 856 os::Posix::print_rlimit_info(&st); 857 os::print_memory_info(&st); 858 os::Linux::print_proc_sys_info(&st); 859 os::Linux::print_container_info(&st); 860 } 861 862 pthread_attr_destroy(&attr); 863 864 if (ret != 0) { 865 // Need to clean up stuff we've allocated so far 866 thread->set_osthread(NULL); 867 delete osthread; 868 return false; 869 } 870 871 // Store pthread info into the OSThread 872 osthread->set_pthread_id(tid); 873 874 // Wait until child thread is either initialized or aborted 875 { 876 Monitor* sync_with_child = osthread->startThread_lock(); 877 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 878 while ((state = osthread->get_state()) == ALLOCATED) { 879 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 880 } 881 } 882 } 883 884 // Aborted due to thread limit being reached 885 if (state == ZOMBIE) { 886 thread->set_osthread(NULL); 887 delete osthread; 888 return false; 889 } 890 891 // The thread is returned suspended (in state INITIALIZED), 892 // and is started higher up in the call chain 893 assert(state == INITIALIZED, "race condition"); 894 return true; 895 } 896 897 ///////////////////////////////////////////////////////////////////////////// 898 // attach existing thread 899 900 // bootstrap the main thread 901 bool os::create_main_thread(JavaThread* thread) { 902 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 903 return create_attached_thread(thread); 904 } 905 906 bool os::create_attached_thread(JavaThread* thread) { 907 #ifdef ASSERT 908 thread->verify_not_published(); 909 #endif 910 911 // Allocate the OSThread object 912 OSThread* osthread = new OSThread(NULL, NULL); 913 914 if (osthread == NULL) { 915 return false; 916 } 917 918 // Store pthread info into the OSThread 919 osthread->set_thread_id(os::Linux::gettid()); 920 osthread->set_pthread_id(::pthread_self()); 921 922 // initialize floating point control register 923 os::Linux::init_thread_fpu_state(); 924 925 // Initial thread state is RUNNABLE 926 osthread->set_state(RUNNABLE); 927 928 thread->set_osthread(osthread); 929 930 if (UseNUMA) { 931 int lgrp_id = os::numa_get_group_id(); 932 if (lgrp_id != -1) { 933 thread->set_lgrp_id(lgrp_id); 934 } 935 } 936 937 if (os::is_primordial_thread()) { 938 // If current thread is primordial thread, its stack is mapped on demand, 939 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 940 // the entire stack region to avoid SEGV in stack banging. 941 // It is also useful to get around the heap-stack-gap problem on SuSE 942 // kernel (see 4821821 for details). We first expand stack to the top 943 // of yellow zone, then enable stack yellow zone (order is significant, 944 // enabling yellow zone first will crash JVM on SuSE Linux), so there 945 // is no gap between the last two virtual memory regions. 946 947 JavaThread *jt = (JavaThread *)thread; 948 address addr = jt->stack_reserved_zone_base(); 949 assert(addr != NULL, "initialization problem?"); 950 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 951 952 osthread->set_expanding_stack(); 953 os::Linux::manually_expand_stack(jt, addr); 954 osthread->clear_expanding_stack(); 955 } 956 957 // initialize signal mask for this thread 958 // and save the caller's signal mask 959 os::Linux::hotspot_sigmask(thread); 960 961 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 962 os::current_thread_id(), (uintx) pthread_self()); 963 964 return true; 965 } 966 967 void os::pd_start_thread(Thread* thread) { 968 OSThread * osthread = thread->osthread(); 969 assert(osthread->get_state() != INITIALIZED, "just checking"); 970 Monitor* sync_with_child = osthread->startThread_lock(); 971 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 972 sync_with_child->notify(); 973 } 974 975 // Free Linux resources related to the OSThread 976 void os::free_thread(OSThread* osthread) { 977 assert(osthread != NULL, "osthread not set"); 978 979 // We are told to free resources of the argument thread, 980 // but we can only really operate on the current thread. 981 assert(Thread::current()->osthread() == osthread, 982 "os::free_thread but not current thread"); 983 984 #ifdef ASSERT 985 sigset_t current; 986 sigemptyset(¤t); 987 pthread_sigmask(SIG_SETMASK, NULL, ¤t); 988 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!"); 989 #endif 990 991 // Restore caller's signal mask 992 sigset_t sigmask = osthread->caller_sigmask(); 993 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 994 995 delete osthread; 996 } 997 998 ////////////////////////////////////////////////////////////////////////////// 999 // primordial thread 1000 1001 // Check if current thread is the primordial thread, similar to Solaris thr_main. 1002 bool os::is_primordial_thread(void) { 1003 if (suppress_primordial_thread_resolution) { 1004 return false; 1005 } 1006 char dummy; 1007 // If called before init complete, thread stack bottom will be null. 1008 // Can be called if fatal error occurs before initialization. 1009 if (os::Linux::initial_thread_stack_bottom() == NULL) return false; 1010 assert(os::Linux::initial_thread_stack_bottom() != NULL && 1011 os::Linux::initial_thread_stack_size() != 0, 1012 "os::init did not locate primordial thread's stack region"); 1013 if ((address)&dummy >= os::Linux::initial_thread_stack_bottom() && 1014 (address)&dummy < os::Linux::initial_thread_stack_bottom() + 1015 os::Linux::initial_thread_stack_size()) { 1016 return true; 1017 } else { 1018 return false; 1019 } 1020 } 1021 1022 // Find the virtual memory area that contains addr 1023 static bool find_vma(address addr, address* vma_low, address* vma_high) { 1024 FILE *fp = fopen("/proc/self/maps", "r"); 1025 if (fp) { 1026 address low, high; 1027 while (!feof(fp)) { 1028 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 1029 if (low <= addr && addr < high) { 1030 if (vma_low) *vma_low = low; 1031 if (vma_high) *vma_high = high; 1032 fclose(fp); 1033 return true; 1034 } 1035 } 1036 for (;;) { 1037 int ch = fgetc(fp); 1038 if (ch == EOF || ch == (int)'\n') break; 1039 } 1040 } 1041 fclose(fp); 1042 } 1043 return false; 1044 } 1045 1046 // Locate primordial thread stack. This special handling of primordial thread stack 1047 // is needed because pthread_getattr_np() on most (all?) Linux distros returns 1048 // bogus value for the primordial process thread. While the launcher has created 1049 // the VM in a new thread since JDK 6, we still have to allow for the use of the 1050 // JNI invocation API from a primordial thread. 1051 void os::Linux::capture_initial_stack(size_t max_size) { 1052 1053 // max_size is either 0 (which means accept OS default for thread stacks) or 1054 // a user-specified value known to be at least the minimum needed. If we 1055 // are actually on the primordial thread we can make it appear that we have a 1056 // smaller max_size stack by inserting the guard pages at that location. But we 1057 // cannot do anything to emulate a larger stack than what has been provided by 1058 // the OS or threading library. In fact if we try to use a stack greater than 1059 // what is set by rlimit then we will crash the hosting process. 1060 1061 // Maximum stack size is the easy part, get it from RLIMIT_STACK. 1062 // If this is "unlimited" then it will be a huge value. 1063 struct rlimit rlim; 1064 getrlimit(RLIMIT_STACK, &rlim); 1065 size_t stack_size = rlim.rlim_cur; 1066 1067 // 6308388: a bug in ld.so will relocate its own .data section to the 1068 // lower end of primordial stack; reduce ulimit -s value a little bit 1069 // so we won't install guard page on ld.so's data section. 1070 // But ensure we don't underflow the stack size - allow 1 page spare 1071 if (stack_size >= (size_t)(3 * page_size())) { 1072 stack_size -= 2 * page_size(); 1073 } 1074 1075 // Try to figure out where the stack base (top) is. This is harder. 1076 // 1077 // When an application is started, glibc saves the initial stack pointer in 1078 // a global variable "__libc_stack_end", which is then used by system 1079 // libraries. __libc_stack_end should be pretty close to stack top. The 1080 // variable is available since the very early days. However, because it is 1081 // a private interface, it could disappear in the future. 1082 // 1083 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 1084 // to __libc_stack_end, it is very close to stack top, but isn't the real 1085 // stack top. Note that /proc may not exist if VM is running as a chroot 1086 // program, so reading /proc/<pid>/stat could fail. Also the contents of 1087 // /proc/<pid>/stat could change in the future (though unlikely). 1088 // 1089 // We try __libc_stack_end first. If that doesn't work, look for 1090 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 1091 // as a hint, which should work well in most cases. 1092 1093 uintptr_t stack_start; 1094 1095 // try __libc_stack_end first 1096 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1097 if (p && *p) { 1098 stack_start = *p; 1099 } else { 1100 // see if we can get the start_stack field from /proc/self/stat 1101 FILE *fp; 1102 int pid; 1103 char state; 1104 int ppid; 1105 int pgrp; 1106 int session; 1107 int nr; 1108 int tpgrp; 1109 unsigned long flags; 1110 unsigned long minflt; 1111 unsigned long cminflt; 1112 unsigned long majflt; 1113 unsigned long cmajflt; 1114 unsigned long utime; 1115 unsigned long stime; 1116 long cutime; 1117 long cstime; 1118 long prio; 1119 long nice; 1120 long junk; 1121 long it_real; 1122 uintptr_t start; 1123 uintptr_t vsize; 1124 intptr_t rss; 1125 uintptr_t rsslim; 1126 uintptr_t scodes; 1127 uintptr_t ecode; 1128 int i; 1129 1130 // Figure what the primordial thread stack base is. Code is inspired 1131 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1132 // followed by command name surrounded by parentheses, state, etc. 1133 char stat[2048]; 1134 int statlen; 1135 1136 fp = fopen("/proc/self/stat", "r"); 1137 if (fp) { 1138 statlen = fread(stat, 1, 2047, fp); 1139 stat[statlen] = '\0'; 1140 fclose(fp); 1141 1142 // Skip pid and the command string. Note that we could be dealing with 1143 // weird command names, e.g. user could decide to rename java launcher 1144 // to "java 1.4.2 :)", then the stat file would look like 1145 // 1234 (java 1.4.2 :)) R ... ... 1146 // We don't really need to know the command string, just find the last 1147 // occurrence of ")" and then start parsing from there. See bug 4726580. 1148 char * s = strrchr(stat, ')'); 1149 1150 i = 0; 1151 if (s) { 1152 // Skip blank chars 1153 do { s++; } while (s && isspace(*s)); 1154 1155 #define _UFM UINTX_FORMAT 1156 #define _DFM INTX_FORMAT 1157 1158 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 1159 // 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 1160 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, 1161 &state, // 3 %c 1162 &ppid, // 4 %d 1163 &pgrp, // 5 %d 1164 &session, // 6 %d 1165 &nr, // 7 %d 1166 &tpgrp, // 8 %d 1167 &flags, // 9 %lu 1168 &minflt, // 10 %lu 1169 &cminflt, // 11 %lu 1170 &majflt, // 12 %lu 1171 &cmajflt, // 13 %lu 1172 &utime, // 14 %lu 1173 &stime, // 15 %lu 1174 &cutime, // 16 %ld 1175 &cstime, // 17 %ld 1176 &prio, // 18 %ld 1177 &nice, // 19 %ld 1178 &junk, // 20 %ld 1179 &it_real, // 21 %ld 1180 &start, // 22 UINTX_FORMAT 1181 &vsize, // 23 UINTX_FORMAT 1182 &rss, // 24 INTX_FORMAT 1183 &rsslim, // 25 UINTX_FORMAT 1184 &scodes, // 26 UINTX_FORMAT 1185 &ecode, // 27 UINTX_FORMAT 1186 &stack_start); // 28 UINTX_FORMAT 1187 } 1188 1189 #undef _UFM 1190 #undef _DFM 1191 1192 if (i != 28 - 2) { 1193 assert(false, "Bad conversion from /proc/self/stat"); 1194 // product mode - assume we are the primordial thread, good luck in the 1195 // embedded case. 1196 warning("Can't detect primordial thread stack location - bad conversion"); 1197 stack_start = (uintptr_t) &rlim; 1198 } 1199 } else { 1200 // For some reason we can't open /proc/self/stat (for example, running on 1201 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1202 // most cases, so don't abort: 1203 warning("Can't detect primordial thread stack location - no /proc/self/stat"); 1204 stack_start = (uintptr_t) &rlim; 1205 } 1206 } 1207 1208 // Now we have a pointer (stack_start) very close to the stack top, the 1209 // next thing to do is to figure out the exact location of stack top. We 1210 // can find out the virtual memory area that contains stack_start by 1211 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1212 // and its upper limit is the real stack top. (again, this would fail if 1213 // running inside chroot, because /proc may not exist.) 1214 1215 uintptr_t stack_top; 1216 address low, high; 1217 if (find_vma((address)stack_start, &low, &high)) { 1218 // success, "high" is the true stack top. (ignore "low", because initial 1219 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1220 stack_top = (uintptr_t)high; 1221 } else { 1222 // failed, likely because /proc/self/maps does not exist 1223 warning("Can't detect primordial thread stack location - find_vma failed"); 1224 // best effort: stack_start is normally within a few pages below the real 1225 // stack top, use it as stack top, and reduce stack size so we won't put 1226 // guard page outside stack. 1227 stack_top = stack_start; 1228 stack_size -= 16 * page_size(); 1229 } 1230 1231 // stack_top could be partially down the page so align it 1232 stack_top = align_up(stack_top, page_size()); 1233 1234 // Allowed stack value is minimum of max_size and what we derived from rlimit 1235 if (max_size > 0) { 1236 _initial_thread_stack_size = MIN2(max_size, stack_size); 1237 } else { 1238 // Accept the rlimit max, but if stack is unlimited then it will be huge, so 1239 // clamp it at 8MB as we do on Solaris 1240 _initial_thread_stack_size = MIN2(stack_size, 8*M); 1241 } 1242 _initial_thread_stack_size = align_down(_initial_thread_stack_size, page_size()); 1243 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1244 1245 assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!"); 1246 1247 if (log_is_enabled(Info, os, thread)) { 1248 // See if we seem to be on primordial process thread 1249 bool primordial = uintptr_t(&rlim) > uintptr_t(_initial_thread_stack_bottom) && 1250 uintptr_t(&rlim) < stack_top; 1251 1252 log_info(os, thread)("Capturing initial stack in %s thread: req. size: " SIZE_FORMAT "K, actual size: " 1253 SIZE_FORMAT "K, top=" INTPTR_FORMAT ", bottom=" INTPTR_FORMAT, 1254 primordial ? "primordial" : "user", max_size / K, _initial_thread_stack_size / K, 1255 stack_top, intptr_t(_initial_thread_stack_bottom)); 1256 } 1257 } 1258 1259 //////////////////////////////////////////////////////////////////////////////// 1260 // time support 1261 1262 // Time since start-up in seconds to a fine granularity. 1263 // Used by VMSelfDestructTimer and the MemProfiler. 1264 double os::elapsedTime() { 1265 1266 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution 1267 } 1268 1269 jlong os::elapsed_counter() { 1270 return javaTimeNanos() - initial_time_count; 1271 } 1272 1273 jlong os::elapsed_frequency() { 1274 return NANOSECS_PER_SEC; // nanosecond resolution 1275 } 1276 1277 bool os::supports_vtime() { return true; } 1278 bool os::enable_vtime() { return false; } 1279 bool os::vtime_enabled() { return false; } 1280 1281 double os::elapsedVTime() { 1282 struct rusage usage; 1283 int retval = getrusage(RUSAGE_THREAD, &usage); 1284 if (retval == 0) { 1285 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); 1286 } else { 1287 // better than nothing, but not much 1288 return elapsedTime(); 1289 } 1290 } 1291 1292 jlong os::javaTimeMillis() { 1293 timeval time; 1294 int status = gettimeofday(&time, NULL); 1295 assert(status != -1, "linux error"); 1296 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1297 } 1298 1299 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) { 1300 timeval time; 1301 int status = gettimeofday(&time, NULL); 1302 assert(status != -1, "linux error"); 1303 seconds = jlong(time.tv_sec); 1304 nanos = jlong(time.tv_usec) * 1000; 1305 } 1306 1307 1308 #ifndef CLOCK_MONOTONIC 1309 #define CLOCK_MONOTONIC (1) 1310 #endif 1311 1312 void os::Linux::clock_init() { 1313 // we do dlopen's in this particular order due to bug in linux 1314 // dynamical loader (see 6348968) leading to crash on exit 1315 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1316 if (handle == NULL) { 1317 handle = dlopen("librt.so", RTLD_LAZY); 1318 } 1319 1320 if (handle) { 1321 int (*clock_getres_func)(clockid_t, struct timespec*) = 1322 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1323 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1324 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1325 if (clock_getres_func && clock_gettime_func) { 1326 // See if monotonic clock is supported by the kernel. Note that some 1327 // early implementations simply return kernel jiffies (updated every 1328 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1329 // for nano time (though the monotonic property is still nice to have). 1330 // It's fixed in newer kernels, however clock_getres() still returns 1331 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1332 // resolution for now. Hopefully as people move to new kernels, this 1333 // won't be a problem. 1334 struct timespec res; 1335 struct timespec tp; 1336 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1337 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1338 // yes, monotonic clock is supported 1339 _clock_gettime = clock_gettime_func; 1340 return; 1341 } else { 1342 // close librt if there is no monotonic clock 1343 dlclose(handle); 1344 } 1345 } 1346 } 1347 warning("No monotonic clock was available - timed services may " \ 1348 "be adversely affected if the time-of-day clock changes"); 1349 } 1350 1351 #ifndef SYS_clock_getres 1352 #if defined(X86) || defined(PPC64) || defined(S390) 1353 #define SYS_clock_getres AMD64_ONLY(229) IA32_ONLY(266) PPC64_ONLY(247) S390_ONLY(261) 1354 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1355 #else 1356 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1357 #define sys_clock_getres(x,y) -1 1358 #endif 1359 #else 1360 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1361 #endif 1362 1363 void os::Linux::fast_thread_clock_init() { 1364 if (!UseLinuxPosixThreadCPUClocks) { 1365 return; 1366 } 1367 clockid_t clockid; 1368 struct timespec tp; 1369 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1370 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1371 1372 // Switch to using fast clocks for thread cpu time if 1373 // the sys_clock_getres() returns 0 error code. 1374 // Note, that some kernels may support the current thread 1375 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1376 // returned by the pthread_getcpuclockid(). 1377 // If the fast Posix clocks are supported then the sys_clock_getres() 1378 // must return at least tp.tv_sec == 0 which means a resolution 1379 // better than 1 sec. This is extra check for reliability. 1380 1381 if (pthread_getcpuclockid_func && 1382 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1383 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1384 _supports_fast_thread_cpu_time = true; 1385 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1386 } 1387 } 1388 1389 jlong os::javaTimeNanos() { 1390 if (os::supports_monotonic_clock()) { 1391 struct timespec tp; 1392 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1393 assert(status == 0, "gettime error"); 1394 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1395 return result; 1396 } else { 1397 timeval time; 1398 int status = gettimeofday(&time, NULL); 1399 assert(status != -1, "linux error"); 1400 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1401 return 1000 * usecs; 1402 } 1403 } 1404 1405 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1406 if (os::supports_monotonic_clock()) { 1407 info_ptr->max_value = ALL_64_BITS; 1408 1409 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1410 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1411 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1412 } else { 1413 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1414 info_ptr->max_value = ALL_64_BITS; 1415 1416 // gettimeofday is a real time clock so it skips 1417 info_ptr->may_skip_backward = true; 1418 info_ptr->may_skip_forward = true; 1419 } 1420 1421 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1422 } 1423 1424 // Return the real, user, and system times in seconds from an 1425 // arbitrary fixed point in the past. 1426 bool os::getTimesSecs(double* process_real_time, 1427 double* process_user_time, 1428 double* process_system_time) { 1429 struct tms ticks; 1430 clock_t real_ticks = times(&ticks); 1431 1432 if (real_ticks == (clock_t) (-1)) { 1433 return false; 1434 } else { 1435 double ticks_per_second = (double) clock_tics_per_sec; 1436 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1437 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1438 *process_real_time = ((double) real_ticks) / ticks_per_second; 1439 1440 return true; 1441 } 1442 } 1443 1444 1445 char * os::local_time_string(char *buf, size_t buflen) { 1446 struct tm t; 1447 time_t long_time; 1448 time(&long_time); 1449 localtime_r(&long_time, &t); 1450 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1451 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1452 t.tm_hour, t.tm_min, t.tm_sec); 1453 return buf; 1454 } 1455 1456 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1457 return localtime_r(clock, res); 1458 } 1459 1460 //////////////////////////////////////////////////////////////////////////////// 1461 // runtime exit support 1462 1463 // Note: os::shutdown() might be called very early during initialization, or 1464 // called from signal handler. Before adding something to os::shutdown(), make 1465 // sure it is async-safe and can handle partially initialized VM. 1466 void os::shutdown() { 1467 1468 // allow PerfMemory to attempt cleanup of any persistent resources 1469 perfMemory_exit(); 1470 1471 // needs to remove object in file system 1472 AttachListener::abort(); 1473 1474 // flush buffered output, finish log files 1475 ostream_abort(); 1476 1477 // Check for abort hook 1478 abort_hook_t abort_hook = Arguments::abort_hook(); 1479 if (abort_hook != NULL) { 1480 abort_hook(); 1481 } 1482 1483 } 1484 1485 // Note: os::abort() might be called very early during initialization, or 1486 // called from signal handler. Before adding something to os::abort(), make 1487 // sure it is async-safe and can handle partially initialized VM. 1488 void os::abort(bool dump_core, void* siginfo, const void* context) { 1489 os::shutdown(); 1490 if (dump_core) { 1491 if (DumpPrivateMappingsInCore) { 1492 ClassLoader::close_jrt_image(); 1493 } 1494 #ifndef PRODUCT 1495 fdStream out(defaultStream::output_fd()); 1496 out.print_raw("Current thread is "); 1497 char buf[16]; 1498 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1499 out.print_raw_cr(buf); 1500 out.print_raw_cr("Dumping core ..."); 1501 #endif 1502 ::abort(); // dump core 1503 } 1504 1505 ::exit(1); 1506 } 1507 1508 // Die immediately, no exit hook, no abort hook, no cleanup. 