1 /* 2 * Copyright (c) 1999, 2018, 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 "memory/allocation.inline.hpp" 37 #include "memory/filemap.hpp" 38 #include "oops/oop.inline.hpp" 39 #include "os_linux.inline.hpp" 40 #include "os_share_linux.hpp" 41 #include "osContainer_linux.hpp" 42 #include "prims/jniFastGetField.hpp" 43 #include "prims/jvm_misc.hpp" 44 #include "runtime/arguments.hpp" 45 #include "runtime/atomic.hpp" 46 #include "runtime/extendedPC.hpp" 47 #include "runtime/globals.hpp" 48 #include "runtime/interfaceSupport.inline.hpp" 49 #include "runtime/init.hpp" 50 #include "runtime/java.hpp" 51 #include "runtime/javaCalls.hpp" 52 #include "runtime/mutexLocker.hpp" 53 #include "runtime/objectMonitor.hpp" 54 #include "runtime/orderAccess.hpp" 55 #include "runtime/osThread.hpp" 56 #include "runtime/perfMemory.hpp" 57 #include "runtime/sharedRuntime.hpp" 58 #include "runtime/statSampler.hpp" 59 #include "runtime/stubRoutines.hpp" 60 #include "runtime/thread.inline.hpp" 61 #include "runtime/threadCritical.hpp" 62 #include "runtime/threadSMR.hpp" 63 #include "runtime/timer.hpp" 64 #include "semaphore_posix.hpp" 65 #include "services/attachListener.hpp" 66 #include "services/memTracker.hpp" 67 #include "services/runtimeService.hpp" 68 #include "utilities/align.hpp" 69 #include "utilities/decoder.hpp" 70 #include "utilities/defaultStream.hpp" 71 #include "utilities/events.hpp" 72 #include "utilities/elfFile.hpp" 73 #include "utilities/growableArray.hpp" 74 #include "utilities/macros.hpp" 75 #include "utilities/vmError.hpp" 76 77 // put OS-includes here 78 # include <sys/types.h> 79 # include <sys/mman.h> 80 # include <sys/stat.h> 81 # include <sys/select.h> 82 # include <pthread.h> 83 # include <signal.h> 84 # include <errno.h> 85 # include <dlfcn.h> 86 # include <stdio.h> 87 # include <unistd.h> 88 # include <sys/resource.h> 89 # include <pthread.h> 90 # include <sys/stat.h> 91 # include <sys/time.h> 92 # include <sys/times.h> 93 # include <sys/utsname.h> 94 # include <sys/socket.h> 95 # include <sys/wait.h> 96 # include <pwd.h> 97 # include <poll.h> 98 # include <fcntl.h> 99 # include <string.h> 100 # include <syscall.h> 101 # include <sys/sysinfo.h> 102 # include <gnu/libc-version.h> 103 # include <sys/ipc.h> 104 # include <sys/shm.h> 105 # include <link.h> 106 # include <stdint.h> 107 # include <inttypes.h> 108 # include <sys/ioctl.h> 109 110 #ifndef _GNU_SOURCE 111 #define _GNU_SOURCE 112 #include <sched.h> 113 #undef _GNU_SOURCE 114 #else 115 #include <sched.h> 116 #endif 117 118 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling 119 // getrusage() is prepared to handle the associated failure. 120 #ifndef RUSAGE_THREAD 121 #define RUSAGE_THREAD (1) /* only the calling thread */ 122 #endif 123 124 #define MAX_PATH (2 * K) 125 126 #define MAX_SECS 100000000 127 128 // for timer info max values which include all bits 129 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 130 131 #define LARGEPAGES_BIT (1 << 6) 132 #define DAX_SHARED_BIT (1 << 8) 133 //////////////////////////////////////////////////////////////////////////////// 134 // global variables 135 julong os::Linux::_physical_memory = 0; 136 137 address os::Linux::_initial_thread_stack_bottom = NULL; 138 uintptr_t os::Linux::_initial_thread_stack_size = 0; 139 140 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 141 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL; 142 Mutex* os::Linux::_createThread_lock = NULL; 143 pthread_t os::Linux::_main_thread; 144 int os::Linux::_page_size = -1; 145 bool os::Linux::_supports_fast_thread_cpu_time = false; 146 uint32_t os::Linux::_os_version = 0; 147 const char * os::Linux::_glibc_version = NULL; 148 const char * os::Linux::_libpthread_version = NULL; 149 150 static jlong initial_time_count=0; 151 152 static int clock_tics_per_sec = 100; 153 154 // If the VM might have been created on the primordial thread, we need to resolve the 155 // primordial thread stack bounds and check if the current thread might be the 156 // primordial thread in places. If we know that the primordial thread is never used, 157 // such as when the VM was created by one of the standard java launchers, we can 158 // avoid this 159 static bool suppress_primordial_thread_resolution = false; 160 161 // For diagnostics to print a message once. see run_periodic_checks 162 static sigset_t check_signal_done; 163 static bool check_signals = true; 164 165 // Signal number used to suspend/resume a thread 166 167 // do not use any signal number less than SIGSEGV, see 4355769 168 static int SR_signum = SIGUSR2; 169 sigset_t SR_sigset; 170 171 // utility functions 172 173 static int SR_initialize(); 174 175 julong os::available_memory() { 176 return Linux::available_memory(); 177 } 178 179 julong os::Linux::available_memory() { 180 // values in struct sysinfo are "unsigned long" 181 struct sysinfo si; 182 julong avail_mem; 183 184 if (OSContainer::is_containerized()) { 185 jlong mem_limit, mem_usage; 186 if ((mem_limit = OSContainer::memory_limit_in_bytes()) < 1) { 187 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value", 188 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit); 189 } 190 if (mem_limit > 0 && (mem_usage = OSContainer::memory_usage_in_bytes()) < 1) { 191 log_debug(os, container)("container memory usage failed: " JLONG_FORMAT ", using host value", mem_usage); 192 } 193 if (mem_limit > 0 && mem_usage > 0 ) { 194 avail_mem = mem_limit > mem_usage ? (julong)mem_limit - (julong)mem_usage : 0; 195 log_trace(os)("available container memory: " JULONG_FORMAT, avail_mem); 196 return avail_mem; 197 } 198 } 199 200 sysinfo(&si); 201 avail_mem = (julong)si.freeram * si.mem_unit; 202 log_trace(os)("available memory: " JULONG_FORMAT, avail_mem); 203 return avail_mem; 204 } 205 206 julong os::physical_memory() { 207 jlong phys_mem = 0; 208 if (OSContainer::is_containerized()) { 209 jlong mem_limit; 210 if ((mem_limit = OSContainer::memory_limit_in_bytes()) > 0) { 211 log_trace(os)("total container memory: " JLONG_FORMAT, mem_limit); 212 return mem_limit; 213 } 214 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value", 215 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit); 216 } 217 218 phys_mem = Linux::physical_memory(); 219 log_trace(os)("total system memory: " JLONG_FORMAT, phys_mem); 220 return phys_mem; 221 } 222 223 // Return true if user is running as root. 224 225 bool os::have_special_privileges() { 226 static bool init = false; 227 static bool privileges = false; 228 if (!init) { 229 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 230 init = true; 231 } 232 return privileges; 233 } 234 235 236 #ifndef SYS_gettid 237 // i386: 224, ia64: 1105, amd64: 186, sparc 143 238 #ifdef __ia64__ 239 #define SYS_gettid 1105 240 #else 241 #ifdef __i386__ 242 #define SYS_gettid 224 243 #else 244 #ifdef __amd64__ 245 #define SYS_gettid 186 246 #else 247 #ifdef __sparc__ 248 #define SYS_gettid 143 249 #else 250 #error define gettid for the arch 251 #endif 252 #endif 253 #endif 254 #endif 255 #endif 256 257 258 // pid_t gettid() 259 // 260 // Returns the kernel thread id of the currently running thread. Kernel 261 // thread id is used to access /proc. 262 pid_t os::Linux::gettid() { 263 int rslt = syscall(SYS_gettid); 264 assert(rslt != -1, "must be."); // old linuxthreads implementation? 265 return (pid_t)rslt; 266 } 267 268 // Most versions of linux have a bug where the number of processors are 269 // determined by looking at the /proc file system. In a chroot environment, 270 // the system call returns 1. 271 static bool unsafe_chroot_detected = false; 272 static const char *unstable_chroot_error = "/proc file system not found.\n" 273 "Java may be unstable running multithreaded in a chroot " 274 "environment on Linux when /proc filesystem is not mounted."; 275 276 void os::Linux::initialize_system_info() { 277 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 278 if (processor_count() == 1) { 279 pid_t pid = os::Linux::gettid(); 280 char fname[32]; 281 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 282 FILE *fp = fopen(fname, "r"); 283 if (fp == NULL) { 284 unsafe_chroot_detected = true; 285 } else { 286 fclose(fp); 287 } 288 } 289 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 290 assert(processor_count() > 0, "linux error"); 291 } 292 293 void os::init_system_properties_values() { 294 // The next steps are taken in the product version: 295 // 296 // Obtain the JAVA_HOME value from the location of libjvm.so. 297 // This library should be located at: 298 // <JAVA_HOME>/lib/{client|server}/libjvm.so. 299 // 300 // If "/jre/lib/" appears at the right place in the path, then we 301 // assume libjvm.so is installed in a JDK and we use this path. 302 // 303 // Otherwise exit with message: "Could not create the Java virtual machine." 304 // 305 // The following extra steps are taken in the debugging version: 306 // 307 // If "/jre/lib/" does NOT appear at the right place in the path 308 // instead of exit check for $JAVA_HOME environment variable. 309 // 310 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 311 // then we append a fake suffix "hotspot/libjvm.so" to this path so 312 // it looks like libjvm.so is installed there 313 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so. 314 // 315 // Otherwise exit. 316 // 317 // Important note: if the location of libjvm.so changes this 318 // code needs to be changed accordingly. 319 320 // See ld(1): 321 // The linker uses the following search paths to locate required 322 // shared libraries: 323 // 1: ... 324 // ... 325 // 7: The default directories, normally /lib and /usr/lib. 326 #ifndef OVERRIDE_LIBPATH 327 #if defined(AMD64) || (defined(_LP64) && defined(SPARC)) || defined(PPC64) || defined(S390) 328 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 329 #else 330 #define DEFAULT_LIBPATH "/lib:/usr/lib" 331 #endif 332 #else 333 #define DEFAULT_LIBPATH OVERRIDE_LIBPATH 334 #endif 335 336 // Base path of extensions installed on the system. 337 #define SYS_EXT_DIR "/usr/java/packages" 338 #define EXTENSIONS_DIR "/lib/ext" 339 340 // Buffer that fits several sprintfs. 341 // Note that the space for the colon and the trailing null are provided 342 // by the nulls included by the sizeof operator. 343 const size_t bufsize = 344 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends. 345 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir 346 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal); 347 348 // sysclasspath, java_home, dll_dir 349 { 350 char *pslash; 351 os::jvm_path(buf, bufsize); 352 353 // Found the full path to libjvm.so. 354 // Now cut the path to <java_home>/jre if we can. 355 pslash = strrchr(buf, '/'); 356 if (pslash != NULL) { 357 *pslash = '\0'; // Get rid of /libjvm.so. 358 } 359 pslash = strrchr(buf, '/'); 360 if (pslash != NULL) { 361 *pslash = '\0'; // Get rid of /{client|server|hotspot}. 362 } 363 Arguments::set_dll_dir(buf); 364 365 if (pslash != NULL) { 366 pslash = strrchr(buf, '/'); 367 if (pslash != NULL) { 368 *pslash = '\0'; // Get rid of /lib. 369 } 370 } 371 Arguments::set_java_home(buf); 372 if (!set_boot_path('/', ':')) { 373 vm_exit_during_initialization("Failed setting boot class path.", NULL); 374 } 375 } 376 377 // Where to look for native libraries. 378 // 379 // Note: Due to a legacy implementation, most of the library path 380 // is set in the launcher. This was to accomodate linking restrictions 381 // on legacy Linux implementations (which are no longer supported). 382 // Eventually, all the library path setting will be done here. 383 // 384 // However, to prevent the proliferation of improperly built native 385 // libraries, the new path component /usr/java/packages is added here. 386 // Eventually, all the library path setting will be done here. 387 { 388 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It 389 // should always exist (until the legacy problem cited above is 390 // addressed). 391 const char *v = ::getenv("LD_LIBRARY_PATH"); 392 const char *v_colon = ":"; 393 if (v == NULL) { v = ""; v_colon = ""; } 394 // That's +1 for the colon and +1 for the trailing '\0'. 395 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char, 396 strlen(v) + 1 + 397 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1, 398 mtInternal); 399 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon); 400 Arguments::set_library_path(ld_library_path); 401 FREE_C_HEAP_ARRAY(char, ld_library_path); 402 } 403 404 // Extensions directories. 405 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home()); 406 Arguments::set_ext_dirs(buf); 407 408 FREE_C_HEAP_ARRAY(char, buf); 409 410 #undef DEFAULT_LIBPATH 411 #undef SYS_EXT_DIR 412 #undef EXTENSIONS_DIR 413 } 414 415 //////////////////////////////////////////////////////////////////////////////// 416 // breakpoint support 417 418 void os::breakpoint() { 419 BREAKPOINT; 420 } 421 422 extern "C" void breakpoint() { 423 // use debugger to set breakpoint here 424 } 425 426 //////////////////////////////////////////////////////////////////////////////// 427 // signal support 428 429 debug_only(static bool signal_sets_initialized = false); 430 static sigset_t unblocked_sigs, vm_sigs; 431 432 void os::Linux::signal_sets_init() { 433 // Should also have an assertion stating we are still single-threaded. 434 assert(!signal_sets_initialized, "Already initialized"); 435 // Fill in signals that are necessarily unblocked for all threads in 436 // the VM. Currently, we unblock the following signals: 437 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 438 // by -Xrs (=ReduceSignalUsage)); 439 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 440 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 441 // the dispositions or masks wrt these signals. 442 // Programs embedding the VM that want to use the above signals for their 443 // own purposes must, at this time, use the "-Xrs" option to prevent 444 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 445 // (See bug 4345157, and other related bugs). 446 // In reality, though, unblocking these signals is really a nop, since 447 // these signals are not blocked by default. 448 sigemptyset(&unblocked_sigs); 449 sigaddset(&unblocked_sigs, SIGILL); 450 sigaddset(&unblocked_sigs, SIGSEGV); 451 sigaddset(&unblocked_sigs, SIGBUS); 452 sigaddset(&unblocked_sigs, SIGFPE); 453 #if defined(PPC64) 454 sigaddset(&unblocked_sigs, SIGTRAP); 455 #endif 456 sigaddset(&unblocked_sigs, SR_signum); 457 458 if (!ReduceSignalUsage) { 459 if (!os::Posix::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 460 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 461 } 462 if (!os::Posix::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 463 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 464 } 465 if (!os::Posix::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 466 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 467 } 468 } 469 // Fill in signals that are blocked by all but the VM thread. 470 sigemptyset(&vm_sigs); 471 if (!ReduceSignalUsage) { 472 sigaddset(&vm_sigs, BREAK_SIGNAL); 473 } 474 debug_only(signal_sets_initialized = true); 475 476 } 477 478 // These are signals that are unblocked while a thread is running Java. 479 // (For some reason, they get blocked by default.) 480 sigset_t* os::Linux::unblocked_signals() { 481 assert(signal_sets_initialized, "Not initialized"); 482 return &unblocked_sigs; 483 } 484 485 // These are the signals that are blocked while a (non-VM) thread is 486 // running Java. Only the VM thread handles these signals. 487 sigset_t* os::Linux::vm_signals() { 488 assert(signal_sets_initialized, "Not initialized"); 489 return &vm_sigs; 490 } 491 492 void os::Linux::hotspot_sigmask(Thread* thread) { 493 494 //Save caller's signal mask before setting VM signal mask 495 sigset_t caller_sigmask; 496 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 497 498 OSThread* osthread = thread->osthread(); 499 osthread->set_caller_sigmask(caller_sigmask); 500 501 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 502 503 if (!ReduceSignalUsage) { 504 if (thread->is_VM_thread()) { 505 // Only the VM thread handles BREAK_SIGNAL ... 506 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 507 } else { 508 // ... all other threads block BREAK_SIGNAL 509 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 510 } 511 } 512 } 513 514 ////////////////////////////////////////////////////////////////////////////// 515 // detecting pthread library 516 517 void os::Linux::libpthread_init() { 518 // Save glibc and pthread version strings. 519 #if !defined(_CS_GNU_LIBC_VERSION) || \ 520 !defined(_CS_GNU_LIBPTHREAD_VERSION) 521 #error "glibc too old (< 2.3.2)" 522 #endif 523 524 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 525 assert(n > 0, "cannot retrieve glibc version"); 526 char *str = (char *)malloc(n, mtInternal); 527 confstr(_CS_GNU_LIBC_VERSION, str, n); 528 os::Linux::set_glibc_version(str); 529 530 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 531 assert(n > 0, "cannot retrieve pthread version"); 532 str = (char *)malloc(n, mtInternal); 533 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 534 os::Linux::set_libpthread_version(str); 535 } 536 537 ///////////////////////////////////////////////////////////////////////////// 538 // thread stack expansion 539 540 // os::Linux::manually_expand_stack() takes care of expanding the thread 541 // stack. Note that this is normally not needed: pthread stacks allocate 542 // thread stack using mmap() without MAP_NORESERVE, so the stack is already 543 // committed. Therefore it is not necessary to expand the stack manually. 544 // 545 // Manually expanding the stack was historically needed on LinuxThreads 546 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays 547 // it is kept to deal with very rare corner cases: 548 // 549 // For one, user may run the VM on an own implementation of threads 550 // whose stacks are - like the old LinuxThreads - implemented using 551 // mmap(MAP_GROWSDOWN). 552 // 553 // Also, this coding may be needed if the VM is running on the primordial 554 // thread. Normally we avoid running on the primordial thread; however, 555 // user may still invoke the VM on the primordial thread. 556 // 557 // The following historical comment describes the details about running 558 // on a thread stack allocated with mmap(MAP_GROWSDOWN): 559 560 561 // Force Linux kernel to expand current thread stack. If "bottom" is close 562 // to the stack guard, caller should block all signals. 563 // 564 // MAP_GROWSDOWN: 565 // A special mmap() flag that is used to implement thread stacks. It tells 566 // kernel that the memory region should extend downwards when needed. This 567 // allows early versions of LinuxThreads to only mmap the first few pages 568 // when creating a new thread. Linux kernel will automatically expand thread 569 // stack as needed (on page faults). 570 // 571 // However, because the memory region of a MAP_GROWSDOWN stack can grow on 572 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 573 // region, it's hard to tell if the fault is due to a legitimate stack 574 // access or because of reading/writing non-exist memory (e.g. buffer 575 // overrun). As a rule, if the fault happens below current stack pointer, 576 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the 577 // application (see Linux kernel fault.c). 578 // 579 // This Linux feature can cause SIGSEGV when VM bangs thread stack for 580 // stack overflow detection. 581 // 582 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 583 // not use MAP_GROWSDOWN. 584 // 585 // To get around the problem and allow stack banging on Linux, we need to 586 // manually expand thread stack after receiving the SIGSEGV. 587 // 588 // There are two ways to expand thread stack to address "bottom", we used 589 // both of them in JVM before 1.5: 590 // 1. adjust stack pointer first so that it is below "bottom", and then 591 // touch "bottom" 592 // 2. mmap() the page in question 593 // 594 // Now alternate signal stack is gone, it's harder to use 2. For instance, 595 // if current sp is already near the lower end of page 101, and we need to 596 // call mmap() to map page 100, it is possible that part of the mmap() frame 597 // will be placed in page 100. When page 100 is mapped, it is zero-filled. 598 // That will destroy the mmap() frame and cause VM to crash. 599 // 600 // The following code works by adjusting sp first, then accessing the "bottom" 601 // page to force a page fault. Linux kernel will then automatically expand the 602 // stack mapping. 603 // 604 // _expand_stack_to() assumes its frame size is less than page size, which 605 // should always be true if the function is not inlined. 606 607 static void NOINLINE _expand_stack_to(address bottom) { 608 address sp; 609 size_t size; 610 volatile char *p; 611 612 // Adjust bottom to point to the largest address within the same page, it 613 // gives us a one-page buffer if alloca() allocates slightly more memory. 614 bottom = (address)align_down((uintptr_t)bottom, os::Linux::page_size()); 615 bottom += os::Linux::page_size() - 1; 616 617 // sp might be slightly above current stack pointer; if that's the case, we 618 // will alloca() a little more space than necessary, which is OK. Don't use 619 // os::current_stack_pointer(), as its result can be slightly below current 620 // stack pointer, causing us to not alloca enough to reach "bottom". 621 sp = (address)&sp; 622 623 if (sp > bottom) { 624 size = sp - bottom; 625 p = (volatile char *)alloca(size); 626 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 627 p[0] = '\0'; 628 } 629 } 630 631 void os::Linux::expand_stack_to(address bottom) { 632 _expand_stack_to(bottom); 633 } 634 635 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 636 assert(t!=NULL, "just checking"); 637 assert(t->osthread()->expanding_stack(), "expand should be set"); 638 assert(t->stack_base() != NULL, "stack_base was not initialized"); 639 640 if (addr < t->stack_base() && addr >= t->stack_reserved_zone_base()) { 641 sigset_t mask_all, old_sigset; 642 sigfillset(&mask_all); 643 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 644 _expand_stack_to(addr); 645 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 646 return true; 647 } 648 return false; 649 } 650 651 ////////////////////////////////////////////////////////////////////////////// 652 // create new thread 653 654 // Thread start routine for all newly created threads 655 static void *thread_native_entry(Thread *thread) { 656 657 thread->record_stack_base_and_size(); 658 659 // Try to randomize the cache line index of hot stack frames. 660 // This helps when threads of the same stack traces evict each other's 661 // cache lines. The threads can be either from the same JVM instance, or 662 // from different JVM instances. The benefit is especially true for 663 // processors with hyperthreading technology. 664 static int counter = 0; 665 int pid = os::current_process_id(); 666 alloca(((pid ^ counter++) & 7) * 128); 667 668 thread->initialize_thread_current(); 669 670 OSThread* osthread = thread->osthread(); 671 Monitor* sync = osthread->startThread_lock(); 672 673 osthread->set_thread_id(os::current_thread_id()); 674 675 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 676 os::current_thread_id(), (uintx) pthread_self()); 677 678 if (UseNUMA) { 679 int lgrp_id = os::numa_get_group_id(); 680 if (lgrp_id != -1) { 681 thread->set_lgrp_id(lgrp_id); 682 } 683 } 684 // initialize signal mask for this thread 685 os::Linux::hotspot_sigmask(thread); 686 687 // initialize floating point control register 688 os::Linux::init_thread_fpu_state(); 689 690 // handshaking with parent thread 691 { 692 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 693 694 // notify parent thread 695 osthread->set_state(INITIALIZED); 696 sync->notify_all(); 697 698 // wait until os::start_thread() 699 while (osthread->get_state() == INITIALIZED) { 700 sync->wait(Mutex::_no_safepoint_check_flag); 701 } 702 } 703 704 // call one more level start routine 705 thread->call_run(); 706 707 // Note: at this point the thread object may already have deleted itself. 708 // Prevent dereferencing it from here on out. 709 thread = NULL; 710 711 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 712 os::current_thread_id(), (uintx) pthread_self()); 713 714 return 0; 715 } 716 717 bool os::create_thread(Thread* thread, ThreadType thr_type, 718 size_t req_stack_size) { 719 assert(thread->osthread() == NULL, "caller responsible"); 720 721 // Allocate the OSThread object 722 OSThread* osthread = new OSThread(NULL, NULL); 723 if (osthread == NULL) { 724 return false; 725 } 726 727 // set the correct thread state 728 osthread->set_thread_type(thr_type); 729 730 // Initial state is ALLOCATED but not INITIALIZED 731 osthread->set_state(ALLOCATED); 732 733 thread->set_osthread(osthread); 734 735 // init thread attributes 736 pthread_attr_t attr; 737 pthread_attr_init(&attr); 738 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 739 740 // Calculate stack size if it's not specified by caller. 741 size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size); 742 // In the Linux NPTL pthread implementation the guard size mechanism 743 // is not implemented properly. The posix standard requires adding 744 // the size of the guard pages to the stack size, instead Linux 745 // takes the space out of 'stacksize'. Thus we adapt the requested 746 // stack_size by the size of the guard pages to mimick proper 747 // behaviour. However, be careful not to end up with a size 748 // of zero due to overflow. Don't add the guard page in that case. 749 size_t guard_size = os::Linux::default_guard_size(thr_type); 750 if (stack_size <= SIZE_MAX - guard_size) { 751 stack_size += guard_size; 752 } 753 assert(is_aligned(stack_size, os::vm_page_size()), "stack_size not aligned"); 754 755 int status = pthread_attr_setstacksize(&attr, stack_size); 756 assert_status(status == 0, status, "pthread_attr_setstacksize"); 757 758 // Configure glibc guard page. 759 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 760 761 ThreadState state; 762 763 { 764 pthread_t tid; 765 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread); 766 767 char buf[64]; 768 if (ret == 0) { 769 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ", 770 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 771 } else { 772 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.", 773 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 774 } 775 776 pthread_attr_destroy(&attr); 777 778 if (ret != 0) { 779 // Need to clean up stuff we've allocated so far 780 thread->set_osthread(NULL); 781 delete osthread; 782 return false; 783 } 784 785 // Store pthread info into the OSThread 786 osthread->set_pthread_id(tid); 787 788 // Wait until child thread is either initialized or aborted 789 { 790 Monitor* sync_with_child = osthread->startThread_lock(); 791 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 792 while ((state = osthread->get_state()) == ALLOCATED) { 793 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 794 } 795 } 796 } 797 798 // Aborted due to thread limit being reached 799 if (state == ZOMBIE) { 800 thread->set_osthread(NULL); 801 delete osthread; 802 return false; 803 } 804 805 // The thread is returned suspended (in state INITIALIZED), 806 // and is started higher up in the call chain 807 assert(state == INITIALIZED, "race condition"); 808 return true; 809 } 810 811 ///////////////////////////////////////////////////////////////////////////// 812 // attach existing thread 813 814 // bootstrap the main thread 815 bool os::create_main_thread(JavaThread* thread) { 816 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 817 return create_attached_thread(thread); 818 } 819 820 bool os::create_attached_thread(JavaThread* thread) { 821 #ifdef ASSERT 822 thread->verify_not_published(); 823 #endif 824 825 // Allocate the OSThread object 826 OSThread* osthread = new OSThread(NULL, NULL); 827 828 if (osthread == NULL) { 829 return false; 830 } 831 832 // Store pthread info into the OSThread 833 osthread->set_thread_id(os::Linux::gettid()); 834 osthread->set_pthread_id(::pthread_self()); 835 836 // initialize floating point control register 837 os::Linux::init_thread_fpu_state(); 838 839 // Initial thread state is RUNNABLE 840 osthread->set_state(RUNNABLE); 841 842 thread->set_osthread(osthread); 843 844 if (UseNUMA) { 845 int lgrp_id = os::numa_get_group_id(); 846 if (lgrp_id != -1) { 847 thread->set_lgrp_id(lgrp_id); 848 } 849 } 850 851 if (os::is_primordial_thread()) { 852 // If current thread is primordial thread, its stack is mapped on demand, 853 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 854 // the entire stack region to avoid SEGV in stack banging. 855 // It is also useful to get around the heap-stack-gap problem on SuSE 856 // kernel (see 4821821 for details). We first expand stack to the top 857 // of yellow zone, then enable stack yellow zone (order is significant, 858 // enabling yellow zone first will crash JVM on SuSE Linux), so there 859 // is no gap between the last two virtual memory regions. 860 861 JavaThread *jt = (JavaThread *)thread; 862 address addr = jt->stack_reserved_zone_base(); 863 assert(addr != NULL, "initialization problem?"); 864 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 865 866 osthread->set_expanding_stack(); 867 os::Linux::manually_expand_stack(jt, addr); 868 osthread->clear_expanding_stack(); 869 } 870 871 // initialize signal mask for this thread 872 // and save the caller's signal mask 873 os::Linux::hotspot_sigmask(thread); 874 875 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 876 os::current_thread_id(), (uintx) pthread_self()); 877 878 return true; 879 } 880 881 void os::pd_start_thread(Thread* thread) { 882 OSThread * osthread = thread->osthread(); 883 assert(osthread->get_state() != INITIALIZED, "just checking"); 884 Monitor* sync_with_child = osthread->startThread_lock(); 885 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 886 sync_with_child->notify(); 887 } 888 889 // Free Linux resources related to the OSThread 890 void os::free_thread(OSThread* osthread) { 891 assert(osthread != NULL, "osthread not set"); 892 893 // We are told to free resources of the argument thread, 894 // but we can only really operate on the current thread. 895 assert(Thread::current()->osthread() == osthread, 896 "os::free_thread but not current thread"); 897 898 #ifdef ASSERT 899 sigset_t current; 900 sigemptyset(¤t); 901 pthread_sigmask(SIG_SETMASK, NULL, ¤t); 902 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!"); 903 #endif 904 905 // Restore caller's signal mask 906 sigset_t sigmask = osthread->caller_sigmask(); 907 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 908 909 delete osthread; 910 } 911 912 ////////////////////////////////////////////////////////////////////////////// 913 // primordial thread 914 915 // Check if current thread is the primordial thread, similar to Solaris thr_main. 916 bool os::is_primordial_thread(void) { 917 if (suppress_primordial_thread_resolution) { 918 return false; 919 } 920 char dummy; 921 // If called before init complete, thread stack bottom will be null. 922 // Can be called if fatal error occurs before initialization. 923 if (os::Linux::initial_thread_stack_bottom() == NULL) return false; 924 assert(os::Linux::initial_thread_stack_bottom() != NULL && 925 os::Linux::initial_thread_stack_size() != 0, 926 "os::init did not locate primordial thread's stack region"); 927 if ((address)&dummy >= os::Linux::initial_thread_stack_bottom() && 928 (address)&dummy < os::Linux::initial_thread_stack_bottom() + 929 os::Linux::initial_thread_stack_size()) { 930 return true; 931 } else { 932 return false; 933 } 934 } 935 936 // Find the virtual memory area that contains addr 937 static bool find_vma(address addr, address* vma_low, address* vma_high) { 938 FILE *fp = fopen("/proc/self/maps", "r"); 939 if (fp) { 940 address low, high; 941 while (!feof(fp)) { 942 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 943 if (low <= addr && addr < high) { 944 if (vma_low) *vma_low = low; 945 if (vma_high) *vma_high = high; 946 fclose(fp); 947 return true; 948 } 949 } 950 for (;;) { 951 int ch = fgetc(fp); 952 if (ch == EOF || ch == (int)'\n') break; 953 } 954 } 955 fclose(fp); 956 } 957 return false; 958 } 959 960 // Locate primordial thread stack. This special handling of primordial thread stack 961 // is needed because pthread_getattr_np() on most (all?) Linux distros returns 962 // bogus value for the primordial process thread. While the launcher has created 963 // the VM in a new thread since JDK 6, we still have to allow for the use of the 964 // JNI invocation API from a primordial thread. 965 void os::Linux::capture_initial_stack(size_t max_size) { 966 967 // max_size is either 0 (which means accept OS default for thread stacks) or 968 // a user-specified value known to be at least the minimum needed. If we 969 // are actually on the primordial thread we can make it appear that we have a 970 // smaller max_size stack by inserting the guard pages at that location. But we 971 // cannot do anything to emulate a larger stack than what has been provided by 972 // the OS or threading library. In fact if we try to use a stack greater than 973 // what is set by rlimit then we will crash the hosting process. 974 975 // Maximum stack size is the easy part, get it from RLIMIT_STACK. 976 // If this is "unlimited" then it will be a huge value. 977 struct rlimit rlim; 978 getrlimit(RLIMIT_STACK, &rlim); 979 size_t stack_size = rlim.rlim_cur; 980 981 // 6308388: a bug in ld.so will relocate its own .data section to the 982 // lower end of primordial stack; reduce ulimit -s value a little bit 983 // so we won't install guard page on ld.so's data section. 984 // But ensure we don't underflow the stack size - allow 1 page spare 985 if (stack_size >= (size_t)(3 * page_size())) { 986 stack_size -= 2 * page_size(); 987 } 988 989 // Try to figure out where the stack base (top) is. This is harder. 990 // 991 // When an application is started, glibc saves the initial stack pointer in 992 // a global variable "__libc_stack_end", which is then used by system 993 // libraries. __libc_stack_end should be pretty close to stack top. The 994 // variable is available since the very early days. However, because it is 995 // a private interface, it could disappear in the future. 996 // 997 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 998 // to __libc_stack_end, it is very close to stack top, but isn't the real 999 // stack top. Note that /proc may not exist if VM is running as a chroot 1000 // program, so reading /proc/<pid>/stat could fail. Also the contents of 1001 // /proc/<pid>/stat could change in the future (though unlikely). 1002 // 1003 // We try __libc_stack_end first. If that doesn't work, look for 1004 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 1005 // as a hint, which should work well in most cases. 1006 1007 uintptr_t stack_start; 1008 1009 // try __libc_stack_end first 1010 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1011 if (p && *p) { 1012 stack_start = *p; 1013 } else { 1014 // see if we can get the start_stack field from /proc/self/stat 1015 FILE *fp; 1016 int pid; 1017 char state; 1018 int ppid; 1019 int pgrp; 1020 int session; 1021 int nr; 1022 int tpgrp; 1023 unsigned long flags; 1024 unsigned long minflt; 1025 unsigned long cminflt; 1026 unsigned long majflt; 1027 unsigned long cmajflt; 1028 unsigned long utime; 1029 unsigned long stime; 1030 long cutime; 1031 long cstime; 1032 long prio; 1033 long nice; 1034 long junk; 1035 long it_real; 1036 uintptr_t start; 1037 uintptr_t vsize; 1038 intptr_t rss; 1039 uintptr_t rsslim; 1040 uintptr_t scodes; 1041 uintptr_t ecode; 1042 int i; 1043 1044 // Figure what the primordial thread stack base is. Code is inspired 1045 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1046 // followed by command name surrounded by parentheses, state, etc. 1047 char stat[2048]; 1048 int statlen; 1049 1050 fp = fopen("/proc/self/stat", "r"); 1051 if (fp) { 1052 statlen = fread(stat, 1, 2047, fp); 1053 stat[statlen] = '\0'; 1054 fclose(fp); 1055 1056 // Skip pid and the command string. Note that we could be dealing with 1057 // weird command names, e.g. user could decide to rename java launcher 1058 // to "java 1.4.2 :)", then the stat file would look like 1059 // 1234 (java 1.4.2 :)) R ... ... 1060 // We don't really need to know the command string, just find the last 1061 // occurrence of ")" and then start parsing from there. See bug 4726580. 1062 char * s = strrchr(stat, ')'); 1063 1064 i = 0; 1065 if (s) { 1066 // Skip blank chars 1067 do { s++; } while (s && isspace(*s)); 1068 1069 #define _UFM UINTX_FORMAT 1070 #define _DFM INTX_FORMAT 1071 1072 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 1073 // 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 1074 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, 1075 &state, // 3 %c 1076 &ppid, // 4 %d 1077 &pgrp, // 5 %d 1078 &session, // 6 %d 1079 &nr, // 7 %d 1080 &tpgrp, // 8 %d 1081 &flags, // 9 %lu 1082 &minflt, // 10 %lu 1083 &cminflt, // 11 %lu 1084 &majflt, // 12 %lu 1085 &cmajflt, // 13 %lu 1086 &utime, // 14 %lu 1087 &stime, // 15 %lu 1088 &cutime, // 16 %ld 1089 &cstime, // 17 %ld 1090 &prio, // 18 %ld 1091 &nice, // 19 %ld 1092 &junk, // 20 %ld 1093 &it_real, // 21 %ld 1094 &start, // 22 UINTX_FORMAT 1095 &vsize, // 23 UINTX_FORMAT 1096 &rss, // 24 INTX_FORMAT 1097 &rsslim, // 25 UINTX_FORMAT 1098 &scodes, // 26 UINTX_FORMAT 1099 &ecode, // 27 UINTX_FORMAT 1100 &stack_start); // 28 UINTX_FORMAT 1101 } 1102 1103 #undef _UFM 1104 #undef _DFM 1105 1106 if (i != 28 - 2) { 1107 assert(false, "Bad conversion from /proc/self/stat"); 1108 // product mode - assume we are the primordial thread, good luck in the 1109 // embedded case. 1110 warning("Can't detect primordial thread stack location - bad conversion"); 1111 stack_start = (uintptr_t) &rlim; 1112 } 1113 } else { 1114 // For some reason we can't open /proc/self/stat (for example, running on 1115 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1116 // most cases, so don't abort: 1117 warning("Can't detect primordial thread stack location - no /proc/self/stat"); 1118 stack_start = (uintptr_t) &rlim; 1119 } 1120 } 1121 1122 // Now we have a pointer (stack_start) very close to the stack top, the 1123 // next thing to do is to figure out the exact location of stack top. We 1124 // can find out the virtual memory area that contains stack_start by 1125 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1126 // and its upper limit is the real stack top. (again, this would fail if 1127 // running inside chroot, because /proc may not exist.) 1128 1129 uintptr_t stack_top; 1130 address low, high; 1131 if (find_vma((address)stack_start, &low, &high)) { 1132 // success, "high" is the true stack top. (ignore "low", because initial 1133 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1134 stack_top = (uintptr_t)high; 1135 } else { 1136 // failed, likely because /proc/self/maps does not exist 1137 warning("Can't detect primordial thread stack location - find_vma failed"); 1138 // best effort: stack_start is normally within a few pages below the real 1139 // stack top, use it as stack top, and reduce stack size so we won't put 1140 // guard page outside stack. 1141 stack_top = stack_start; 1142 stack_size -= 16 * page_size(); 1143 } 1144 1145 // stack_top could be partially down the page so align it 1146 stack_top = align_up(stack_top, page_size()); 1147 1148 // Allowed stack value is minimum of max_size and what we derived from rlimit 1149 if (max_size > 0) { 1150 _initial_thread_stack_size = MIN2(max_size, stack_size); 1151 } else { 1152 // Accept the rlimit max, but if stack is unlimited then it will be huge, so 1153 // clamp it at 8MB as we do on Solaris 1154 _initial_thread_stack_size = MIN2(stack_size, 8*M); 1155 } 1156 _initial_thread_stack_size = align_down(_initial_thread_stack_size, page_size()); 1157 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1158 1159 assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!"); 1160 1161 if (log_is_enabled(Info, os, thread)) { 1162 // See if we seem to be on primordial process thread 1163 bool primordial = uintptr_t(&rlim) > uintptr_t(_initial_thread_stack_bottom) && 1164 uintptr_t(&rlim) < stack_top; 1165 1166 log_info(os, thread)("Capturing initial stack in %s thread: req. size: " SIZE_FORMAT "K, actual size: " 1167 SIZE_FORMAT "K, top=" INTPTR_FORMAT ", bottom=" INTPTR_FORMAT, 1168 primordial ? "primordial" : "user", max_size / K, _initial_thread_stack_size / K, 1169 stack_top, intptr_t(_initial_thread_stack_bottom)); 1170 } 1171 } 1172 1173 //////////////////////////////////////////////////////////////////////////////// 1174 // time support 1175 1176 #ifndef SUPPORTS_CLOCK_MONOTONIC 1177 #error "Build platform doesn't support clock_gettime and related functionality" 1178 #endif 1179 1180 // Time since start-up in seconds to a fine granularity. 1181 // Used by VMSelfDestructTimer and the MemProfiler. 1182 double os::elapsedTime() { 1183 1184 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution 1185 } 1186 1187 jlong os::elapsed_counter() { 1188 return javaTimeNanos() - initial_time_count; 1189 } 1190 1191 jlong os::elapsed_frequency() { 1192 return NANOSECS_PER_SEC; // nanosecond resolution 1193 } 1194 1195 bool os::supports_vtime() { return true; } 1196 bool os::enable_vtime() { return false; } 1197 bool os::vtime_enabled() { return false; } 1198 1199 double os::elapsedVTime() { 1200 struct rusage usage; 1201 int retval = getrusage(RUSAGE_THREAD, &usage); 1202 if (retval == 0) { 1203 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); 1204 } else { 1205 // better than nothing, but not much 1206 return elapsedTime(); 1207 } 1208 } 1209 1210 jlong os::javaTimeMillis() { 1211 timeval time; 1212 int status = gettimeofday(&time, NULL); 1213 assert(status != -1, "linux error"); 1214 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1215 } 1216 1217 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) { 1218 timeval time; 1219 int status = gettimeofday(&time, NULL); 1220 assert(status != -1, "linux error"); 1221 seconds = jlong(time.tv_sec); 1222 nanos = jlong(time.tv_usec) * 1000; 1223 } 1224 1225 void os::Linux::fast_thread_clock_init() { 1226 if (!UseLinuxPosixThreadCPUClocks) { 1227 return; 1228 } 1229 clockid_t clockid; 1230 struct timespec tp; 1231 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1232 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1233 1234 // Switch to using fast clocks for thread cpu time if 1235 // the clock_getres() returns 0 error code. 1236 // Note, that some kernels may support the current thread 1237 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1238 // returned by the pthread_getcpuclockid(). 1239 // If the fast Posix clocks are supported then the clock_getres() 1240 // must return at least tp.tv_sec == 0 which means a resolution 1241 // better than 1 sec. This is extra check for reliability. 1242 1243 if (pthread_getcpuclockid_func && 1244 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1245 os::Posix::clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1246 _supports_fast_thread_cpu_time = true; 1247 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1248 } 1249 } 1250 1251 jlong os::javaTimeNanos() { 1252 if (os::supports_monotonic_clock()) { 1253 struct timespec tp; 1254 int status = os::Posix::clock_gettime(CLOCK_MONOTONIC, &tp); 1255 assert(status == 0, "gettime error"); 1256 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1257 return result; 1258 } else { 1259 timeval time; 1260 int status = gettimeofday(&time, NULL); 1261 assert(status != -1, "linux error"); 1262 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1263 return 1000 * usecs; 1264 } 1265 } 1266 1267 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1268 if (os::supports_monotonic_clock()) { 1269 info_ptr->max_value = ALL_64_BITS; 1270 1271 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1272 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1273 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1274 } else { 1275 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1276 info_ptr->max_value = ALL_64_BITS; 1277 1278 // gettimeofday is a real time clock so it skips 1279 info_ptr->may_skip_backward = true; 1280 info_ptr->may_skip_forward = true; 1281 } 1282 1283 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1284 } 1285 1286 // Return the real, user, and system times in seconds from an 1287 // arbitrary fixed point in the past. 1288 bool os::getTimesSecs(double* process_real_time, 1289 double* process_user_time, 1290 double* process_system_time) { 1291 struct tms ticks; 1292 clock_t real_ticks = times(&ticks); 1293 1294 if (real_ticks == (clock_t) (-1)) { 1295 return false; 1296 } else { 1297 double ticks_per_second = (double) clock_tics_per_sec; 1298 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1299 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1300 *process_real_time = ((double) real_ticks) / ticks_per_second; 1301 1302 return true; 1303 } 1304 } 1305 1306 1307 char * os::local_time_string(char *buf, size_t buflen) { 1308 struct tm t; 1309 time_t long_time; 1310 time(&long_time); 1311 localtime_r(&long_time, &t); 1312 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1313 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1314 t.tm_hour, t.tm_min, t.tm_sec); 1315 return buf; 1316 } 1317 1318 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1319 return localtime_r(clock, res); 1320 } 1321 1322 //////////////////////////////////////////////////////////////////////////////// 1323 // runtime exit support 1324 1325 // Note: os::shutdown() might be called very early during initialization, or 1326 // called from signal handler. Before adding something to os::shutdown(), make 1327 // sure it is async-safe and can handle partially initialized VM. 1328 void os::shutdown() { 1329 1330 // allow PerfMemory to attempt cleanup of any persistent resources 1331 perfMemory_exit(); 1332 1333 // needs to remove object in file system 1334 AttachListener::abort(); 1335 1336 // flush buffered output, finish log files 1337 ostream_abort(); 1338 1339 // Check for abort hook 1340 abort_hook_t abort_hook = Arguments::abort_hook(); 1341 if (abort_hook != NULL) { 1342 abort_hook(); 1343 } 1344 1345 } 1346 1347 // Note: os::abort() might be called very early during initialization, or 1348 // called from signal handler. Before adding something to os::abort(), make 1349 // sure it is async-safe and can handle partially initialized VM. 1350 void os::abort(bool dump_core, void* siginfo, const void* context) { 1351 os::shutdown(); 1352 if (dump_core) { 1353 #ifndef PRODUCT 1354 fdStream out(defaultStream::output_fd()); 1355 out.print_raw("Current thread is "); 1356 char buf[16]; 1357 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1358 out.print_raw_cr(buf); 1359 out.print_raw_cr("Dumping core ..."); 1360 #endif 1361 ::abort(); // dump core 1362 } 1363 1364 ::exit(1); 1365 } 1366 1367 // Die immediately, no exit hook, no abort hook, no cleanup. 