1509 void os::die() { 1510 ::abort(); 1511 } 1512 1513 1514 // This method is a copy of JDK's sysGetLastErrorString 1515 // from src/solaris/hpi/src/system_md.c 1516 1517 size_t os::lasterror(char *buf, size_t len) { 1518 if (errno == 0) return 0; 1519 1520 const char *s = os::strerror(errno); 1521 size_t n = ::strlen(s); 1522 if (n >= len) { 1523 n = len - 1; 1524 } 1525 ::strncpy(buf, s, n); 1526 buf[n] = '\0'; 1527 return n; 1528 } 1529 1530 // thread_id is kernel thread id (similar to Solaris LWP id) 1531 intx os::current_thread_id() { return os::Linux::gettid(); } 1532 int os::current_process_id() { 1533 return ::getpid(); 1534 } 1535 1536 // DLL functions 1537 1538 const char* os::dll_file_extension() { return ".so"; } 1539 1540 // This must be hard coded because it's the system's temporary 1541 // directory not the java application's temp directory, ala java.io.tmpdir. 1542 const char* os::get_temp_directory() { return "/tmp"; } 1543 1544 static bool file_exists(const char* filename) { 1545 struct stat statbuf; 1546 if (filename == NULL || strlen(filename) == 0) { 1547 return false; 1548 } 1549 return os::stat(filename, &statbuf) == 0; 1550 } 1551 1552 // check if addr is inside libjvm.so 1553 bool os::address_is_in_vm(address addr) { 1554 static address libjvm_base_addr; 1555 Dl_info dlinfo; 1556 1557 if (libjvm_base_addr == NULL) { 1558 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) { 1559 libjvm_base_addr = (address)dlinfo.dli_fbase; 1560 } 1561 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1562 } 1563 1564 if (dladdr((void *)addr, &dlinfo) != 0) { 1565 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1566 } 1567 1568 return false; 1569 } 1570 1571 bool os::dll_address_to_function_name(address addr, char *buf, 1572 int buflen, int *offset, 1573 bool demangle) { 1574 // buf is not optional, but offset is optional 1575 assert(buf != NULL, "sanity check"); 1576 1577 Dl_info dlinfo; 1578 1579 if (dladdr((void*)addr, &dlinfo) != 0) { 1580 // see if we have a matching symbol 1581 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) { 1582 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) { 1583 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1584 } 1585 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1586 return true; 1587 } 1588 // no matching symbol so try for just file info 1589 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) { 1590 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1591 buf, buflen, offset, dlinfo.dli_fname, demangle)) { 1592 return true; 1593 } 1594 } 1595 } 1596 1597 buf[0] = '\0'; 1598 if (offset != NULL) *offset = -1; 1599 return false; 1600 } 1601 1602 struct _address_to_library_name { 1603 address addr; // input : memory address 1604 size_t buflen; // size of fname 1605 char* fname; // output: library name 1606 address base; // library base addr 1607 }; 1608 1609 static int address_to_library_name_callback(struct dl_phdr_info *info, 1610 size_t size, void *data) { 1611 int i; 1612 bool found = false; 1613 address libbase = NULL; 1614 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1615 1616 // iterate through all loadable segments 1617 for (i = 0; i < info->dlpi_phnum; i++) { 1618 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1619 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1620 // base address of a library is the lowest address of its loaded 1621 // segments. 1622 if (libbase == NULL || libbase > segbase) { 1623 libbase = segbase; 1624 } 1625 // see if 'addr' is within current segment 1626 if (segbase <= d->addr && 1627 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1628 found = true; 1629 } 1630 } 1631 } 1632 1633 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1634 // so dll_address_to_library_name() can fall through to use dladdr() which 1635 // can figure out executable name from argv[0]. 1636 if (found && info->dlpi_name && info->dlpi_name[0]) { 1637 d->base = libbase; 1638 if (d->fname) { 1639 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1640 } 1641 return 1; 1642 } 1643 return 0; 1644 } 1645 1646 bool os::dll_address_to_library_name(address addr, char* buf, 1647 int buflen, int* offset) { 1648 // buf is not optional, but offset is optional 1649 assert(buf != NULL, "sanity check"); 1650 1651 Dl_info dlinfo; 1652 struct _address_to_library_name data; 1653 1654 // There is a bug in old glibc dladdr() implementation that it could resolve 1655 // to wrong library name if the .so file has a base address != NULL. Here 1656 // we iterate through the program headers of all loaded libraries to find 1657 // out which library 'addr' really belongs to. This workaround can be 1658 // removed once the minimum requirement for glibc is moved to 2.3.x. 1659 data.addr = addr; 1660 data.fname = buf; 1661 data.buflen = buflen; 1662 data.base = NULL; 1663 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1664 1665 if (rslt) { 1666 // buf already contains library name 1667 if (offset) *offset = addr - data.base; 1668 return true; 1669 } 1670 if (dladdr((void*)addr, &dlinfo) != 0) { 1671 if (dlinfo.dli_fname != NULL) { 1672 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1673 } 1674 if (dlinfo.dli_fbase != NULL && offset != NULL) { 1675 *offset = addr - (address)dlinfo.dli_fbase; 1676 } 1677 return true; 1678 } 1679 1680 buf[0] = '\0'; 1681 if (offset) *offset = -1; 1682 return false; 1683 } 1684 1685 // Loads .dll/.so and 1686 // in case of error it checks if .dll/.so was built for the 1687 // same architecture as Hotspot is running on 1688 1689 1690 // Remember the stack's state. The Linux dynamic linker will change 1691 // the stack to 'executable' at most once, so we must safepoint only once. 1692 bool os::Linux::_stack_is_executable = false; 1693 1694 // VM operation that loads a library. This is necessary if stack protection 1695 // of the Java stacks can be lost during loading the library. If we 1696 // do not stop the Java threads, they can stack overflow before the stacks 1697 // are protected again. 1698 class VM_LinuxDllLoad: public VM_Operation { 1699 private: 1700 const char *_filename; 1701 char *_ebuf; 1702 int _ebuflen; 1703 void *_lib; 1704 public: 1705 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) : 1706 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {} 1707 VMOp_Type type() const { return VMOp_LinuxDllLoad; } 1708 void doit() { 1709 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen); 1710 os::Linux::_stack_is_executable = true; 1711 } 1712 void* loaded_library() { return _lib; } 1713 }; 1714 1715 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) { 1716 void * result = NULL; 1717 bool load_attempted = false; 1718 1719 // Check whether the library to load might change execution rights 1720 // of the stack. If they are changed, the protection of the stack 1721 // guard pages will be lost. We need a safepoint to fix this. 1722 // 1723 // See Linux man page execstack(8) for more info. 1724 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) { 1725 if (!ElfFile::specifies_noexecstack(filename)) { 1726 if (!is_init_completed()) { 1727 os::Linux::_stack_is_executable = true; 1728 // This is OK - No Java threads have been created yet, and hence no 1729 // stack guard pages to fix. 1730 // 1731 // Dynamic loader will make all stacks executable after 1732 // this function returns, and will not do that again. 1733 assert(Threads::number_of_threads() == 0, "no Java threads should exist yet."); 1734 } else { 1735 warning("You have loaded library %s which might have disabled stack guard. " 1736 "The VM will try to fix the stack guard now.\n" 1737 "It's highly recommended that you fix the library with " 1738 "'execstack -c <libfile>', or link it with '-z noexecstack'.", 1739 filename); 1740 1741 assert(Thread::current()->is_Java_thread(), "must be Java thread"); 1742 JavaThread *jt = JavaThread::current(); 1743 if (jt->thread_state() != _thread_in_native) { 1744 // This happens when a compiler thread tries to load a hsdis-<arch>.so file 1745 // that requires ExecStack. Cannot enter safe point. Let's give up. 1746 warning("Unable to fix stack guard. Giving up."); 1747 } else { 1748 if (!LoadExecStackDllInVMThread) { 1749 // This is for the case where the DLL has an static 1750 // constructor function that executes JNI code. We cannot 1751 // load such DLLs in the VMThread. 1752 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1753 } 1754 1755 ThreadInVMfromNative tiv(jt); 1756 debug_only(VMNativeEntryWrapper vew;) 1757 1758 VM_LinuxDllLoad op(filename, ebuf, ebuflen); 1759 VMThread::execute(&op); 1760 if (LoadExecStackDllInVMThread) { 1761 result = op.loaded_library(); 1762 } 1763 load_attempted = true; 1764 } 1765 } 1766 } 1767 } 1768 1769 if (!load_attempted) { 1770 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1771 } 1772 1773 if (result != NULL) { 1774 // Successful loading 1775 return result; 1776 } 1777 1778 Elf32_Ehdr elf_head; 1779 int diag_msg_max_length=ebuflen-strlen(ebuf); 1780 char* diag_msg_buf=ebuf+strlen(ebuf); 1781 1782 if (diag_msg_max_length==0) { 1783 // No more space in ebuf for additional diagnostics message 1784 return NULL; 1785 } 1786 1787 1788 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1789 1790 if (file_descriptor < 0) { 1791 // Can't open library, report dlerror() message 1792 return NULL; 1793 } 1794 1795 bool failed_to_read_elf_head= 1796 (sizeof(elf_head)!= 1797 (::read(file_descriptor, &elf_head,sizeof(elf_head)))); 1798 1799 ::close(file_descriptor); 1800 if (failed_to_read_elf_head) { 1801 // file i/o error - report dlerror() msg 1802 return NULL; 1803 } 1804 1805 typedef struct { 1806 Elf32_Half code; // Actual value as defined in elf.h 1807 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1808 unsigned char elf_class; // 32 or 64 bit 1809 unsigned char endianess; // MSB or LSB 1810 char* name; // String representation 1811 } arch_t; 1812 1813 #ifndef EM_486 1814 #define EM_486 6 /* Intel 80486 */ 1815 #endif 1816 #ifndef EM_AARCH64 1817 #define EM_AARCH64 183 /* ARM AARCH64 */ 1818 #endif 1819 1820 static const arch_t arch_array[]={ 1821 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1822 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1823 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1824 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1825 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1826 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1827 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1828 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1829 #if defined(VM_LITTLE_ENDIAN) 1830 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64 LE"}, 1831 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2LSB, (char*)"SuperH"}, 1832 #else 1833 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}, 1834 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2MSB, (char*)"SuperH BE"}, 1835 #endif 1836 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1837 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1838 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1839 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1840 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1841 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1842 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}, 1843 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"}, 1844 }; 1845 1846 #if (defined IA32) 1847 static Elf32_Half running_arch_code=EM_386; 1848 #elif (defined AMD64) 1849 static Elf32_Half running_arch_code=EM_X86_64; 1850 #elif (defined IA64) 1851 static Elf32_Half running_arch_code=EM_IA_64; 1852 #elif (defined __sparc) && (defined _LP64) 1853 static Elf32_Half running_arch_code=EM_SPARCV9; 1854 #elif (defined __sparc) && (!defined _LP64) 1855 static Elf32_Half running_arch_code=EM_SPARC; 1856 #elif (defined __powerpc64__) 1857 static Elf32_Half running_arch_code=EM_PPC64; 1858 #elif (defined __powerpc__) 1859 static Elf32_Half running_arch_code=EM_PPC; 1860 #elif (defined AARCH64) 1861 static Elf32_Half running_arch_code=EM_AARCH64; 1862 #elif (defined ARM) 1863 static Elf32_Half running_arch_code=EM_ARM; 1864 #elif (defined S390) 1865 static Elf32_Half running_arch_code=EM_S390; 1866 #elif (defined ALPHA) 1867 static Elf32_Half running_arch_code=EM_ALPHA; 1868 #elif (defined MIPSEL) 1869 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1870 #elif (defined PARISC) 1871 static Elf32_Half running_arch_code=EM_PARISC; 1872 #elif (defined MIPS) 1873 static Elf32_Half running_arch_code=EM_MIPS; 1874 #elif (defined M68K) 1875 static Elf32_Half running_arch_code=EM_68K; 1876 #elif (defined SH) 1877 static Elf32_Half running_arch_code=EM_SH; 1878 #else 1879 #error Method os::dll_load requires that one of following is defined:\ 1880 AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, S390, SH, __sparc 1881 #endif 1882 1883 // Identify compatability class for VM's architecture and library's architecture 1884 // Obtain string descriptions for architectures 1885 1886 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1887 int running_arch_index=-1; 1888 1889 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) { 1890 if (running_arch_code == arch_array[i].code) { 1891 running_arch_index = i; 1892 } 1893 if (lib_arch.code == arch_array[i].code) { 1894 lib_arch.compat_class = arch_array[i].compat_class; 1895 lib_arch.name = arch_array[i].name; 1896 } 1897 } 1898 1899 assert(running_arch_index != -1, 1900 "Didn't find running architecture code (running_arch_code) in arch_array"); 1901 if (running_arch_index == -1) { 1902 // Even though running architecture detection failed 1903 // we may still continue with reporting dlerror() message 1904 return NULL; 1905 } 1906 1907 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1908 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1909 return NULL; 1910 } 1911 1912 #ifndef S390 1913 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1914 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1915 return NULL; 1916 } 1917 #endif // !S390 1918 1919 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1920 if (lib_arch.name!=NULL) { 1921 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1922 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1923 lib_arch.name, arch_array[running_arch_index].name); 1924 } else { 1925 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1926 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1927 lib_arch.code, 1928 arch_array[running_arch_index].name); 1929 } 1930 } 1931 1932 return NULL; 1933 } 1934 1935 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, 1936 int ebuflen) { 1937 void * result = ::dlopen(filename, RTLD_LAZY); 1938 if (result == NULL) { 1939 ::strncpy(ebuf, ::dlerror(), ebuflen - 1); 1940 ebuf[ebuflen-1] = '\0'; 1941 } 1942 return result; 1943 } 1944 1945 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, 1946 int ebuflen) { 1947 void * result = NULL; 1948 if (LoadExecStackDllInVMThread) { 1949 result = dlopen_helper(filename, ebuf, ebuflen); 1950 } 1951 1952 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a 1953 // library that requires an executable stack, or which does not have this 1954 // stack attribute set, dlopen changes the stack attribute to executable. The 1955 // read protection of the guard pages gets lost. 1956 // 1957 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad 1958 // may have been queued at the same time. 1959 1960 if (!_stack_is_executable) { 1961 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) { 1962 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized 1963 jt->stack_guards_enabled()) { // No pending stack overflow exceptions 1964 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) { 1965 warning("Attempt to reguard stack yellow zone failed."); 1966 } 1967 } 1968 } 1969 } 1970 1971 return result; 1972 } 1973 1974 void* os::dll_lookup(void* handle, const char* name) { 1975 void* res = dlsym(handle, name); 1976 return res; 1977 } 1978 1979 void* os::get_default_process_handle() { 1980 return (void*)::dlopen(NULL, RTLD_LAZY); 1981 } 1982 1983 static bool _print_ascii_file(const char* filename, outputStream* st, const char* hdr = NULL) { 1984 int fd = ::open(filename, O_RDONLY); 1985 if (fd == -1) { 1986 return false; 1987 } 1988 1989 if (hdr != NULL) { 1990 st->print_cr("%s", hdr); 1991 } 1992 1993 char buf[33]; 1994 int bytes; 1995 buf[32] = '\0'; 1996 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) { 1997 st->print_raw(buf, bytes); 1998 } 1999 2000 ::close(fd); 2001 2002 return true; 2003 } 2004 2005 void os::print_dll_info(outputStream *st) { 2006 st->print_cr("Dynamic libraries:"); 2007 2008 char fname[32]; 2009 pid_t pid = os::Linux::gettid(); 2010 2011 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 2012 2013 if (!_print_ascii_file(fname, st)) { 2014 st->print("Can not get library information for pid = %d\n", pid); 2015 } 2016 } 2017 2018 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) { 2019 FILE *procmapsFile = NULL; 2020 2021 // Open the procfs maps file for the current process 2022 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) { 2023 // Allocate PATH_MAX for file name plus a reasonable size for other fields. 2024 char line[PATH_MAX + 100]; 2025 2026 // Read line by line from 'file' 2027 while (fgets(line, sizeof(line), procmapsFile) != NULL) { 2028 u8 base, top, offset, inode; 2029 char permissions[5]; 2030 char device[6]; 2031 char name[PATH_MAX + 1]; 2032 2033 // Parse fields from line 2034 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %7s " INT64_FORMAT " %s", 2035 &base, &top, permissions, &offset, device, &inode, name); 2036 2037 // Filter by device id '00:00' so that we only get file system mapped files. 2038 if (strcmp(device, "00:00") != 0) { 2039 2040 // Call callback with the fields of interest 2041 if(callback(name, (address)base, (address)top, param)) { 2042 // Oops abort, callback aborted 2043 fclose(procmapsFile); 2044 return 1; 2045 } 2046 } 2047 } 2048 fclose(procmapsFile); 2049 } 2050 return 0; 2051 } 2052 2053 void os::print_os_info_brief(outputStream* st) { 2054 os::Linux::print_distro_info(st); 2055 2056 os::Posix::print_uname_info(st); 2057 2058 os::Linux::print_libversion_info(st); 2059 2060 } 2061 2062 void os::print_os_info(outputStream* st) { 2063 st->print("OS:"); 2064 2065 os::Linux::print_distro_info(st); 2066 2067 os::Posix::print_uname_info(st); 2068 2069 // Print warning if unsafe chroot environment detected 2070 if (unsafe_chroot_detected) { 2071 st->print("WARNING!! "); 2072 st->print_cr("%s", unstable_chroot_error); 2073 } 2074 2075 os::Linux::print_libversion_info(st); 2076 2077 os::Posix::print_rlimit_info(st); 2078 2079 os::Posix::print_load_average(st); 2080 2081 os::Linux::print_full_memory_info(st); 2082 2083 os::Linux::print_proc_sys_info(st); 2084 2085 os::Linux::print_ld_preload_file(st); 2086 2087 os::Linux::print_container_info(st); 2088 2089 VM_Version::print_platform_virtualization_info(st); 2090 2091 os::Linux::print_steal_info(st); 2092 } 2093 2094 // Try to identify popular distros. 2095 // Most Linux distributions have a /etc/XXX-release file, which contains 2096 // the OS version string. Newer Linux distributions have a /etc/lsb-release 2097 // file that also contains the OS version string. Some have more than one 2098 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and 2099 // /etc/redhat-release.), so the order is important. 2100 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have 2101 // their own specific XXX-release file as well as a redhat-release file. 2102 // Because of this the XXX-release file needs to be searched for before the 2103 // redhat-release file. 2104 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the 2105 // search for redhat-release / SuSE-release needs to be before lsb-release. 2106 // Since the lsb-release file is the new standard it needs to be searched 2107 // before the older style release files. 2108 // Searching system-release (Red Hat) and os-release (other Linuxes) are a 2109 // next to last resort. The os-release file is a new standard that contains 2110 // distribution information and the system-release file seems to be an old 2111 // standard that has been replaced by the lsb-release and os-release files. 