1368 void os::die() { 1369 ::abort(); 1370 } 1371 1372 // thread_id is kernel thread id (similar to Solaris LWP id) 1373 intx os::current_thread_id() { return os::Linux::gettid(); } 1374 int os::current_process_id() { 1375 return ::getpid(); 1376 } 1377 1378 // DLL functions 1379 1380 const char* os::dll_file_extension() { return ".so"; } 1381 1382 // This must be hard coded because it's the system's temporary 1383 // directory not the java application's temp directory, ala java.io.tmpdir. 1384 const char* os::get_temp_directory() { return "/tmp"; } 1385 1386 static bool file_exists(const char* filename) { 1387 struct stat statbuf; 1388 if (filename == NULL || strlen(filename) == 0) { 1389 return false; 1390 } 1391 return os::stat(filename, &statbuf) == 0; 1392 } 1393 1394 // check if addr is inside libjvm.so 1395 bool os::address_is_in_vm(address addr) { 1396 static address libjvm_base_addr; 1397 Dl_info dlinfo; 1398 1399 if (libjvm_base_addr == NULL) { 1400 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) { 1401 libjvm_base_addr = (address)dlinfo.dli_fbase; 1402 } 1403 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1404 } 1405 1406 if (dladdr((void *)addr, &dlinfo) != 0) { 1407 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1408 } 1409 1410 return false; 1411 } 1412 1413 bool os::dll_address_to_function_name(address addr, char *buf, 1414 int buflen, int *offset, 1415 bool demangle) { 1416 // buf is not optional, but offset is optional 1417 assert(buf != NULL, "sanity check"); 1418 1419 Dl_info dlinfo; 1420 1421 if (dladdr((void*)addr, &dlinfo) != 0) { 1422 // see if we have a matching symbol 1423 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) { 1424 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) { 1425 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1426 } 1427 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1428 return true; 1429 } 1430 // no matching symbol so try for just file info 1431 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) { 1432 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1433 buf, buflen, offset, dlinfo.dli_fname, demangle)) { 1434 return true; 1435 } 1436 } 1437 } 1438 1439 buf[0] = '\0'; 1440 if (offset != NULL) *offset = -1; 1441 return false; 1442 } 1443 1444 struct _address_to_library_name { 1445 address addr; // input : memory address 1446 size_t buflen; // size of fname 1447 char* fname; // output: library name 1448 address base; // library base addr 1449 }; 1450 1451 static int address_to_library_name_callback(struct dl_phdr_info *info, 1452 size_t size, void *data) { 1453 int i; 1454 bool found = false; 1455 address libbase = NULL; 1456 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1457 1458 // iterate through all loadable segments 1459 for (i = 0; i < info->dlpi_phnum; i++) { 1460 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1461 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1462 // base address of a library is the lowest address of its loaded 1463 // segments. 1464 if (libbase == NULL || libbase > segbase) { 1465 libbase = segbase; 1466 } 1467 // see if 'addr' is within current segment 1468 if (segbase <= d->addr && 1469 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1470 found = true; 1471 } 1472 } 1473 } 1474 1475 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1476 // so dll_address_to_library_name() can fall through to use dladdr() which 1477 // can figure out executable name from argv[0]. 1478 if (found && info->dlpi_name && info->dlpi_name[0]) { 1479 d->base = libbase; 1480 if (d->fname) { 1481 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1482 } 1483 return 1; 1484 } 1485 return 0; 1486 } 1487 1488 bool os::dll_address_to_library_name(address addr, char* buf, 1489 int buflen, int* offset) { 1490 // buf is not optional, but offset is optional 1491 assert(buf != NULL, "sanity check"); 1492 1493 Dl_info dlinfo; 1494 struct _address_to_library_name data; 1495 1496 // There is a bug in old glibc dladdr() implementation that it could resolve 1497 // to wrong library name if the .so file has a base address != NULL. Here 1498 // we iterate through the program headers of all loaded libraries to find 1499 // out which library 'addr' really belongs to. This workaround can be 1500 // removed once the minimum requirement for glibc is moved to 2.3.x. 1501 data.addr = addr; 1502 data.fname = buf; 1503 data.buflen = buflen; 1504 data.base = NULL; 1505 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1506 1507 if (rslt) { 1508 // buf already contains library name 1509 if (offset) *offset = addr - data.base; 1510 return true; 1511 } 1512 if (dladdr((void*)addr, &dlinfo) != 0) { 1513 if (dlinfo.dli_fname != NULL) { 1514 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1515 } 1516 if (dlinfo.dli_fbase != NULL && offset != NULL) { 1517 *offset = addr - (address)dlinfo.dli_fbase; 1518 } 1519 return true; 1520 } 1521 1522 buf[0] = '\0'; 1523 if (offset) *offset = -1; 1524 return false; 1525 } 1526 1527 // Loads .dll/.so and 1528 // in case of error it checks if .dll/.so was built for the 1529 // same architecture as Hotspot is running on 1530 1531 1532 // Remember the stack's state. The Linux dynamic linker will change 1533 // the stack to 'executable' at most once, so we must safepoint only once. 1534 bool os::Linux::_stack_is_executable = false; 1535 1536 // VM operation that loads a library. This is necessary if stack protection 1537 // of the Java stacks can be lost during loading the library. If we 1538 // do not stop the Java threads, they can stack overflow before the stacks 1539 // are protected again. 1540 class VM_LinuxDllLoad: public VM_Operation { 1541 private: 1542 const char *_filename; 1543 char *_ebuf; 1544 int _ebuflen; 1545 void *_lib; 1546 public: 1547 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) : 1548 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {} 1549 VMOp_Type type() const { return VMOp_LinuxDllLoad; } 1550 void doit() { 1551 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen); 1552 os::Linux::_stack_is_executable = true; 1553 } 1554 void* loaded_library() { return _lib; } 1555 }; 1556 1557 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) { 1558 void * result = NULL; 1559 bool load_attempted = false; 1560 1561 // Check whether the library to load might change execution rights 1562 // of the stack. If they are changed, the protection of the stack 1563 // guard pages will be lost. We need a safepoint to fix this. 1564 // 1565 // See Linux man page execstack(8) for more info. 1566 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) { 1567 if (!ElfFile::specifies_noexecstack(filename)) { 1568 if (!is_init_completed()) { 1569 os::Linux::_stack_is_executable = true; 1570 // This is OK - No Java threads have been created yet, and hence no 1571 // stack guard pages to fix. 1572 // 1573 // Dynamic loader will make all stacks executable after 1574 // this function returns, and will not do that again. 1575 assert(Threads::number_of_threads() == 0, "no Java threads should exist yet."); 1576 } else { 1577 warning("You have loaded library %s which might have disabled stack guard. " 1578 "The VM will try to fix the stack guard now.\n" 1579 "It's highly recommended that you fix the library with " 1580 "'execstack -c <libfile>', or link it with '-z noexecstack'.", 1581 filename); 1582 1583 assert(Thread::current()->is_Java_thread(), "must be Java thread"); 1584 JavaThread *jt = JavaThread::current(); 1585 if (jt->thread_state() != _thread_in_native) { 1586 // This happens when a compiler thread tries to load a hsdis-<arch>.so file 1587 // that requires ExecStack. Cannot enter safe point. Let's give up. 1588 warning("Unable to fix stack guard. Giving up."); 1589 } else { 1590 if (!LoadExecStackDllInVMThread) { 1591 // This is for the case where the DLL has an static 1592 // constructor function that executes JNI code. We cannot 1593 // load such DLLs in the VMThread. 1594 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1595 } 1596 1597 ThreadInVMfromNative tiv(jt); 1598 debug_only(VMNativeEntryWrapper vew;) 1599 1600 VM_LinuxDllLoad op(filename, ebuf, ebuflen); 1601 VMThread::execute(&op); 1602 if (LoadExecStackDllInVMThread) { 1603 result = op.loaded_library(); 1604 } 1605 load_attempted = true; 1606 } 1607 } 1608 } 1609 } 1610 1611 if (!load_attempted) { 1612 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1613 } 1614 1615 if (result != NULL) { 1616 // Successful loading 1617 return result; 1618 } 1619 1620 Elf32_Ehdr elf_head; 1621 int diag_msg_max_length=ebuflen-strlen(ebuf); 1622 char* diag_msg_buf=ebuf+strlen(ebuf); 1623 1624 if (diag_msg_max_length==0) { 1625 // No more space in ebuf for additional diagnostics message 1626 return NULL; 1627 } 1628 1629 1630 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1631 1632 if (file_descriptor < 0) { 1633 // Can't open library, report dlerror() message 1634 return NULL; 1635 } 1636 1637 bool failed_to_read_elf_head= 1638 (sizeof(elf_head)!= 1639 (::read(file_descriptor, &elf_head,sizeof(elf_head)))); 1640 1641 ::close(file_descriptor); 1642 if (failed_to_read_elf_head) { 1643 // file i/o error - report dlerror() msg 1644 return NULL; 1645 } 1646 1647 typedef struct { 1648 Elf32_Half code; // Actual value as defined in elf.h 1649 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1650 unsigned char elf_class; // 32 or 64 bit 1651 unsigned char endianess; // MSB or LSB 1652 char* name; // String representation 1653 } arch_t; 1654 1655 #ifndef EM_486 1656 #define EM_486 6 /* Intel 80486 */ 1657 #endif 1658 #ifndef EM_AARCH64 1659 #define EM_AARCH64 183 /* ARM AARCH64 */ 1660 #endif 1661 1662 static const arch_t arch_array[]={ 1663 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1664 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1665 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1666 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1667 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1668 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1669 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1670 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1671 #if defined(VM_LITTLE_ENDIAN) 1672 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64 LE"}, 1673 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2LSB, (char*)"SuperH"}, 1674 #else 1675 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}, 1676 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2MSB, (char*)"SuperH BE"}, 1677 #endif 1678 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1679 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1680 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1681 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1682 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1683 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1684 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}, 1685 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"}, 1686 }; 1687 1688 #if (defined IA32) 1689 static Elf32_Half running_arch_code=EM_386; 1690 #elif (defined AMD64) || (defined X32) 1691 static Elf32_Half running_arch_code=EM_X86_64; 1692 #elif (defined IA64) 1693 static Elf32_Half running_arch_code=EM_IA_64; 1694 #elif (defined __sparc) && (defined _LP64) 1695 static Elf32_Half running_arch_code=EM_SPARCV9; 1696 #elif (defined __sparc) && (!defined _LP64) 1697 static Elf32_Half running_arch_code=EM_SPARC; 1698 #elif (defined __powerpc64__) 1699 static Elf32_Half running_arch_code=EM_PPC64; 1700 #elif (defined __powerpc__) 1701 static Elf32_Half running_arch_code=EM_PPC; 1702 #elif (defined AARCH64) 1703 static Elf32_Half running_arch_code=EM_AARCH64; 1704 #elif (defined ARM) 1705 static Elf32_Half running_arch_code=EM_ARM; 1706 #elif (defined S390) 1707 static Elf32_Half running_arch_code=EM_S390; 1708 #elif (defined ALPHA) 1709 static Elf32_Half running_arch_code=EM_ALPHA; 1710 #elif (defined MIPSEL) 1711 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1712 #elif (defined PARISC) 1713 static Elf32_Half running_arch_code=EM_PARISC; 1714 #elif (defined MIPS) 1715 static Elf32_Half running_arch_code=EM_MIPS; 1716 #elif (defined M68K) 1717 static Elf32_Half running_arch_code=EM_68K; 1718 #elif (defined SH) 1719 static Elf32_Half running_arch_code=EM_SH; 1720 #else 1721 #error Method os::dll_load requires that one of following is defined:\ 1722 AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, S390, SH, __sparc 1723 #endif 1724 1725 // Identify compatability class for VM's architecture and library's architecture 1726 // Obtain string descriptions for architectures 1727 1728 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1729 int running_arch_index=-1; 1730 1731 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) { 1732 if (running_arch_code == arch_array[i].code) { 1733 running_arch_index = i; 1734 } 1735 if (lib_arch.code == arch_array[i].code) { 1736 lib_arch.compat_class = arch_array[i].compat_class; 1737 lib_arch.name = arch_array[i].name; 1738 } 1739 } 1740 1741 assert(running_arch_index != -1, 1742 "Didn't find running architecture code (running_arch_code) in arch_array"); 1743 if (running_arch_index == -1) { 1744 // Even though running architecture detection failed 1745 // we may still continue with reporting dlerror() message 1746 return NULL; 1747 } 1748 1749 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1750 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1751 return NULL; 1752 } 1753 1754 #ifndef S390 1755 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1756 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1757 return NULL; 1758 } 1759 #endif // !S390 1760 1761 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1762 if (lib_arch.name!=NULL) { 1763 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1764 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1765 lib_arch.name, arch_array[running_arch_index].name); 1766 } else { 1767 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1768 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1769 lib_arch.code, 1770 arch_array[running_arch_index].name); 1771 } 1772 } 1773 1774 return NULL; 1775 } 1776 1777 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, 1778 int ebuflen) { 1779 void * result = ::dlopen(filename, RTLD_LAZY); 1780 if (result == NULL) { 1781 ::strncpy(ebuf, ::dlerror(), ebuflen - 1); 1782 ebuf[ebuflen-1] = '\0'; 1783 } 1784 return result; 1785 } 1786 1787 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, 1788 int ebuflen) { 1789 void * result = NULL; 1790 if (LoadExecStackDllInVMThread) { 1791 result = dlopen_helper(filename, ebuf, ebuflen); 1792 } 1793 1794 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a 1795 // library that requires an executable stack, or which does not have this 1796 // stack attribute set, dlopen changes the stack attribute to executable. The 1797 // read protection of the guard pages gets lost. 1798 // 1799 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad 1800 // may have been queued at the same time. 1801 1802 if (!_stack_is_executable) { 1803 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) { 1804 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized 1805 jt->stack_guards_enabled()) { // No pending stack overflow exceptions 1806 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) { 1807 warning("Attempt to reguard stack yellow zone failed."); 1808 } 1809 } 1810 } 1811 } 1812 1813 return result; 1814 } 1815 1816 void* os::dll_lookup(void* handle, const char* name) { 1817 void* res = dlsym(handle, name); 1818 return res; 1819 } 1820 1821 void* os::get_default_process_handle() { 1822 return (void*)::dlopen(NULL, RTLD_LAZY); 1823 } 1824 1825 static bool _print_ascii_file(const char* filename, outputStream* st, const char* hdr = NULL) { 1826 int fd = ::open(filename, O_RDONLY); 1827 if (fd == -1) { 1828 return false; 1829 } 1830 1831 if (hdr != NULL) { 1832 st->print_cr("%s", hdr); 1833 } 1834 1835 char buf[33]; 1836 int bytes; 1837 buf[32] = '\0'; 1838 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) { 1839 st->print_raw(buf, bytes); 1840 } 1841 1842 ::close(fd); 1843 1844 return true; 1845 } 1846 1847 void os::print_dll_info(outputStream *st) { 1848 st->print_cr("Dynamic libraries:"); 1849 1850 char fname[32]; 1851 pid_t pid = os::Linux::gettid(); 1852 1853 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 1854 1855 if (!_print_ascii_file(fname, st)) { 1856 st->print("Can not get library information for pid = %d\n", pid); 1857 } 1858 } 1859 1860 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) { 1861 FILE *procmapsFile = NULL; 1862 1863 // Open the procfs maps file for the current process 1864 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) { 1865 // Allocate PATH_MAX for file name plus a reasonable size for other fields. 1866 char line[PATH_MAX + 100]; 1867 1868 // Read line by line from 'file' 1869 while (fgets(line, sizeof(line), procmapsFile) != NULL) { 1870 u8 base, top, offset, inode; 1871 char permissions[5]; 1872 char device[6]; 1873 char name[PATH_MAX + 1]; 1874 1875 // Parse fields from line 1876 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %5s " INT64_FORMAT " %s", 1877 &base, &top, permissions, &offset, device, &inode, name); 1878 1879 // Filter by device id '00:00' so that we only get file system mapped files. 1880 if (strcmp(device, "00:00") != 0) { 1881 1882 // Call callback with the fields of interest 1883 if(callback(name, (address)base, (address)top, param)) { 1884 // Oops abort, callback aborted 1885 fclose(procmapsFile); 1886 return 1; 1887 } 1888 } 1889 } 1890 fclose(procmapsFile); 1891 } 1892 return 0; 1893 } 1894 1895 void os::print_os_info_brief(outputStream* st) { 1896 os::Linux::print_distro_info(st); 1897 1898 os::Posix::print_uname_info(st); 1899 1900 os::Linux::print_libversion_info(st); 1901 1902 } 1903 1904 void os::print_os_info(outputStream* st) { 1905 st->print("OS:"); 1906 1907 os::Linux::print_distro_info(st); 1908 1909 os::Posix::print_uname_info(st); 1910 1911 // Print warning if unsafe chroot environment detected 1912 if (unsafe_chroot_detected) { 1913 st->print("WARNING!! "); 1914 st->print_cr("%s", unstable_chroot_error); 1915 } 1916 1917 os::Linux::print_libversion_info(st); 1918 1919 os::Posix::print_rlimit_info(st); 1920 1921 os::Posix::print_load_average(st); 1922 1923 os::Linux::print_full_memory_info(st); 1924 1925 os::Linux::print_proc_sys_info(st); 1926 1927 os::Linux::print_ld_preload_file(st); 1928 1929 os::Linux::print_container_info(st); 1930 } 1931 1932 // Try to identify popular distros. 1933 // Most Linux distributions have a /etc/XXX-release file, which contains 1934 // the OS version string. Newer Linux distributions have a /etc/lsb-release 1935 // file that also contains the OS version string. Some have more than one 1936 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and 1937 // /etc/redhat-release.), so the order is important. 1938 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have 1939 // their own specific XXX-release file as well as a redhat-release file. 1940 // Because of this the XXX-release file needs to be searched for before the 1941 // redhat-release file. 1942 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the 1943 // search for redhat-release / SuSE-release needs to be before lsb-release. 1944 // Since the lsb-release file is the new standard it needs to be searched 1945 // before the older style release files. 1946 // Searching system-release (Red Hat) and os-release (other Linuxes) are a 1947 // next to last resort. The os-release file is a new standard that contains 1948 // distribution information and the system-release file seems to be an old 1949 // standard that has been replaced by the lsb-release and os-release files. 