2112 // Searching for the debian_version file is the last resort. It contains 2113 // an informative string like "6.0.6" or "wheezy/sid". Because of this 2114 // "Debian " is printed before the contents of the debian_version file. 2115 2116 const char* distro_files[] = { 2117 "/etc/oracle-release", 2118 "/etc/mandriva-release", 2119 "/etc/mandrake-release", 2120 "/etc/sun-release", 2121 "/etc/redhat-release", 2122 "/etc/SuSE-release", 2123 "/etc/lsb-release", 2124 "/etc/turbolinux-release", 2125 "/etc/gentoo-release", 2126 "/etc/ltib-release", 2127 "/etc/angstrom-version", 2128 "/etc/system-release", 2129 "/etc/os-release", 2130 NULL }; 2131 2132 void os::Linux::print_distro_info(outputStream* st) { 2133 for (int i = 0;; i++) { 2134 const char* file = distro_files[i]; 2135 if (file == NULL) { 2136 break; // done 2137 } 2138 // If file prints, we found it. 2139 if (_print_ascii_file(file, st)) { 2140 return; 2141 } 2142 } 2143 2144 if (file_exists("/etc/debian_version")) { 2145 st->print("Debian "); 2146 _print_ascii_file("/etc/debian_version", st); 2147 } else { 2148 st->print("Linux"); 2149 } 2150 st->cr(); 2151 } 2152 2153 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) { 2154 char buf[256]; 2155 while (fgets(buf, sizeof(buf), fp)) { 2156 // Edit out extra stuff in expected format 2157 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) { 2158 char* ptr = strstr(buf, "\""); // the name is in quotes 2159 if (ptr != NULL) { 2160 ptr++; // go beyond first quote 2161 char* nl = strchr(ptr, '\"'); 2162 if (nl != NULL) *nl = '\0'; 2163 strncpy(distro, ptr, length); 2164 } else { 2165 ptr = strstr(buf, "="); 2166 ptr++; // go beyond equals then 2167 char* nl = strchr(ptr, '\n'); 2168 if (nl != NULL) *nl = '\0'; 2169 strncpy(distro, ptr, length); 2170 } 2171 return; 2172 } else if (get_first_line) { 2173 char* nl = strchr(buf, '\n'); 2174 if (nl != NULL) *nl = '\0'; 2175 strncpy(distro, buf, length); 2176 return; 2177 } 2178 } 2179 // print last line and close 2180 char* nl = strchr(buf, '\n'); 2181 if (nl != NULL) *nl = '\0'; 2182 strncpy(distro, buf, length); 2183 } 2184 2185 static void parse_os_info(char* distro, size_t length, const char* file) { 2186 FILE* fp = fopen(file, "r"); 2187 if (fp != NULL) { 2188 // if suse format, print out first line 2189 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0); 2190 parse_os_info_helper(fp, distro, length, get_first_line); 2191 fclose(fp); 2192 } 2193 } 2194 2195 void os::get_summary_os_info(char* buf, size_t buflen) { 2196 for (int i = 0;; i++) { 2197 const char* file = distro_files[i]; 2198 if (file == NULL) { 2199 break; // ran out of distro_files 2200 } 2201 if (file_exists(file)) { 2202 parse_os_info(buf, buflen, file); 2203 return; 2204 } 2205 } 2206 // special case for debian 2207 if (file_exists("/etc/debian_version")) { 2208 strncpy(buf, "Debian ", buflen); 2209 if (buflen > 7) { 2210 parse_os_info(&buf[7], buflen-7, "/etc/debian_version"); 2211 } 2212 } else { 2213 strncpy(buf, "Linux", buflen); 2214 } 2215 } 2216 2217 void os::Linux::print_libversion_info(outputStream* st) { 2218 // libc, pthread 2219 st->print("libc:"); 2220 st->print("%s ", os::Linux::glibc_version()); 2221 st->print("%s ", os::Linux::libpthread_version()); 2222 st->cr(); 2223 } 2224 2225 void os::Linux::print_proc_sys_info(outputStream* st) { 2226 st->cr(); 2227 st->print_cr("/proc/sys/kernel/threads-max (system-wide limit on the number of threads):"); 2228 _print_ascii_file("/proc/sys/kernel/threads-max", st); 2229 st->cr(); 2230 st->cr(); 2231 2232 st->print_cr("/proc/sys/vm/max_map_count (maximum number of memory map areas a process may have):"); 2233 _print_ascii_file("/proc/sys/vm/max_map_count", st); 2234 st->cr(); 2235 st->cr(); 2236 2237 st->print_cr("/proc/sys/kernel/pid_max (system-wide limit on number of process identifiers):"); 2238 _print_ascii_file("/proc/sys/kernel/pid_max", st); 2239 st->cr(); 2240 st->cr(); 2241 } 2242 2243 void os::Linux::print_full_memory_info(outputStream* st) { 2244 st->print("\n/proc/meminfo:\n"); 2245 _print_ascii_file("/proc/meminfo", st); 2246 st->cr(); 2247 } 2248 2249 void os::Linux::print_ld_preload_file(outputStream* st) { 2250 _print_ascii_file("/etc/ld.so.preload", st, "\n/etc/ld.so.preload:"); 2251 st->cr(); 2252 } 2253 2254 void os::Linux::print_container_info(outputStream* st) { 2255 if (!OSContainer::is_containerized()) { 2256 return; 2257 } 2258 2259 st->print("container (cgroup) information:\n"); 2260 2261 const char *p_ct = OSContainer::container_type(); 2262 st->print("container_type: %s\n", p_ct != NULL ? p_ct : "failed"); 2263 2264 char *p = OSContainer::cpu_cpuset_cpus(); 2265 st->print("cpu_cpuset_cpus: %s\n", p != NULL ? p : "failed"); 2266 free(p); 2267 2268 p = OSContainer::cpu_cpuset_memory_nodes(); 2269 st->print("cpu_memory_nodes: %s\n", p != NULL ? p : "failed"); 2270 free(p); 2271 2272 int i = OSContainer::active_processor_count(); 2273 if (i > 0) { 2274 st->print("active_processor_count: %d\n", i); 2275 } else { 2276 st->print("active_processor_count: failed\n"); 2277 } 2278 2279 i = OSContainer::cpu_quota(); 2280 st->print("cpu_quota: %d\n", i); 2281 2282 i = OSContainer::cpu_period(); 2283 st->print("cpu_period: %d\n", i); 2284 2285 i = OSContainer::cpu_shares(); 2286 st->print("cpu_shares: %d\n", i); 2287 2288 jlong j = OSContainer::memory_limit_in_bytes(); 2289 st->print("memory_limit_in_bytes: " JLONG_FORMAT "\n", j); 2290 2291 j = OSContainer::memory_and_swap_limit_in_bytes(); 2292 st->print("memory_and_swap_limit_in_bytes: " JLONG_FORMAT "\n", j); 2293 2294 j = OSContainer::memory_soft_limit_in_bytes(); 2295 st->print("memory_soft_limit_in_bytes: " JLONG_FORMAT "\n", j); 2296 2297 j = OSContainer::OSContainer::memory_usage_in_bytes(); 2298 st->print("memory_usage_in_bytes: " JLONG_FORMAT "\n", j); 2299 2300 j = OSContainer::OSContainer::memory_max_usage_in_bytes(); 2301 st->print("memory_max_usage_in_bytes: " JLONG_FORMAT "\n", j); 2302 st->cr(); 2303 } 2304 2305 void os::Linux::print_steal_info(outputStream* st) { 2306 if (has_initial_tick_info) { 2307 CPUPerfTicks pticks; 2308 bool res = os::Linux::get_tick_information(&pticks, -1); 2309 2310 if (res && pticks.has_steal_ticks) { 2311 uint64_t steal_ticks_difference = pticks.steal - initial_steal_ticks; 2312 uint64_t total_ticks_difference = pticks.total - initial_total_ticks; 2313 double steal_ticks_perc = 0.0; 2314 if (total_ticks_difference != 0) { 2315 steal_ticks_perc = (double) steal_ticks_difference / total_ticks_difference; 2316 } 2317 st->print_cr("Steal ticks since vm start: " UINT64_FORMAT, steal_ticks_difference); 2318 st->print_cr("Steal ticks percentage since vm start:%7.3f", steal_ticks_perc); 2319 } 2320 } 2321 } 2322 2323 void os::print_memory_info(outputStream* st) { 2324 2325 st->print("Memory:"); 2326 st->print(" %dk page", os::vm_page_size()>>10); 2327 2328 // values in struct sysinfo are "unsigned long" 2329 struct sysinfo si; 2330 sysinfo(&si); 2331 2332 st->print(", physical " UINT64_FORMAT "k", 2333 os::physical_memory() >> 10); 2334 st->print("(" UINT64_FORMAT "k free)", 2335 os::available_memory() >> 10); 2336 st->print(", swap " UINT64_FORMAT "k", 2337 ((jlong)si.totalswap * si.mem_unit) >> 10); 2338 st->print("(" UINT64_FORMAT "k free)", 2339 ((jlong)si.freeswap * si.mem_unit) >> 10); 2340 st->cr(); 2341 } 2342 2343 // Print the first "model name" line and the first "flags" line 2344 // that we find and nothing more. We assume "model name" comes 2345 // before "flags" so if we find a second "model name", then the 2346 // "flags" field is considered missing. 2347 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) { 2348 #if defined(IA32) || defined(AMD64) 2349 // Other platforms have less repetitive cpuinfo files 2350 FILE *fp = fopen("/proc/cpuinfo", "r"); 2351 if (fp) { 2352 while (!feof(fp)) { 2353 if (fgets(buf, buflen, fp)) { 2354 // Assume model name comes before flags 2355 bool model_name_printed = false; 2356 if (strstr(buf, "model name") != NULL) { 2357 if (!model_name_printed) { 2358 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n"); 2359 st->print_raw(buf); 2360 model_name_printed = true; 2361 } else { 2362 // model name printed but not flags? Odd, just return 2363 fclose(fp); 2364 return true; 2365 } 2366 } 2367 // print the flags line too 2368 if (strstr(buf, "flags") != NULL) { 2369 st->print_raw(buf); 2370 fclose(fp); 2371 return true; 2372 } 2373 } 2374 } 2375 fclose(fp); 2376 } 2377 #endif // x86 platforms 2378 return false; 2379 } 2380 2381 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) { 2382 // Only print the model name if the platform provides this as a summary 2383 if (!print_model_name_and_flags(st, buf, buflen)) { 2384 st->print("\n/proc/cpuinfo:\n"); 2385 if (!_print_ascii_file("/proc/cpuinfo", st)) { 2386 st->print_cr(" <Not Available>"); 2387 } 2388 } 2389 } 2390 2391 #if defined(AMD64) || defined(IA32) || defined(X32) 2392 const char* search_string = "model name"; 2393 #elif defined(M68K) 2394 const char* search_string = "CPU"; 2395 #elif defined(PPC64) 2396 const char* search_string = "cpu"; 2397 #elif defined(S390) 2398 const char* search_string = "machine ="; 2399 #elif defined(SPARC) 2400 const char* search_string = "cpu"; 2401 #else 2402 const char* search_string = "Processor"; 2403 #endif 2404 2405 // Parses the cpuinfo file for string representing the model name. 2406 void os::get_summary_cpu_info(char* cpuinfo, size_t length) { 2407 FILE* fp = fopen("/proc/cpuinfo", "r"); 2408 if (fp != NULL) { 2409 while (!feof(fp)) { 2410 char buf[256]; 2411 if (fgets(buf, sizeof(buf), fp)) { 2412 char* start = strstr(buf, search_string); 2413 if (start != NULL) { 2414 char *ptr = start + strlen(search_string); 2415 char *end = buf + strlen(buf); 2416 while (ptr != end) { 2417 // skip whitespace and colon for the rest of the name. 2418 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') { 2419 break; 2420 } 2421 ptr++; 2422 } 2423 if (ptr != end) { 2424 // reasonable string, get rid of newline and keep the rest 2425 char* nl = strchr(buf, '\n'); 2426 if (nl != NULL) *nl = '\0'; 2427 strncpy(cpuinfo, ptr, length); 2428 fclose(fp); 2429 return; 2430 } 2431 } 2432 } 2433 } 2434 fclose(fp); 2435 } 2436 // cpuinfo not found or parsing failed, just print generic string. The entire 2437 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86) 2438 #if defined(AARCH64) 2439 strncpy(cpuinfo, "AArch64", length); 2440 #elif defined(AMD64) 2441 strncpy(cpuinfo, "x86_64", length); 2442 #elif defined(ARM) // Order wrt. AARCH64 is relevant! 2443 strncpy(cpuinfo, "ARM", length); 2444 #elif defined(IA32) 2445 strncpy(cpuinfo, "x86_32", length); 2446 #elif defined(IA64) 2447 strncpy(cpuinfo, "IA64", length); 2448 #elif defined(PPC) 2449 strncpy(cpuinfo, "PPC64", length); 2450 #elif defined(S390) 2451 strncpy(cpuinfo, "S390", length); 2452 #elif defined(SPARC) 2453 strncpy(cpuinfo, "sparcv9", length); 2454 #elif defined(ZERO_LIBARCH) 2455 strncpy(cpuinfo, ZERO_LIBARCH, length); 2456 #else 2457 strncpy(cpuinfo, "unknown", length); 2458 #endif 2459 } 2460 2461 static void print_signal_handler(outputStream* st, int sig, 2462 char* buf, size_t buflen); 2463 2464 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2465 st->print_cr("Signal Handlers:"); 2466 print_signal_handler(st, SIGSEGV, buf, buflen); 2467 print_signal_handler(st, SIGBUS , buf, buflen); 2468 print_signal_handler(st, SIGFPE , buf, buflen); 2469 print_signal_handler(st, SIGPIPE, buf, buflen); 2470 print_signal_handler(st, SIGXFSZ, buf, buflen); 2471 print_signal_handler(st, SIGILL , buf, buflen); 2472 print_signal_handler(st, SR_signum, buf, buflen); 2473 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2474 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2475 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2476 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2477 #if defined(PPC64) 2478 print_signal_handler(st, SIGTRAP, buf, buflen); 2479 #endif 2480 } 2481 2482 static char saved_jvm_path[MAXPATHLEN] = {0}; 2483 2484 // Find the full path to the current module, libjvm.so 2485 void os::jvm_path(char *buf, jint buflen) { 2486 // Error checking. 2487 if (buflen < MAXPATHLEN) { 2488 assert(false, "must use a large-enough buffer"); 2489 buf[0] = '\0'; 2490 return; 2491 } 2492 // Lazy resolve the path to current module. 2493 if (saved_jvm_path[0] != 0) { 2494 strcpy(buf, saved_jvm_path); 2495 return; 2496 } 2497 2498 char dli_fname[MAXPATHLEN]; 2499 bool ret = dll_address_to_library_name( 2500 CAST_FROM_FN_PTR(address, os::jvm_path), 2501 dli_fname, sizeof(dli_fname), NULL); 2502 assert(ret, "cannot locate libjvm"); 2503 char *rp = NULL; 2504 if (ret && dli_fname[0] != '\0') { 2505 rp = os::Posix::realpath(dli_fname, buf, buflen); 2506 } 2507 if (rp == NULL) { 2508 return; 2509 } 2510 2511 if (Arguments::sun_java_launcher_is_altjvm()) { 2512 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical 2513 // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so". 2514 // If "/jre/lib/" appears at the right place in the string, then 2515 // assume we are installed in a JDK and we're done. Otherwise, check 2516 // for a JAVA_HOME environment variable and fix up the path so it 2517 // looks like libjvm.so is installed there (append a fake suffix 2518 // hotspot/libjvm.so). 2519 const char *p = buf + strlen(buf) - 1; 2520 for (int count = 0; p > buf && count < 5; ++count) { 2521 for (--p; p > buf && *p != '/'; --p) 2522 /* empty */ ; 2523 } 2524 2525 if (strncmp(p, "/jre/lib/", 9) != 0) { 2526 // Look for JAVA_HOME in the environment. 2527 char* java_home_var = ::getenv("JAVA_HOME"); 2528 if (java_home_var != NULL && java_home_var[0] != 0) { 2529 char* jrelib_p; 2530 int len; 2531 2532 // Check the current module name "libjvm.so". 2533 p = strrchr(buf, '/'); 2534 if (p == NULL) { 2535 return; 2536 } 2537 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2538 2539 rp = os::Posix::realpath(java_home_var, buf, buflen); 2540 if (rp == NULL) { 2541 return; 2542 } 2543 2544 // determine if this is a legacy image or modules image 2545 // modules image doesn't have "jre" subdirectory 2546 len = strlen(buf); 2547 assert(len < buflen, "Ran out of buffer room"); 2548 jrelib_p = buf + len; 2549 snprintf(jrelib_p, buflen-len, "/jre/lib"); 2550 if (0 != access(buf, F_OK)) { 2551 snprintf(jrelib_p, buflen-len, "/lib"); 2552 } 2553 2554 if (0 == access(buf, F_OK)) { 2555 // Use current module name "libjvm.so" 2556 len = strlen(buf); 2557 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so"); 2558 } else { 2559 // Go back to path of .so 2560 rp = os::Posix::realpath(dli_fname, buf, buflen); 2561 if (rp == NULL) { 2562 return; 2563 } 2564 } 2565 } 2566 } 2567 } 2568 2569 strncpy(saved_jvm_path, buf, MAXPATHLEN); 2570 saved_jvm_path[MAXPATHLEN - 1] = '\0'; 2571 } 2572 2573 void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2574 // no prefix required, not even "_" 2575 } 2576 2577 void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2578 // no suffix required 2579 } 2580 2581 //////////////////////////////////////////////////////////////////////////////// 2582 // sun.misc.Signal support 2583 2584 static volatile jint sigint_count = 0; 2585 2586 static void UserHandler(int sig, void *siginfo, void *context) { 2587 // 4511530 - sem_post is serialized and handled by the manager thread. When 2588 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2589 // don't want to flood the manager thread with sem_post requests. 2590 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) { 2591 return; 2592 } 2593 2594 // Ctrl-C is pressed during error reporting, likely because the error 2595 // handler fails to abort. Let VM die immediately. 2596 if (sig == SIGINT && VMError::is_error_reported()) { 2597 os::die(); 2598 } 2599 2600 os::signal_notify(sig); 2601 } 2602 2603 void* os::user_handler() { 2604 return CAST_FROM_FN_PTR(void*, UserHandler); 2605 } 2606 2607 static struct timespec create_semaphore_timespec(unsigned int sec, int nsec) { 2608 struct timespec ts; 2609 // Semaphore's are always associated with CLOCK_REALTIME 2610 os::Linux::clock_gettime(CLOCK_REALTIME, &ts); 2611 // see os_posix.cpp for discussion on overflow checking 2612 if (sec >= MAX_SECS) { 2613 ts.tv_sec += MAX_SECS; 2614 ts.tv_nsec = 0; 2615 } else { 2616 ts.tv_sec += sec; 2617 ts.tv_nsec += nsec; 2618 if (ts.tv_nsec >= NANOSECS_PER_SEC) { 2619 ts.tv_nsec -= NANOSECS_PER_SEC; 2620 ++ts.tv_sec; // note: this must be <= max_secs 2621 } 2622 } 2623 2624 return ts; 2625 } 2626 2627 extern "C" { 2628 typedef void (*sa_handler_t)(int); 2629 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2630 } 2631 2632 void* os::signal(int signal_number, void* handler) { 2633 struct sigaction sigAct, oldSigAct; 2634 2635 sigfillset(&(sigAct.sa_mask)); 2636 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2637 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2638 2639 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2640 // -1 means registration failed 2641 return (void *)-1; 2642 } 2643 2644 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2645 } 2646 2647 void os::signal_raise(int signal_number) { 2648 ::raise(signal_number); 2649 } 2650 2651 // The following code is moved from os.cpp for making this 2652 // code platform specific, which it is by its very nature. 2653 2654 // Will be modified when max signal is changed to be dynamic 2655 int os::sigexitnum_pd() { 2656 return NSIG; 2657 } 2658 2659 // a counter for each possible signal value 2660 static volatile jint pending_signals[NSIG+1] = { 0 }; 2661 2662 // Linux(POSIX) specific hand shaking semaphore. 2663 static Semaphore* sig_sem = NULL; 2664 static PosixSemaphore sr_semaphore; 2665 2666 static void jdk_misc_signal_init() { 2667 // Initialize signal structures 2668 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2669 2670 // Initialize signal semaphore 2671 sig_sem = new Semaphore(); 2672 } 2673 2674 void os::signal_notify(int sig) { 2675 if (sig_sem != NULL) { 2676 Atomic::inc(&pending_signals[sig]); 2677 sig_sem->signal(); 2678 } else { 2679 // Signal thread is not created with ReduceSignalUsage and jdk_misc_signal_init 2680 // initialization isn't called. 2681 assert(ReduceSignalUsage, "signal semaphore should be created"); 2682 } 2683 } 2684 2685 static int check_pending_signals() { 2686 Atomic::store(0, &sigint_count); 2687 for (;;) { 2688 for (int i = 0; i < NSIG + 1; i++) { 2689 jint n = pending_signals[i]; 2690 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2691 return i; 2692 } 2693 } 2694 JavaThread *thread = JavaThread::current(); 2695 ThreadBlockInVM tbivm(thread); 2696 2697 bool threadIsSuspended; 2698 do { 2699 thread->set_suspend_equivalent(); 2700 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2701 sig_sem->wait(); 2702 2703 // were we externally suspended while we were waiting? 2704 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2705 if (threadIsSuspended) { 2706 // The semaphore has been incremented, but while we were waiting 2707 // another thread suspended us. We don't want to continue running 2708 // while suspended because that would surprise the thread that 2709 // suspended us. 2710 sig_sem->signal(); 2711 2712 thread->java_suspend_self(); 2713 } 2714 } while (threadIsSuspended); 2715 } 2716 } 2717 2718 int os::signal_wait() { 2719 return check_pending_signals(); 2720 } 2721 2722 //////////////////////////////////////////////////////////////////////////////// 2723 // Virtual Memory 2724 2725 int os::vm_page_size() { 2726 // Seems redundant as all get out 2727 assert(os::Linux::page_size() != -1, "must call os::init"); 2728 return os::Linux::page_size(); 2729 } 2730 2731 // Solaris allocates memory by pages. 2732 int os::vm_allocation_granularity() { 2733 assert(os::Linux::page_size() != -1, "must call os::init"); 2734 return os::Linux::page_size(); 2735 } 2736 2737 // Rationale behind this function: 2738 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2739 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2740 // samples for JITted code. Here we create private executable mapping over the code cache 2741 // and then we can use standard (well, almost, as mapping can change) way to provide 2742 // info for the reporting script by storing timestamp and location of symbol 2743 void linux_wrap_code(char* base, size_t size) { 2744 static volatile jint cnt = 0; 2745 2746 if (!UseOprofile) { 2747 return; 2748 } 2749 2750 char buf[PATH_MAX+1]; 2751 int num = Atomic::add(1, &cnt); 2752 2753 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2754 os::get_temp_directory(), os::current_process_id(), num); 2755 unlink(buf); 2756 2757 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2758 2759 if (fd != -1) { 2760 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2761 if (rv != (off_t)-1) { 2762 if (::write(fd, "", 1) == 1) { 2763 mmap(base, size, 2764 PROT_READ|PROT_WRITE|PROT_EXEC, 2765 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2766 } 2767 } 2768 ::close(fd); 2769 unlink(buf); 2770 } 2771 } 2772 2773 static bool recoverable_mmap_error(int err) { 2774 // See if the error is one we can let the caller handle. This 2775 // list of errno values comes from JBS-6843484. I can't find a 2776 // Linux man page that documents this specific set of errno 2777 // values so while this list currently matches Solaris, it may 2778 // change as we gain experience with this failure mode. 2779 switch (err) { 2780 case EBADF: 2781 case EINVAL: 2782 case ENOTSUP: 2783 // let the caller deal with these errors 2784 return true; 2785 2786 default: 2787 // Any remaining errors on this OS can cause our reserved mapping 2788 // to be lost. That can cause confusion where different data 2789 // structures think they have the same memory mapped. The worst 2790 // scenario is if both the VM and a library think they have the 2791 // same memory mapped. 2792 return false; 2793 } 2794 } 2795 2796 static void warn_fail_commit_memory(char* addr, size_t size, bool exec, 2797 int err) { 2798 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2799 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec, 2800 os::strerror(err), err); 2801 } 2802 2803 static void warn_fail_commit_memory(char* addr, size_t size, 2804 size_t alignment_hint, bool exec, 2805 int err) { 2806 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2807 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, 2808 alignment_hint, exec, os::strerror(err), err); 2809 } 2810 2811 // NOTE: Linux kernel does not really reserve the pages for us. 2812 // All it does is to check if there are enough free pages 2813 // left at the time of mmap(). This could be a potential 2814 // problem. 2815 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) { 2816 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2817 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2818 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2819 if (res != (uintptr_t) MAP_FAILED) { 2820 if (UseNUMAInterleaving) { 2821 numa_make_global(addr, size); 2822 } 2823 return 0; 2824 } 2825 2826 int err = errno; // save errno from mmap() call above 2827 2828 if (!recoverable_mmap_error(err)) { 2829 warn_fail_commit_memory(addr, size, exec, err); 2830 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory."); 2831 } 2832 2833 return err; 2834 } 2835 2836 bool os::pd_commit_memory(char* addr, size_t size, bool exec) { 2837 return os::Linux::commit_memory_impl(addr, size, exec) == 0; 2838 } 2839 2840 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec, 2841 const char* mesg) { 2842 assert(mesg != NULL, "mesg must be specified"); 2843 int err = os::Linux::commit_memory_impl(addr, size, exec); 2844 if (err != 0) { 2845 // the caller wants all commit errors to exit with the specified mesg: 2846 warn_fail_commit_memory(addr, size, exec, err); 2847 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2848 } 2849 } 2850 2851 // Define MAP_HUGETLB here so we can build HotSpot on old systems. 2852 #ifndef MAP_HUGETLB 2853 #define MAP_HUGETLB 0x40000 2854 #endif 2855 2856 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2857 #ifndef MADV_HUGEPAGE 2858 #define MADV_HUGEPAGE 14 2859 #endif 2860 2861 int os::Linux::commit_memory_impl(char* addr, size_t size, 2862 size_t alignment_hint, bool exec) { 2863 int err = os::Linux::commit_memory_impl(addr, size, exec); 2864 if (err == 0) { 2865 realign_memory(addr, size, alignment_hint); 2866 } 2867 return err; 2868 } 2869 2870 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, 2871 bool exec) { 2872 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0; 2873 } 2874 2875 void os::pd_commit_memory_or_exit(char* addr, size_t size, 2876 size_t alignment_hint, bool exec, 2877 const char* mesg) { 2878 assert(mesg != NULL, "mesg must be specified"); 2879 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec); 2880 if (err != 0) { 2881 // the caller wants all commit errors to exit with the specified mesg: 2882 warn_fail_commit_memory(addr, size, alignment_hint, exec, err); 2883 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2884 } 2885 } 2886 2887 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2888 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) { 2889 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2890 // be supported or the memory may already be backed by huge pages. 2891 ::madvise(addr, bytes, MADV_HUGEPAGE); 2892 } 2893 } 2894 2895 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) { 2896 // This method works by doing an mmap over an existing mmaping and effectively discarding 2897 // the existing pages. However it won't work for SHM-based large pages that cannot be 2898 // uncommitted at all. We don't do anything in this case to avoid creating a segment with 2899 // small pages on top of the SHM segment. This method always works for small pages, so we 2900 // allow that in any case. 2901 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) { 2902 commit_memory(addr, bytes, alignment_hint, !ExecMem); 2903 } 2904 } 2905 2906 void os::numa_make_global(char *addr, size_t bytes) { 2907 Linux::numa_interleave_memory(addr, bytes); 2908 } 2909 2910 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the 2911 // bind policy to MPOL_PREFERRED for the current thread. 