1950 // Searching for the debian_version file is the last resort. It contains 1951 // an informative string like "6.0.6" or "wheezy/sid". Because of this 1952 // "Debian " is printed before the contents of the debian_version file. 1953 1954 const char* distro_files[] = { 1955 "/etc/oracle-release", 1956 "/etc/mandriva-release", 1957 "/etc/mandrake-release", 1958 "/etc/sun-release", 1959 "/etc/redhat-release", 1960 "/etc/SuSE-release", 1961 "/etc/lsb-release", 1962 "/etc/turbolinux-release", 1963 "/etc/gentoo-release", 1964 "/etc/ltib-release", 1965 "/etc/angstrom-version", 1966 "/etc/system-release", 1967 "/etc/os-release", 1968 NULL }; 1969 1970 void os::Linux::print_distro_info(outputStream* st) { 1971 for (int i = 0;; i++) { 1972 const char* file = distro_files[i]; 1973 if (file == NULL) { 1974 break; // done 1975 } 1976 // If file prints, we found it. 1977 if (_print_ascii_file(file, st)) { 1978 return; 1979 } 1980 } 1981 1982 if (file_exists("/etc/debian_version")) { 1983 st->print("Debian "); 1984 _print_ascii_file("/etc/debian_version", st); 1985 } else { 1986 st->print("Linux"); 1987 } 1988 st->cr(); 1989 } 1990 1991 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) { 1992 char buf[256]; 1993 while (fgets(buf, sizeof(buf), fp)) { 1994 // Edit out extra stuff in expected format 1995 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) { 1996 char* ptr = strstr(buf, "\""); // the name is in quotes 1997 if (ptr != NULL) { 1998 ptr++; // go beyond first quote 1999 char* nl = strchr(ptr, '\"'); 2000 if (nl != NULL) *nl = '\0'; 2001 strncpy(distro, ptr, length); 2002 } else { 2003 ptr = strstr(buf, "="); 2004 ptr++; // go beyond equals then 2005 char* nl = strchr(ptr, '\n'); 2006 if (nl != NULL) *nl = '\0'; 2007 strncpy(distro, ptr, length); 2008 } 2009 return; 2010 } else if (get_first_line) { 2011 char* nl = strchr(buf, '\n'); 2012 if (nl != NULL) *nl = '\0'; 2013 strncpy(distro, buf, length); 2014 return; 2015 } 2016 } 2017 // print last line and close 2018 char* nl = strchr(buf, '\n'); 2019 if (nl != NULL) *nl = '\0'; 2020 strncpy(distro, buf, length); 2021 } 2022 2023 static void parse_os_info(char* distro, size_t length, const char* file) { 2024 FILE* fp = fopen(file, "r"); 2025 if (fp != NULL) { 2026 // if suse format, print out first line 2027 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0); 2028 parse_os_info_helper(fp, distro, length, get_first_line); 2029 fclose(fp); 2030 } 2031 } 2032 2033 void os::get_summary_os_info(char* buf, size_t buflen) { 2034 for (int i = 0;; i++) { 2035 const char* file = distro_files[i]; 2036 if (file == NULL) { 2037 break; // ran out of distro_files 2038 } 2039 if (file_exists(file)) { 2040 parse_os_info(buf, buflen, file); 2041 return; 2042 } 2043 } 2044 // special case for debian 2045 if (file_exists("/etc/debian_version")) { 2046 strncpy(buf, "Debian ", buflen); 2047 if (buflen > 7) { 2048 parse_os_info(&buf[7], buflen-7, "/etc/debian_version"); 2049 } 2050 } else { 2051 strncpy(buf, "Linux", buflen); 2052 } 2053 } 2054 2055 void os::Linux::print_libversion_info(outputStream* st) { 2056 // libc, pthread 2057 st->print("libc:"); 2058 st->print("%s ", os::Linux::glibc_version()); 2059 st->print("%s ", os::Linux::libpthread_version()); 2060 st->cr(); 2061 } 2062 2063 void os::Linux::print_proc_sys_info(outputStream* st) { 2064 st->cr(); 2065 st->print_cr("/proc/sys/kernel/threads-max (system-wide limit on the number of threads):"); 2066 _print_ascii_file("/proc/sys/kernel/threads-max", st); 2067 st->cr(); 2068 st->cr(); 2069 2070 st->print_cr("/proc/sys/vm/max_map_count (maximum number of memory map areas a process may have):"); 2071 _print_ascii_file("/proc/sys/vm/max_map_count", st); 2072 st->cr(); 2073 st->cr(); 2074 2075 st->print_cr("/proc/sys/kernel/pid_max (system-wide limit on number of process identifiers):"); 2076 _print_ascii_file("/proc/sys/kernel/pid_max", st); 2077 st->cr(); 2078 st->cr(); 2079 } 2080 2081 void os::Linux::print_full_memory_info(outputStream* st) { 2082 st->print("\n/proc/meminfo:\n"); 2083 _print_ascii_file("/proc/meminfo", st); 2084 st->cr(); 2085 } 2086 2087 void os::Linux::print_ld_preload_file(outputStream* st) { 2088 _print_ascii_file("/etc/ld.so.preload", st, "\n/etc/ld.so.preload:"); 2089 st->cr(); 2090 } 2091 2092 void os::Linux::print_container_info(outputStream* st) { 2093 if (!OSContainer::is_containerized()) { 2094 return; 2095 } 2096 2097 st->print("container (cgroup) information:\n"); 2098 2099 const char *p_ct = OSContainer::container_type(); 2100 st->print("container_type: %s\n", p_ct != NULL ? p_ct : "failed"); 2101 2102 char *p = OSContainer::cpu_cpuset_cpus(); 2103 st->print("cpu_cpuset_cpus: %s\n", p != NULL ? p : "failed"); 2104 free(p); 2105 2106 p = OSContainer::cpu_cpuset_memory_nodes(); 2107 st->print("cpu_memory_nodes: %s\n", p != NULL ? p : "failed"); 2108 free(p); 2109 2110 int i = OSContainer::active_processor_count(); 2111 if (i > 0) { 2112 st->print("active_processor_count: %d\n", i); 2113 } else { 2114 st->print("active_processor_count: failed\n"); 2115 } 2116 2117 i = OSContainer::cpu_quota(); 2118 st->print("cpu_quota: %d\n", i); 2119 2120 i = OSContainer::cpu_period(); 2121 st->print("cpu_period: %d\n", i); 2122 2123 i = OSContainer::cpu_shares(); 2124 st->print("cpu_shares: %d\n", i); 2125 2126 jlong j = OSContainer::memory_limit_in_bytes(); 2127 st->print("memory_limit_in_bytes: " JLONG_FORMAT "\n", j); 2128 2129 j = OSContainer::memory_and_swap_limit_in_bytes(); 2130 st->print("memory_and_swap_limit_in_bytes: " JLONG_FORMAT "\n", j); 2131 2132 j = OSContainer::memory_soft_limit_in_bytes(); 2133 st->print("memory_soft_limit_in_bytes: " JLONG_FORMAT "\n", j); 2134 2135 j = OSContainer::OSContainer::memory_usage_in_bytes(); 2136 st->print("memory_usage_in_bytes: " JLONG_FORMAT "\n", j); 2137 2138 j = OSContainer::OSContainer::memory_max_usage_in_bytes(); 2139 st->print("memory_max_usage_in_bytes: " JLONG_FORMAT "\n", j); 2140 st->cr(); 2141 } 2142 2143 void os::print_memory_info(outputStream* st) { 2144 2145 st->print("Memory:"); 2146 st->print(" %dk page", os::vm_page_size()>>10); 2147 2148 // values in struct sysinfo are "unsigned long" 2149 struct sysinfo si; 2150 sysinfo(&si); 2151 2152 st->print(", physical " UINT64_FORMAT "k", 2153 os::physical_memory() >> 10); 2154 st->print("(" UINT64_FORMAT "k free)", 2155 os::available_memory() >> 10); 2156 st->print(", swap " UINT64_FORMAT "k", 2157 ((jlong)si.totalswap * si.mem_unit) >> 10); 2158 st->print("(" UINT64_FORMAT "k free)", 2159 ((jlong)si.freeswap * si.mem_unit) >> 10); 2160 st->cr(); 2161 } 2162 2163 // Print the first "model name" line and the first "flags" line 2164 // that we find and nothing more. We assume "model name" comes 2165 // before "flags" so if we find a second "model name", then the 2166 // "flags" field is considered missing. 2167 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) { 2168 #if defined(IA32) || defined(AMD64) 2169 // Other platforms have less repetitive cpuinfo files 2170 FILE *fp = fopen("/proc/cpuinfo", "r"); 2171 if (fp) { 2172 while (!feof(fp)) { 2173 if (fgets(buf, buflen, fp)) { 2174 // Assume model name comes before flags 2175 bool model_name_printed = false; 2176 if (strstr(buf, "model name") != NULL) { 2177 if (!model_name_printed) { 2178 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n"); 2179 st->print_raw(buf); 2180 model_name_printed = true; 2181 } else { 2182 // model name printed but not flags? Odd, just return 2183 fclose(fp); 2184 return true; 2185 } 2186 } 2187 // print the flags line too 2188 if (strstr(buf, "flags") != NULL) { 2189 st->print_raw(buf); 2190 fclose(fp); 2191 return true; 2192 } 2193 } 2194 } 2195 fclose(fp); 2196 } 2197 #endif // x86 platforms 2198 return false; 2199 } 2200 2201 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) { 2202 // Only print the model name if the platform provides this as a summary 2203 if (!print_model_name_and_flags(st, buf, buflen)) { 2204 st->print("\n/proc/cpuinfo:\n"); 2205 if (!_print_ascii_file("/proc/cpuinfo", st)) { 2206 st->print_cr(" <Not Available>"); 2207 } 2208 } 2209 } 2210 2211 #if defined(AMD64) || defined(IA32) || defined(X32) 2212 const char* search_string = "model name"; 2213 #elif defined(M68K) 2214 const char* search_string = "CPU"; 2215 #elif defined(PPC64) 2216 const char* search_string = "cpu"; 2217 #elif defined(S390) 2218 const char* search_string = "processor"; 2219 #elif defined(SPARC) 2220 const char* search_string = "cpu"; 2221 #else 2222 const char* search_string = "Processor"; 2223 #endif 2224 2225 // Parses the cpuinfo file for string representing the model name. 2226 void os::get_summary_cpu_info(char* cpuinfo, size_t length) { 2227 FILE* fp = fopen("/proc/cpuinfo", "r"); 2228 if (fp != NULL) { 2229 while (!feof(fp)) { 2230 char buf[256]; 2231 if (fgets(buf, sizeof(buf), fp)) { 2232 char* start = strstr(buf, search_string); 2233 if (start != NULL) { 2234 char *ptr = start + strlen(search_string); 2235 char *end = buf + strlen(buf); 2236 while (ptr != end) { 2237 // skip whitespace and colon for the rest of the name. 2238 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') { 2239 break; 2240 } 2241 ptr++; 2242 } 2243 if (ptr != end) { 2244 // reasonable string, get rid of newline and keep the rest 2245 char* nl = strchr(buf, '\n'); 2246 if (nl != NULL) *nl = '\0'; 2247 strncpy(cpuinfo, ptr, length); 2248 fclose(fp); 2249 return; 2250 } 2251 } 2252 } 2253 } 2254 fclose(fp); 2255 } 2256 // cpuinfo not found or parsing failed, just print generic string. The entire 2257 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86) 2258 #if defined(AARCH64) 2259 strncpy(cpuinfo, "AArch64", length); 2260 #elif defined(AMD64) 2261 strncpy(cpuinfo, "x86_64", length); 2262 #elif defined(ARM) // Order wrt. AARCH64 is relevant! 2263 strncpy(cpuinfo, "ARM", length); 2264 #elif defined(IA32) 2265 strncpy(cpuinfo, "x86_32", length); 2266 #elif defined(IA64) 2267 strncpy(cpuinfo, "IA64", length); 2268 #elif defined(PPC) 2269 strncpy(cpuinfo, "PPC64", length); 2270 #elif defined(S390) 2271 strncpy(cpuinfo, "S390", length); 2272 #elif defined(SPARC) 2273 strncpy(cpuinfo, "sparcv9", length); 2274 #elif defined(ZERO_LIBARCH) 2275 strncpy(cpuinfo, ZERO_LIBARCH, length); 2276 #else 2277 strncpy(cpuinfo, "unknown", length); 2278 #endif 2279 } 2280 2281 static void print_signal_handler(outputStream* st, int sig, 2282 char* buf, size_t buflen); 2283 2284 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2285 st->print_cr("Signal Handlers:"); 2286 print_signal_handler(st, SIGSEGV, buf, buflen); 2287 print_signal_handler(st, SIGBUS , buf, buflen); 2288 print_signal_handler(st, SIGFPE , buf, buflen); 2289 print_signal_handler(st, SIGPIPE, buf, buflen); 2290 print_signal_handler(st, SIGXFSZ, buf, buflen); 2291 print_signal_handler(st, SIGILL , buf, buflen); 2292 print_signal_handler(st, SR_signum, buf, buflen); 2293 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2294 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2295 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2296 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2297 #if defined(PPC64) 2298 print_signal_handler(st, SIGTRAP, buf, buflen); 2299 #endif 2300 } 2301 2302 static char saved_jvm_path[MAXPATHLEN] = {0}; 2303 2304 // Find the full path to the current module, libjvm.so 2305 void os::jvm_path(char *buf, jint buflen) { 2306 // Error checking. 2307 if (buflen < MAXPATHLEN) { 2308 assert(false, "must use a large-enough buffer"); 2309 buf[0] = '\0'; 2310 return; 2311 } 2312 // Lazy resolve the path to current module. 2313 if (saved_jvm_path[0] != 0) { 2314 strcpy(buf, saved_jvm_path); 2315 return; 2316 } 2317 2318 char dli_fname[MAXPATHLEN]; 2319 bool ret = dll_address_to_library_name( 2320 CAST_FROM_FN_PTR(address, os::jvm_path), 2321 dli_fname, sizeof(dli_fname), NULL); 2322 assert(ret, "cannot locate libjvm"); 2323 char *rp = NULL; 2324 if (ret && dli_fname[0] != '\0') { 2325 rp = os::Posix::realpath(dli_fname, buf, buflen); 2326 } 2327 if (rp == NULL) { 2328 return; 2329 } 2330 2331 if (Arguments::sun_java_launcher_is_altjvm()) { 2332 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical 2333 // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so". 2334 // If "/jre/lib/" appears at the right place in the string, then 2335 // assume we are installed in a JDK and we're done. Otherwise, check 2336 // for a JAVA_HOME environment variable and fix up the path so it 2337 // looks like libjvm.so is installed there (append a fake suffix 2338 // hotspot/libjvm.so). 2339 const char *p = buf + strlen(buf) - 1; 2340 for (int count = 0; p > buf && count < 5; ++count) { 2341 for (--p; p > buf && *p != '/'; --p) 2342 /* empty */ ; 2343 } 2344 2345 if (strncmp(p, "/jre/lib/", 9) != 0) { 2346 // Look for JAVA_HOME in the environment. 2347 char* java_home_var = ::getenv("JAVA_HOME"); 2348 if (java_home_var != NULL && java_home_var[0] != 0) { 2349 char* jrelib_p; 2350 int len; 2351 2352 // Check the current module name "libjvm.so". 2353 p = strrchr(buf, '/'); 2354 if (p == NULL) { 2355 return; 2356 } 2357 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2358 2359 rp = os::Posix::realpath(java_home_var, buf, buflen); 2360 if (rp == NULL) { 2361 return; 2362 } 2363 2364 // determine if this is a legacy image or modules image 2365 // modules image doesn't have "jre" subdirectory 2366 len = strlen(buf); 2367 assert(len < buflen, "Ran out of buffer room"); 2368 jrelib_p = buf + len; 2369 snprintf(jrelib_p, buflen-len, "/jre/lib"); 2370 if (0 != access(buf, F_OK)) { 2371 snprintf(jrelib_p, buflen-len, "/lib"); 2372 } 2373 2374 if (0 == access(buf, F_OK)) { 2375 // Use current module name "libjvm.so" 2376 len = strlen(buf); 2377 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so"); 2378 } else { 2379 // Go back to path of .so 2380 rp = os::Posix::realpath(dli_fname, buf, buflen); 2381 if (rp == NULL) { 2382 return; 2383 } 2384 } 2385 } 2386 } 2387 } 2388 2389 strncpy(saved_jvm_path, buf, MAXPATHLEN); 2390 saved_jvm_path[MAXPATHLEN - 1] = '\0'; 2391 } 2392 2393 void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2394 // no prefix required, not even "_" 2395 } 2396 2397 void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2398 // no suffix required 2399 } 2400 2401 //////////////////////////////////////////////////////////////////////////////// 2402 // sun.misc.Signal support 2403 2404 static volatile jint sigint_count = 0; 2405 2406 static void UserHandler(int sig, void *siginfo, void *context) { 2407 // 4511530 - sem_post is serialized and handled by the manager thread. When 2408 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2409 // don't want to flood the manager thread with sem_post requests. 2410 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) { 2411 return; 2412 } 2413 2414 // Ctrl-C is pressed during error reporting, likely because the error 2415 // handler fails to abort. Let VM die immediately. 2416 if (sig == SIGINT && VMError::is_error_reported()) { 2417 os::die(); 2418 } 2419 2420 os::signal_notify(sig); 2421 } 2422 2423 void* os::user_handler() { 2424 return CAST_FROM_FN_PTR(void*, UserHandler); 2425 } 2426 2427 static struct timespec create_semaphore_timespec(unsigned int sec, int nsec) { 2428 struct timespec ts; 2429 // Semaphore's are always associated with CLOCK_REALTIME 2430 os::Posix::clock_gettime(CLOCK_REALTIME, &ts); 2431 // see os_posix.cpp for discussion on overflow checking 2432 if (sec >= MAX_SECS) { 2433 ts.tv_sec += MAX_SECS; 2434 ts.tv_nsec = 0; 2435 } else { 2436 ts.tv_sec += sec; 2437 ts.tv_nsec += nsec; 2438 if (ts.tv_nsec >= NANOSECS_PER_SEC) { 2439 ts.tv_nsec -= NANOSECS_PER_SEC; 2440 ++ts.tv_sec; // note: this must be <= max_secs 2441 } 2442 } 2443 2444 return ts; 2445 } 2446 2447 extern "C" { 2448 typedef void (*sa_handler_t)(int); 2449 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2450 } 2451 2452 void* os::signal(int signal_number, void* handler) { 2453 struct sigaction sigAct, oldSigAct; 2454 2455 sigfillset(&(sigAct.sa_mask)); 2456 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2457 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2458 2459 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2460 // -1 means registration failed 2461 return (void *)-1; 2462 } 2463 2464 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2465 } 2466 2467 void os::signal_raise(int signal_number) { 2468 ::raise(signal_number); 2469 } 2470 2471 // The following code is moved from os.cpp for making this 2472 // code platform specific, which it is by its very nature. 2473 2474 // Will be modified when max signal is changed to be dynamic 2475 int os::sigexitnum_pd() { 2476 return NSIG; 2477 } 2478 2479 // a counter for each possible signal value 2480 static volatile jint pending_signals[NSIG+1] = { 0 }; 2481 2482 // Linux(POSIX) specific hand shaking semaphore. 2483 static Semaphore* sig_sem = NULL; 2484 static PosixSemaphore sr_semaphore; 2485 2486 static void jdk_misc_signal_init() { 2487 // Initialize signal structures 2488 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2489 2490 // Initialize signal semaphore 2491 sig_sem = new Semaphore(); 2492 } 2493 2494 void os::signal_notify(int sig) { 2495 if (sig_sem != NULL) { 2496 Atomic::inc(&pending_signals[sig]); 2497 sig_sem->signal(); 2498 } else { 2499 // Signal thread is not created with ReduceSignalUsage and jdk_misc_signal_init 2500 // initialization isn't called. 2501 assert(ReduceSignalUsage, "signal semaphore should be created"); 2502 } 2503 } 2504 2505 static int check_pending_signals() { 2506 Atomic::store(0, &sigint_count); 2507 for (;;) { 2508 for (int i = 0; i < NSIG + 1; i++) { 2509 jint n = pending_signals[i]; 2510 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2511 return i; 2512 } 2513 } 2514 JavaThread *thread = JavaThread::current(); 2515 ThreadBlockInVM tbivm(thread); 2516 2517 bool threadIsSuspended; 2518 do { 2519 thread->set_suspend_equivalent(); 2520 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2521 sig_sem->wait(); 2522 2523 // were we externally suspended while we were waiting? 2524 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2525 if (threadIsSuspended) { 2526 // The semaphore has been incremented, but while we were waiting 2527 // another thread suspended us. We don't want to continue running 2528 // while suspended because that would surprise the thread that 2529 // suspended us. 2530 sig_sem->signal(); 2531 2532 thread->java_suspend_self(); 2533 } 2534 } while (threadIsSuspended); 2535 } 2536 } 2537 2538 int os::signal_wait() { 2539 return check_pending_signals(); 2540 } 2541 2542 //////////////////////////////////////////////////////////////////////////////// 2543 // Virtual Memory 2544 2545 int os::vm_page_size() { 2546 // Seems redundant as all get out 2547 assert(os::Linux::page_size() != -1, "must call os::init"); 2548 return os::Linux::page_size(); 2549 } 2550 2551 // Solaris allocates memory by pages. 2552 int os::vm_allocation_granularity() { 2553 assert(os::Linux::page_size() != -1, "must call os::init"); 2554 return os::Linux::page_size(); 2555 } 2556 2557 // Rationale behind this function: 2558 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2559 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2560 // samples for JITted code. Here we create private executable mapping over the code cache 2561 // and then we can use standard (well, almost, as mapping can change) way to provide 2562 // info for the reporting script by storing timestamp and location of symbol 2563 void linux_wrap_code(char* base, size_t size) { 2564 static volatile jint cnt = 0; 2565 2566 if (!UseOprofile) { 2567 return; 2568 } 2569 2570 char buf[PATH_MAX+1]; 2571 int num = Atomic::add(1, &cnt); 2572 2573 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2574 os::get_temp_directory(), os::current_process_id(), num); 2575 unlink(buf); 2576 2577 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2578 2579 if (fd != -1) { 2580 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2581 if (rv != (off_t)-1) { 2582 if (::write(fd, "", 1) == 1) { 2583 mmap(base, size, 2584 PROT_READ|PROT_WRITE|PROT_EXEC, 2585 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2586 } 2587 } 2588 ::close(fd); 2589 unlink(buf); 2590 } 2591 } 2592 2593 static bool recoverable_mmap_error(int err) { 2594 // See if the error is one we can let the caller handle. This 2595 // list of errno values comes from JBS-6843484. I can't find a 2596 // Linux man page that documents this specific set of errno 2597 // values so while this list currently matches Solaris, it may 2598 // change as we gain experience with this failure mode. 2599 switch (err) { 2600 case EBADF: 2601 case EINVAL: 2602 case ENOTSUP: 2603 // let the caller deal with these errors 2604 return true; 2605 2606 default: 2607 // Any remaining errors on this OS can cause our reserved mapping 2608 // to be lost. That can cause confusion where different data 2609 // structures think they have the same memory mapped. The worst 2610 // scenario is if both the VM and a library think they have the 2611 // same memory mapped. 2612 return false; 2613 } 2614 } 2615 2616 static void warn_fail_commit_memory(char* addr, size_t size, bool exec, 2617 int err) { 2618 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2619 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec, 2620 os::strerror(err), err); 2621 } 2622 2623 static void warn_fail_commit_memory(char* addr, size_t size, 2624 size_t alignment_hint, bool exec, 2625 int err) { 2626 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2627 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, 2628 alignment_hint, exec, os::strerror(err), err); 2629 } 2630 2631 // NOTE: Linux kernel does not really reserve the pages for us. 2632 // All it does is to check if there are enough free pages 2633 // left at the time of mmap(). This could be a potential 2634 // problem. 2635 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) { 2636 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2637 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2638 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2639 if (res != (uintptr_t) MAP_FAILED) { 2640 if (UseNUMAInterleaving) { 2641 numa_make_global(addr, size); 2642 } 2643 return 0; 2644 } 2645 2646 int err = errno; // save errno from mmap() call above 2647 2648 if (!recoverable_mmap_error(err)) { 2649 warn_fail_commit_memory(addr, size, exec, err); 2650 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory."); 2651 } 2652 2653 return err; 2654 } 2655 2656 bool os::pd_commit_memory(char* addr, size_t size, bool exec) { 2657 return os::Linux::commit_memory_impl(addr, size, exec) == 0; 2658 } 2659 2660 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec, 2661 const char* mesg) { 2662 assert(mesg != NULL, "mesg must be specified"); 2663 int err = os::Linux::commit_memory_impl(addr, size, exec); 2664 if (err != 0) { 2665 // the caller wants all commit errors to exit with the specified mesg: 2666 warn_fail_commit_memory(addr, size, exec, err); 2667 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2668 } 2669 } 2670 2671 // Define MAP_HUGETLB here so we can build HotSpot on old systems. 