2912 #define USE_MPOL_PREFERRED 0 2913 2914 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2915 // To make NUMA and large pages more robust when both enabled, we need to ease 2916 // the requirements on where the memory should be allocated. MPOL_BIND is the 2917 // default policy and it will force memory to be allocated on the specified 2918 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on 2919 // the specified node, but will not force it. Using this policy will prevent 2920 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no 2921 // free large pages. 2922 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED); 2923 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2924 } 2925 2926 bool os::numa_topology_changed() { return false; } 2927 2928 size_t os::numa_get_groups_num() { 2929 // Return just the number of nodes in which it's possible to allocate memory 2930 // (in numa terminology, configured nodes). 2931 return Linux::numa_num_configured_nodes(); 2932 } 2933 2934 int os::numa_get_group_id() { 2935 int cpu_id = Linux::sched_getcpu(); 2936 if (cpu_id != -1) { 2937 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2938 if (lgrp_id != -1) { 2939 return lgrp_id; 2940 } 2941 } 2942 return 0; 2943 } 2944 2945 int os::Linux::get_existing_num_nodes() { 2946 int node; 2947 int highest_node_number = Linux::numa_max_node(); 2948 int num_nodes = 0; 2949 2950 // Get the total number of nodes in the system including nodes without memory. 2951 for (node = 0; node <= highest_node_number; node++) { 2952 if (isnode_in_existing_nodes(node)) { 2953 num_nodes++; 2954 } 2955 } 2956 return num_nodes; 2957 } 2958 2959 size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2960 int highest_node_number = Linux::numa_max_node(); 2961 size_t i = 0; 2962 2963 // Map all node ids in which it is possible to allocate memory. Also nodes are 2964 // not always consecutively available, i.e. available from 0 to the highest 2965 // node number. If the nodes have been bound explicitly using numactl membind, 2966 // then allocate memory from those nodes only. 2967 for (int node = 0; node <= highest_node_number; node++) { 2968 if (Linux::isnode_in_bound_nodes((unsigned int)node)) { 2969 ids[i++] = node; 2970 } 2971 } 2972 return i; 2973 } 2974 2975 bool os::get_page_info(char *start, page_info* info) { 2976 return false; 2977 } 2978 2979 char *os::scan_pages(char *start, char* end, page_info* page_expected, 2980 page_info* page_found) { 2981 return end; 2982 } 2983 2984 2985 int os::Linux::sched_getcpu_syscall(void) { 2986 unsigned int cpu = 0; 2987 int retval = -1; 2988 2989 #if defined(IA32) 2990 #ifndef SYS_getcpu 2991 #define SYS_getcpu 318 2992 #endif 2993 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 2994 #elif defined(AMD64) 2995 // Unfortunately we have to bring all these macros here from vsyscall.h 2996 // to be able to compile on old linuxes. 2997 #define __NR_vgetcpu 2 2998 #define VSYSCALL_START (-10UL << 20) 2999 #define VSYSCALL_SIZE 1024 3000 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 3001 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 3002 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 3003 retval = vgetcpu(&cpu, NULL, NULL); 3004 #endif 3005 3006 return (retval == -1) ? retval : cpu; 3007 } 3008 3009 void os::Linux::sched_getcpu_init() { 3010 // sched_getcpu() should be in libc. 3011 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 3012 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 3013 3014 // If it's not, try a direct syscall. 3015 if (sched_getcpu() == -1) { 3016 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 3017 (void*)&sched_getcpu_syscall)); 3018 } 3019 3020 if (sched_getcpu() == -1) { 3021 vm_exit_during_initialization("getcpu(2) system call not supported by kernel"); 3022 } 3023 } 3024 3025 // Something to do with the numa-aware allocator needs these symbols 3026 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 3027 extern "C" JNIEXPORT void numa_error(char *where) { } 3028 3029 // Handle request to load libnuma symbol version 1.1 (API v1). If it fails 3030 // load symbol from base version instead. 3031 void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 3032 void *f = dlvsym(handle, name, "libnuma_1.1"); 3033 if (f == NULL) { 3034 f = dlsym(handle, name); 3035 } 3036 return f; 3037 } 3038 3039 // Handle request to load libnuma symbol version 1.2 (API v2) only. 3040 // Return NULL if the symbol is not defined in this particular version. 3041 void* os::Linux::libnuma_v2_dlsym(void* handle, const char* name) { 3042 return dlvsym(handle, name, "libnuma_1.2"); 3043 } 3044 3045 bool os::Linux::libnuma_init() { 3046 if (sched_getcpu() != -1) { // Requires sched_getcpu() support 3047 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 3048 if (handle != NULL) { 3049 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 3050 libnuma_dlsym(handle, "numa_node_to_cpus"))); 3051 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 3052 libnuma_dlsym(handle, "numa_max_node"))); 3053 set_numa_num_configured_nodes(CAST_TO_FN_PTR(numa_num_configured_nodes_func_t, 3054 libnuma_dlsym(handle, "numa_num_configured_nodes"))); 3055 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 3056 libnuma_dlsym(handle, "numa_available"))); 3057 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 3058 libnuma_dlsym(handle, "numa_tonode_memory"))); 3059 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 3060 libnuma_dlsym(handle, "numa_interleave_memory"))); 3061 set_numa_interleave_memory_v2(CAST_TO_FN_PTR(numa_interleave_memory_v2_func_t, 3062 libnuma_v2_dlsym(handle, "numa_interleave_memory"))); 3063 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t, 3064 libnuma_dlsym(handle, "numa_set_bind_policy"))); 3065 set_numa_bitmask_isbitset(CAST_TO_FN_PTR(numa_bitmask_isbitset_func_t, 3066 libnuma_dlsym(handle, "numa_bitmask_isbitset"))); 3067 set_numa_distance(CAST_TO_FN_PTR(numa_distance_func_t, 3068 libnuma_dlsym(handle, "numa_distance"))); 3069 set_numa_get_membind(CAST_TO_FN_PTR(numa_get_membind_func_t, 3070 libnuma_v2_dlsym(handle, "numa_get_membind"))); 3071 3072 if (numa_available() != -1) { 3073 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 3074 set_numa_all_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_all_nodes_ptr")); 3075 set_numa_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_nodes_ptr")); 3076 // Create an index -> node mapping, since nodes are not always consecutive 3077 _nindex_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 3078 rebuild_nindex_to_node_map(); 3079 // Create a cpu -> node mapping 3080 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 3081 rebuild_cpu_to_node_map(); 3082 return true; 3083 } 3084 } 3085 } 3086 return false; 3087 } 3088 3089 size_t os::Linux::default_guard_size(os::ThreadType thr_type) { 3090 // Creating guard page is very expensive. Java thread has HotSpot 3091 // guard pages, only enable glibc guard page for non-Java threads. 3092 // (Remember: compiler thread is a Java thread, too!) 3093 return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size()); 3094 } 3095 3096 void os::Linux::rebuild_nindex_to_node_map() { 3097 int highest_node_number = Linux::numa_max_node(); 3098 3099 nindex_to_node()->clear(); 3100 for (int node = 0; node <= highest_node_number; node++) { 3101 if (Linux::isnode_in_existing_nodes(node)) { 3102 nindex_to_node()->append(node); 3103 } 3104 } 3105 } 3106 3107 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 3108 // The table is later used in get_node_by_cpu(). 3109 void os::Linux::rebuild_cpu_to_node_map() { 3110 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 3111 // in libnuma (possible values are starting from 16, 3112 // and continuing up with every other power of 2, but less 3113 // than the maximum number of CPUs supported by kernel), and 3114 // is a subject to change (in libnuma version 2 the requirements 3115 // are more reasonable) we'll just hardcode the number they use 3116 // in the library. 3117 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 3118 3119 size_t cpu_num = processor_count(); 3120 size_t cpu_map_size = NCPUS / BitsPerCLong; 3121 size_t cpu_map_valid_size = 3122 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 3123 3124 cpu_to_node()->clear(); 3125 cpu_to_node()->at_grow(cpu_num - 1); 3126 3127 size_t node_num = get_existing_num_nodes(); 3128 3129 int distance = 0; 3130 int closest_distance = INT_MAX; 3131 int closest_node = 0; 3132 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal); 3133 for (size_t i = 0; i < node_num; i++) { 3134 // Check if node is configured (not a memory-less node). If it is not, find 3135 // the closest configured node. Check also if node is bound, i.e. it's allowed 3136 // to allocate memory from the node. If it's not allowed, map cpus in that node 3137 // to the closest node from which memory allocation is allowed. 3138 if (!isnode_in_configured_nodes(nindex_to_node()->at(i)) || 3139 !isnode_in_bound_nodes(nindex_to_node()->at(i))) { 3140 closest_distance = INT_MAX; 3141 // Check distance from all remaining nodes in the system. Ignore distance 3142 // from itself, from another non-configured node, and from another non-bound 3143 // node. 3144 for (size_t m = 0; m < node_num; m++) { 3145 if (m != i && 3146 isnode_in_configured_nodes(nindex_to_node()->at(m)) && 3147 isnode_in_bound_nodes(nindex_to_node()->at(m))) { 3148 distance = numa_distance(nindex_to_node()->at(i), nindex_to_node()->at(m)); 3149 // If a closest node is found, update. There is always at least one 3150 // configured and bound node in the system so there is always at least 3151 // one node close. 3152 if (distance != 0 && distance < closest_distance) { 3153 closest_distance = distance; 3154 closest_node = nindex_to_node()->at(m); 3155 } 3156 } 3157 } 3158 } else { 3159 // Current node is already a configured node. 3160 closest_node = nindex_to_node()->at(i); 3161 } 3162 3163 // Get cpus from the original node and map them to the closest node. If node 3164 // is a configured node (not a memory-less node), then original node and 3165 // closest node are the same. 3166 if (numa_node_to_cpus(nindex_to_node()->at(i), cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 3167 for (size_t j = 0; j < cpu_map_valid_size; j++) { 3168 if (cpu_map[j] != 0) { 3169 for (size_t k = 0; k < BitsPerCLong; k++) { 3170 if (cpu_map[j] & (1UL << k)) { 3171 cpu_to_node()->at_put(j * BitsPerCLong + k, closest_node); 3172 } 3173 } 3174 } 3175 } 3176 } 3177 } 3178 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 3179 } 3180 3181 int os::Linux::get_node_by_cpu(int cpu_id) { 3182 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 3183 return cpu_to_node()->at(cpu_id); 3184 } 3185 return -1; 3186 } 3187 3188 GrowableArray<int>* os::Linux::_cpu_to_node; 3189 GrowableArray<int>* os::Linux::_nindex_to_node; 3190 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 3191 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 3192 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 3193 os::Linux::numa_num_configured_nodes_func_t os::Linux::_numa_num_configured_nodes; 3194 os::Linux::numa_available_func_t os::Linux::_numa_available; 3195 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 3196 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 3197 os::Linux::numa_interleave_memory_v2_func_t os::Linux::_numa_interleave_memory_v2; 3198 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy; 3199 os::Linux::numa_bitmask_isbitset_func_t os::Linux::_numa_bitmask_isbitset; 3200 os::Linux::numa_distance_func_t os::Linux::_numa_distance; 3201 os::Linux::numa_get_membind_func_t os::Linux::_numa_get_membind; 3202 unsigned long* os::Linux::_numa_all_nodes; 3203 struct bitmask* os::Linux::_numa_all_nodes_ptr; 3204 struct bitmask* os::Linux::_numa_nodes_ptr; 3205 3206 bool os::pd_uncommit_memory(char* addr, size_t size) { 3207 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 3208 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 3209 return res != (uintptr_t) MAP_FAILED; 3210 } 3211 3212 static address get_stack_commited_bottom(address bottom, size_t size) { 3213 address nbot = bottom; 3214 address ntop = bottom + size; 3215 3216 size_t page_sz = os::vm_page_size(); 3217 unsigned pages = size / page_sz; 3218 3219 unsigned char vec[1]; 3220 unsigned imin = 1, imax = pages + 1, imid; 3221 int mincore_return_value = 0; 3222 3223 assert(imin <= imax, "Unexpected page size"); 3224 3225 while (imin < imax) { 3226 imid = (imax + imin) / 2; 3227 nbot = ntop - (imid * page_sz); 3228 3229 // Use a trick with mincore to check whether the page is mapped or not. 3230 // mincore sets vec to 1 if page resides in memory and to 0 if page 3231 // is swapped output but if page we are asking for is unmapped 3232 // it returns -1,ENOMEM 3233 mincore_return_value = mincore(nbot, page_sz, vec); 3234 3235 if (mincore_return_value == -1) { 3236 // Page is not mapped go up 3237 // to find first mapped page 3238 if (errno != EAGAIN) { 3239 assert(errno == ENOMEM, "Unexpected mincore errno"); 3240 imax = imid; 3241 } 3242 } else { 3243 // Page is mapped go down 3244 // to find first not mapped page 3245 imin = imid + 1; 3246 } 3247 } 3248 3249 nbot = nbot + page_sz; 3250 3251 // Adjust stack bottom one page up if last checked page is not mapped 3252 if (mincore_return_value == -1) { 3253 nbot = nbot + page_sz; 3254 } 3255 3256 return nbot; 3257 } 3258 3259 bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) { 3260 int mincore_return_value; 3261 const size_t stripe = 1024; // query this many pages each time 3262 unsigned char vec[stripe + 1]; 3263 // set a guard 3264 vec[stripe] = 'X'; 3265 3266 const size_t page_sz = os::vm_page_size(); 3267 size_t pages = size / page_sz; 3268 3269 assert(is_aligned(start, page_sz), "Start address must be page aligned"); 3270 assert(is_aligned(size, page_sz), "Size must be page aligned"); 3271 3272 committed_start = NULL; 3273 3274 int loops = (pages + stripe - 1) / stripe; 3275 int committed_pages = 0; 3276 address loop_base = start; 3277 bool found_range = false; 3278 3279 for (int index = 0; index < loops && !found_range; index ++) { 3280 assert(pages > 0, "Nothing to do"); 3281 int pages_to_query = (pages >= stripe) ? stripe : pages; 3282 pages -= pages_to_query; 3283 3284 // Get stable read 3285 while ((mincore_return_value = mincore(loop_base, pages_to_query * page_sz, vec)) == -1 && errno == EAGAIN); 3286 3287 // During shutdown, some memory goes away without properly notifying NMT, 3288 // E.g. ConcurrentGCThread/WatcherThread can exit without deleting thread object. 3289 // Bailout and return as not committed for now. 3290 if (mincore_return_value == -1 && errno == ENOMEM) { 3291 return false; 3292 } 3293 3294 assert(vec[stripe] == 'X', "overflow guard"); 3295 assert(mincore_return_value == 0, "Range must be valid"); 3296 // Process this stripe 3297 for (int vecIdx = 0; vecIdx < pages_to_query; vecIdx ++) { 3298 if ((vec[vecIdx] & 0x01) == 0) { // not committed 3299 // End of current contiguous region 3300 if (committed_start != NULL) { 3301 found_range = true; 3302 break; 3303 } 3304 } else { // committed 3305 // Start of region 3306 if (committed_start == NULL) { 3307 committed_start = loop_base + page_sz * vecIdx; 3308 } 3309 committed_pages ++; 3310 } 3311 } 3312 3313 loop_base += pages_to_query * page_sz; 3314 } 3315 3316 if (committed_start != NULL) { 3317 assert(committed_pages > 0, "Must have committed region"); 3318 assert(committed_pages <= int(size / page_sz), "Can not commit more than it has"); 3319 assert(committed_start >= start && committed_start < start + size, "Out of range"); 3320 committed_size = page_sz * committed_pages; 3321 return true; 3322 } else { 3323 assert(committed_pages == 0, "Should not have committed region"); 3324 return false; 3325 } 3326 } 3327 3328 3329 // Linux uses a growable mapping for the stack, and if the mapping for 3330 // the stack guard pages is not removed when we detach a thread the 3331 // stack cannot grow beyond the pages where the stack guard was 3332 // mapped. If at some point later in the process the stack expands to 3333 // that point, the Linux kernel cannot expand the stack any further 3334 // because the guard pages are in the way, and a segfault occurs. 3335 // 3336 // However, it's essential not to split the stack region by unmapping 3337 // a region (leaving a hole) that's already part of the stack mapping, 3338 // so if the stack mapping has already grown beyond the guard pages at 3339 // the time we create them, we have to truncate the stack mapping. 3340 // So, we need to know the extent of the stack mapping when 3341 // create_stack_guard_pages() is called. 3342 3343 // We only need this for stacks that are growable: at the time of 3344 // writing thread stacks don't use growable mappings (i.e. those 3345 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 3346 // only applies to the main thread. 3347 3348 // If the (growable) stack mapping already extends beyond the point 3349 // where we're going to put our guard pages, truncate the mapping at 3350 // that point by munmap()ping it. This ensures that when we later 3351 // munmap() the guard pages we don't leave a hole in the stack 3352 // mapping. This only affects the main/primordial thread 3353 3354 bool os::pd_create_stack_guard_pages(char* addr, size_t size) { 3355 if (os::is_primordial_thread()) { 3356 // As we manually grow stack up to bottom inside create_attached_thread(), 3357 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and 3358 // we don't need to do anything special. 3359 // Check it first, before calling heavy function. 3360 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom(); 3361 unsigned char vec[1]; 3362 3363 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) { 3364 // Fallback to slow path on all errors, including EAGAIN 3365 stack_extent = (uintptr_t) get_stack_commited_bottom( 3366 os::Linux::initial_thread_stack_bottom(), 3367 (size_t)addr - stack_extent); 3368 } 3369 3370 if (stack_extent < (uintptr_t)addr) { 3371 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent)); 3372 } 3373 } 3374 3375 return os::commit_memory(addr, size, !ExecMem); 3376 } 3377 3378 // If this is a growable mapping, remove the guard pages entirely by 3379 // munmap()ping them. If not, just call uncommit_memory(). This only 3380 // affects the main/primordial thread, but guard against future OS changes. 3381 // It's safe to always unmap guard pages for primordial thread because we 3382 // always place it right after end of the mapped region. 3383 3384 bool os::remove_stack_guard_pages(char* addr, size_t size) { 3385 uintptr_t stack_extent, stack_base; 3386 3387 if (os::is_primordial_thread()) { 3388 return ::munmap(addr, size) == 0; 3389 } 3390 3391 return os::uncommit_memory(addr, size); 3392 } 3393 3394 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 3395 // at 'requested_addr'. If there are existing memory mappings at the same 3396 // location, however, they will be overwritten. If 'fixed' is false, 3397 // 'requested_addr' is only treated as a hint, the return value may or 3398 // may not start from the requested address. Unlike Linux mmap(), this 3399 // function returns NULL to indicate failure. 3400 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 3401 char * addr; 3402 int flags; 3403 3404 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 3405 if (fixed) { 3406 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 3407 flags |= MAP_FIXED; 3408 } 3409 3410 // Map reserved/uncommitted pages PROT_NONE so we fail early if we 3411 // touch an uncommitted page. Otherwise, the read/write might 3412 // succeed if we have enough swap space to back the physical page. 3413 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, 3414 flags, -1, 0); 3415 3416 return addr == MAP_FAILED ? NULL : addr; 3417 } 3418 3419 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address 3420 // (req_addr != NULL) or with a given alignment. 3421 // - bytes shall be a multiple of alignment. 3422 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3423 // - alignment sets the alignment at which memory shall be allocated. 3424 // It must be a multiple of allocation granularity. 3425 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3426 // req_addr or NULL. 3427 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) { 3428 3429 size_t extra_size = bytes; 3430 if (req_addr == NULL && alignment > 0) { 3431 extra_size += alignment; 3432 } 3433 3434 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE, 3435 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 3436 -1, 0); 3437 if (start == MAP_FAILED) { 3438 start = NULL; 3439 } else { 3440 if (req_addr != NULL) { 3441 if (start != req_addr) { 3442 ::munmap(start, extra_size); 3443 start = NULL; 3444 } 3445 } else { 3446 char* const start_aligned = align_up(start, alignment); 3447 char* const end_aligned = start_aligned + bytes; 3448 char* const end = start + extra_size; 3449 if (start_aligned > start) { 3450 ::munmap(start, start_aligned - start); 3451 } 3452 if (end_aligned < end) { 3453 ::munmap(end_aligned, end - end_aligned); 3454 } 3455 start = start_aligned; 3456 } 3457 } 3458 return start; 3459 } 3460 3461 static int anon_munmap(char * addr, size_t size) { 3462 return ::munmap(addr, size) == 0; 3463 } 3464 3465 char* os::pd_reserve_memory(size_t bytes, char* requested_addr, 3466 size_t alignment_hint) { 3467 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 3468 } 3469 3470 bool os::pd_release_memory(char* addr, size_t size) { 3471 return anon_munmap(addr, size); 3472 } 3473 3474 static bool linux_mprotect(char* addr, size_t size, int prot) { 3475 // Linux wants the mprotect address argument to be page aligned. 3476 char* bottom = (char*)align_down((intptr_t)addr, os::Linux::page_size()); 3477 3478 // According to SUSv3, mprotect() should only be used with mappings 3479 // established by mmap(), and mmap() always maps whole pages. Unaligned 3480 // 'addr' likely indicates problem in the VM (e.g. trying to change 3481 // protection of malloc'ed or statically allocated memory). Check the 3482 // caller if you hit this assert. 3483 assert(addr == bottom, "sanity check"); 3484 3485 size = align_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 3486 return ::mprotect(bottom, size, prot) == 0; 3487 } 3488 3489 // Set protections specified 3490 bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 3491 bool is_committed) { 3492 unsigned int p = 0; 3493 switch (prot) { 3494 case MEM_PROT_NONE: p = PROT_NONE; break; 3495 case MEM_PROT_READ: p = PROT_READ; break; 3496 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 3497 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 3498 default: 3499 ShouldNotReachHere(); 3500 } 3501 // is_committed is unused. 