2672 #ifndef MAP_HUGETLB 2673 #define MAP_HUGETLB 0x40000 2674 #endif 2675 2676 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2677 #ifndef MADV_HUGEPAGE 2678 #define MADV_HUGEPAGE 14 2679 #endif 2680 2681 int os::Linux::commit_memory_impl(char* addr, size_t size, 2682 size_t alignment_hint, bool exec) { 2683 int err = os::Linux::commit_memory_impl(addr, size, exec); 2684 if (err == 0) { 2685 realign_memory(addr, size, alignment_hint); 2686 } 2687 return err; 2688 } 2689 2690 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, 2691 bool exec) { 2692 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0; 2693 } 2694 2695 void os::pd_commit_memory_or_exit(char* addr, size_t size, 2696 size_t alignment_hint, bool exec, 2697 const char* mesg) { 2698 assert(mesg != NULL, "mesg must be specified"); 2699 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec); 2700 if (err != 0) { 2701 // the caller wants all commit errors to exit with the specified mesg: 2702 warn_fail_commit_memory(addr, size, alignment_hint, exec, err); 2703 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2704 } 2705 } 2706 2707 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2708 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) { 2709 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2710 // be supported or the memory may already be backed by huge pages. 2711 ::madvise(addr, bytes, MADV_HUGEPAGE); 2712 } 2713 } 2714 2715 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) { 2716 // This method works by doing an mmap over an existing mmaping and effectively discarding 2717 // the existing pages. However it won't work for SHM-based large pages that cannot be 2718 // uncommitted at all. We don't do anything in this case to avoid creating a segment with 2719 // small pages on top of the SHM segment. This method always works for small pages, so we 2720 // allow that in any case. 2721 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) { 2722 commit_memory(addr, bytes, alignment_hint, !ExecMem); 2723 } 2724 } 2725 2726 void os::numa_make_global(char *addr, size_t bytes) { 2727 Linux::numa_interleave_memory(addr, bytes); 2728 } 2729 2730 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the 2731 // bind policy to MPOL_PREFERRED for the current thread. 2732 #define USE_MPOL_PREFERRED 0 2733 2734 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2735 // To make NUMA and large pages more robust when both enabled, we need to ease 2736 // the requirements on where the memory should be allocated. MPOL_BIND is the 2737 // default policy and it will force memory to be allocated on the specified 2738 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on 2739 // the specified node, but will not force it. Using this policy will prevent 2740 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no 2741 // free large pages. 2742 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED); 2743 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2744 } 2745 2746 bool os::numa_topology_changed() { return false; } 2747 2748 size_t os::numa_get_groups_num() { 2749 // Return just the number of nodes in which it's possible to allocate memory 2750 // (in numa terminology, configured nodes). 2751 return Linux::numa_num_configured_nodes(); 2752 } 2753 2754 int os::numa_get_group_id() { 2755 int cpu_id = Linux::sched_getcpu(); 2756 if (cpu_id != -1) { 2757 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2758 if (lgrp_id != -1) { 2759 return lgrp_id; 2760 } 2761 } 2762 return 0; 2763 } 2764 2765 int os::Linux::get_existing_num_nodes() { 2766 int node; 2767 int highest_node_number = Linux::numa_max_node(); 2768 int num_nodes = 0; 2769 2770 // Get the total number of nodes in the system including nodes without memory. 2771 for (node = 0; node <= highest_node_number; node++) { 2772 if (isnode_in_existing_nodes(node)) { 2773 num_nodes++; 2774 } 2775 } 2776 return num_nodes; 2777 } 2778 2779 size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2780 int highest_node_number = Linux::numa_max_node(); 2781 size_t i = 0; 2782 2783 // Map all node ids in which it is possible to allocate memory. Also nodes are 2784 // not always consecutively available, i.e. available from 0 to the highest 2785 // node number. If the nodes have been bound explicitly using numactl membind, 2786 // then allocate memory from those nodes only. 2787 for (int node = 0; node <= highest_node_number; node++) { 2788 if (Linux::isnode_in_bound_nodes((unsigned int)node)) { 2789 ids[i++] = node; 2790 } 2791 } 2792 return i; 2793 } 2794 2795 bool os::get_page_info(char *start, page_info* info) { 2796 return false; 2797 } 2798 2799 char *os::scan_pages(char *start, char* end, page_info* page_expected, 2800 page_info* page_found) { 2801 return end; 2802 } 2803 2804 2805 int os::Linux::sched_getcpu_syscall(void) { 2806 unsigned int cpu = 0; 2807 int retval = -1; 2808 2809 #if defined(IA32) 2810 #ifndef SYS_getcpu 2811 #define SYS_getcpu 318 2812 #endif 2813 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 2814 #elif defined(AMD64) 2815 // Unfortunately we have to bring all these macros here from vsyscall.h 2816 // to be able to compile on old linuxes. 2817 #define __NR_vgetcpu 2 2818 #define VSYSCALL_START (-10UL << 20) 2819 #define VSYSCALL_SIZE 1024 2820 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 2821 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 2822 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 2823 retval = vgetcpu(&cpu, NULL, NULL); 2824 #endif 2825 2826 return (retval == -1) ? retval : cpu; 2827 } 2828 2829 void os::Linux::sched_getcpu_init() { 2830 // sched_getcpu() should be in libc. 2831 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2832 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2833 2834 // If it's not, try a direct syscall. 2835 if (sched_getcpu() == -1) { 2836 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2837 (void*)&sched_getcpu_syscall)); 2838 } 2839 2840 if (sched_getcpu() == -1) { 2841 vm_exit_during_initialization("getcpu(2) system call not supported by kernel"); 2842 } 2843 } 2844 2845 // Something to do with the numa-aware allocator needs these symbols 2846 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 2847 extern "C" JNIEXPORT void numa_error(char *where) { } 2848 2849 // Handle request to load libnuma symbol version 1.1 (API v1). If it fails 2850 // load symbol from base version instead. 2851 void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2852 void *f = dlvsym(handle, name, "libnuma_1.1"); 2853 if (f == NULL) { 2854 f = dlsym(handle, name); 2855 } 2856 return f; 2857 } 2858 2859 // Handle request to load libnuma symbol version 1.2 (API v2) only. 2860 // Return NULL if the symbol is not defined in this particular version. 2861 void* os::Linux::libnuma_v2_dlsym(void* handle, const char* name) { 2862 return dlvsym(handle, name, "libnuma_1.2"); 2863 } 2864 2865 bool os::Linux::libnuma_init() { 2866 if (sched_getcpu() != -1) { // Requires sched_getcpu() support 2867 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2868 if (handle != NULL) { 2869 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2870 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2871 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2872 libnuma_dlsym(handle, "numa_max_node"))); 2873 set_numa_num_configured_nodes(CAST_TO_FN_PTR(numa_num_configured_nodes_func_t, 2874 libnuma_dlsym(handle, "numa_num_configured_nodes"))); 2875 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2876 libnuma_dlsym(handle, "numa_available"))); 2877 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2878 libnuma_dlsym(handle, "numa_tonode_memory"))); 2879 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2880 libnuma_dlsym(handle, "numa_interleave_memory"))); 2881 set_numa_interleave_memory_v2(CAST_TO_FN_PTR(numa_interleave_memory_v2_func_t, 2882 libnuma_v2_dlsym(handle, "numa_interleave_memory"))); 2883 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t, 2884 libnuma_dlsym(handle, "numa_set_bind_policy"))); 2885 set_numa_bitmask_isbitset(CAST_TO_FN_PTR(numa_bitmask_isbitset_func_t, 2886 libnuma_dlsym(handle, "numa_bitmask_isbitset"))); 2887 set_numa_distance(CAST_TO_FN_PTR(numa_distance_func_t, 2888 libnuma_dlsym(handle, "numa_distance"))); 2889 set_numa_get_membind(CAST_TO_FN_PTR(numa_get_membind_func_t, 2890 libnuma_v2_dlsym(handle, "numa_get_membind"))); 2891 2892 if (numa_available() != -1) { 2893 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2894 set_numa_all_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_all_nodes_ptr")); 2895 set_numa_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_nodes_ptr")); 2896 // Create an index -> node mapping, since nodes are not always consecutive 2897 _nindex_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 2898 rebuild_nindex_to_node_map(); 2899 // Create a cpu -> node mapping 2900 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 2901 rebuild_cpu_to_node_map(); 2902 return true; 2903 } 2904 } 2905 } 2906 return false; 2907 } 2908 2909 size_t os::Linux::default_guard_size(os::ThreadType thr_type) { 2910 // Creating guard page is very expensive. Java thread has HotSpot 2911 // guard pages, only enable glibc guard page for non-Java threads. 2912 // (Remember: compiler thread is a Java thread, too!) 2913 return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size()); 2914 } 2915 2916 void os::Linux::rebuild_nindex_to_node_map() { 2917 int highest_node_number = Linux::numa_max_node(); 2918 2919 nindex_to_node()->clear(); 2920 for (int node = 0; node <= highest_node_number; node++) { 2921 if (Linux::isnode_in_existing_nodes(node)) { 2922 nindex_to_node()->append(node); 2923 } 2924 } 2925 } 2926 2927 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2928 // The table is later used in get_node_by_cpu(). 2929 void os::Linux::rebuild_cpu_to_node_map() { 2930 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2931 // in libnuma (possible values are starting from 16, 2932 // and continuing up with every other power of 2, but less 2933 // than the maximum number of CPUs supported by kernel), and 2934 // is a subject to change (in libnuma version 2 the requirements 2935 // are more reasonable) we'll just hardcode the number they use 2936 // in the library. 2937 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2938 2939 size_t cpu_num = processor_count(); 2940 size_t cpu_map_size = NCPUS / BitsPerCLong; 2941 size_t cpu_map_valid_size = 2942 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2943 2944 cpu_to_node()->clear(); 2945 cpu_to_node()->at_grow(cpu_num - 1); 2946 2947 size_t node_num = get_existing_num_nodes(); 2948 2949 int distance = 0; 2950 int closest_distance = INT_MAX; 2951 int closest_node = 0; 2952 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal); 2953 for (size_t i = 0; i < node_num; i++) { 2954 // Check if node is configured (not a memory-less node). If it is not, find 2955 // the closest configured node. Check also if node is bound, i.e. it's allowed 2956 // to allocate memory from the node. If it's not allowed, map cpus in that node 2957 // to the closest node from which memory allocation is allowed. 2958 if (!isnode_in_configured_nodes(nindex_to_node()->at(i)) || 2959 !isnode_in_bound_nodes(nindex_to_node()->at(i))) { 2960 closest_distance = INT_MAX; 2961 // Check distance from all remaining nodes in the system. Ignore distance 2962 // from itself, from another non-configured node, and from another non-bound 2963 // node. 2964 for (size_t m = 0; m < node_num; m++) { 2965 if (m != i && 2966 isnode_in_configured_nodes(nindex_to_node()->at(m)) && 2967 isnode_in_bound_nodes(nindex_to_node()->at(m))) { 2968 distance = numa_distance(nindex_to_node()->at(i), nindex_to_node()->at(m)); 2969 // If a closest node is found, update. There is always at least one 2970 // configured and bound node in the system so there is always at least 2971 // one node close. 2972 if (distance != 0 && distance < closest_distance) { 2973 closest_distance = distance; 2974 closest_node = nindex_to_node()->at(m); 2975 } 2976 } 2977 } 2978 } else { 2979 // Current node is already a configured node. 2980 closest_node = nindex_to_node()->at(i); 2981 } 2982 2983 // Get cpus from the original node and map them to the closest node. If node 2984 // is a configured node (not a memory-less node), then original node and 2985 // closest node are the same. 2986 if (numa_node_to_cpus(nindex_to_node()->at(i), cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2987 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2988 if (cpu_map[j] != 0) { 2989 for (size_t k = 0; k < BitsPerCLong; k++) { 2990 if (cpu_map[j] & (1UL << k)) { 2991 cpu_to_node()->at_put(j * BitsPerCLong + k, closest_node); 2992 } 2993 } 2994 } 2995 } 2996 } 2997 } 2998 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 2999 } 3000 3001 int os::Linux::get_node_by_cpu(int cpu_id) { 3002 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 3003 return cpu_to_node()->at(cpu_id); 3004 } 3005 return -1; 3006 } 3007 3008 GrowableArray<int>* os::Linux::_cpu_to_node; 3009 GrowableArray<int>* os::Linux::_nindex_to_node; 3010 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 3011 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 3012 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 3013 os::Linux::numa_num_configured_nodes_func_t os::Linux::_numa_num_configured_nodes; 3014 os::Linux::numa_available_func_t os::Linux::_numa_available; 3015 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 3016 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 3017 os::Linux::numa_interleave_memory_v2_func_t os::Linux::_numa_interleave_memory_v2; 3018 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy; 3019 os::Linux::numa_bitmask_isbitset_func_t os::Linux::_numa_bitmask_isbitset; 3020 os::Linux::numa_distance_func_t os::Linux::_numa_distance; 3021 os::Linux::numa_get_membind_func_t os::Linux::_numa_get_membind; 3022 unsigned long* os::Linux::_numa_all_nodes; 3023 struct bitmask* os::Linux::_numa_all_nodes_ptr; 3024 struct bitmask* os::Linux::_numa_nodes_ptr; 3025 3026 bool os::pd_uncommit_memory(char* addr, size_t size) { 3027 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 3028 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 3029 return res != (uintptr_t) MAP_FAILED; 3030 } 3031 3032 static address get_stack_commited_bottom(address bottom, size_t size) { 3033 address nbot = bottom; 3034 address ntop = bottom + size; 3035 3036 size_t page_sz = os::vm_page_size(); 3037 unsigned pages = size / page_sz; 3038 3039 unsigned char vec[1]; 3040 unsigned imin = 1, imax = pages + 1, imid; 3041 int mincore_return_value = 0; 3042 3043 assert(imin <= imax, "Unexpected page size"); 3044 3045 while (imin < imax) { 3046 imid = (imax + imin) / 2; 3047 nbot = ntop - (imid * page_sz); 3048 3049 // Use a trick with mincore to check whether the page is mapped or not. 3050 // mincore sets vec to 1 if page resides in memory and to 0 if page 3051 // is swapped output but if page we are asking for is unmapped 3052 // it returns -1,ENOMEM 3053 mincore_return_value = mincore(nbot, page_sz, vec); 3054 3055 if (mincore_return_value == -1) { 3056 // Page is not mapped go up 3057 // to find first mapped page 3058 if (errno != EAGAIN) { 3059 assert(errno == ENOMEM, "Unexpected mincore errno"); 3060 imax = imid; 3061 } 3062 } else { 3063 // Page is mapped go down 3064 // to find first not mapped page 3065 imin = imid + 1; 3066 } 3067 } 3068 3069 nbot = nbot + page_sz; 3070 3071 // Adjust stack bottom one page up if last checked page is not mapped 3072 if (mincore_return_value == -1) { 3073 nbot = nbot + page_sz; 3074 } 3075 3076 return nbot; 3077 } 3078 3079 bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) { 3080 int mincore_return_value; 3081 const size_t stripe = 1024; // query this many pages each time 3082 unsigned char vec[stripe + 1]; 3083 // set a guard 3084 vec[stripe] = 'X'; 3085 3086 const size_t page_sz = os::vm_page_size(); 3087 size_t pages = size / page_sz; 3088 3089 assert(is_aligned(start, page_sz), "Start address must be page aligned"); 3090 assert(is_aligned(size, page_sz), "Size must be page aligned"); 3091 3092 committed_start = NULL; 3093 3094 int loops = (pages + stripe - 1) / stripe; 3095 int committed_pages = 0; 3096 address loop_base = start; 3097 bool found_range = false; 3098 3099 for (int index = 0; index < loops && !found_range; index ++) { 3100 assert(pages > 0, "Nothing to do"); 3101 int pages_to_query = (pages >= stripe) ? stripe : pages; 3102 pages -= pages_to_query; 3103 3104 // Get stable read 3105 while ((mincore_return_value = mincore(loop_base, pages_to_query * page_sz, vec)) == -1 && errno == EAGAIN); 3106 3107 // During shutdown, some memory goes away without properly notifying NMT, 3108 // E.g. ConcurrentGCThread/WatcherThread can exit without deleting thread object. 3109 // Bailout and return as not committed for now. 3110 if (mincore_return_value == -1 && errno == ENOMEM) { 3111 return false; 3112 } 3113 3114 assert(vec[stripe] == 'X', "overflow guard"); 3115 assert(mincore_return_value == 0, "Range must be valid"); 3116 // Process this stripe 3117 for (int vecIdx = 0; vecIdx < pages_to_query; vecIdx ++) { 3118 if ((vec[vecIdx] & 0x01) == 0) { // not committed 3119 // End of current contiguous region 3120 if (committed_start != NULL) { 3121 found_range = true; 3122 break; 3123 } 3124 } else { // committed 3125 // Start of region 3126 if (committed_start == NULL) { 3127 committed_start = loop_base + page_sz * vecIdx; 3128 } 3129 committed_pages ++; 3130 } 3131 } 3132 3133 loop_base += pages_to_query * page_sz; 3134 } 3135 3136 if (committed_start != NULL) { 3137 assert(committed_pages > 0, "Must have committed region"); 3138 assert(committed_pages <= int(size / page_sz), "Can not commit more than it has"); 3139 assert(committed_start >= start && committed_start < start + size, "Out of range"); 3140 committed_size = page_sz * committed_pages; 3141 return true; 3142 } else { 3143 assert(committed_pages == 0, "Should not have committed region"); 3144 return false; 3145 } 3146 } 3147 3148 3149 // Linux uses a growable mapping for the stack, and if the mapping for 3150 // the stack guard pages is not removed when we detach a thread the 3151 // stack cannot grow beyond the pages where the stack guard was 3152 // mapped. If at some point later in the process the stack expands to 3153 // that point, the Linux kernel cannot expand the stack any further 3154 // because the guard pages are in the way, and a segfault occurs. 3155 // 3156 // However, it's essential not to split the stack region by unmapping 3157 // a region (leaving a hole) that's already part of the stack mapping, 3158 // so if the stack mapping has already grown beyond the guard pages at 3159 // the time we create them, we have to truncate the stack mapping. 3160 // So, we need to know the extent of the stack mapping when 3161 // create_stack_guard_pages() is called. 3162 3163 // We only need this for stacks that are growable: at the time of 3164 // writing thread stacks don't use growable mappings (i.e. those 3165 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 3166 // only applies to the main thread. 3167 3168 // If the (growable) stack mapping already extends beyond the point 3169 // where we're going to put our guard pages, truncate the mapping at 3170 // that point by munmap()ping it. This ensures that when we later 3171 // munmap() the guard pages we don't leave a hole in the stack 3172 // mapping. This only affects the main/primordial thread 3173 3174 bool os::pd_create_stack_guard_pages(char* addr, size_t size) { 3175 if (os::is_primordial_thread()) { 3176 // As we manually grow stack up to bottom inside create_attached_thread(), 3177 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and 3178 // we don't need to do anything special. 3179 // Check it first, before calling heavy function. 3180 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom(); 3181 unsigned char vec[1]; 3182 3183 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) { 3184 // Fallback to slow path on all errors, including EAGAIN 3185 stack_extent = (uintptr_t) get_stack_commited_bottom( 3186 os::Linux::initial_thread_stack_bottom(), 3187 (size_t)addr - stack_extent); 3188 } 3189 3190 if (stack_extent < (uintptr_t)addr) { 3191 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent)); 3192 } 3193 } 3194 3195 return os::commit_memory(addr, size, !ExecMem); 3196 } 3197 3198 // If this is a growable mapping, remove the guard pages entirely by 3199 // munmap()ping them. If not, just call uncommit_memory(). This only 3200 // affects the main/primordial thread, but guard against future OS changes. 3201 // It's safe to always unmap guard pages for primordial thread because we 3202 // always place it right after end of the mapped region. 3203 3204 bool os::remove_stack_guard_pages(char* addr, size_t size) { 3205 uintptr_t stack_extent, stack_base; 3206 3207 if (os::is_primordial_thread()) { 3208 return ::munmap(addr, size) == 0; 3209 } 3210 3211 return os::uncommit_memory(addr, size); 3212 } 3213 3214 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 3215 // at 'requested_addr'. If there are existing memory mappings at the same 3216 // location, however, they will be overwritten. If 'fixed' is false, 3217 // 'requested_addr' is only treated as a hint, the return value may or 3218 // may not start from the requested address. Unlike Linux mmap(), this 3219 // function returns NULL to indicate failure. 3220 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 3221 char * addr; 3222 int flags; 3223 3224 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 3225 if (fixed) { 3226 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 3227 flags |= MAP_FIXED; 3228 } 3229 3230 // Map reserved/uncommitted pages PROT_NONE so we fail early if we 3231 // touch an uncommitted page. Otherwise, the read/write might 3232 // succeed if we have enough swap space to back the physical page. 3233 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, 3234 flags, -1, 0); 3235 3236 return addr == MAP_FAILED ? NULL : addr; 3237 } 3238 3239 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address 3240 // (req_addr != NULL) or with a given alignment. 3241 // - bytes shall be a multiple of alignment. 3242 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3243 // - alignment sets the alignment at which memory shall be allocated. 3244 // It must be a multiple of allocation granularity. 3245 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3246 // req_addr or NULL. 3247 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) { 3248 3249 size_t extra_size = bytes; 3250 if (req_addr == NULL && alignment > 0) { 3251 extra_size += alignment; 3252 } 3253 3254 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE, 3255 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 3256 -1, 0); 3257 if (start == MAP_FAILED) { 3258 start = NULL; 3259 } else { 3260 if (req_addr != NULL) { 3261 if (start != req_addr) { 3262 ::munmap(start, extra_size); 3263 start = NULL; 3264 } 3265 } else { 3266 char* const start_aligned = align_up(start, alignment); 3267 char* const end_aligned = start_aligned + bytes; 3268 char* const end = start + extra_size; 3269 if (start_aligned > start) { 3270 ::munmap(start, start_aligned - start); 3271 } 3272 if (end_aligned < end) { 3273 ::munmap(end_aligned, end - end_aligned); 3274 } 3275 start = start_aligned; 3276 } 3277 } 3278 return start; 3279 } 3280 3281 static int anon_munmap(char * addr, size_t size) { 3282 return ::munmap(addr, size) == 0; 3283 } 3284 3285 char* os::pd_reserve_memory(size_t bytes, char* requested_addr, 3286 size_t alignment_hint) { 3287 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 3288 } 3289 3290 bool os::pd_release_memory(char* addr, size_t size) { 3291 return anon_munmap(addr, size); 3292 } 3293 3294 static bool linux_mprotect(char* addr, size_t size, int prot) { 3295 // Linux wants the mprotect address argument to be page aligned. 3296 char* bottom = (char*)align_down((intptr_t)addr, os::Linux::page_size()); 3297 3298 // According to SUSv3, mprotect() should only be used with mappings 3299 // established by mmap(), and mmap() always maps whole pages. Unaligned 3300 // 'addr' likely indicates problem in the VM (e.g. trying to change 3301 // protection of malloc'ed or statically allocated memory). Check the 3302 // caller if you hit this assert. 3303 assert(addr == bottom, "sanity check"); 3304 3305 size = align_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 3306 return ::mprotect(bottom, size, prot) == 0; 3307 } 3308 3309 // Set protections specified 3310 bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 3311 bool is_committed) { 3312 unsigned int p = 0; 3313 switch (prot) { 3314 case MEM_PROT_NONE: p = PROT_NONE; break; 3315 case MEM_PROT_READ: p = PROT_READ; break; 3316 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 3317 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 3318 default: 3319 ShouldNotReachHere(); 3320 } 3321 // is_committed is unused. 3322 return linux_mprotect(addr, bytes, p); 3323 } 3324 3325 bool os::guard_memory(char* addr, size_t size) { 3326 return linux_mprotect(addr, size, PROT_NONE); 3327 } 3328 3329 bool os::unguard_memory(char* addr, size_t size) { 3330 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 3331 } 3332 3333 bool os::Linux::transparent_huge_pages_sanity_check(bool warn, 3334 size_t page_size) { 3335 bool result = false; 3336 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE, 3337 MAP_ANONYMOUS|MAP_PRIVATE, 3338 -1, 0); 3339 if (p != MAP_FAILED) { 3340 void *aligned_p = align_up(p, page_size); 3341 3342 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0; 3343 3344 munmap(p, page_size * 2); 3345 } 3346 3347 if (warn && !result) { 3348 warning("TransparentHugePages is not supported by the operating system."); 3349 } 3350 3351 return result; 3352 } 3353 3354 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 3355 bool result = false; 3356 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE, 3357 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 3358 -1, 0); 3359 3360 if (p != MAP_FAILED) { 3361 // We don't know if this really is a huge page or not. 3362 FILE *fp = fopen("/proc/self/maps", "r"); 3363 if (fp) { 3364 while (!feof(fp)) { 3365 char chars[257]; 3366 long x = 0; 3367 if (fgets(chars, sizeof(chars), fp)) { 3368 if (sscanf(chars, "%lx-%*x", &x) == 1 3369 && x == (long)p) { 3370 if (strstr (chars, "hugepage")) { 3371 result = true; 3372 break; 3373 } 3374 } 3375 } 3376 } 3377 fclose(fp); 3378 } 3379 munmap(p, page_size); 3380 } 3381 3382 if (warn && !result) { 3383 warning("HugeTLBFS is not supported by the operating system."); 3384 } 3385 3386 return result; 3387 } 3388 3389 // Set the coredump_filter bits to include largepages in core dump (bit 6) 3390 // 3391 // From the coredump_filter documentation: 3392 // 3393 // - (bit 0) anonymous private memory 3394 // - (bit 1) anonymous shared memory 3395 // - (bit 2) file-backed private memory 3396 // - (bit 3) file-backed shared memory 3397 // - (bit 4) ELF header pages in file-backed private memory areas (it is 3398 // effective only if the bit 2 is cleared) 3399 // - (bit 5) hugetlb private memory 3400 // - (bit 6) hugetlb shared memory 3401 // - (bit 7) dax private memory 3402 // - (bit 8) dax shared memory 3403 // 3404 static void set_coredump_filter(bool largepages, bool dax_shared) { 3405 FILE *f; 3406 long cdm; 3407 bool filter_changed = false; 3408 3409 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 3410 return; 3411 } 3412 3413 if (fscanf(f, "%lx", &cdm) != 1) { 3414 fclose(f); 3415 return; 3416 } 3417 3418 rewind(f); 3419 3420 if (largepages && (cdm & LARGEPAGES_BIT) == 0) { 3421 cdm |= LARGEPAGES_BIT; 3422 filter_changed = true; 3423 } 3424 if (dax_shared && (cdm & DAX_SHARED_BIT) == 0) { 3425 cdm |= DAX_SHARED_BIT; 3426 filter_changed = true; 3427 } 3428 if (filter_changed) { 3429 fprintf(f, "%#lx", cdm); 3430 } 3431 3432 fclose(f); 3433 } 3434 3435 // Large page support 3436 3437 static size_t _large_page_size = 0; 3438 3439 size_t os::Linux::find_large_page_size() { 3440 size_t large_page_size = 0; 3441 3442 // large_page_size on Linux is used to round up heap size. x86 uses either 3443 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3444 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3445 // page as large as 256M. 3446 // 3447 // Here we try to figure out page size by parsing /proc/meminfo and looking 3448 // for a line with the following format: 3449 // Hugepagesize: 2048 kB 3450 // 3451 // If we can't determine the value (e.g. /proc is not mounted, or the text 3452 // format has been changed), we'll use the largest page size supported by 3453 // the processor. 3454 3455 #ifndef ZERO 3456 large_page_size = 3457 AARCH64_ONLY(2 * M) 3458 AMD64_ONLY(2 * M) 3459 ARM32_ONLY(2 * M) 3460 IA32_ONLY(4 * M) 3461 IA64_ONLY(256 * M) 3462 PPC_ONLY(4 * M) 3463 S390_ONLY(1 * M) 3464 SPARC_ONLY(4 * M); 3465 #endif // ZERO 3466 3467 FILE *fp = fopen("/proc/meminfo", "r"); 3468 if (fp) { 3469 while (!feof(fp)) { 3470 int x = 0; 3471 char buf[16]; 3472 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3473 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3474 large_page_size = x * K; 3475 break; 3476 } 3477 } else { 3478 // skip to next line 3479 for (;;) { 3480 int ch = fgetc(fp); 3481 if (ch == EOF || ch == (int)'\n') break; 3482 } 3483 } 3484 } 3485 fclose(fp); 3486 } 3487 3488 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) { 3489 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is " 3490 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size), 3491 proper_unit_for_byte_size(large_page_size)); 3492 } 3493 3494 return large_page_size; 3495 } 3496 3497 size_t os::Linux::setup_large_page_size() { 3498 _large_page_size = Linux::find_large_page_size(); 3499 const size_t default_page_size = (size_t)Linux::page_size(); 3500 if (_large_page_size > default_page_size) { 3501 _page_sizes[0] = _large_page_size; 3502 _page_sizes[1] = default_page_size; 3503 _page_sizes[2] = 0; 3504 } 3505 3506 return _large_page_size; 3507 } 3508 3509 bool os::Linux::setup_large_page_type(size_t page_size) { 3510 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && 3511 FLAG_IS_DEFAULT(UseSHM) && 3512 FLAG_IS_DEFAULT(UseTransparentHugePages)) { 3513 3514 // The type of large pages has not been specified by the user. 3515 3516 // Try UseHugeTLBFS and then UseSHM. 3517 UseHugeTLBFS = UseSHM = true; 3518 3519 // Don't try UseTransparentHugePages since there are known 3520 // performance issues with it turned on. This might change in the future. 3521 UseTransparentHugePages = false; 3522 } 3523 3524 if (UseTransparentHugePages) { 3525 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages); 3526 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) { 3527 UseHugeTLBFS = false; 3528 UseSHM = false; 3529 return true; 3530 } 3531 UseTransparentHugePages = false; 3532 } 3533 3534 if (UseHugeTLBFS) { 3535 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3536 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) { 3537 UseSHM = false; 3538 return true; 3539 } 3540 UseHugeTLBFS = false; 3541 } 3542 3543 return UseSHM; 3544 } 3545 3546 void os::large_page_init() { 3547 if (!UseLargePages && 3548 !UseTransparentHugePages && 3549 !UseHugeTLBFS && 3550 !UseSHM) { 3551 // Not using large pages. 3552 return; 3553 } 3554 3555 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) { 3556 // The user explicitly turned off large pages. 3557 // Ignore the rest of the large pages flags. 3558 UseTransparentHugePages = false; 3559 UseHugeTLBFS = false; 3560 UseSHM = false; 3561 return; 3562 } 3563 3564 size_t large_page_size = Linux::setup_large_page_size(); 3565 UseLargePages = Linux::setup_large_page_type(large_page_size); 3566 3567 set_coredump_filter(true /*largepages*/, false /*dax_shared*/); 3568 } 3569 3570 #ifndef SHM_HUGETLB 3571 #define SHM_HUGETLB 04000 3572 #endif 3573 3574 #define shm_warning_format(format, ...) \ 3575 do { \ 3576 if (UseLargePages && \ 3577 (!FLAG_IS_DEFAULT(UseLargePages) || \ 3578 !FLAG_IS_DEFAULT(UseSHM) || \ 3579 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \ 3580 warning(format, __VA_ARGS__); \ 3581 } \ 3582 } while (0) 3583 3584 #define shm_warning(str) shm_warning_format("%s", str) 3585 3586 #define shm_warning_with_errno(str) \ 3587 do { \ 3588 int err = errno; \ 3589 shm_warning_format(str " (error = %d)", err); \ 3590 } while (0) 3591 3592 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) { 3593 assert(is_aligned(bytes, alignment), "Must be divisible by the alignment"); 3594 3595 if (!is_aligned(alignment, SHMLBA)) { 3596 assert(false, "Code below assumes that alignment is at least SHMLBA aligned"); 3597 return NULL; 3598 } 3599 3600 // To ensure that we get 'alignment' aligned memory from shmat, 3601 // we pre-reserve aligned virtual memory and then attach to that. 3602 3603 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL); 3604 if (pre_reserved_addr == NULL) { 3605 // Couldn't pre-reserve aligned memory. 3606 shm_warning("Failed to pre-reserve aligned memory for shmat."); 3607 return NULL; 3608 } 3609 3610 // SHM_REMAP is needed to allow shmat to map over an existing mapping. 3611 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP); 3612 3613 if ((intptr_t)addr == -1) { 3614 int err = errno; 3615 shm_warning_with_errno("Failed to attach shared memory."); 3616 3617 assert(err != EACCES, "Unexpected error"); 3618 assert(err != EIDRM, "Unexpected error"); 3619 assert(err != EINVAL, "Unexpected error"); 3620 3621 // Since we don't know if the kernel unmapped the pre-reserved memory area 3622 // we can't unmap it, since that would potentially unmap memory that was 3623 // mapped from other threads. 3624 return NULL; 3625 } 3626 3627 return addr; 3628 } 3629 3630 static char* shmat_at_address(int shmid, char* req_addr) { 3631 if (!is_aligned(req_addr, SHMLBA)) { 3632 assert(false, "Requested address needs to be SHMLBA aligned"); 3633 return NULL; 3634 } 3635 3636 char* addr = (char*)shmat(shmid, req_addr, 0); 3637 3638 if ((intptr_t)addr == -1) { 3639 shm_warning_with_errno("Failed to attach shared memory."); 3640 return NULL; 3641 } 3642 3643 return addr; 3644 } 3645 3646 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) { 3647 // If a req_addr has been provided, we assume that the caller has already aligned the address. 3648 if (req_addr != NULL) { 3649 assert(is_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size"); 3650 assert(is_aligned(req_addr, alignment), "Must be divisible by given alignment"); 3651 return shmat_at_address(shmid, req_addr); 3652 } 3653 3654 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically 3655 // return large page size aligned memory addresses when req_addr == NULL. 3656 // However, if the alignment is larger than the large page size, we have 3657 // to manually ensure that the memory returned is 'alignment' aligned. 3658 if (alignment > os::large_page_size()) { 3659 assert(is_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size"); 3660 return shmat_with_alignment(shmid, bytes, alignment); 3661 } else { 3662 return shmat_at_address(shmid, NULL); 3663 } 3664 } 3665 3666 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, 3667 char* req_addr, bool exec) { 3668 // "exec" is passed in but not used. Creating the shared image for 3669 // the code cache doesn't have an SHM_X executable permission to check. 3670 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3671 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3672 assert(is_aligned(req_addr, alignment), "Unaligned address"); 3673 3674 if (!is_aligned(bytes, os::large_page_size())) { 3675 return NULL; // Fallback to small pages. 3676 } 3677 3678 // Create a large shared memory region to attach to based on size. 3679 // Currently, size is the total size of the heap. 3680 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3681 if (shmid == -1) { 3682 // Possible reasons for shmget failure: 3683 // 1. shmmax is too small for Java heap. 3684 // > check shmmax value: cat /proc/sys/kernel/shmmax 3685 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3686 // 2. not enough large page memory. 3687 // > check available large pages: cat /proc/meminfo 3688 // > increase amount of large pages: 3689 // echo new_value > /proc/sys/vm/nr_hugepages 3690 // Note 1: different Linux may use different name for this property, 3691 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3692 // Note 2: it's possible there's enough physical memory available but 3693 // they are so fragmented after a long run that they can't 3694 // coalesce into large pages. Try to reserve large pages when 3695 // the system is still "fresh". 3696 shm_warning_with_errno("Failed to reserve shared memory."); 3697 return NULL; 3698 } 3699 3700 // Attach to the region. 3701 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr); 3702 3703 // Remove shmid. If shmat() is successful, the actual shared memory segment 3704 // will be deleted when it's detached by shmdt() or when the process 3705 // terminates. If shmat() is not successful this will remove the shared 3706 // segment immediately. 3707 shmctl(shmid, IPC_RMID, NULL); 3708 3709 return addr; 3710 } 3711 3712 static void warn_on_large_pages_failure(char* req_addr, size_t bytes, 3713 int error) { 3714 assert(error == ENOMEM, "Only expect to fail if no memory is available"); 3715 3716 bool warn_on_failure = UseLargePages && 3717 (!FLAG_IS_DEFAULT(UseLargePages) || 3718 !FLAG_IS_DEFAULT(UseHugeTLBFS) || 3719 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3720 3721 if (warn_on_failure) { 3722 char msg[128]; 3723 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: " 3724 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error); 3725 warning("%s", msg); 3726 } 3727 } 3728 3729 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, 3730 char* req_addr, 3731 bool exec) { 3732 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3733 assert(is_aligned(bytes, os::large_page_size()), "Unaligned size"); 3734 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3735 3736 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3737 char* addr = (char*)::mmap(req_addr, bytes, prot, 3738 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, 3739 -1, 0); 3740 3741 if (addr == MAP_FAILED) { 3742 warn_on_large_pages_failure(req_addr, bytes, errno); 3743 return NULL; 3744 } 3745 3746 assert(is_aligned(addr, os::large_page_size()), "Must be"); 3747 3748 return addr; 3749 } 3750 3751 // Reserve memory using mmap(MAP_HUGETLB). 3752 // - bytes shall be a multiple of alignment. 3753 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3754 // - alignment sets the alignment at which memory shall be allocated. 3755 // It must be a multiple of allocation granularity. 3756 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3757 // req_addr or NULL. 3758 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, 3759 size_t alignment, 3760 char* req_addr, 3761 bool exec) { 3762 size_t large_page_size = os::large_page_size(); 3763 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes"); 3764 3765 assert(is_aligned(req_addr, alignment), "Must be"); 3766 assert(is_aligned(bytes, alignment), "Must be"); 3767 3768 // First reserve - but not commit - the address range in small pages. 3769 char* const start = anon_mmap_aligned(bytes, alignment, req_addr); 3770 3771 if (start == NULL) { 3772 return NULL; 3773 } 3774 3775 assert(is_aligned(start, alignment), "Must be"); 3776 3777 char* end = start + bytes; 3778 3779 // Find the regions of the allocated chunk that can be promoted to large pages. 3780 char* lp_start = align_up(start, large_page_size); 3781 char* lp_end = align_down(end, large_page_size); 3782 3783 size_t lp_bytes = lp_end - lp_start; 3784 3785 assert(is_aligned(lp_bytes, large_page_size), "Must be"); 3786 3787 if (lp_bytes == 0) { 3788 // The mapped region doesn't even span the start and the end of a large page. 3789 // Fall back to allocate a non-special area. 3790 ::munmap(start, end - start); 3791 return NULL; 3792 } 3793 3794 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3795 3796 void* result; 3797 3798 // Commit small-paged leading area. 3799 if (start != lp_start) { 3800 result = ::mmap(start, lp_start - start, prot, 3801 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3802 -1, 0); 3803 if (result == MAP_FAILED) { 3804 ::munmap(lp_start, end - lp_start); 3805 return NULL; 3806 } 3807 } 3808 3809 // Commit large-paged area. 3810 result = ::mmap(lp_start, lp_bytes, prot, 3811 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB, 3812 -1, 0); 3813 if (result == MAP_FAILED) { 3814 warn_on_large_pages_failure(lp_start, lp_bytes, errno); 3815 // If the mmap above fails, the large pages region will be unmapped and we 3816 // have regions before and after with small pages. Release these regions. 3817 // 3818 // | mapped | unmapped | mapped | 3819 // ^ ^ ^ ^ 3820 // start lp_start lp_end end 3821 // 3822 ::munmap(start, lp_start - start); 3823 ::munmap(lp_end, end - lp_end); 3824 return NULL; 3825 } 3826 3827 // Commit small-paged trailing area. 3828 if (lp_end != end) { 3829 result = ::mmap(lp_end, end - lp_end, prot, 3830 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3831 -1, 0); 3832 if (result == MAP_FAILED) { 3833 ::munmap(start, lp_end - start); 3834 return NULL; 3835 } 3836 } 3837 3838 return start; 3839 } 3840 3841 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, 3842 size_t alignment, 3843 char* req_addr, 3844 bool exec) { 3845 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3846 assert(is_aligned(req_addr, alignment), "Must be"); 3847 assert(is_aligned(alignment, os::vm_allocation_granularity()), "Must be"); 3848 assert(is_power_of_2(os::large_page_size()), "Must be"); 3849 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes"); 3850 3851 if (is_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) { 3852 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec); 3853 } else { 3854 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec); 3855 } 3856 } 3857 3858 char* os::reserve_memory_special(size_t bytes, size_t alignment, 3859 char* req_addr, bool exec) { 3860 assert(UseLargePages, "only for large pages"); 3861 3862 char* addr; 3863 if (UseSHM) { 3864 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec); 3865 } else { 3866 assert(UseHugeTLBFS, "must be"); 3867 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec); 3868 } 3869 3870 if (addr != NULL) { 3871 if (UseNUMAInterleaving) { 3872 numa_make_global(addr, bytes); 3873 } 3874 3875 // The memory is committed 3876 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC); 3877 } 3878 3879 return addr; 3880 } 3881 3882 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) { 3883 // detaching the SHM segment will also delete it, see reserve_memory_special_shm() 3884 return shmdt(base) == 0; 3885 } 3886 3887 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) { 3888 return pd_release_memory(base, bytes); 3889 } 3890 3891 bool os::release_memory_special(char* base, size_t bytes) { 3892 bool res; 3893 if (MemTracker::tracking_level() > NMT_minimal) { 3894 Tracker tkr(Tracker::release); 3895 res = os::Linux::release_memory_special_impl(base, bytes); 3896 if (res) { 3897 tkr.record((address)base, bytes); 3898 } 3899 3900 } else { 3901 res = os::Linux::release_memory_special_impl(base, bytes); 3902 } 3903 return res; 3904 } 3905 3906 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) { 3907 assert(UseLargePages, "only for large pages"); 3908 bool res; 3909 3910 if (UseSHM) { 3911 res = os::Linux::release_memory_special_shm(base, bytes); 3912 } else { 3913 assert(UseHugeTLBFS, "must be"); 3914 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes); 3915 } 3916 return res; 3917 } 3918 3919 size_t os::large_page_size() { 3920 return _large_page_size; 3921 } 3922 3923 // With SysV SHM the entire memory region must be allocated as shared 3924 // memory. 3925 // HugeTLBFS allows application to commit large page memory on demand. 3926 // However, when committing memory with HugeTLBFS fails, the region 3927 // that was supposed to be committed will lose the old reservation 3928 // and allow other threads to steal that memory region. Because of this 3929 // behavior we can't commit HugeTLBFS memory. 3930 bool os::can_commit_large_page_memory() { 3931 return UseTransparentHugePages; 3932 } 3933 3934 bool os::can_execute_large_page_memory() { 3935 return UseTransparentHugePages || UseHugeTLBFS; 3936 } 3937 3938 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr, int file_desc) { 3939 assert(file_desc >= 0, "file_desc is not valid"); 3940 char* result = pd_attempt_reserve_memory_at(bytes, requested_addr); 3941 if (result != NULL) { 3942 if (replace_existing_mapping_with_file_mapping(result, bytes, file_desc) == NULL) { 3943 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory")); 3944 } 3945 } 3946 return result; 3947 } 3948 3949 // Reserve memory at an arbitrary address, only if that area is 3950 // available (and not reserved for something else). 3951 3952 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 3953 const int max_tries = 10; 3954 char* base[max_tries]; 3955 size_t size[max_tries]; 3956 const size_t gap = 0x000000; 3957 3958 // Assert only that the size is a multiple of the page size, since 3959 // that's all that mmap requires, and since that's all we really know 3960 // about at this low abstraction level. If we need higher alignment, 3961 // we can either pass an alignment to this method or verify alignment 3962 // in one of the methods further up the call chain. See bug 5044738. 3963 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 3964 3965 // Repeatedly allocate blocks until the block is allocated at the 3966 // right spot. 3967 3968 // Linux mmap allows caller to pass an address as hint; give it a try first, 3969 // if kernel honors the hint then we can return immediately. 