3502 return linux_mprotect(addr, bytes, p); 3503 } 3504 3505 bool os::guard_memory(char* addr, size_t size) { 3506 return linux_mprotect(addr, size, PROT_NONE); 3507 } 3508 3509 bool os::unguard_memory(char* addr, size_t size) { 3510 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 3511 } 3512 3513 bool os::Linux::transparent_huge_pages_sanity_check(bool warn, 3514 size_t page_size) { 3515 bool result = false; 3516 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE, 3517 MAP_ANONYMOUS|MAP_PRIVATE, 3518 -1, 0); 3519 if (p != MAP_FAILED) { 3520 void *aligned_p = align_up(p, page_size); 3521 3522 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0; 3523 3524 munmap(p, page_size * 2); 3525 } 3526 3527 if (warn && !result) { 3528 warning("TransparentHugePages is not supported by the operating system."); 3529 } 3530 3531 return result; 3532 } 3533 3534 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 3535 bool result = false; 3536 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE, 3537 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 3538 -1, 0); 3539 3540 if (p != MAP_FAILED) { 3541 // We don't know if this really is a huge page or not. 3542 FILE *fp = fopen("/proc/self/maps", "r"); 3543 if (fp) { 3544 while (!feof(fp)) { 3545 char chars[257]; 3546 long x = 0; 3547 if (fgets(chars, sizeof(chars), fp)) { 3548 if (sscanf(chars, "%lx-%*x", &x) == 1 3549 && x == (long)p) { 3550 if (strstr (chars, "hugepage")) { 3551 result = true; 3552 break; 3553 } 3554 } 3555 } 3556 } 3557 fclose(fp); 3558 } 3559 munmap(p, page_size); 3560 } 3561 3562 if (warn && !result) { 3563 warning("HugeTLBFS is not supported by the operating system."); 3564 } 3565 3566 return result; 3567 } 3568 3569 // From the coredump_filter documentation: 3570 // 3571 // - (bit 0) anonymous private memory 3572 // - (bit 1) anonymous shared memory 3573 // - (bit 2) file-backed private memory 3574 // - (bit 3) file-backed shared memory 3575 // - (bit 4) ELF header pages in file-backed private memory areas (it is 3576 // effective only if the bit 2 is cleared) 3577 // - (bit 5) hugetlb private memory 3578 // - (bit 6) hugetlb shared memory 3579 // - (bit 7) dax private memory 3580 // - (bit 8) dax shared memory 3581 // 3582 static void set_coredump_filter(CoredumpFilterBit bit) { 3583 FILE *f; 3584 long cdm; 3585 3586 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 3587 return; 3588 } 3589 3590 if (fscanf(f, "%lx", &cdm) != 1) { 3591 fclose(f); 3592 return; 3593 } 3594 3595 long saved_cdm = cdm; 3596 rewind(f); 3597 cdm |= bit; 3598 3599 if (cdm != saved_cdm) { 3600 fprintf(f, "%#lx", cdm); 3601 } 3602 3603 fclose(f); 3604 } 3605 3606 // Large page support 3607 3608 static size_t _large_page_size = 0; 3609 3610 size_t os::Linux::find_large_page_size() { 3611 size_t large_page_size = 0; 3612 3613 // large_page_size on Linux is used to round up heap size. x86 uses either 3614 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3615 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3616 // page as large as 256M. 3617 // 3618 // Here we try to figure out page size by parsing /proc/meminfo and looking 3619 // for a line with the following format: 3620 // Hugepagesize: 2048 kB 3621 // 3622 // If we can't determine the value (e.g. /proc is not mounted, or the text 3623 // format has been changed), we'll use the largest page size supported by 3624 // the processor. 3625 3626 #ifndef ZERO 3627 large_page_size = 3628 AARCH64_ONLY(2 * M) 3629 AMD64_ONLY(2 * M) 3630 ARM32_ONLY(2 * M) 3631 IA32_ONLY(4 * M) 3632 IA64_ONLY(256 * M) 3633 PPC_ONLY(4 * M) 3634 S390_ONLY(1 * M) 3635 SPARC_ONLY(4 * M); 3636 #endif // ZERO 3637 3638 FILE *fp = fopen("/proc/meminfo", "r"); 3639 if (fp) { 3640 while (!feof(fp)) { 3641 int x = 0; 3642 char buf[16]; 3643 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3644 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3645 large_page_size = x * K; 3646 break; 3647 } 3648 } else { 3649 // skip to next line 3650 for (;;) { 3651 int ch = fgetc(fp); 3652 if (ch == EOF || ch == (int)'\n') break; 3653 } 3654 } 3655 } 3656 fclose(fp); 3657 } 3658 3659 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) { 3660 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is " 3661 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size), 3662 proper_unit_for_byte_size(large_page_size)); 3663 } 3664 3665 return large_page_size; 3666 } 3667 3668 size_t os::Linux::setup_large_page_size() { 3669 _large_page_size = Linux::find_large_page_size(); 3670 const size_t default_page_size = (size_t)Linux::page_size(); 3671 if (_large_page_size > default_page_size) { 3672 _page_sizes[0] = _large_page_size; 3673 _page_sizes[1] = default_page_size; 3674 _page_sizes[2] = 0; 3675 } 3676 3677 return _large_page_size; 3678 } 3679 3680 bool os::Linux::setup_large_page_type(size_t page_size) { 3681 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && 3682 FLAG_IS_DEFAULT(UseSHM) && 3683 FLAG_IS_DEFAULT(UseTransparentHugePages)) { 3684 3685 // The type of large pages has not been specified by the user. 3686 3687 // Try UseHugeTLBFS and then UseSHM. 3688 UseHugeTLBFS = UseSHM = true; 3689 3690 // Don't try UseTransparentHugePages since there are known 3691 // performance issues with it turned on. This might change in the future. 3692 UseTransparentHugePages = false; 3693 } 3694 3695 if (UseTransparentHugePages) { 3696 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages); 3697 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) { 3698 UseHugeTLBFS = false; 3699 UseSHM = false; 3700 return true; 3701 } 3702 UseTransparentHugePages = false; 3703 } 3704 3705 if (UseHugeTLBFS) { 3706 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3707 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) { 3708 UseSHM = false; 3709 return true; 3710 } 3711 UseHugeTLBFS = false; 3712 } 3713 3714 return UseSHM; 3715 } 3716 3717 void os::large_page_init() { 3718 if (!UseLargePages && 3719 !UseTransparentHugePages && 3720 !UseHugeTLBFS && 3721 !UseSHM) { 3722 // Not using large pages. 3723 return; 3724 } 3725 3726 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) { 3727 // The user explicitly turned off large pages. 3728 // Ignore the rest of the large pages flags. 3729 UseTransparentHugePages = false; 3730 UseHugeTLBFS = false; 3731 UseSHM = false; 3732 return; 3733 } 3734 3735 size_t large_page_size = Linux::setup_large_page_size(); 3736 UseLargePages = Linux::setup_large_page_type(large_page_size); 3737 3738 set_coredump_filter(LARGEPAGES_BIT); 3739 } 3740 3741 #ifndef SHM_HUGETLB 3742 #define SHM_HUGETLB 04000 3743 #endif 3744 3745 #define shm_warning_format(format, ...) \ 3746 do { \ 3747 if (UseLargePages && \ 3748 (!FLAG_IS_DEFAULT(UseLargePages) || \ 3749 !FLAG_IS_DEFAULT(UseSHM) || \ 3750 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \ 3751 warning(format, __VA_ARGS__); \ 3752 } \ 3753 } while (0) 3754 3755 #define shm_warning(str) shm_warning_format("%s", str) 3756 3757 #define shm_warning_with_errno(str) \ 3758 do { \ 3759 int err = errno; \ 3760 shm_warning_format(str " (error = %d)", err); \ 3761 } while (0) 3762 3763 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) { 3764 assert(is_aligned(bytes, alignment), "Must be divisible by the alignment"); 3765 3766 if (!is_aligned(alignment, SHMLBA)) { 3767 assert(false, "Code below assumes that alignment is at least SHMLBA aligned"); 3768 return NULL; 3769 } 3770 3771 // To ensure that we get 'alignment' aligned memory from shmat, 3772 // we pre-reserve aligned virtual memory and then attach to that. 3773 3774 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL); 3775 if (pre_reserved_addr == NULL) { 3776 // Couldn't pre-reserve aligned memory. 3777 shm_warning("Failed to pre-reserve aligned memory for shmat."); 3778 return NULL; 3779 } 3780 3781 // SHM_REMAP is needed to allow shmat to map over an existing mapping. 3782 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP); 3783 3784 if ((intptr_t)addr == -1) { 3785 int err = errno; 3786 shm_warning_with_errno("Failed to attach shared memory."); 3787 3788 assert(err != EACCES, "Unexpected error"); 3789 assert(err != EIDRM, "Unexpected error"); 3790 assert(err != EINVAL, "Unexpected error"); 3791 3792 // Since we don't know if the kernel unmapped the pre-reserved memory area 3793 // we can't unmap it, since that would potentially unmap memory that was 3794 // mapped from other threads. 3795 return NULL; 3796 } 3797 3798 return addr; 3799 } 3800 3801 static char* shmat_at_address(int shmid, char* req_addr) { 3802 if (!is_aligned(req_addr, SHMLBA)) { 3803 assert(false, "Requested address needs to be SHMLBA aligned"); 3804 return NULL; 3805 } 3806 3807 char* addr = (char*)shmat(shmid, req_addr, 0); 3808 3809 if ((intptr_t)addr == -1) { 3810 shm_warning_with_errno("Failed to attach shared memory."); 3811 return NULL; 3812 } 3813 3814 return addr; 3815 } 3816 3817 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) { 3818 // If a req_addr has been provided, we assume that the caller has already aligned the address. 3819 if (req_addr != NULL) { 3820 assert(is_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size"); 3821 assert(is_aligned(req_addr, alignment), "Must be divisible by given alignment"); 3822 return shmat_at_address(shmid, req_addr); 3823 } 3824 3825 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically 3826 // return large page size aligned memory addresses when req_addr == NULL. 3827 // However, if the alignment is larger than the large page size, we have 3828 // to manually ensure that the memory returned is 'alignment' aligned. 3829 if (alignment > os::large_page_size()) { 3830 assert(is_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size"); 3831 return shmat_with_alignment(shmid, bytes, alignment); 3832 } else { 3833 return shmat_at_address(shmid, NULL); 3834 } 3835 } 3836 3837 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, 3838 char* req_addr, bool exec) { 3839 // "exec" is passed in but not used. Creating the shared image for 3840 // the code cache doesn't have an SHM_X executable permission to check. 3841 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3842 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3843 assert(is_aligned(req_addr, alignment), "Unaligned address"); 3844 3845 if (!is_aligned(bytes, os::large_page_size())) { 3846 return NULL; // Fallback to small pages. 3847 } 3848 3849 // Create a large shared memory region to attach to based on size. 3850 // Currently, size is the total size of the heap. 3851 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3852 if (shmid == -1) { 3853 // Possible reasons for shmget failure: 3854 // 1. shmmax is too small for Java heap. 3855 // > check shmmax value: cat /proc/sys/kernel/shmmax 3856 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3857 // 2. not enough large page memory. 3858 // > check available large pages: cat /proc/meminfo 3859 // > increase amount of large pages: 3860 // echo new_value > /proc/sys/vm/nr_hugepages 3861 // Note 1: different Linux may use different name for this property, 3862 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3863 // Note 2: it's possible there's enough physical memory available but 3864 // they are so fragmented after a long run that they can't 3865 // coalesce into large pages. Try to reserve large pages when 3866 // the system is still "fresh". 3867 shm_warning_with_errno("Failed to reserve shared memory."); 3868 return NULL; 3869 } 3870 3871 // Attach to the region. 3872 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr); 3873 3874 // Remove shmid. If shmat() is successful, the actual shared memory segment 3875 // will be deleted when it's detached by shmdt() or when the process 3876 // terminates. If shmat() is not successful this will remove the shared 3877 // segment immediately. 3878 shmctl(shmid, IPC_RMID, NULL); 3879 3880 return addr; 3881 } 3882 3883 static void warn_on_large_pages_failure(char* req_addr, size_t bytes, 3884 int error) { 3885 assert(error == ENOMEM, "Only expect to fail if no memory is available"); 3886 3887 bool warn_on_failure = UseLargePages && 3888 (!FLAG_IS_DEFAULT(UseLargePages) || 3889 !FLAG_IS_DEFAULT(UseHugeTLBFS) || 3890 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3891 3892 if (warn_on_failure) { 3893 char msg[128]; 3894 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: " 3895 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error); 3896 warning("%s", msg); 3897 } 3898 } 3899 3900 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, 3901 char* req_addr, 3902 bool exec) { 3903 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3904 assert(is_aligned(bytes, os::large_page_size()), "Unaligned size"); 3905 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3906 3907 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3908 char* addr = (char*)::mmap(req_addr, bytes, prot, 3909 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, 3910 -1, 0); 3911 3912 if (addr == MAP_FAILED) { 3913 warn_on_large_pages_failure(req_addr, bytes, errno); 3914 return NULL; 3915 } 3916 3917 assert(is_aligned(addr, os::large_page_size()), "Must be"); 3918 3919 return addr; 3920 } 3921 3922 // Reserve memory using mmap(MAP_HUGETLB). 3923 // - bytes shall be a multiple of alignment. 3924 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3925 // - alignment sets the alignment at which memory shall be allocated. 3926 // It must be a multiple of allocation granularity. 3927 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3928 // req_addr or NULL. 3929 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, 3930 size_t alignment, 3931 char* req_addr, 3932 bool exec) { 3933 size_t large_page_size = os::large_page_size(); 3934 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes"); 3935 3936 assert(is_aligned(req_addr, alignment), "Must be"); 3937 assert(is_aligned(bytes, alignment), "Must be"); 3938 3939 // First reserve - but not commit - the address range in small pages. 3940 char* const start = anon_mmap_aligned(bytes, alignment, req_addr); 3941 3942 if (start == NULL) { 3943 return NULL; 3944 } 3945 3946 assert(is_aligned(start, alignment), "Must be"); 3947 3948 char* end = start + bytes; 3949 3950 // Find the regions of the allocated chunk that can be promoted to large pages. 3951 char* lp_start = align_up(start, large_page_size); 3952 char* lp_end = align_down(end, large_page_size); 3953 3954 size_t lp_bytes = lp_end - lp_start; 3955 3956 assert(is_aligned(lp_bytes, large_page_size), "Must be"); 3957 3958 if (lp_bytes == 0) { 3959 // The mapped region doesn't even span the start and the end of a large page. 3960 // Fall back to allocate a non-special area. 3961 ::munmap(start, end - start); 3962 return NULL; 3963 } 3964 3965 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3966 3967 void* result; 3968 3969 // Commit small-paged leading area. 3970 if (start != lp_start) { 3971 result = ::mmap(start, lp_start - start, prot, 3972 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3973 -1, 0); 3974 if (result == MAP_FAILED) { 3975 ::munmap(lp_start, end - lp_start); 3976 return NULL; 3977 } 3978 } 3979 3980 // Commit large-paged area. 3981 result = ::mmap(lp_start, lp_bytes, prot, 3982 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB, 3983 -1, 0); 3984 if (result == MAP_FAILED) { 3985 warn_on_large_pages_failure(lp_start, lp_bytes, errno); 3986 // If the mmap above fails, the large pages region will be unmapped and we 3987 // have regions before and after with small pages. Release these regions. 3988 // 3989 // | mapped | unmapped | mapped | 3990 // ^ ^ ^ ^ 3991 // start lp_start lp_end end 3992 // 3993 ::munmap(start, lp_start - start); 3994 ::munmap(lp_end, end - lp_end); 3995 return NULL; 3996 } 3997 3998 // Commit small-paged trailing area. 3999 if (lp_end != end) { 4000 result = ::mmap(lp_end, end - lp_end, prot, 4001 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 4002 -1, 0); 4003 if (result == MAP_FAILED) { 4004 ::munmap(start, lp_end - start); 4005 return NULL; 4006 } 4007 } 4008 4009 return start; 4010 } 4011 4012 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, 4013 size_t alignment, 4014 char* req_addr, 4015 bool exec) { 4016 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 4017 assert(is_aligned(req_addr, alignment), "Must be"); 4018 assert(is_aligned(alignment, os::vm_allocation_granularity()), "Must be"); 4019 assert(is_power_of_2(os::large_page_size()), "Must be"); 4020 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes"); 4021 4022 if (is_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) { 4023 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec); 4024 } else { 4025 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec); 4026 } 4027 } 4028 4029 char* os::reserve_memory_special(size_t bytes, size_t alignment, 4030 char* req_addr, bool exec) { 4031 assert(UseLargePages, "only for large pages"); 4032 4033 char* addr; 4034 if (UseSHM) { 4035 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec); 4036 } else { 4037 assert(UseHugeTLBFS, "must be"); 4038 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec); 4039 } 4040 4041 if (addr != NULL) { 4042 if (UseNUMAInterleaving) { 4043 numa_make_global(addr, bytes); 4044 } 4045 4046 // The memory is committed 4047 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC); 4048 } 4049 4050 return addr; 4051 } 4052 4053 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) { 4054 // detaching the SHM segment will also delete it, see reserve_memory_special_shm() 4055 return shmdt(base) == 0; 4056 } 4057 4058 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) { 4059 return pd_release_memory(base, bytes); 4060 } 4061 4062 bool os::release_memory_special(char* base, size_t bytes) { 4063 bool res; 4064 if (MemTracker::tracking_level() > NMT_minimal) { 4065 Tracker tkr(Tracker::release); 4066 res = os::Linux::release_memory_special_impl(base, bytes); 4067 if (res) { 4068 tkr.record((address)base, bytes); 4069 } 4070 4071 } else { 4072 res = os::Linux::release_memory_special_impl(base, bytes); 4073 } 4074 return res; 4075 } 4076 4077 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) { 4078 assert(UseLargePages, "only for large pages"); 4079 bool res; 4080 4081 if (UseSHM) { 4082 res = os::Linux::release_memory_special_shm(base, bytes); 4083 } else { 4084 assert(UseHugeTLBFS, "must be"); 4085 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes); 4086 } 4087 return res; 4088 } 4089 4090 size_t os::large_page_size() { 4091 return _large_page_size; 4092 } 4093 4094 // With SysV SHM the entire memory region must be allocated as shared 4095 // memory. 4096 // HugeTLBFS allows application to commit large page memory on demand. 4097 // However, when committing memory with HugeTLBFS fails, the region 4098 // that was supposed to be committed will lose the old reservation 4099 // and allow other threads to steal that memory region. Because of this 4100 // behavior we can't commit HugeTLBFS memory. 4101 bool os::can_commit_large_page_memory() { 4102 return UseTransparentHugePages; 4103 } 4104 4105 bool os::can_execute_large_page_memory() { 4106 return UseTransparentHugePages || UseHugeTLBFS; 4107 } 4108 4109 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr, int file_desc) { 4110 assert(file_desc >= 0, "file_desc is not valid"); 4111 char* result = pd_attempt_reserve_memory_at(bytes, requested_addr); 4112 if (result != NULL) { 4113 if (replace_existing_mapping_with_file_mapping(result, bytes, file_desc) == NULL) { 4114 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory")); 4115 } 4116 } 4117 return result; 4118 } 4119 4120 // Reserve memory at an arbitrary address, only if that area is 4121 // available (and not reserved for something else). 4122 4123 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 4124 const int max_tries = 10; 4125 char* base[max_tries]; 4126 size_t size[max_tries]; 4127 const size_t gap = 0x000000; 4128 4129 // Assert only that the size is a multiple of the page size, since 4130 // that's all that mmap requires, and since that's all we really know 4131 // about at this low abstraction level. If we need higher alignment, 4132 // we can either pass an alignment to this method or verify alignment 4133 // in one of the methods further up the call chain. See bug 5044738. 4134 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 4135 4136 // Repeatedly allocate blocks until the block is allocated at the 4137 // right spot. 4138 4139 // Linux mmap allows caller to pass an address as hint; give it a try first, 4140 // if kernel honors the hint then we can return immediately. 4141 char * addr = anon_mmap(requested_addr, bytes, false); 4142 if (addr == requested_addr) { 4143 return requested_addr; 4144 } 4145 4146 if (addr != NULL) { 4147 // mmap() is successful but it fails to reserve at the requested address 4148 anon_munmap(addr, bytes); 4149 } 4150 4151 int i; 4152 for (i = 0; i < max_tries; ++i) { 4153 base[i] = reserve_memory(bytes); 4154 4155 if (base[i] != NULL) { 4156 // Is this the block we wanted? 4157 if (base[i] == requested_addr) { 4158 size[i] = bytes; 4159 break; 4160 } 4161 4162 // Does this overlap the block we wanted? Give back the overlapped 4163 // parts and try again. 4164 4165 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i]; 4166 if (top_overlap >= 0 && (size_t)top_overlap < bytes) { 4167 unmap_memory(base[i], top_overlap); 4168 base[i] += top_overlap; 4169 size[i] = bytes - top_overlap; 4170 } else { 4171 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr; 4172 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) { 4173 unmap_memory(requested_addr, bottom_overlap); 4174 size[i] = bytes - bottom_overlap; 4175 } else { 4176 size[i] = bytes; 4177 } 4178 } 4179 } 4180 } 4181 4182 // Give back the unused reserved pieces. 4183 4184 for (int j = 0; j < i; ++j) { 4185 if (base[j] != NULL) { 4186 unmap_memory(base[j], size[j]); 4187 } 4188 } 4189 4190 if (i < max_tries) { 4191 return requested_addr; 4192 } else { 4193 return NULL; 4194 } 4195 } 4196 4197 size_t os::read(int fd, void *buf, unsigned int nBytes) { 4198 return ::read(fd, buf, nBytes); 4199 } 4200 4201 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) { 4202 return ::pread(fd, buf, nBytes, offset); 4203 } 4204 4205 // Short sleep, direct OS call. 4206 // 4207 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee 4208 // sched_yield(2) will actually give up the CPU: 4209 // 4210 // * Alone on this pariticular CPU, keeps running. 4211 // * Before the introduction of "skip_buddy" with "compat_yield" disabled 4212 // (pre 2.6.39). 4213 // 4214 // So calling this with 0 is an alternative. 