3970 char * addr = anon_mmap(requested_addr, bytes, false); 3971 if (addr == requested_addr) { 3972 return requested_addr; 3973 } 3974 3975 if (addr != NULL) { 3976 // mmap() is successful but it fails to reserve at the requested address 3977 anon_munmap(addr, bytes); 3978 } 3979 3980 int i; 3981 for (i = 0; i < max_tries; ++i) { 3982 base[i] = reserve_memory(bytes); 3983 3984 if (base[i] != NULL) { 3985 // Is this the block we wanted? 3986 if (base[i] == requested_addr) { 3987 size[i] = bytes; 3988 break; 3989 } 3990 3991 // Does this overlap the block we wanted? Give back the overlapped 3992 // parts and try again. 3993 3994 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i]; 3995 if (top_overlap >= 0 && (size_t)top_overlap < bytes) { 3996 unmap_memory(base[i], top_overlap); 3997 base[i] += top_overlap; 3998 size[i] = bytes - top_overlap; 3999 } else { 4000 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr; 4001 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) { 4002 unmap_memory(requested_addr, bottom_overlap); 4003 size[i] = bytes - bottom_overlap; 4004 } else { 4005 size[i] = bytes; 4006 } 4007 } 4008 } 4009 } 4010 4011 // Give back the unused reserved pieces. 4012 4013 for (int j = 0; j < i; ++j) { 4014 if (base[j] != NULL) { 4015 unmap_memory(base[j], size[j]); 4016 } 4017 } 4018 4019 if (i < max_tries) { 4020 return requested_addr; 4021 } else { 4022 return NULL; 4023 } 4024 } 4025 4026 size_t os::read(int fd, void *buf, unsigned int nBytes) { 4027 return ::read(fd, buf, nBytes); 4028 } 4029 4030 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) { 4031 return ::pread(fd, buf, nBytes, offset); 4032 } 4033 4034 // Short sleep, direct OS call. 4035 // 4036 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee 4037 // sched_yield(2) will actually give up the CPU: 4038 // 4039 // * Alone on this pariticular CPU, keeps running. 4040 // * Before the introduction of "skip_buddy" with "compat_yield" disabled 4041 // (pre 2.6.39). 4042 // 4043 // So calling this with 0 is an alternative. 4044 // 4045 void os::naked_short_sleep(jlong ms) { 4046 struct timespec req; 4047 4048 assert(ms < 1000, "Un-interruptable sleep, short time use only"); 4049 req.tv_sec = 0; 4050 if (ms > 0) { 4051 req.tv_nsec = (ms % 1000) * 1000000; 4052 } else { 4053 req.tv_nsec = 1; 4054 } 4055 4056 nanosleep(&req, NULL); 4057 4058 return; 4059 } 4060 4061 // Sleep forever; naked call to OS-specific sleep; use with CAUTION 4062 void os::infinite_sleep() { 4063 while (true) { // sleep forever ... 4064 ::sleep(100); // ... 100 seconds at a time 4065 } 4066 } 4067 4068 // Used to convert frequent JVM_Yield() to nops 4069 bool os::dont_yield() { 4070 return DontYieldALot; 4071 } 4072 4073 void os::naked_yield() { 4074 sched_yield(); 4075 } 4076 4077 //////////////////////////////////////////////////////////////////////////////// 4078 // thread priority support 4079 4080 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 4081 // only supports dynamic priority, static priority must be zero. For real-time 4082 // applications, Linux supports SCHED_RR which allows static priority (1-99). 4083 // However, for large multi-threaded applications, SCHED_RR is not only slower 4084 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 4085 // of 5 runs - Sep 2005). 4086 // 4087 // The following code actually changes the niceness of kernel-thread/LWP. It 4088 // has an assumption that setpriority() only modifies one kernel-thread/LWP, 4089 // not the entire user process, and user level threads are 1:1 mapped to kernel 4090 // threads. It has always been the case, but could change in the future. For 4091 // this reason, the code should not be used as default (ThreadPriorityPolicy=0). 4092 // It is only used when ThreadPriorityPolicy=1 and requires root privilege. 4093 4094 int os::java_to_os_priority[CriticalPriority + 1] = { 4095 19, // 0 Entry should never be used 4096 4097 4, // 1 MinPriority 4098 3, // 2 4099 2, // 3 4100 4101 1, // 4 4102 0, // 5 NormPriority 4103 -1, // 6 4104 4105 -2, // 7 4106 -3, // 8 4107 -4, // 9 NearMaxPriority 4108 4109 -5, // 10 MaxPriority 4110 4111 -5 // 11 CriticalPriority 4112 }; 4113 4114 static int prio_init() { 4115 if (ThreadPriorityPolicy == 1) { 4116 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 4117 // if effective uid is not root. Perhaps, a more elegant way of doing 4118 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 4119 if (geteuid() != 0) { 4120 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 4121 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 4122 } 4123 ThreadPriorityPolicy = 0; 4124 } 4125 } 4126 if (UseCriticalJavaThreadPriority) { 4127 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority]; 4128 } 4129 return 0; 4130 } 4131 4132 OSReturn os::set_native_priority(Thread* thread, int newpri) { 4133 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK; 4134 4135 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 4136 return (ret == 0) ? OS_OK : OS_ERR; 4137 } 4138 4139 OSReturn os::get_native_priority(const Thread* const thread, 4140 int *priority_ptr) { 4141 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) { 4142 *priority_ptr = java_to_os_priority[NormPriority]; 4143 return OS_OK; 4144 } 4145 4146 errno = 0; 4147 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 4148 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 4149 } 4150 4151 //////////////////////////////////////////////////////////////////////////////// 4152 // suspend/resume support 4153 4154 // The low-level signal-based suspend/resume support is a remnant from the 4155 // old VM-suspension that used to be for java-suspension, safepoints etc, 4156 // within hotspot. Currently used by JFR's OSThreadSampler 4157 // 4158 // The remaining code is greatly simplified from the more general suspension 4159 // code that used to be used. 4160 // 4161 // The protocol is quite simple: 4162 // - suspend: 4163 // - sends a signal to the target thread 4164 // - polls the suspend state of the osthread using a yield loop 4165 // - target thread signal handler (SR_handler) sets suspend state 4166 // and blocks in sigsuspend until continued 4167 // - resume: 4168 // - sets target osthread state to continue 4169 // - sends signal to end the sigsuspend loop in the SR_handler 4170 // 4171 // Note that the SR_lock plays no role in this suspend/resume protocol, 4172 // but is checked for NULL in SR_handler as a thread termination indicator. 4173 // The SR_lock is, however, used by JavaThread::java_suspend()/java_resume() APIs. 4174 // 4175 // Note that resume_clear_context() and suspend_save_context() are needed 4176 // by SR_handler(), so that fetch_frame_from_ucontext() works, 4177 // which in part is used by: 4178 // - Forte Analyzer: AsyncGetCallTrace() 4179 // - StackBanging: get_frame_at_stack_banging_point() 4180 4181 static void resume_clear_context(OSThread *osthread) { 4182 osthread->set_ucontext(NULL); 4183 osthread->set_siginfo(NULL); 4184 } 4185 4186 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, 4187 ucontext_t* context) { 4188 osthread->set_ucontext(context); 4189 osthread->set_siginfo(siginfo); 4190 } 4191 4192 // Handler function invoked when a thread's execution is suspended or 4193 // resumed. We have to be careful that only async-safe functions are 4194 // called here (Note: most pthread functions are not async safe and 4195 // should be avoided.) 4196 // 4197 // Note: sigwait() is a more natural fit than sigsuspend() from an 4198 // interface point of view, but sigwait() prevents the signal hander 4199 // from being run. libpthread would get very confused by not having 4200 // its signal handlers run and prevents sigwait()'s use with the 4201 // mutex granting granting signal. 4202 // 4203 // Currently only ever called on the VMThread and JavaThreads (PC sampling) 4204 // 4205 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 4206 // Save and restore errno to avoid confusing native code with EINTR 4207 // after sigsuspend. 4208 int old_errno = errno; 4209 4210 Thread* thread = Thread::current_or_null_safe(); 4211 assert(thread != NULL, "Missing current thread in SR_handler"); 4212 4213 // On some systems we have seen signal delivery get "stuck" until the signal 4214 // mask is changed as part of thread termination. Check that the current thread 4215 // has not already terminated (via SR_lock()) - else the following assertion 4216 // will fail because the thread is no longer a JavaThread as the ~JavaThread 4217 // destructor has completed. 4218 4219 if (thread->SR_lock() == NULL) { 4220 return; 4221 } 4222 4223 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread"); 4224 4225 OSThread* osthread = thread->osthread(); 4226 4227 os::SuspendResume::State current = osthread->sr.state(); 4228 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) { 4229 suspend_save_context(osthread, siginfo, context); 4230 4231 // attempt to switch the state, we assume we had a SUSPEND_REQUEST 4232 os::SuspendResume::State state = osthread->sr.suspended(); 4233 if (state == os::SuspendResume::SR_SUSPENDED) { 4234 sigset_t suspend_set; // signals for sigsuspend() 4235 sigemptyset(&suspend_set); 4236 // get current set of blocked signals and unblock resume signal 4237 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 4238 sigdelset(&suspend_set, SR_signum); 4239 4240 sr_semaphore.signal(); 4241 // wait here until we are resumed 4242 while (1) { 4243 sigsuspend(&suspend_set); 4244 4245 os::SuspendResume::State result = osthread->sr.running(); 4246 if (result == os::SuspendResume::SR_RUNNING) { 4247 sr_semaphore.signal(); 4248 break; 4249 } 4250 } 4251 4252 } else if (state == os::SuspendResume::SR_RUNNING) { 4253 // request was cancelled, continue 4254 } else { 4255 ShouldNotReachHere(); 4256 } 4257 4258 resume_clear_context(osthread); 4259 } else if (current == os::SuspendResume::SR_RUNNING) { 4260 // request was cancelled, continue 4261 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) { 4262 // ignore 4263 } else { 4264 // ignore 4265 } 4266 4267 errno = old_errno; 4268 } 4269 4270 static int SR_initialize() { 4271 struct sigaction act; 4272 char *s; 4273 4274 // Get signal number to use for suspend/resume 4275 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 4276 int sig = ::strtol(s, 0, 10); 4277 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769. 4278 sig < NSIG) { // Must be legal signal and fit into sigflags[]. 4279 SR_signum = sig; 4280 } else { 4281 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.", 4282 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum); 4283 } 4284 } 4285 4286 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 4287 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 4288 4289 sigemptyset(&SR_sigset); 4290 sigaddset(&SR_sigset, SR_signum); 4291 4292 // Set up signal handler for suspend/resume 4293 act.sa_flags = SA_RESTART|SA_SIGINFO; 4294 act.sa_handler = (void (*)(int)) SR_handler; 4295 4296 // SR_signum is blocked by default. 4297 // 4528190 - We also need to block pthread restart signal (32 on all 4298 // supported Linux platforms). Note that LinuxThreads need to block 4299 // this signal for all threads to work properly. So we don't have 4300 // to use hard-coded signal number when setting up the mask. 4301 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 4302 4303 if (sigaction(SR_signum, &act, 0) == -1) { 4304 return -1; 4305 } 4306 4307 // Save signal flag 4308 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 4309 return 0; 4310 } 4311 4312 static int sr_notify(OSThread* osthread) { 4313 int status = pthread_kill(osthread->pthread_id(), SR_signum); 4314 assert_status(status == 0, status, "pthread_kill"); 4315 return status; 4316 } 4317 4318 // "Randomly" selected value for how long we want to spin 4319 // before bailing out on suspending a thread, also how often 4320 // we send a signal to a thread we want to resume 4321 static const int RANDOMLY_LARGE_INTEGER = 1000000; 4322 static const int RANDOMLY_LARGE_INTEGER2 = 100; 4323 4324 // returns true on success and false on error - really an error is fatal 4325 // but this seems the normal response to library errors 4326 static bool do_suspend(OSThread* osthread) { 4327 assert(osthread->sr.is_running(), "thread should be running"); 4328 assert(!sr_semaphore.trywait(), "semaphore has invalid state"); 4329 4330 // mark as suspended and send signal 4331 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) { 4332 // failed to switch, state wasn't running? 4333 ShouldNotReachHere(); 4334 return false; 4335 } 4336 4337 if (sr_notify(osthread) != 0) { 4338 ShouldNotReachHere(); 4339 } 4340 4341 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED 4342 while (true) { 4343 if (sr_semaphore.timedwait(create_semaphore_timespec(0, 2 * NANOSECS_PER_MILLISEC))) { 4344 break; 4345 } else { 4346 // timeout 4347 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend(); 4348 if (cancelled == os::SuspendResume::SR_RUNNING) { 4349 return false; 4350 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) { 4351 // make sure that we consume the signal on the semaphore as well 4352 sr_semaphore.wait(); 4353 break; 4354 } else { 4355 ShouldNotReachHere(); 4356 return false; 4357 } 4358 } 4359 } 4360 4361 guarantee(osthread->sr.is_suspended(), "Must be suspended"); 4362 return true; 4363 } 4364 4365 static void do_resume(OSThread* osthread) { 4366 assert(osthread->sr.is_suspended(), "thread should be suspended"); 4367 assert(!sr_semaphore.trywait(), "invalid semaphore state"); 4368 4369 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) { 4370 // failed to switch to WAKEUP_REQUEST 4371 ShouldNotReachHere(); 4372 return; 4373 } 4374 4375 while (true) { 4376 if (sr_notify(osthread) == 0) { 4377 if (sr_semaphore.timedwait(create_semaphore_timespec(0, 2 * NANOSECS_PER_MILLISEC))) { 4378 if (osthread->sr.is_running()) { 4379 return; 4380 } 4381 } 4382 } else { 4383 ShouldNotReachHere(); 4384 } 4385 } 4386 4387 guarantee(osthread->sr.is_running(), "Must be running!"); 4388 } 4389 4390 /////////////////////////////////////////////////////////////////////////////////// 4391 // signal handling (except suspend/resume) 4392 4393 // This routine may be used by user applications as a "hook" to catch signals. 4394 // The user-defined signal handler must pass unrecognized signals to this 4395 // routine, and if it returns true (non-zero), then the signal handler must 4396 // return immediately. If the flag "abort_if_unrecognized" is true, then this 4397 // routine will never retun false (zero), but instead will execute a VM panic 4398 // routine kill the process. 4399 // 4400 // If this routine returns false, it is OK to call it again. This allows 4401 // the user-defined signal handler to perform checks either before or after 4402 // the VM performs its own checks. Naturally, the user code would be making 4403 // a serious error if it tried to handle an exception (such as a null check 4404 // or breakpoint) that the VM was generating for its own correct operation. 4405 // 4406 // This routine may recognize any of the following kinds of signals: 4407 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 4408 // It should be consulted by handlers for any of those signals. 4409 // 4410 // The caller of this routine must pass in the three arguments supplied 4411 // to the function referred to in the "sa_sigaction" (not the "sa_handler") 4412 // field of the structure passed to sigaction(). This routine assumes that 4413 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 4414 // 4415 // Note that the VM will print warnings if it detects conflicting signal 4416 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 4417 // 4418 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo, 4419 siginfo_t* siginfo, 4420 void* ucontext, 4421 int abort_if_unrecognized); 4422 4423 static void signalHandler(int sig, siginfo_t* info, void* uc) { 4424 assert(info != NULL && uc != NULL, "it must be old kernel"); 4425 int orig_errno = errno; // Preserve errno value over signal handler. 4426 JVM_handle_linux_signal(sig, info, uc, true); 4427 errno = orig_errno; 4428 } 4429 4430 4431 // This boolean allows users to forward their own non-matching signals 4432 // to JVM_handle_linux_signal, harmlessly. 4433 bool os::Linux::signal_handlers_are_installed = false; 4434 4435 // For signal-chaining 4436 struct sigaction sigact[NSIG]; 4437 uint64_t sigs = 0; 4438 #if (64 < NSIG-1) 4439 #error "Not all signals can be encoded in sigs. Adapt its type!" 4440 #endif 4441 bool os::Linux::libjsig_is_loaded = false; 4442 typedef struct sigaction *(*get_signal_t)(int); 4443 get_signal_t os::Linux::get_signal_action = NULL; 4444 4445 struct sigaction* os::Linux::get_chained_signal_action(int sig) { 4446 struct sigaction *actp = NULL; 4447 4448 if (libjsig_is_loaded) { 4449 // Retrieve the old signal handler from libjsig 4450 actp = (*get_signal_action)(sig); 4451 } 4452 if (actp == NULL) { 4453 // Retrieve the preinstalled signal handler from jvm 4454 actp = get_preinstalled_handler(sig); 4455 } 4456 4457 return actp; 4458 } 4459 4460 static bool call_chained_handler(struct sigaction *actp, int sig, 4461 siginfo_t *siginfo, void *context) { 4462 // Call the old signal handler 4463 if (actp->sa_handler == SIG_DFL) { 4464 // It's more reasonable to let jvm treat it as an unexpected exception 4465 // instead of taking the default action. 4466 return false; 4467 } else if (actp->sa_handler != SIG_IGN) { 4468 if ((actp->sa_flags & SA_NODEFER) == 0) { 4469 // automaticlly block the signal 4470 sigaddset(&(actp->sa_mask), sig); 4471 } 4472 4473 sa_handler_t hand = NULL; 4474 sa_sigaction_t sa = NULL; 4475 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 4476 // retrieve the chained handler 4477 if (siginfo_flag_set) { 4478 sa = actp->sa_sigaction; 4479 } else { 4480 hand = actp->sa_handler; 4481 } 4482 4483 if ((actp->sa_flags & SA_RESETHAND) != 0) { 4484 actp->sa_handler = SIG_DFL; 4485 } 4486 4487 // try to honor the signal mask 4488 sigset_t oset; 4489 sigemptyset(&oset); 4490 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 4491 4492 // call into the chained handler 4493 if (siginfo_flag_set) { 4494 (*sa)(sig, siginfo, context); 4495 } else { 4496 (*hand)(sig); 4497 } 4498 4499 // restore the signal mask 4500 pthread_sigmask(SIG_SETMASK, &oset, NULL); 4501 } 4502 // Tell jvm's signal handler the signal is taken care of. 4503 return true; 4504 } 4505 4506 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 4507 bool chained = false; 4508 // signal-chaining 4509 if (UseSignalChaining) { 4510 struct sigaction *actp = get_chained_signal_action(sig); 4511 if (actp != NULL) { 4512 chained = call_chained_handler(actp, sig, siginfo, context); 4513 } 4514 } 4515 return chained; 4516 } 4517 4518 struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 4519 if ((((uint64_t)1 << (sig-1)) & sigs) != 0) { 4520 return &sigact[sig]; 4521 } 4522 return NULL; 4523 } 4524 4525 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 4526 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4527 sigact[sig] = oldAct; 4528 sigs |= (uint64_t)1 << (sig-1); 4529 } 4530 4531 // for diagnostic 4532 int sigflags[NSIG]; 4533 4534 int os::Linux::get_our_sigflags(int sig) { 4535 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4536 return sigflags[sig]; 4537 } 4538 4539 void os::Linux::set_our_sigflags(int sig, int flags) { 4540 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4541 if (sig > 0 && sig < NSIG) { 4542 sigflags[sig] = flags; 4543 } 4544 } 4545 4546 void os::Linux::set_signal_handler(int sig, bool set_installed) { 4547 // Check for overwrite. 4548 struct sigaction oldAct; 4549 sigaction(sig, (struct sigaction*)NULL, &oldAct); 4550 4551 void* oldhand = oldAct.sa_sigaction 4552 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4553 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4554 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 4555 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 4556 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 4557 if (AllowUserSignalHandlers || !set_installed) { 4558 // Do not overwrite; user takes responsibility to forward to us. 4559 return; 4560 } else if (UseSignalChaining) { 4561 // save the old handler in jvm 4562 save_preinstalled_handler(sig, oldAct); 4563 // libjsig also interposes the sigaction() call below and saves the 4564 // old sigaction on it own. 4565 } else { 4566 fatal("Encountered unexpected pre-existing sigaction handler " 4567 "%#lx for signal %d.", (long)oldhand, sig); 4568 } 4569 } 4570 4571 struct sigaction sigAct; 4572 sigfillset(&(sigAct.sa_mask)); 4573 sigAct.sa_handler = SIG_DFL; 4574 if (!set_installed) { 4575 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4576 } else { 4577 sigAct.sa_sigaction = signalHandler; 4578 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4579 } 4580 // Save flags, which are set by ours 4581 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4582 sigflags[sig] = sigAct.sa_flags; 4583 4584 int ret = sigaction(sig, &sigAct, &oldAct); 4585 assert(ret == 0, "check"); 4586 4587 void* oldhand2 = oldAct.sa_sigaction 4588 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4589 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4590 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 4591 } 4592 4593 // install signal handlers for signals that HotSpot needs to 4594 // handle in order to support Java-level exception handling. 4595 4596 void os::Linux::install_signal_handlers() { 4597 if (!signal_handlers_are_installed) { 4598 signal_handlers_are_installed = true; 4599 4600 // signal-chaining 4601 typedef void (*signal_setting_t)(); 4602 signal_setting_t begin_signal_setting = NULL; 4603 signal_setting_t end_signal_setting = NULL; 4604 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4605 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 4606 if (begin_signal_setting != NULL) { 4607 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4608 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 4609 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 4610 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 4611 libjsig_is_loaded = true; 4612 assert(UseSignalChaining, "should enable signal-chaining"); 4613 } 4614 if (libjsig_is_loaded) { 4615 // Tell libjsig jvm is setting signal handlers 4616 (*begin_signal_setting)(); 4617 } 4618 4619 set_signal_handler(SIGSEGV, true); 4620 set_signal_handler(SIGPIPE, true); 4621 set_signal_handler(SIGBUS, true); 4622 set_signal_handler(SIGILL, true); 4623 set_signal_handler(SIGFPE, true); 4624 #if defined(PPC64) 4625 set_signal_handler(SIGTRAP, true); 4626 #endif 4627 set_signal_handler(SIGXFSZ, true); 4628 4629 if (libjsig_is_loaded) { 4630 // Tell libjsig jvm finishes setting signal handlers 4631 (*end_signal_setting)(); 4632 } 4633 4634 // We don't activate signal checker if libjsig is in place, we trust ourselves 4635 // and if UserSignalHandler is installed all bets are off. 4636 // Log that signal checking is off only if -verbose:jni is specified. 