4215 // 4216 void os::naked_short_sleep(jlong ms) { 4217 struct timespec req; 4218 4219 assert(ms < 1000, "Un-interruptable sleep, short time use only"); 4220 req.tv_sec = 0; 4221 if (ms > 0) { 4222 req.tv_nsec = (ms % 1000) * 1000000; 4223 } else { 4224 req.tv_nsec = 1; 4225 } 4226 4227 nanosleep(&req, NULL); 4228 4229 return; 4230 } 4231 4232 // Sleep forever; naked call to OS-specific sleep; use with CAUTION 4233 void os::infinite_sleep() { 4234 while (true) { // sleep forever ... 4235 ::sleep(100); // ... 100 seconds at a time 4236 } 4237 } 4238 4239 // Used to convert frequent JVM_Yield() to nops 4240 bool os::dont_yield() { 4241 return DontYieldALot; 4242 } 4243 4244 void os::naked_yield() { 4245 sched_yield(); 4246 } 4247 4248 //////////////////////////////////////////////////////////////////////////////// 4249 // thread priority support 4250 4251 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 4252 // only supports dynamic priority, static priority must be zero. For real-time 4253 // applications, Linux supports SCHED_RR which allows static priority (1-99). 4254 // However, for large multi-threaded applications, SCHED_RR is not only slower 4255 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 4256 // of 5 runs - Sep 2005). 4257 // 4258 // The following code actually changes the niceness of kernel-thread/LWP. It 4259 // has an assumption that setpriority() only modifies one kernel-thread/LWP, 4260 // not the entire user process, and user level threads are 1:1 mapped to kernel 4261 // threads. It has always been the case, but could change in the future. For 4262 // this reason, the code should not be used as default (ThreadPriorityPolicy=0). 4263 // It is only used when ThreadPriorityPolicy=1 and may require system level permission 4264 // (e.g., root privilege or CAP_SYS_NICE capability). 4265 4266 int os::java_to_os_priority[CriticalPriority + 1] = { 4267 19, // 0 Entry should never be used 4268 4269 4, // 1 MinPriority 4270 3, // 2 4271 2, // 3 4272 4273 1, // 4 4274 0, // 5 NormPriority 4275 -1, // 6 4276 4277 -2, // 7 4278 -3, // 8 4279 -4, // 9 NearMaxPriority 4280 4281 -5, // 10 MaxPriority 4282 4283 -5 // 11 CriticalPriority 4284 }; 4285 4286 static int prio_init() { 4287 if (ThreadPriorityPolicy == 1) { 4288 if (geteuid() != 0) { 4289 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 4290 warning("-XX:ThreadPriorityPolicy=1 may require system level permission, " \ 4291 "e.g., being the root user. If the necessary permission is not " \ 4292 "possessed, changes to priority will be silently ignored."); 4293 } 4294 } 4295 } 4296 if (UseCriticalJavaThreadPriority) { 4297 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority]; 4298 } 4299 return 0; 4300 } 4301 4302 OSReturn os::set_native_priority(Thread* thread, int newpri) { 4303 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK; 4304 4305 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 4306 return (ret == 0) ? OS_OK : OS_ERR; 4307 } 4308 4309 OSReturn os::get_native_priority(const Thread* const thread, 4310 int *priority_ptr) { 4311 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) { 4312 *priority_ptr = java_to_os_priority[NormPriority]; 4313 return OS_OK; 4314 } 4315 4316 errno = 0; 4317 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 4318 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 4319 } 4320 4321 // Hint to the underlying OS that a task switch would not be good. 4322 // Void return because it's a hint and can fail. 4323 void os::hint_no_preempt() {} 4324 4325 //////////////////////////////////////////////////////////////////////////////// 4326 // suspend/resume support 4327 4328 // The low-level signal-based suspend/resume support is a remnant from the 4329 // old VM-suspension that used to be for java-suspension, safepoints etc, 4330 // within hotspot. Currently used by JFR's OSThreadSampler 4331 // 4332 // The remaining code is greatly simplified from the more general suspension 4333 // code that used to be used. 4334 // 4335 // The protocol is quite simple: 4336 // - suspend: 4337 // - sends a signal to the target thread 4338 // - polls the suspend state of the osthread using a yield loop 4339 // - target thread signal handler (SR_handler) sets suspend state 4340 // and blocks in sigsuspend until continued 4341 // - resume: 4342 // - sets target osthread state to continue 4343 // - sends signal to end the sigsuspend loop in the SR_handler 4344 // 4345 // Note that the SR_lock plays no role in this suspend/resume protocol, 4346 // but is checked for NULL in SR_handler as a thread termination indicator. 4347 // The SR_lock is, however, used by JavaThread::java_suspend()/java_resume() APIs. 4348 // 4349 // Note that resume_clear_context() and suspend_save_context() are needed 4350 // by SR_handler(), so that fetch_frame_from_ucontext() works, 4351 // which in part is used by: 4352 // - Forte Analyzer: AsyncGetCallTrace() 4353 // - StackBanging: get_frame_at_stack_banging_point() 4354 4355 static void resume_clear_context(OSThread *osthread) { 4356 osthread->set_ucontext(NULL); 4357 osthread->set_siginfo(NULL); 4358 } 4359 4360 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, 4361 ucontext_t* context) { 4362 osthread->set_ucontext(context); 4363 osthread->set_siginfo(siginfo); 4364 } 4365 4366 // Handler function invoked when a thread's execution is suspended or 4367 // resumed. We have to be careful that only async-safe functions are 4368 // called here (Note: most pthread functions are not async safe and 4369 // should be avoided.) 4370 // 4371 // Note: sigwait() is a more natural fit than sigsuspend() from an 4372 // interface point of view, but sigwait() prevents the signal hander 4373 // from being run. libpthread would get very confused by not having 4374 // its signal handlers run and prevents sigwait()'s use with the 4375 // mutex granting granting signal. 4376 // 4377 // Currently only ever called on the VMThread and JavaThreads (PC sampling) 4378 // 4379 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 4380 // Save and restore errno to avoid confusing native code with EINTR 4381 // after sigsuspend. 4382 int old_errno = errno; 4383 4384 Thread* thread = Thread::current_or_null_safe(); 4385 assert(thread != NULL, "Missing current thread in SR_handler"); 4386 4387 // On some systems we have seen signal delivery get "stuck" until the signal 4388 // mask is changed as part of thread termination. Check that the current thread 4389 // has not already terminated (via SR_lock()) - else the following assertion 4390 // will fail because the thread is no longer a JavaThread as the ~JavaThread 4391 // destructor has completed. 4392 4393 if (thread->SR_lock() == NULL) { 4394 return; 4395 } 4396 4397 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread"); 4398 4399 OSThread* osthread = thread->osthread(); 4400 4401 os::SuspendResume::State current = osthread->sr.state(); 4402 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) { 4403 suspend_save_context(osthread, siginfo, context); 4404 4405 // attempt to switch the state, we assume we had a SUSPEND_REQUEST 4406 os::SuspendResume::State state = osthread->sr.suspended(); 4407 if (state == os::SuspendResume::SR_SUSPENDED) { 4408 sigset_t suspend_set; // signals for sigsuspend() 4409 sigemptyset(&suspend_set); 4410 // get current set of blocked signals and unblock resume signal 4411 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 4412 sigdelset(&suspend_set, SR_signum); 4413 4414 sr_semaphore.signal(); 4415 // wait here until we are resumed 4416 while (1) { 4417 sigsuspend(&suspend_set); 4418 4419 os::SuspendResume::State result = osthread->sr.running(); 4420 if (result == os::SuspendResume::SR_RUNNING) { 4421 sr_semaphore.signal(); 4422 break; 4423 } 4424 } 4425 4426 } else if (state == os::SuspendResume::SR_RUNNING) { 4427 // request was cancelled, continue 4428 } else { 4429 ShouldNotReachHere(); 4430 } 4431 4432 resume_clear_context(osthread); 4433 } else if (current == os::SuspendResume::SR_RUNNING) { 4434 // request was cancelled, continue 4435 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) { 4436 // ignore 4437 } else { 4438 // ignore 4439 } 4440 4441 errno = old_errno; 4442 } 4443 4444 static int SR_initialize() { 4445 struct sigaction act; 4446 char *s; 4447 4448 // Get signal number to use for suspend/resume 4449 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 4450 int sig = ::strtol(s, 0, 10); 4451 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769. 4452 sig < NSIG) { // Must be legal signal and fit into sigflags[]. 4453 SR_signum = sig; 4454 } else { 4455 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.", 4456 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum); 4457 } 4458 } 4459 4460 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 4461 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 4462 4463 sigemptyset(&SR_sigset); 4464 sigaddset(&SR_sigset, SR_signum); 4465 4466 // Set up signal handler for suspend/resume 4467 act.sa_flags = SA_RESTART|SA_SIGINFO; 4468 act.sa_handler = (void (*)(int)) SR_handler; 4469 4470 // SR_signum is blocked by default. 4471 // 4528190 - We also need to block pthread restart signal (32 on all 4472 // supported Linux platforms). Note that LinuxThreads need to block 4473 // this signal for all threads to work properly. So we don't have 4474 // to use hard-coded signal number when setting up the mask. 4475 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 4476 4477 if (sigaction(SR_signum, &act, 0) == -1) { 4478 return -1; 4479 } 4480 4481 // Save signal flag 4482 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 4483 return 0; 4484 } 4485 4486 static int sr_notify(OSThread* osthread) { 4487 int status = pthread_kill(osthread->pthread_id(), SR_signum); 4488 assert_status(status == 0, status, "pthread_kill"); 4489 return status; 4490 } 4491 4492 // "Randomly" selected value for how long we want to spin 4493 // before bailing out on suspending a thread, also how often 4494 // we send a signal to a thread we want to resume 4495 static const int RANDOMLY_LARGE_INTEGER = 1000000; 4496 static const int RANDOMLY_LARGE_INTEGER2 = 100; 4497 4498 // returns true on success and false on error - really an error is fatal 4499 // but this seems the normal response to library errors 4500 static bool do_suspend(OSThread* osthread) { 4501 assert(osthread->sr.is_running(), "thread should be running"); 4502 assert(!sr_semaphore.trywait(), "semaphore has invalid state"); 4503 4504 // mark as suspended and send signal 4505 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) { 4506 // failed to switch, state wasn't running? 4507 ShouldNotReachHere(); 4508 return false; 4509 } 4510 4511 if (sr_notify(osthread) != 0) { 4512 ShouldNotReachHere(); 4513 } 4514 4515 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED 4516 while (true) { 4517 if (sr_semaphore.timedwait(create_semaphore_timespec(0, 2 * NANOSECS_PER_MILLISEC))) { 4518 break; 4519 } else { 4520 // timeout 4521 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend(); 4522 if (cancelled == os::SuspendResume::SR_RUNNING) { 4523 return false; 4524 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) { 4525 // make sure that we consume the signal on the semaphore as well 4526 sr_semaphore.wait(); 4527 break; 4528 } else { 4529 ShouldNotReachHere(); 4530 return false; 4531 } 4532 } 4533 } 4534 4535 guarantee(osthread->sr.is_suspended(), "Must be suspended"); 4536 return true; 4537 } 4538 4539 static void do_resume(OSThread* osthread) { 4540 assert(osthread->sr.is_suspended(), "thread should be suspended"); 4541 assert(!sr_semaphore.trywait(), "invalid semaphore state"); 4542 4543 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) { 4544 // failed to switch to WAKEUP_REQUEST 4545 ShouldNotReachHere(); 4546 return; 4547 } 4548 4549 while (true) { 4550 if (sr_notify(osthread) == 0) { 4551 if (sr_semaphore.timedwait(create_semaphore_timespec(0, 2 * NANOSECS_PER_MILLISEC))) { 4552 if (osthread->sr.is_running()) { 4553 return; 4554 } 4555 } 4556 } else { 4557 ShouldNotReachHere(); 4558 } 4559 } 4560 4561 guarantee(osthread->sr.is_running(), "Must be running!"); 4562 } 4563 4564 /////////////////////////////////////////////////////////////////////////////////// 4565 // signal handling (except suspend/resume) 4566 4567 // This routine may be used by user applications as a "hook" to catch signals. 4568 // The user-defined signal handler must pass unrecognized signals to this 4569 // routine, and if it returns true (non-zero), then the signal handler must 4570 // return immediately. If the flag "abort_if_unrecognized" is true, then this 4571 // routine will never retun false (zero), but instead will execute a VM panic 4572 // routine kill the process. 4573 // 4574 // If this routine returns false, it is OK to call it again. This allows 4575 // the user-defined signal handler to perform checks either before or after 4576 // the VM performs its own checks. Naturally, the user code would be making 4577 // a serious error if it tried to handle an exception (such as a null check 4578 // or breakpoint) that the VM was generating for its own correct operation. 4579 // 4580 // This routine may recognize any of the following kinds of signals: 4581 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 4582 // It should be consulted by handlers for any of those signals. 4583 // 4584 // The caller of this routine must pass in the three arguments supplied 4585 // to the function referred to in the "sa_sigaction" (not the "sa_handler") 4586 // field of the structure passed to sigaction(). This routine assumes that 4587 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 4588 // 4589 // Note that the VM will print warnings if it detects conflicting signal 4590 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 4591 // 4592 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo, 4593 siginfo_t* siginfo, 4594 void* ucontext, 4595 int abort_if_unrecognized); 4596 4597 static void signalHandler(int sig, siginfo_t* info, void* uc) { 4598 assert(info != NULL && uc != NULL, "it must be old kernel"); 4599 int orig_errno = errno; // Preserve errno value over signal handler. 4600 JVM_handle_linux_signal(sig, info, uc, true); 4601 errno = orig_errno; 4602 } 4603 4604 4605 // This boolean allows users to forward their own non-matching signals 4606 // to JVM_handle_linux_signal, harmlessly. 4607 bool os::Linux::signal_handlers_are_installed = false; 4608 4609 // For signal-chaining 4610 bool os::Linux::libjsig_is_loaded = false; 4611 typedef struct sigaction *(*get_signal_t)(int); 4612 get_signal_t os::Linux::get_signal_action = NULL; 4613 4614 struct sigaction* os::Linux::get_chained_signal_action(int sig) { 4615 struct sigaction *actp = NULL; 4616 4617 if (libjsig_is_loaded) { 4618 // Retrieve the old signal handler from libjsig 4619 actp = (*get_signal_action)(sig); 4620 } 4621 if (actp == NULL) { 4622 // Retrieve the preinstalled signal handler from jvm 4623 actp = os::Posix::get_preinstalled_handler(sig); 4624 } 4625 4626 return actp; 4627 } 4628 4629 static bool call_chained_handler(struct sigaction *actp, int sig, 4630 siginfo_t *siginfo, void *context) { 4631 // Call the old signal handler 4632 if (actp->sa_handler == SIG_DFL) { 4633 // It's more reasonable to let jvm treat it as an unexpected exception 4634 // instead of taking the default action. 4635 return false; 4636 } else if (actp->sa_handler != SIG_IGN) { 4637 if ((actp->sa_flags & SA_NODEFER) == 0) { 4638 // automaticlly block the signal 4639 sigaddset(&(actp->sa_mask), sig); 4640 } 4641 4642 sa_handler_t hand = NULL; 4643 sa_sigaction_t sa = NULL; 4644 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 4645 // retrieve the chained handler 4646 if (siginfo_flag_set) { 4647 sa = actp->sa_sigaction; 4648 } else { 4649 hand = actp->sa_handler; 4650 } 4651 4652 if ((actp->sa_flags & SA_RESETHAND) != 0) { 4653 actp->sa_handler = SIG_DFL; 4654 } 4655 4656 // try to honor the signal mask 4657 sigset_t oset; 4658 sigemptyset(&oset); 4659 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 4660 4661 // call into the chained handler 4662 if (siginfo_flag_set) { 4663 (*sa)(sig, siginfo, context); 4664 } else { 4665 (*hand)(sig); 4666 } 4667 4668 // restore the signal mask 4669 pthread_sigmask(SIG_SETMASK, &oset, NULL); 4670 } 4671 // Tell jvm's signal handler the signal is taken care of. 4672 return true; 4673 } 4674 4675 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 4676 bool chained = false; 4677 // signal-chaining 4678 if (UseSignalChaining) { 4679 struct sigaction *actp = get_chained_signal_action(sig); 4680 if (actp != NULL) { 4681 chained = call_chained_handler(actp, sig, siginfo, context); 4682 } 4683 } 4684 return chained; 4685 } 4686 4687 // for diagnostic 4688 int sigflags[NSIG]; 4689 4690 int os::Linux::get_our_sigflags(int sig) { 4691 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4692 return sigflags[sig]; 4693 } 4694 4695 void os::Linux::set_our_sigflags(int sig, int flags) { 4696 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4697 if (sig > 0 && sig < NSIG) { 4698 sigflags[sig] = flags; 4699 } 4700 } 4701 4702 void os::Linux::set_signal_handler(int sig, bool set_installed) { 4703 // Check for overwrite. 4704 struct sigaction oldAct; 4705 sigaction(sig, (struct sigaction*)NULL, &oldAct); 4706 4707 void* oldhand = oldAct.sa_sigaction 4708 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4709 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4710 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 4711 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 4712 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 4713 if (AllowUserSignalHandlers || !set_installed) { 4714 // Do not overwrite; user takes responsibility to forward to us. 4715 return; 4716 } else if (UseSignalChaining) { 4717 // save the old handler in jvm 4718 os::Posix::save_preinstalled_handler(sig, oldAct); 4719 // libjsig also interposes the sigaction() call below and saves the 4720 // old sigaction on it own. 4721 } else { 4722 fatal("Encountered unexpected pre-existing sigaction handler " 4723 "%#lx for signal %d.", (long)oldhand, sig); 4724 } 4725 } 4726 4727 struct sigaction sigAct; 4728 sigfillset(&(sigAct.sa_mask)); 4729 sigAct.sa_handler = SIG_DFL; 4730 if (!set_installed) { 4731 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4732 } else { 4733 sigAct.sa_sigaction = signalHandler; 4734 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4735 } 4736 // Save flags, which are set by ours 4737 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4738 sigflags[sig] = sigAct.sa_flags; 4739 4740 int ret = sigaction(sig, &sigAct, &oldAct); 4741 assert(ret == 0, "check"); 4742 4743 void* oldhand2 = oldAct.sa_sigaction 4744 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4745 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4746 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 4747 } 4748 4749 // install signal handlers for signals that HotSpot needs to 4750 // handle in order to support Java-level exception handling. 4751 4752 void os::Linux::install_signal_handlers() { 4753 if (!signal_handlers_are_installed) { 4754 signal_handlers_are_installed = true; 4755 4756 // signal-chaining 4757 typedef void (*signal_setting_t)(); 4758 signal_setting_t begin_signal_setting = NULL; 4759 signal_setting_t end_signal_setting = NULL; 4760 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4761 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 4762 if (begin_signal_setting != NULL) { 4763 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4764 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 4765 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 4766 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 4767 libjsig_is_loaded = true; 4768 assert(UseSignalChaining, "should enable signal-chaining"); 4769 } 4770 if (libjsig_is_loaded) { 4771 // Tell libjsig jvm is setting signal handlers 4772 (*begin_signal_setting)(); 4773 } 4774 4775 set_signal_handler(SIGSEGV, true); 4776 set_signal_handler(SIGPIPE, true); 4777 set_signal_handler(SIGBUS, true); 4778 set_signal_handler(SIGILL, true); 4779 set_signal_handler(SIGFPE, true); 4780 #if defined(PPC64) 4781 set_signal_handler(SIGTRAP, true); 4782 #endif 4783 set_signal_handler(SIGXFSZ, true); 4784 4785 if (libjsig_is_loaded) { 4786 // Tell libjsig jvm finishes setting signal handlers 4787 (*end_signal_setting)(); 4788 } 4789 4790 // We don't activate signal checker if libjsig is in place, we trust ourselves 4791 // and if UserSignalHandler is installed all bets are off. 4792 // Log that signal checking is off only if -verbose:jni is specified. 4793 if (CheckJNICalls) { 4794 if (libjsig_is_loaded) { 4795 if (PrintJNIResolving) { 4796 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 4797 } 4798 check_signals = false; 4799 } 4800 if (AllowUserSignalHandlers) { 4801 if (PrintJNIResolving) { 4802 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 4803 } 4804 check_signals = false; 4805 } 4806 } 4807 } 4808 } 4809 4810 // This is the fastest way to get thread cpu time on Linux. 4811 // Returns cpu time (user+sys) for any thread, not only for current. 4812 // POSIX compliant clocks are implemented in the kernels 2.6.16+. 4813 // It might work on 2.6.10+ with a special kernel/glibc patch. 4814 // For reference, please, see IEEE Std 1003.1-2004: 4815 // http://www.unix.org/single_unix_specification 4816 4817 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 4818 struct timespec tp; 4819 int rc = os::Linux::clock_gettime(clockid, &tp); 4820 assert(rc == 0, "clock_gettime is expected to return 0 code"); 4821 4822 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 4823 } 4824 4825 void os::Linux::initialize_os_info() { 4826 assert(_os_version == 0, "OS info already initialized"); 4827 4828 struct utsname _uname; 4829 4830 uint32_t major; 4831 uint32_t minor; 4832 uint32_t fix; 4833 4834 int rc; 4835 4836 // Kernel version is unknown if 4837 // verification below fails. 4838 _os_version = 0x01000000; 4839 4840 rc = uname(&_uname); 4841 if (rc != -1) { 4842 4843 rc = sscanf(_uname.release,"%d.%d.%d", &major, &minor, &fix); 4844 if (rc == 3) { 4845 4846 if (major < 256 && minor < 256 && fix < 256) { 4847 // Kernel version format is as expected, 4848 // set it overriding unknown state. 4849 _os_version = (major << 16) | 4850 (minor << 8 ) | 4851 (fix << 0 ) ; 4852 } 4853 } 4854 } 4855 } 4856 4857 uint32_t os::Linux::os_version() { 4858 assert(_os_version != 0, "not initialized"); 4859 return _os_version & 0x00FFFFFF; 4860 } 4861 4862 bool os::Linux::os_version_is_known() { 4863 assert(_os_version != 0, "not initialized"); 4864 return _os_version & 0x01000000 ? false : true; 4865 } 4866 4867 ///// 4868 // glibc on Linux platform uses non-documented flag 4869 // to indicate, that some special sort of signal 4870 // trampoline is used. 4871 // We will never set this flag, and we should 4872 // ignore this flag in our diagnostic 4873 #ifdef SIGNIFICANT_SIGNAL_MASK 4874 #undef SIGNIFICANT_SIGNAL_MASK 4875 #endif 4876 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 4877 4878 static const char* get_signal_handler_name(address handler, 4879 char* buf, int buflen) { 4880 int offset = 0; 4881 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 4882 if (found) { 4883 // skip directory names 4884 const char *p1, *p2; 4885 p1 = buf; 4886 size_t len = strlen(os::file_separator()); 4887 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 4888 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 4889 } else { 4890 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 4891 } 4892 return buf; 4893 } 4894 4895 static void print_signal_handler(outputStream* st, int sig, 4896 char* buf, size_t buflen) { 4897 struct sigaction sa; 4898 4899 sigaction(sig, NULL, &sa); 4900 4901 // See comment for SIGNIFICANT_SIGNAL_MASK define 4902 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4903 4904 st->print("%s: ", os::exception_name(sig, buf, buflen)); 4905 4906 address handler = (sa.sa_flags & SA_SIGINFO) 4907 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 4908 : CAST_FROM_FN_PTR(address, sa.sa_handler); 4909 4910 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 4911 st->print("SIG_DFL"); 4912 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 4913 st->print("SIG_IGN"); 4914 } else { 4915 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 4916 } 4917 4918 st->print(", sa_mask[0]="); 4919 os::Posix::print_signal_set_short(st, &sa.sa_mask); 4920 4921 address rh = VMError::get_resetted_sighandler(sig); 4922 // May be, handler was resetted by VMError? 4923 if (rh != NULL) { 4924 handler = rh; 4925 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 4926 } 4927 4928 st->print(", sa_flags="); 4929 os::Posix::print_sa_flags(st, sa.sa_flags); 4930 4931 // Check: is it our handler? 4932 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 4933 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 4934 // It is our signal handler 4935 // check for flags, reset system-used one! 4936 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 4937 st->print( 4938 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 4939 os::Linux::get_our_sigflags(sig)); 4940 } 4941 } 4942 st->cr(); 4943 } 4944 4945 4946 #define DO_SIGNAL_CHECK(sig) \ 4947 do { \ 4948 if (!sigismember(&check_signal_done, sig)) { \ 4949 os::Linux::check_signal_handler(sig); \ 4950 } \ 4951 } while (0) 4952 4953 // This method is a periodic task to check for misbehaving JNI applications 4954 // under CheckJNI, we can add any periodic checks here 4955 4956 void os::run_periodic_checks() { 4957 if (check_signals == false) return; 4958 4959 // SEGV and BUS if overridden could potentially prevent 4960 // generation of hs*.log in the event of a crash, debugging 4961 // such a case can be very challenging, so we absolutely 4962 // check the following for a good measure: 4963 DO_SIGNAL_CHECK(SIGSEGV); 4964 DO_SIGNAL_CHECK(SIGILL); 4965 DO_SIGNAL_CHECK(SIGFPE); 4966 DO_SIGNAL_CHECK(SIGBUS); 4967 DO_SIGNAL_CHECK(SIGPIPE); 4968 DO_SIGNAL_CHECK(SIGXFSZ); 4969 #if defined(PPC64) 4970 DO_SIGNAL_CHECK(SIGTRAP); 4971 #endif 4972 4973 // ReduceSignalUsage allows the user to override these handlers 4974 // see comments at the very top and jvm_md.h 4975 if (!ReduceSignalUsage) { 4976 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 4977 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 4978 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 4979 DO_SIGNAL_CHECK(BREAK_SIGNAL); 4980 } 4981 4982 DO_SIGNAL_CHECK(SR_signum); 4983 } 4984 4985 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 4986 4987 static os_sigaction_t os_sigaction = NULL; 4988 4989 void os::Linux::check_signal_handler(int sig) { 4990 char buf[O_BUFLEN]; 4991 address jvmHandler = NULL; 4992 4993 4994 struct sigaction act; 4995 if (os_sigaction == NULL) { 4996 // only trust the default sigaction, in case it has been interposed 4997 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 4998 if (os_sigaction == NULL) return; 4999 } 5000 5001 os_sigaction(sig, (struct sigaction*)NULL, &act); 5002 5003 5004 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 5005 5006 address thisHandler = (act.sa_flags & SA_SIGINFO) 5007 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 5008 : CAST_FROM_FN_PTR(address, act.sa_handler); 5009 5010 5011 switch (sig) { 5012 case SIGSEGV: 5013 case SIGBUS: 5014 case SIGFPE: 5015 case SIGPIPE: 5016 case SIGILL: 5017 case SIGXFSZ: 5018 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 5019 break; 5020 5021 case SHUTDOWN1_SIGNAL: 5022 case SHUTDOWN2_SIGNAL: 5023 case SHUTDOWN3_SIGNAL: 5024 case BREAK_SIGNAL: 5025 jvmHandler = (address)user_handler(); 5026 break; 5027 5028 default: 5029 if (sig == SR_signum) { 5030 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 5031 } else { 5032 return; 5033 } 5034 break; 5035 } 5036 5037 if (thisHandler != jvmHandler) { 5038 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 5039 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 5040 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 5041 // No need to check this sig any longer 5042 sigaddset(&check_signal_done, sig); 5043 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN 5044 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) { 5045 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell", 5046 exception_name(sig, buf, O_BUFLEN)); 5047 } 5048 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 5049 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 5050 tty->print("expected:"); 5051 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig)); 5052 tty->cr(); 5053 tty->print(" found:"); 5054 os::Posix::print_sa_flags(tty, act.sa_flags); 5055 tty->cr(); 5056 // No need to check this sig any longer 5057 sigaddset(&check_signal_done, sig); 5058 } 5059 5060 // Dump all the signal 5061 if (sigismember(&check_signal_done, sig)) { 5062 print_signal_handlers(tty, buf, O_BUFLEN); 5063 } 5064 } 5065 5066 extern void report_error(char* file_name, int line_no, char* title, 5067 char* format, ...); 5068 5069 // this is called _before_ most of the global arguments have been parsed 5070 void os::init(void) { 5071 char dummy; // used to get a guess on initial stack address 5072 5073 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 5074 5075 init_random(1234567); 5076 5077 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 5078 if (Linux::page_size() == -1) { 5079 fatal("os_linux.cpp: os::init: sysconf failed (%s)", 5080 os::strerror(errno)); 5081 } 5082 init_page_sizes((size_t) Linux::page_size()); 5083 5084 Linux::initialize_system_info(); 5085 5086 Linux::initialize_os_info(); 5087 5088 os::Linux::CPUPerfTicks pticks; 5089 bool res = os::Linux::get_tick_information(&pticks, -1); 5090 5091 if (res && pticks.has_steal_ticks) { 5092 has_initial_tick_info = true; 5093 initial_total_ticks = pticks.total; 5094 initial_steal_ticks = pticks.steal; 5095 } 5096 5097 // _main_thread points to the thread that created/loaded the JVM. 5098 Linux::_main_thread = pthread_self(); 5099 5100 Linux::clock_init(); 5101 initial_time_count = javaTimeNanos(); 5102 5103 // retrieve entry point for pthread_setname_np 5104 Linux::_pthread_setname_np = 5105 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np"); 5106 5107 os::Posix::init(); 5108 } 5109 5110 // To install functions for atexit system call 5111 extern "C" { 5112 static void perfMemory_exit_helper() { 5113 perfMemory_exit(); 5114 } 5115 } 5116 5117 void os::pd_init_container_support() { 5118 OSContainer::init(); 5119 } 5120 5121 // this is called _after_ the global arguments have been parsed 5122 jint os::init_2(void) { 5123 5124 os::Posix::init_2(); 5125 5126 Linux::fast_thread_clock_init(); 5127 5128 // initialize suspend/resume support - must do this before signal_sets_init() 5129 if (SR_initialize() != 0) { 5130 perror("SR_initialize failed"); 5131 return JNI_ERR; 5132 } 5133 5134 Linux::signal_sets_init(); 5135 Linux::install_signal_handlers(); 5136 // Initialize data for jdk.internal.misc.Signal 5137 if (!ReduceSignalUsage) { 5138 jdk_misc_signal_init(); 5139 } 5140 5141 // Check and sets minimum stack sizes against command line options 5142 if (Posix::set_minimum_stack_sizes() == JNI_ERR) { 5143 return JNI_ERR; 5144 } 5145 5146 #if defined(IA32) 5147 // Need to ensure we've determined the process's initial stack to 5148 // perform the workaround 5149 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 5150 workaround_expand_exec_shield_cs_limit(); 5151 #else 5152 suppress_primordial_thread_resolution = Arguments::created_by_java_launcher(); 5153 if (!suppress_primordial_thread_resolution) { 5154 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 5155 } 5156 #endif 5157 5158 Linux::libpthread_init(); 5159 Linux::sched_getcpu_init(); 5160 log_info(os)("HotSpot is running with %s, %s", 5161 Linux::glibc_version(), Linux::libpthread_version()); 5162 5163 if (UseNUMA) { 5164 if (!Linux::libnuma_init()) { 5165 UseNUMA = false; 5166 } else { 5167 if ((Linux::numa_max_node() < 1) || Linux::isbound_to_single_node()) { 5168 // If there's only one node (they start from 0) or if the process 5169 // is bound explicitly to a single node using membind, disable NUMA. 5170 UseNUMA = false; 5171 } 5172 } 5173 5174 if (UseParallelGC && UseNUMA && UseLargePages && !can_commit_large_page_memory()) { 5175 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way 5176 // we can make the adaptive lgrp chunk resizing work. If the user specified both 5177 // UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn 5178 // and disable adaptive resizing. 5179 if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) { 5180 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, " 5181 "disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)"); 5182 UseAdaptiveSizePolicy = false; 5183 UseAdaptiveNUMAChunkSizing = false; 5184 } 5185 } 5186 5187 if (!UseNUMA && ForceNUMA) { 5188 UseNUMA = true; 5189 } 5190 } 5191 5192 if (MaxFDLimit) { 5193 // set the number of file descriptors to max. print out error 5194 // if getrlimit/setrlimit fails but continue regardless. 5195 struct rlimit nbr_files; 5196 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 5197 if (status != 0) { 5198 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno)); 5199 } else { 5200 nbr_files.rlim_cur = nbr_files.rlim_max; 5201 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 5202 if (status != 0) { 5203 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno)); 5204 } 5205 } 5206 } 5207 5208 // Initialize lock used to serialize thread creation (see os::create_thread) 5209 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 5210 5211 // at-exit methods are called in the reverse order of their registration. 5212 // atexit functions are called on return from main or as a result of a 5213 // call to exit(3C). There can be only 32 of these functions registered 5214 // and atexit() does not set errno. 5215 5216 if (PerfAllowAtExitRegistration) { 5217 // only register atexit functions if PerfAllowAtExitRegistration is set. 5218 // atexit functions can be delayed until process exit time, which 5219 // can be problematic for embedded VM situations. Embedded VMs should 5220 // call DestroyJavaVM() to assure that VM resources are released. 5221 5222 // note: perfMemory_exit_helper atexit function may be removed in 5223 // the future if the appropriate cleanup code can be added to the 5224 // VM_Exit VMOperation's doit method. 5225 if (atexit(perfMemory_exit_helper) != 0) { 5226 warning("os::init_2 atexit(perfMemory_exit_helper) failed"); 5227 } 5228 } 5229 5230 // initialize thread priority policy 5231 prio_init(); 5232 5233 if (!FLAG_IS_DEFAULT(AllocateHeapAt)) { 5234 set_coredump_filter(DAX_SHARED_BIT); 5235 } 5236 5237 if (DumpPrivateMappingsInCore) { 5238 set_coredump_filter(FILE_BACKED_PVT_BIT); 5239 } 5240 5241 if (DumpSharedMappingsInCore) { 5242 set_coredump_filter(FILE_BACKED_SHARED_BIT); 5243 } 5244 5245 return JNI_OK; 5246 } 5247 5248 // Mark the polling page as unreadable 5249 void os::make_polling_page_unreadable(void) { 5250 if (!guard_memory((char*)_polling_page, Linux::page_size())) { 5251 fatal("Could not disable polling page"); 5252 } 5253 } 5254 5255 // Mark the polling page as readable 5256 void os::make_polling_page_readable(void) { 5257 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 5258 fatal("Could not enable polling page"); 5259 } 5260 } 5261 5262 // older glibc versions don't have this macro (which expands to 5263 // an optimized bit-counting function) so we have to roll our own 5264 #ifndef CPU_COUNT 5265 5266 static int _cpu_count(const cpu_set_t* cpus) { 5267 int count = 0; 5268 // only look up to the number of configured processors 5269 for (int i = 0; i < os::processor_count(); i++) { 5270 if (CPU_ISSET(i, cpus)) { 5271 count++; 5272 } 5273 } 5274 return count; 5275 } 5276 5277 #define CPU_COUNT(cpus) _cpu_count(cpus) 5278 5279 #endif // CPU_COUNT 5280 5281 // Get the current number of available processors for this process. 5282 // This value can change at any time during a process's lifetime. 5283 // sched_getaffinity gives an accurate answer as it accounts for cpusets. 5284 // If it appears there may be more than 1024 processors then we do a 5285 // dynamic check - see 6515172 for details. 5286 // If anything goes wrong we fallback to returning the number of online 5287 // processors - which can be greater than the number available to the process. 5288 int os::Linux::active_processor_count() { 5289 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors 5290 cpu_set_t* cpus_p = &cpus; 5291 int cpus_size = sizeof(cpu_set_t); 5292 5293 int configured_cpus = os::processor_count(); // upper bound on available cpus 5294 int cpu_count = 0; 5295 5296 // old build platforms may not support dynamic cpu sets 5297 #ifdef CPU_ALLOC 5298 5299 // To enable easy testing of the dynamic path on different platforms we 5300 // introduce a diagnostic flag: UseCpuAllocPath 5301 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) { 5302 // kernel may use a mask bigger than cpu_set_t 5303 log_trace(os)("active_processor_count: using dynamic path %s" 5304 "- configured processors: %d", 5305 UseCpuAllocPath ? "(forced) " : "", 5306 configured_cpus); 5307 cpus_p = CPU_ALLOC(configured_cpus); 5308 if (cpus_p != NULL) { 5309 cpus_size = CPU_ALLOC_SIZE(configured_cpus); 5310 // zero it just to be safe 5311 CPU_ZERO_S(cpus_size, cpus_p); 5312 } 5313 else { 5314 // failed to allocate so fallback to online cpus 5315 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 5316 log_trace(os)("active_processor_count: " 5317 "CPU_ALLOC failed (%s) - using " 5318 "online processor count: %d", 5319 os::strerror(errno), online_cpus); 5320 return online_cpus; 5321 } 5322 } 5323 else { 5324 log_trace(os)("active_processor_count: using static path - configured processors: %d", 5325 configured_cpus); 5326 } 5327 #else // CPU_ALLOC 5328 // these stubs won't be executed 5329 #define CPU_COUNT_S(size, cpus) -1 5330 #define CPU_FREE(cpus) 5331 5332 log_trace(os)("active_processor_count: only static path available - configured processors: %d", 5333 configured_cpus); 5334 #endif // CPU_ALLOC 5335 5336 // pid 0 means the current thread - which we have to assume represents the process 5337 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) { 5338 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 5339 cpu_count = CPU_COUNT_S(cpus_size, cpus_p); 5340 } 5341 else { 5342 cpu_count = CPU_COUNT(cpus_p); 5343 } 5344 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count); 5345 } 5346 else { 5347 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN); 5348 warning("sched_getaffinity failed (%s)- using online processor count (%d) " 5349 "which may exceed available processors", os::strerror(errno), cpu_count); 5350 } 5351 5352 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 5353 CPU_FREE(cpus_p); 5354 } 5355 5356 assert(cpu_count > 0 && cpu_count <= os::processor_count(), "sanity check"); 5357 return cpu_count; 5358 } 5359 5360 // Determine the active processor count from one of 5361 // three different sources: 5362 // 5363 // 1. User option -XX:ActiveProcessorCount 5364 // 2. kernel os calls (sched_getaffinity or sysconf(_SC_NPROCESSORS_ONLN) 5365 // 3. extracted from cgroup cpu subsystem (shares and quotas) 5366 // 5367 // Option 1, if specified, will always override. 5368 // If the cgroup subsystem is active and configured, we 5369 // will return the min of the cgroup and option 2 results. 5370 // This is required since tools, such as numactl, that 5371 // alter cpu affinity do not update cgroup subsystem 5372 // cpuset configuration files. 5373 int os::active_processor_count() { 5374 // User has overridden the number of active processors 5375 if (ActiveProcessorCount > 0) { 5376 log_trace(os)("active_processor_count: " 5377 "active processor count set by user : %d", 5378 ActiveProcessorCount); 5379 return ActiveProcessorCount; 5380 } 5381 5382 int active_cpus; 5383 if (OSContainer::is_containerized()) { 5384 active_cpus = OSContainer::active_processor_count(); 5385 log_trace(os)("active_processor_count: determined by OSContainer: %d", 5386 active_cpus); 5387 } else { 5388 active_cpus = os::Linux::active_processor_count(); 5389 } 5390 5391 return active_cpus; 5392 } 5393 5394 uint os::processor_id() { 5395 const int id = Linux::sched_getcpu(); 5396 assert(id >= 0 && id < _processor_count, "Invalid processor id"); 5397 return (uint)id; 5398 } 5399 5400 void os::set_native_thread_name(const char *name) { 5401 if (Linux::_pthread_setname_np) { 5402 char buf [16]; // according to glibc manpage, 16 chars incl. '/0' 5403 snprintf(buf, sizeof(buf), "%s", name); 5404 buf[sizeof(buf) - 1] = '\0'; 5405 const int rc = Linux::_pthread_setname_np(pthread_self(), buf); 5406 // ERANGE should not happen; all other errors should just be ignored. 5407 assert(rc != ERANGE, "pthread_setname_np failed"); 5408 } 5409 } 5410 5411 bool os::distribute_processes(uint length, uint* distribution) { 5412 // Not yet implemented. 5413 return false; 5414 } 5415 5416 bool os::bind_to_processor(uint processor_id) { 5417 // Not yet implemented. 5418 return false; 5419 } 5420 5421 /// 5422 5423 void os::SuspendedThreadTask::internal_do_task() { 5424 if (do_suspend(_thread->osthread())) { 5425 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext()); 5426 do_task(context); 5427 do_resume(_thread->osthread()); 5428 } 5429 } 5430 5431 //////////////////////////////////////////////////////////////////////////////// 5432 // debug support 5433 5434 bool os::find(address addr, outputStream* st) { 5435 Dl_info dlinfo; 5436 memset(&dlinfo, 0, sizeof(dlinfo)); 5437 if (dladdr(addr, &dlinfo) != 0) { 5438 st->print(PTR_FORMAT ": ", p2i(addr)); 5439 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) { 5440 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname, 5441 p2i(addr) - p2i(dlinfo.dli_saddr)); 5442 } else if (dlinfo.dli_fbase != NULL) { 5443 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase)); 5444 } else { 5445 st->print("<absolute address>"); 5446 } 5447 if (dlinfo.dli_fname != NULL) { 5448 st->print(" in %s", dlinfo.dli_fname); 5449 } 5450 if (dlinfo.dli_fbase != NULL) { 5451 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase)); 5452 } 5453 st->cr(); 5454 5455 if (Verbose) { 5456 // decode some bytes around the PC 5457 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size()); 5458 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size()); 5459 address lowest = (address) dlinfo.dli_sname; 5460 if (!lowest) lowest = (address) dlinfo.dli_fbase; 5461 if (begin < lowest) begin = lowest; 5462 Dl_info dlinfo2; 5463 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr 5464 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) { 5465 end = (address) dlinfo2.dli_saddr; 5466 } 5467 Disassembler::decode(begin, end, st); 5468 } 5469 return true; 5470 } 5471 return false; 5472 } 5473 5474 //////////////////////////////////////////////////////////////////////////////// 5475 // misc 5476 5477 // This does not do anything on Linux. This is basically a hook for being 5478 // able to use structured exception handling (thread-local exception filters) 5479 // on, e.g., Win32. 5480 void 5481 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method, 5482 JavaCallArguments* args, Thread* thread) { 5483 f(value, method, args, thread); 5484 } 5485 5486 void os::print_statistics() { 5487 } 5488 5489 bool os::message_box(const char* title, const char* message) { 5490 int i; 5491 fdStream err(defaultStream::error_fd()); 5492 for (i = 0; i < 78; i++) err.print_raw("="); 5493 err.cr(); 5494 err.print_raw_cr(title); 5495 for (i = 0; i < 78; i++) err.print_raw("-"); 5496 err.cr(); 5497 err.print_raw_cr(message); 5498 for (i = 0; i < 78; i++) err.print_raw("="); 5499 err.cr(); 5500 5501 char buf[16]; 5502 // Prevent process from exiting upon "read error" without consuming all CPU 5503 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 5504 5505 return buf[0] == 'y' || buf[0] == 'Y'; 5506 } 5507 5508 // Is a (classpath) directory empty? 5509 bool os::dir_is_empty(const char* path) { 5510 DIR *dir = NULL; 5511 struct dirent *ptr; 5512 5513 dir = opendir(path); 5514 if (dir == NULL) return true; 5515 5516 // Scan the directory 5517 bool result = true; 5518 while (result && (ptr = readdir(dir)) != NULL) { 5519 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 5520 result = false; 5521 } 5522 } 5523 closedir(dir); 5524 return result; 5525 } 5526 5527 // This code originates from JDK's sysOpen and open64_w 5528 // from src/solaris/hpi/src/system_md.c 5529 5530 int os::open(const char *path, int oflag, int mode) { 5531 if (strlen(path) > MAX_PATH - 1) { 5532 errno = ENAMETOOLONG; 5533 return -1; 5534 } 5535 5536 // All file descriptors that are opened in the Java process and not 5537 // specifically destined for a subprocess should have the close-on-exec 5538 // flag set. If we don't set it, then careless 3rd party native code 5539 // might fork and exec without closing all appropriate file descriptors 5540 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in 5541 // turn might: 5542 // 5543 // - cause end-of-file to fail to be detected on some file 5544 // descriptors, resulting in mysterious hangs, or 5545 // 5546 // - might cause an fopen in the subprocess to fail on a system 5547 // suffering from bug 1085341. 5548 // 5549 // (Yes, the default setting of the close-on-exec flag is a Unix 5550 // design flaw) 5551 // 5552 // See: 5553 // 1085341: 32-bit stdio routines should support file descriptors >255 5554 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed 5555 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 5556 // 5557 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open(). 5558 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor 5559 // because it saves a system call and removes a small window where the flag 5560 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored 5561 // and we fall back to using FD_CLOEXEC (see below). 5562 #ifdef O_CLOEXEC 5563 oflag |= O_CLOEXEC; 5564 #endif 5565 5566 int fd = ::open64(path, oflag, mode); 5567 if (fd == -1) return -1; 5568 5569 //If the open succeeded, the file might still be a directory 5570 { 5571 struct stat64 buf64; 5572 int ret = ::fstat64(fd, &buf64); 5573 int st_mode = buf64.st_mode; 5574 5575 if (ret != -1) { 5576 if ((st_mode & S_IFMT) == S_IFDIR) { 5577 errno = EISDIR; 5578 ::close(fd); 5579 return -1; 5580 } 5581 } else { 5582 ::close(fd); 5583 return -1; 5584 } 5585 } 5586 5587 #ifdef FD_CLOEXEC 5588 // Validate that the use of the O_CLOEXEC flag on open above worked. 5589 // With recent kernels, we will perform this check exactly once. 5590 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0; 5591 if (!O_CLOEXEC_is_known_to_work) { 5592 int flags = ::fcntl(fd, F_GETFD); 5593 if (flags != -1) { 5594 if ((flags & FD_CLOEXEC) != 0) 5595 O_CLOEXEC_is_known_to_work = 1; 5596 else 5597 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 5598 } 5599 } 5600 #endif 5601 5602 return fd; 5603 } 5604 5605 5606 // create binary file, rewriting existing file if required 5607 int os::create_binary_file(const char* path, bool rewrite_existing) { 5608 int oflags = O_WRONLY | O_CREAT; 5609 if (!rewrite_existing) { 5610 oflags |= O_EXCL; 5611 } 5612 return ::open64(path, oflags, S_IREAD | S_IWRITE); 5613 } 5614 5615 // return current position of file pointer 5616 jlong os::current_file_offset(int fd) { 5617 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 5618 } 5619 5620 // move file pointer to the specified offset 5621 jlong os::seek_to_file_offset(int fd, jlong offset) { 5622 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 5623 } 5624 5625 // This code originates from JDK's sysAvailable 5626 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c 5627 5628 int os::available(int fd, jlong *bytes) { 5629 jlong cur, end; 5630 int mode; 5631 struct stat64 buf64; 5632 5633 if (::fstat64(fd, &buf64) >= 0) { 5634 mode = buf64.st_mode; 5635 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 5636 int n; 5637 if (::ioctl(fd, FIONREAD, &n) >= 0) { 5638 *bytes = n; 5639 return 1; 5640 } 5641 } 5642 } 5643 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 5644 return 0; 5645 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 5646 return 0; 5647 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 5648 return 0; 5649 } 5650 *bytes = end - cur; 5651 return 1; 5652 } 5653 5654 // Map a block of memory. 5655 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset, 5656 char *addr, size_t bytes, bool read_only, 5657 bool allow_exec) { 5658 int prot; 5659 int flags = MAP_PRIVATE; 5660 5661 if (read_only) { 5662 prot = PROT_READ; 5663 } else { 5664 prot = PROT_READ | PROT_WRITE; 5665 } 5666 5667 if (allow_exec) { 5668 prot |= PROT_EXEC; 5669 } 5670 5671 if (addr != NULL) { 5672 flags |= MAP_FIXED; 5673 } 5674 5675 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 5676 fd, file_offset); 5677 if (mapped_address == MAP_FAILED) { 5678 return NULL; 5679 } 5680 return mapped_address; 5681 } 5682 5683 5684 // Remap a block of memory. 5685 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, 5686 char *addr, size_t bytes, bool read_only, 5687 bool allow_exec) { 5688 // same as map_memory() on this OS 5689 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 5690 allow_exec); 5691 } 5692 5693 5694 // Unmap a block of memory. 5695 bool os::pd_unmap_memory(char* addr, size_t bytes) { 5696 return munmap(addr, bytes) == 0; 5697 } 5698 5699 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 5700 5701 static jlong fast_cpu_time(Thread *thread) { 5702 clockid_t clockid; 5703 int rc = os::Linux::pthread_getcpuclockid(thread->osthread()->pthread_id(), 5704 &clockid); 5705 if (rc == 0) { 5706 return os::Linux::fast_thread_cpu_time(clockid); 5707 } else { 5708 // It's possible to encounter a terminated native thread that failed 5709 // to detach itself from the VM - which should result in ESRCH. 5710 assert_status(rc == ESRCH, rc, "pthread_getcpuclockid failed"); 5711 return -1; 5712 } 5713 } 5714 5715 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 5716 // are used by JVM M&M and JVMTI to get user+sys or user CPU time 5717 // of a thread. 5718 // 5719 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns 5720 // the fast estimate available on the platform. 5721 5722 jlong os::current_thread_cpu_time() { 5723 if (os::Linux::supports_fast_thread_cpu_time()) { 5724 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5725 } else { 5726 // return user + sys since the cost is the same 5727 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 5728 } 5729 } 5730 5731 jlong os::thread_cpu_time(Thread* thread) { 5732 // consistent with what current_thread_cpu_time() returns 5733 if (os::Linux::supports_fast_thread_cpu_time()) { 5734 return fast_cpu_time(thread); 5735 } else { 5736 return slow_thread_cpu_time(thread, true /* user + sys */); 5737 } 5738 } 5739 5740 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 5741 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5742 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5743 } else { 5744 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 5745 } 5746 } 5747 5748 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5749 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5750 return fast_cpu_time(thread); 5751 } else { 5752 return slow_thread_cpu_time(thread, user_sys_cpu_time); 5753 } 5754 } 5755 5756 // -1 on error. 5757 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5758 pid_t tid = thread->osthread()->thread_id(); 5759 char *s; 5760 char stat[2048]; 5761 int statlen; 5762 char proc_name[64]; 5763 int count; 5764 long sys_time, user_time; 5765 char cdummy; 5766 int idummy; 5767 long ldummy; 5768 FILE *fp; 5769 5770 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid); 5771 fp = fopen(proc_name, "r"); 5772 if (fp == NULL) return -1; 5773 statlen = fread(stat, 1, 2047, fp); 5774 stat[statlen] = '\0'; 5775 fclose(fp); 5776 5777 // Skip pid and the command string. Note that we could be dealing with 5778 // weird command names, e.g. user could decide to rename java launcher 5779 // to "java 1.4.2 :)", then the stat file would look like 5780 // 1234 (java 1.4.2 :)) R ... ... 5781 // We don't really need to know the command string, just find the last 5782 // occurrence of ")" and then start parsing from there. See bug 4726580. 5783 s = strrchr(stat, ')'); 5784 if (s == NULL) return -1; 5785 5786 // Skip blank chars 5787 do { s++; } while (s && isspace(*s)); 5788 5789 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 5790 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 5791 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 5792 &user_time, &sys_time); 5793 if (count != 13) return -1; 5794 if (user_sys_cpu_time) { 5795 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 5796 } else { 5797 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 5798 } 5799 } 5800 5801 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5802 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5803 info_ptr->may_skip_backward = false; // elapsed time not wall time 5804 info_ptr->may_skip_forward = false; // elapsed time not wall time 5805 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5806 } 5807 5808 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5809 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5810 info_ptr->may_skip_backward = false; // elapsed time not wall time 5811 info_ptr->may_skip_forward = false; // elapsed time not wall time 5812 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5813 } 5814 5815 bool os::is_thread_cpu_time_supported() { 5816 return true; 5817 } 5818 5819 // System loadavg support. Returns -1 if load average cannot be obtained. 5820 // Linux doesn't yet have a (official) notion of processor sets, 5821 // so just return the system wide load average. 5822 int os::loadavg(double loadavg[], int nelem) { 5823 return ::getloadavg(loadavg, nelem); 5824 } 5825 5826 void os::pause() { 5827 char filename[MAX_PATH]; 5828 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 5829 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile); 5830 } else { 5831 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 5832 } 5833 5834 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 5835 if (fd != -1) { 5836 struct stat buf; 5837 ::close(fd); 5838 while (::stat(filename, &buf) == 0) { 5839 (void)::poll(NULL, 0, 100); 5840 } 5841 } else { 5842 jio_fprintf(stderr, 5843 "Could not open pause file '%s', continuing immediately.\n", filename); 5844 } 5845 } 5846 5847 extern char** environ; 5848 5849 // Run the specified command in a separate process. Return its exit value, 5850 // or -1 on failure (e.g. can't fork a new process). 5851 // Unlike system(), this function can be called from signal handler. It 5852 // doesn't block SIGINT et al. 5853 int os::fork_and_exec(char* cmd, bool use_vfork_if_available) { 5854 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5855 5856 pid_t pid ; 5857 5858 if (use_vfork_if_available) { 5859 pid = vfork(); 5860 } else { 5861 pid = fork(); 5862 } 5863 5864 if (pid < 0) { 5865 // fork failed 5866 return -1; 5867 5868 } else if (pid == 0) { 5869 // child process 5870 5871 execve("/bin/sh", (char* const*)argv, environ); 5872 5873 // execve failed 5874 _exit(-1); 5875 5876 } else { 5877 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5878 // care about the actual exit code, for now. 5879 5880 int status; 5881 5882 // Wait for the child process to exit. This returns immediately if 5883 // the child has already exited. */ 5884 while (waitpid(pid, &status, 0) < 0) { 5885 switch (errno) { 5886 case ECHILD: return 0; 5887 case EINTR: break; 5888 default: return -1; 5889 } 5890 } 5891 5892 if (WIFEXITED(status)) { 5893 // The child exited normally; get its exit code. 5894 return WEXITSTATUS(status); 5895 } else if (WIFSIGNALED(status)) { 5896 // The child exited because of a signal 5897 // The best value to return is 0x80 + signal number, 5898 // because that is what all Unix shells do, and because 5899 // it allows callers to distinguish between process exit and 5900 // process death by signal. 5901 return 0x80 + WTERMSIG(status); 5902 } else { 5903 // Unknown exit code; pass it through 5904 return status; 5905 } 5906 } 5907 } 5908 5909 // Get the default path to the core file 5910 // Returns the length of the string 5911 int os::get_core_path(char* buffer, size_t bufferSize) { 5912 /* 5913 * Max length of /proc/sys/kernel/core_pattern is 128 characters. 5914 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt 5915 */ 5916 const int core_pattern_len = 129; 5917 char core_pattern[core_pattern_len] = {0}; 5918 5919 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY); 5920 if (core_pattern_file == -1) { 5921 return -1; 5922 } 5923 5924 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len); 5925 ::close(core_pattern_file); 5926 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') { 5927 return -1; 5928 } 5929 if (core_pattern[ret-1] == '\n') { 5930 core_pattern[ret-1] = '\0'; 5931 } else { 5932 core_pattern[ret] = '\0'; 5933 } 5934 5935 char *pid_pos = strstr(core_pattern, "%p"); 5936 int written; 5937 5938 if (core_pattern[0] == '/') { 5939 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern); 5940 } else { 5941 char cwd[PATH_MAX]; 5942 5943 const char* p = get_current_directory(cwd, PATH_MAX); 5944 if (p == NULL) { 5945 return -1; 5946 } 5947 5948 if (core_pattern[0] == '|') { 5949 written = jio_snprintf(buffer, bufferSize, 5950 "\"%s\" (or dumping to %s/core.%d)", 5951 &core_pattern[1], p, current_process_id()); 5952 } else { 5953 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern); 5954 } 5955 } 5956 5957 if (written < 0) { 5958 return -1; 5959 } 5960 5961 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) { 5962 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY); 5963 5964 if (core_uses_pid_file != -1) { 5965 char core_uses_pid = 0; 5966 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1); 5967 ::close(core_uses_pid_file); 5968 5969 if (core_uses_pid == '1') { 5970 jio_snprintf(buffer + written, bufferSize - written, 5971 ".%d", current_process_id()); 5972 } 5973 } 5974 } 5975 5976 return strlen(buffer); 5977 } 5978 5979 bool os::start_debugging(char *buf, int buflen) { 5980 int len = (int)strlen(buf); 5981 char *p = &buf[len]; 5982 5983 jio_snprintf(p, buflen-len, 5984 "\n\n" 5985 "Do you want to debug the problem?\n\n" 5986 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n" 5987 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n" 5988 "Otherwise, press RETURN to abort...", 5989 os::current_process_id(), os::current_process_id(), 5990 os::current_thread_id(), os::current_thread_id()); 5991 5992 bool yes = os::message_box("Unexpected Error", buf); 5993 5994 if (yes) { 5995 // yes, user asked VM to launch debugger 5996 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d", 5997 os::current_process_id(), os::current_process_id()); 5998 5999 os::fork_and_exec(buf); 6000 yes = false; 6001 } 6002 return yes; 6003 } 6004 6005 6006 // Java/Compiler thread: 6007 // 6008 // Low memory addresses 6009 // P0 +------------------------+ 6010 // | |\ Java thread created by VM does not have glibc 6011 // | glibc guard page | - guard page, attached Java thread usually has 6012 // | |/ 1 glibc guard page. 6013 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 6014 // | |\ 6015 // | HotSpot Guard Pages | - red, yellow and reserved pages 6016 // | |/ 6017 // +------------------------+ JavaThread::stack_reserved_zone_base() 6018 // | |\ 6019 // | Normal Stack | - 6020 // | |/ 6021 // P2 +------------------------+ Thread::stack_base() 6022 // 6023 // Non-Java thread: 6024 // 6025 // Low memory addresses 6026 // P0 +------------------------+ 6027 // | |\ 6028 // | glibc guard page | - usually 1 page 6029 // | |/ 6030 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 6031 // | |\ 6032 // | Normal Stack | - 6033 // | |/ 6034 // P2 +------------------------+ Thread::stack_base() 6035 // 6036 // ** P1 (aka bottom) and size (P2 = P1 - size) are the address and stack size 6037 // returned from pthread_attr_getstack(). 6038 // ** Due to NPTL implementation error, linux takes the glibc guard page out 6039 // of the stack size given in pthread_attr. We work around this for 6040 // threads created by the VM. (We adapt bottom to be P1 and size accordingly.) 6041 // 6042 #ifndef ZERO 6043 static void current_stack_region(address * bottom, size_t * size) { 6044 if (os::is_primordial_thread()) { 6045 // primordial thread needs special handling because pthread_getattr_np() 6046 // may return bogus value. 6047 *bottom = os::Linux::initial_thread_stack_bottom(); 6048 *size = os::Linux::initial_thread_stack_size(); 6049 } else { 6050 pthread_attr_t attr; 6051 6052 int rslt = pthread_getattr_np(pthread_self(), &attr); 6053 6054 // JVM needs to know exact stack location, abort if it fails 6055 if (rslt != 0) { 6056 if (rslt == ENOMEM) { 6057 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np"); 6058 } else { 6059 fatal("pthread_getattr_np failed with error = %d", rslt); 6060 } 6061 } 6062 6063 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) { 6064 fatal("Cannot locate current stack attributes!"); 6065 } 6066 6067 // Work around NPTL stack guard error. 6068 size_t guard_size = 0; 6069 rslt = pthread_attr_getguardsize(&attr, &guard_size); 6070 if (rslt != 0) { 6071 fatal("pthread_attr_getguardsize failed with error = %d", rslt); 6072 } 6073 *bottom += guard_size; 6074 *size -= guard_size; 6075 6076 pthread_attr_destroy(&attr); 6077 6078 } 6079 assert(os::current_stack_pointer() >= *bottom && 6080 os::current_stack_pointer() < *bottom + *size, "just checking"); 6081 } 6082 6083 address os::current_stack_base() { 6084 address bottom; 6085 size_t size; 6086 current_stack_region(&bottom, &size); 6087 return (bottom + size); 6088 } 6089 6090 size_t os::current_stack_size() { 6091 // This stack size includes the usable stack and HotSpot guard pages 6092 // (for the threads that have Hotspot guard pages). 6093 address bottom; 6094 size_t size; 6095 current_stack_region(&bottom, &size); 6096 return size; 6097 } 6098 #endif 6099 6100 static inline struct timespec get_mtime(const char* filename) { 6101 struct stat st; 6102 int ret = os::stat(filename, &st); 6103 assert(ret == 0, "failed to stat() file '%s': %s", filename, strerror(errno)); 6104 return st.st_mtim; 6105 } 6106 6107 int os::compare_file_modified_times(const char* file1, const char* file2) { 6108 struct timespec filetime1 = get_mtime(file1); 6109 struct timespec filetime2 = get_mtime(file2); 6110 int diff = filetime1.tv_sec - filetime2.tv_sec; 6111 if (diff == 0) { 6112 return filetime1.tv_nsec - filetime2.tv_nsec; 6113 } 6114 return diff; 6115 } 6116 6117 /////////////// Unit tests /////////////// 6118 6119 #ifndef PRODUCT 6120 6121 #define test_log(...) \ 6122 do { \ 6123 if (VerboseInternalVMTests) { \ 6124 tty->print_cr(__VA_ARGS__); \ 6125 tty->flush(); \ 6126 } \ 6127 } while (false) 6128 6129 class TestReserveMemorySpecial : AllStatic { 6130 public: 6131 static void small_page_write(void* addr, size_t size) { 6132 size_t page_size = os::vm_page_size(); 6133 6134 char* end = (char*)addr + size; 6135 for (char* p = (char*)addr; p < end; p += page_size) { 6136 *p = 1; 6137 } 6138 } 6139 6140 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) { 6141 if (!UseHugeTLBFS) { 6142 return; 6143 } 6144 6145 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size); 6146 6147 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false); 6148 6149 if (addr != NULL) { 6150 small_page_write(addr, size); 6151 6152 os::Linux::release_memory_special_huge_tlbfs(addr, size); 6153 } 6154 } 6155 6156 static void test_reserve_memory_special_huge_tlbfs_only() { 6157 if (!UseHugeTLBFS) { 6158 return; 6159 } 6160 6161 size_t lp = os::large_page_size(); 6162 6163 for (size_t size = lp; size <= lp * 10; size += lp) { 6164 test_reserve_memory_special_huge_tlbfs_only(size); 6165 } 6166 } 6167 6168 static void test_reserve_memory_special_huge_tlbfs_mixed() { 6169 size_t lp = os::large_page_size(); 6170 size_t ag = os::vm_allocation_granularity(); 6171 6172 // sizes to test 6173 const size_t sizes[] = { 6174 lp, lp + ag, lp + lp / 2, lp * 2, 6175 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2, 6176 lp * 10, lp * 10 + lp / 2 6177 }; 6178 const int num_sizes = sizeof(sizes) / sizeof(size_t); 6179 6180 // For each size/alignment combination, we test three scenarios: 6181 // 1) with req_addr == NULL 6182 // 2) with a non-null req_addr at which we expect to successfully allocate 6183 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we 6184 // expect the allocation to either fail or to ignore req_addr 6185 6186 // Pre-allocate two areas; they shall be as large as the largest allocation 6187 // and aligned to the largest alignment we will be testing. 6188 const size_t mapping_size = sizes[num_sizes - 1] * 2; 6189 char* const mapping1 = (char*) ::mmap(NULL, mapping_size, 6190 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6191 -1, 0); 6192 assert(mapping1 != MAP_FAILED, "should work"); 6193 6194 char* const mapping2 = (char*) ::mmap(NULL, mapping_size, 6195 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6196 -1, 0); 6197 assert(mapping2 != MAP_FAILED, "should work"); 6198 6199 // Unmap the first mapping, but leave the second mapping intact: the first 6200 // mapping will serve as a value for a "good" req_addr (case 2). The second 6201 // mapping, still intact, as "bad" req_addr (case 3). 6202 ::munmap(mapping1, mapping_size); 6203 6204 // Case 1 6205 test_log("%s, req_addr NULL:", __FUNCTION__); 6206 test_log("size align result"); 6207 6208 for (int i = 0; i < num_sizes; i++) { 6209 const size_t size = sizes[i]; 6210 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6211 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false); 6212 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " -> " PTR_FORMAT " %s", 6213 size, alignment, p2i(p), (p != NULL ? "" : "(failed)")); 6214 if (p != NULL) { 6215 assert(is_aligned(p, alignment), "must be"); 6216 small_page_write(p, size); 6217 os::Linux::release_memory_special_huge_tlbfs(p, size); 6218 } 6219 } 6220 } 6221 6222 // Case 2 6223 test_log("%s, req_addr non-NULL:", __FUNCTION__); 6224 test_log("size align req_addr result"); 6225 6226 for (int i = 0; i < num_sizes; i++) { 6227 const size_t size = sizes[i]; 6228 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6229 char* const req_addr = align_up(mapping1, alignment); 6230 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6231 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6232 size, alignment, p2i(req_addr), p2i(p), 6233 ((p != NULL ? (p == req_addr ? "(exact match)" : "") : "(failed)"))); 6234 if (p != NULL) { 6235 assert(p == req_addr, "must be"); 6236 small_page_write(p, size); 6237 os::Linux::release_memory_special_huge_tlbfs(p, size); 6238 } 6239 } 6240 } 6241 6242 // Case 3 6243 test_log("%s, req_addr non-NULL with preexisting mapping:", __FUNCTION__); 6244 test_log("size align req_addr result"); 6245 6246 for (int i = 0; i < num_sizes; i++) { 6247 const size_t size = sizes[i]; 6248 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6249 char* const req_addr = align_up(mapping2, alignment); 6250 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6251 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6252 size, alignment, p2i(req_addr), p2i(p), ((p != NULL ? "" : "(failed)"))); 6253 // as the area around req_addr contains already existing mappings, the API should always 6254 // return NULL (as per contract, it cannot return another address) 6255 assert(p == NULL, "must be"); 6256 } 6257 } 6258 6259 ::munmap(mapping2, mapping_size); 6260 6261 } 6262 6263 static void test_reserve_memory_special_huge_tlbfs() { 6264 if (!UseHugeTLBFS) { 6265 return; 6266 } 6267 6268 test_reserve_memory_special_huge_tlbfs_only(); 6269 test_reserve_memory_special_huge_tlbfs_mixed(); 6270 } 6271 6272 static void test_reserve_memory_special_shm(size_t size, size_t alignment) { 6273 if (!UseSHM) { 6274 return; 6275 } 6276 6277 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment); 6278 6279 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false); 6280 6281 if (addr != NULL) { 6282 assert(is_aligned(addr, alignment), "Check"); 6283 assert(is_aligned(addr, os::large_page_size()), "Check"); 6284 6285 small_page_write(addr, size); 6286 6287 os::Linux::release_memory_special_shm(addr, size); 6288 } 6289 } 6290 6291 static void test_reserve_memory_special_shm() { 6292 size_t lp = os::large_page_size(); 6293 size_t ag = os::vm_allocation_granularity(); 6294 6295 for (size_t size = ag; size < lp * 3; size += ag) { 6296 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6297 test_reserve_memory_special_shm(size, alignment); 6298 } 6299 } 6300 } 6301 6302 static void test() { 6303 test_reserve_memory_special_huge_tlbfs(); 6304 test_reserve_memory_special_shm(); 6305 } 6306 }; 6307 6308 void TestReserveMemorySpecial_test() { 6309 TestReserveMemorySpecial::test(); 6310 } 6311 6312 #endif