4637 if (CheckJNICalls) { 4638 if (libjsig_is_loaded) { 4639 if (PrintJNIResolving) { 4640 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 4641 } 4642 check_signals = false; 4643 } 4644 if (AllowUserSignalHandlers) { 4645 if (PrintJNIResolving) { 4646 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 4647 } 4648 check_signals = false; 4649 } 4650 } 4651 } 4652 } 4653 4654 // This is the fastest way to get thread cpu time on Linux. 4655 // Returns cpu time (user+sys) for any thread, not only for current. 4656 // POSIX compliant clocks are implemented in the kernels 2.6.16+. 4657 // It might work on 2.6.10+ with a special kernel/glibc patch. 4658 // For reference, please, see IEEE Std 1003.1-2004: 4659 // http://www.unix.org/single_unix_specification 4660 4661 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 4662 struct timespec tp; 4663 int rc = os::Posix::clock_gettime(clockid, &tp); 4664 assert(rc == 0, "clock_gettime is expected to return 0 code"); 4665 4666 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 4667 } 4668 4669 void os::Linux::initialize_os_info() { 4670 assert(_os_version == 0, "OS info already initialized"); 4671 4672 struct utsname _uname; 4673 4674 uint32_t major; 4675 uint32_t minor; 4676 uint32_t fix; 4677 4678 int rc; 4679 4680 // Kernel version is unknown if 4681 // verification below fails. 4682 _os_version = 0x01000000; 4683 4684 rc = uname(&_uname); 4685 if (rc != -1) { 4686 4687 rc = sscanf(_uname.release,"%d.%d.%d", &major, &minor, &fix); 4688 if (rc == 3) { 4689 4690 if (major < 256 && minor < 256 && fix < 256) { 4691 // Kernel version format is as expected, 4692 // set it overriding unknown state. 4693 _os_version = (major << 16) | 4694 (minor << 8 ) | 4695 (fix << 0 ) ; 4696 } 4697 } 4698 } 4699 } 4700 4701 uint32_t os::Linux::os_version() { 4702 assert(_os_version != 0, "not initialized"); 4703 return _os_version & 0x00FFFFFF; 4704 } 4705 4706 bool os::Linux::os_version_is_known() { 4707 assert(_os_version != 0, "not initialized"); 4708 return _os_version & 0x01000000 ? false : true; 4709 } 4710 4711 ///// 4712 // glibc on Linux platform uses non-documented flag 4713 // to indicate, that some special sort of signal 4714 // trampoline is used. 4715 // We will never set this flag, and we should 4716 // ignore this flag in our diagnostic 4717 #ifdef SIGNIFICANT_SIGNAL_MASK 4718 #undef SIGNIFICANT_SIGNAL_MASK 4719 #endif 4720 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 4721 4722 static const char* get_signal_handler_name(address handler, 4723 char* buf, int buflen) { 4724 int offset = 0; 4725 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 4726 if (found) { 4727 // skip directory names 4728 const char *p1, *p2; 4729 p1 = buf; 4730 size_t len = strlen(os::file_separator()); 4731 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 4732 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 4733 } else { 4734 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 4735 } 4736 return buf; 4737 } 4738 4739 static void print_signal_handler(outputStream* st, int sig, 4740 char* buf, size_t buflen) { 4741 struct sigaction sa; 4742 4743 sigaction(sig, NULL, &sa); 4744 4745 // See comment for SIGNIFICANT_SIGNAL_MASK define 4746 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4747 4748 st->print("%s: ", os::exception_name(sig, buf, buflen)); 4749 4750 address handler = (sa.sa_flags & SA_SIGINFO) 4751 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 4752 : CAST_FROM_FN_PTR(address, sa.sa_handler); 4753 4754 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 4755 st->print("SIG_DFL"); 4756 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 4757 st->print("SIG_IGN"); 4758 } else { 4759 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 4760 } 4761 4762 st->print(", sa_mask[0]="); 4763 os::Posix::print_signal_set_short(st, &sa.sa_mask); 4764 4765 address rh = VMError::get_resetted_sighandler(sig); 4766 // May be, handler was resetted by VMError? 4767 if (rh != NULL) { 4768 handler = rh; 4769 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 4770 } 4771 4772 st->print(", sa_flags="); 4773 os::Posix::print_sa_flags(st, sa.sa_flags); 4774 4775 // Check: is it our handler? 4776 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 4777 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 4778 // It is our signal handler 4779 // check for flags, reset system-used one! 4780 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 4781 st->print( 4782 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 4783 os::Linux::get_our_sigflags(sig)); 4784 } 4785 } 4786 st->cr(); 4787 } 4788 4789 4790 #define DO_SIGNAL_CHECK(sig) \ 4791 do { \ 4792 if (!sigismember(&check_signal_done, sig)) { \ 4793 os::Linux::check_signal_handler(sig); \ 4794 } \ 4795 } while (0) 4796 4797 // This method is a periodic task to check for misbehaving JNI applications 4798 // under CheckJNI, we can add any periodic checks here 4799 4800 void os::run_periodic_checks() { 4801 if (check_signals == false) return; 4802 4803 // SEGV and BUS if overridden could potentially prevent 4804 // generation of hs*.log in the event of a crash, debugging 4805 // such a case can be very challenging, so we absolutely 4806 // check the following for a good measure: 4807 DO_SIGNAL_CHECK(SIGSEGV); 4808 DO_SIGNAL_CHECK(SIGILL); 4809 DO_SIGNAL_CHECK(SIGFPE); 4810 DO_SIGNAL_CHECK(SIGBUS); 4811 DO_SIGNAL_CHECK(SIGPIPE); 4812 DO_SIGNAL_CHECK(SIGXFSZ); 4813 #if defined(PPC64) 4814 DO_SIGNAL_CHECK(SIGTRAP); 4815 #endif 4816 4817 // ReduceSignalUsage allows the user to override these handlers 4818 // see comments at the very top and jvm_md.h 4819 if (!ReduceSignalUsage) { 4820 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 4821 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 4822 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 4823 DO_SIGNAL_CHECK(BREAK_SIGNAL); 4824 } 4825 4826 DO_SIGNAL_CHECK(SR_signum); 4827 } 4828 4829 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 4830 4831 static os_sigaction_t os_sigaction = NULL; 4832 4833 void os::Linux::check_signal_handler(int sig) { 4834 char buf[O_BUFLEN]; 4835 address jvmHandler = NULL; 4836 4837 4838 struct sigaction act; 4839 if (os_sigaction == NULL) { 4840 // only trust the default sigaction, in case it has been interposed 4841 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 4842 if (os_sigaction == NULL) return; 4843 } 4844 4845 os_sigaction(sig, (struct sigaction*)NULL, &act); 4846 4847 4848 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4849 4850 address thisHandler = (act.sa_flags & SA_SIGINFO) 4851 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 4852 : CAST_FROM_FN_PTR(address, act.sa_handler); 4853 4854 4855 switch (sig) { 4856 case SIGSEGV: 4857 case SIGBUS: 4858 case SIGFPE: 4859 case SIGPIPE: 4860 case SIGILL: 4861 case SIGXFSZ: 4862 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 4863 break; 4864 4865 case SHUTDOWN1_SIGNAL: 4866 case SHUTDOWN2_SIGNAL: 4867 case SHUTDOWN3_SIGNAL: 4868 case BREAK_SIGNAL: 4869 jvmHandler = (address)user_handler(); 4870 break; 4871 4872 default: 4873 if (sig == SR_signum) { 4874 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 4875 } else { 4876 return; 4877 } 4878 break; 4879 } 4880 4881 if (thisHandler != jvmHandler) { 4882 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 4883 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 4884 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 4885 // No need to check this sig any longer 4886 sigaddset(&check_signal_done, sig); 4887 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN 4888 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) { 4889 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell", 4890 exception_name(sig, buf, O_BUFLEN)); 4891 } 4892 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 4893 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 4894 tty->print("expected:"); 4895 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig)); 4896 tty->cr(); 4897 tty->print(" found:"); 4898 os::Posix::print_sa_flags(tty, act.sa_flags); 4899 tty->cr(); 4900 // No need to check this sig any longer 4901 sigaddset(&check_signal_done, sig); 4902 } 4903 4904 // Dump all the signal 4905 if (sigismember(&check_signal_done, sig)) { 4906 print_signal_handlers(tty, buf, O_BUFLEN); 4907 } 4908 } 4909 4910 extern void report_error(char* file_name, int line_no, char* title, 4911 char* format, ...); 4912 4913 // this is called _before_ most of the global arguments have been parsed 4914 void os::init(void) { 4915 char dummy; // used to get a guess on initial stack address 4916 4917 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 4918 4919 init_random(1234567); 4920 4921 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 4922 if (Linux::page_size() == -1) { 4923 fatal("os_linux.cpp: os::init: sysconf failed (%s)", 4924 os::strerror(errno)); 4925 } 4926 init_page_sizes((size_t) Linux::page_size()); 4927 4928 Linux::initialize_system_info(); 4929 4930 Linux::initialize_os_info(); 4931 4932 // _main_thread points to the thread that created/loaded the JVM. 4933 Linux::_main_thread = pthread_self(); 4934 4935 // retrieve entry point for pthread_setname_np 4936 Linux::_pthread_setname_np = 4937 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np"); 4938 4939 os::Posix::init(); 4940 4941 initial_time_count = javaTimeNanos(); 4942 4943 // Always warn if no monotonic clock available 4944 if (!os::Posix::supports_monotonic_clock()) { 4945 warning("No monotonic clock was available - timed services may " \ 4946 "be adversely affected if the time-of-day clock changes"); 4947 } 4948 } 4949 4950 // To install functions for atexit system call 4951 extern "C" { 4952 static void perfMemory_exit_helper() { 4953 perfMemory_exit(); 4954 } 4955 } 4956 4957 void os::pd_init_container_support() { 4958 OSContainer::init(); 4959 } 4960 4961 // this is called _after_ the global arguments have been parsed 4962 jint os::init_2(void) { 4963 4964 // This could be set after os::Posix::init() but all platforms 4965 // have to set it the same so we have to mirror Solaris. 4966 DEBUG_ONLY(os::set_mutex_init_done();) 4967 4968 os::Posix::init_2(); 4969 4970 Linux::fast_thread_clock_init(); 4971 4972 // initialize suspend/resume support - must do this before signal_sets_init() 4973 if (SR_initialize() != 0) { 4974 perror("SR_initialize failed"); 4975 return JNI_ERR; 4976 } 4977 4978 Linux::signal_sets_init(); 4979 Linux::install_signal_handlers(); 4980 // Initialize data for jdk.internal.misc.Signal 4981 if (!ReduceSignalUsage) { 4982 jdk_misc_signal_init(); 4983 } 4984 4985 // Check and sets minimum stack sizes against command line options 4986 if (Posix::set_minimum_stack_sizes() == JNI_ERR) { 4987 return JNI_ERR; 4988 } 4989 4990 suppress_primordial_thread_resolution = Arguments::created_by_java_launcher(); 4991 if (!suppress_primordial_thread_resolution) { 4992 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 4993 } 4994 4995 #if defined(IA32) 4996 workaround_expand_exec_shield_cs_limit(); 4997 #endif 4998 4999 Linux::libpthread_init(); 5000 Linux::sched_getcpu_init(); 5001 log_info(os)("HotSpot is running with %s, %s", 5002 Linux::glibc_version(), Linux::libpthread_version()); 5003 5004 if (UseNUMA) { 5005 if (!Linux::libnuma_init()) { 5006 UseNUMA = false; 5007 } else { 5008 if ((Linux::numa_max_node() < 1) || Linux::isbound_to_single_node()) { 5009 // If there's only one node (they start from 0) or if the process 5010 // is bound explicitly to a single node using membind, disable NUMA. 5011 UseNUMA = false; 5012 } 5013 } 5014 5015 if (UseParallelGC && UseNUMA && UseLargePages && !can_commit_large_page_memory()) { 5016 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way 5017 // we can make the adaptive lgrp chunk resizing work. If the user specified both 5018 // UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn 5019 // and disable adaptive resizing. 5020 if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) { 5021 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, " 5022 "disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)"); 5023 UseAdaptiveSizePolicy = false; 5024 UseAdaptiveNUMAChunkSizing = false; 5025 } 5026 } 5027 5028 if (!UseNUMA && ForceNUMA) { 5029 UseNUMA = true; 5030 } 5031 } 5032 5033 if (MaxFDLimit) { 5034 // set the number of file descriptors to max. print out error 5035 // if getrlimit/setrlimit fails but continue regardless. 5036 struct rlimit nbr_files; 5037 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 5038 if (status != 0) { 5039 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno)); 5040 } else { 5041 nbr_files.rlim_cur = nbr_files.rlim_max; 5042 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 5043 if (status != 0) { 5044 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno)); 5045 } 5046 } 5047 } 5048 5049 // Initialize lock used to serialize thread creation (see os::create_thread) 5050 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 5051 5052 // at-exit methods are called in the reverse order of their registration. 5053 // atexit functions are called on return from main or as a result of a 5054 // call to exit(3C). There can be only 32 of these functions registered 5055 // and atexit() does not set errno. 5056 5057 if (PerfAllowAtExitRegistration) { 5058 // only register atexit functions if PerfAllowAtExitRegistration is set. 5059 // atexit functions can be delayed until process exit time, which 5060 // can be problematic for embedded VM situations. Embedded VMs should 5061 // call DestroyJavaVM() to assure that VM resources are released. 5062 5063 // note: perfMemory_exit_helper atexit function may be removed in 5064 // the future if the appropriate cleanup code can be added to the 5065 // VM_Exit VMOperation's doit method. 5066 if (atexit(perfMemory_exit_helper) != 0) { 5067 warning("os::init_2 atexit(perfMemory_exit_helper) failed"); 5068 } 5069 } 5070 5071 // initialize thread priority policy 5072 prio_init(); 5073 5074 if (!FLAG_IS_DEFAULT(AllocateHeapAt)) { 5075 set_coredump_filter(false /*largepages*/, true /*dax_shared*/); 5076 } 5077 return JNI_OK; 5078 } 5079 5080 // Mark the polling page as unreadable 5081 void os::make_polling_page_unreadable(void) { 5082 if (!guard_memory((char*)_polling_page, Linux::page_size())) { 5083 fatal("Could not disable polling page"); 5084 } 5085 } 5086 5087 // Mark the polling page as readable 5088 void os::make_polling_page_readable(void) { 5089 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 5090 fatal("Could not enable polling page"); 5091 } 5092 } 5093 5094 // older glibc versions don't have this macro (which expands to 5095 // an optimized bit-counting function) so we have to roll our own 5096 #ifndef CPU_COUNT 5097 5098 static int _cpu_count(const cpu_set_t* cpus) { 5099 int count = 0; 5100 // only look up to the number of configured processors 5101 for (int i = 0; i < os::processor_count(); i++) { 5102 if (CPU_ISSET(i, cpus)) { 5103 count++; 5104 } 5105 } 5106 return count; 5107 } 5108 5109 #define CPU_COUNT(cpus) _cpu_count(cpus) 5110 5111 #endif // CPU_COUNT 5112 5113 // Get the current number of available processors for this process. 5114 // This value can change at any time during a process's lifetime. 5115 // sched_getaffinity gives an accurate answer as it accounts for cpusets. 5116 // If it appears there may be more than 1024 processors then we do a 5117 // dynamic check - see 6515172 for details. 5118 // If anything goes wrong we fallback to returning the number of online 5119 // processors - which can be greater than the number available to the process. 5120 int os::Linux::active_processor_count() { 5121 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors 5122 cpu_set_t* cpus_p = &cpus; 5123 int cpus_size = sizeof(cpu_set_t); 5124 5125 int configured_cpus = os::processor_count(); // upper bound on available cpus 5126 int cpu_count = 0; 5127 5128 // old build platforms may not support dynamic cpu sets 5129 #ifdef CPU_ALLOC 5130 5131 // To enable easy testing of the dynamic path on different platforms we 5132 // introduce a diagnostic flag: UseCpuAllocPath 5133 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) { 5134 // kernel may use a mask bigger than cpu_set_t 5135 log_trace(os)("active_processor_count: using dynamic path %s" 5136 "- configured processors: %d", 5137 UseCpuAllocPath ? "(forced) " : "", 5138 configured_cpus); 5139 cpus_p = CPU_ALLOC(configured_cpus); 5140 if (cpus_p != NULL) { 5141 cpus_size = CPU_ALLOC_SIZE(configured_cpus); 5142 // zero it just to be safe 5143 CPU_ZERO_S(cpus_size, cpus_p); 5144 } 5145 else { 5146 // failed to allocate so fallback to online cpus 5147 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 5148 log_trace(os)("active_processor_count: " 5149 "CPU_ALLOC failed (%s) - using " 5150 "online processor count: %d", 5151 os::strerror(errno), online_cpus); 5152 return online_cpus; 5153 } 5154 } 5155 else { 5156 log_trace(os)("active_processor_count: using static path - configured processors: %d", 5157 configured_cpus); 5158 } 5159 #else // CPU_ALLOC 5160 // these stubs won't be executed 5161 #define CPU_COUNT_S(size, cpus) -1 5162 #define CPU_FREE(cpus) 5163 5164 log_trace(os)("active_processor_count: only static path available - configured processors: %d", 5165 configured_cpus); 5166 #endif // CPU_ALLOC 5167 5168 // pid 0 means the current thread - which we have to assume represents the process 5169 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) { 5170 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 5171 cpu_count = CPU_COUNT_S(cpus_size, cpus_p); 5172 } 5173 else { 5174 cpu_count = CPU_COUNT(cpus_p); 5175 } 5176 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count); 5177 } 5178 else { 5179 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN); 5180 warning("sched_getaffinity failed (%s)- using online processor count (%d) " 5181 "which may exceed available processors", os::strerror(errno), cpu_count); 5182 } 5183 5184 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 5185 CPU_FREE(cpus_p); 5186 } 5187 5188 assert(cpu_count > 0 && cpu_count <= os::processor_count(), "sanity check"); 5189 return cpu_count; 5190 } 5191 5192 // Determine the active processor count from one of 5193 // three different sources: 5194 // 5195 // 1. User option -XX:ActiveProcessorCount 5196 // 2. kernel os calls (sched_getaffinity or sysconf(_SC_NPROCESSORS_ONLN) 5197 // 3. extracted from cgroup cpu subsystem (shares and quotas) 5198 // 5199 // Option 1, if specified, will always override. 5200 // If the cgroup subsystem is active and configured, we 5201 // will return the min of the cgroup and option 2 results. 5202 // This is required since tools, such as numactl, that 5203 // alter cpu affinity do not update cgroup subsystem 5204 // cpuset configuration files. 5205 int os::active_processor_count() { 5206 // User has overridden the number of active processors 5207 if (ActiveProcessorCount > 0) { 5208 log_trace(os)("active_processor_count: " 5209 "active processor count set by user : %d", 5210 ActiveProcessorCount); 5211 return ActiveProcessorCount; 5212 } 5213 5214 int active_cpus; 5215 if (OSContainer::is_containerized()) { 5216 active_cpus = OSContainer::active_processor_count(); 5217 log_trace(os)("active_processor_count: determined by OSContainer: %d", 5218 active_cpus); 5219 } else { 5220 active_cpus = os::Linux::active_processor_count(); 5221 } 5222 5223 return active_cpus; 5224 } 5225 5226 uint os::processor_id() { 5227 const int id = Linux::sched_getcpu(); 5228 assert(id >= 0 && id < _processor_count, "Invalid processor id"); 5229 return (uint)id; 5230 } 5231 5232 void os::set_native_thread_name(const char *name) { 5233 if (Linux::_pthread_setname_np) { 5234 char buf [16]; // according to glibc manpage, 16 chars incl. '/0' 5235 snprintf(buf, sizeof(buf), "%s", name); 5236 buf[sizeof(buf) - 1] = '\0'; 5237 const int rc = Linux::_pthread_setname_np(pthread_self(), buf); 5238 // ERANGE should not happen; all other errors should just be ignored. 5239 assert(rc != ERANGE, "pthread_setname_np failed"); 5240 } 5241 } 5242 5243 bool os::distribute_processes(uint length, uint* distribution) { 5244 // Not yet implemented. 5245 return false; 5246 } 5247 5248 bool os::bind_to_processor(uint processor_id) { 5249 // Not yet implemented. 5250 return false; 5251 } 5252 5253 /// 5254 5255 void os::SuspendedThreadTask::internal_do_task() { 5256 if (do_suspend(_thread->osthread())) { 5257 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext()); 5258 do_task(context); 5259 do_resume(_thread->osthread()); 5260 } 5261 } 5262 5263 //////////////////////////////////////////////////////////////////////////////// 5264 // debug support 5265 5266 bool os::find(address addr, outputStream* st) { 5267 Dl_info dlinfo; 5268 memset(&dlinfo, 0, sizeof(dlinfo)); 5269 if (dladdr(addr, &dlinfo) != 0) { 5270 st->print(PTR_FORMAT ": ", p2i(addr)); 5271 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) { 5272 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname, 5273 p2i(addr) - p2i(dlinfo.dli_saddr)); 5274 } else if (dlinfo.dli_fbase != NULL) { 5275 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase)); 5276 } else { 5277 st->print("<absolute address>"); 5278 } 5279 if (dlinfo.dli_fname != NULL) { 5280 st->print(" in %s", dlinfo.dli_fname); 5281 } 5282 if (dlinfo.dli_fbase != NULL) { 5283 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase)); 5284 } 5285 st->cr(); 5286 5287 if (Verbose) { 5288 // decode some bytes around the PC 5289 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size()); 5290 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size()); 5291 address lowest = (address) dlinfo.dli_sname; 5292 if (!lowest) lowest = (address) dlinfo.dli_fbase; 5293 if (begin < lowest) begin = lowest; 5294 Dl_info dlinfo2; 5295 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr 5296 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) { 5297 end = (address) dlinfo2.dli_saddr; 5298 } 5299 Disassembler::decode(begin, end, st); 5300 } 5301 return true; 5302 } 5303 return false; 5304 } 5305 5306 //////////////////////////////////////////////////////////////////////////////// 5307 // misc 5308 5309 // This does not do anything on Linux. This is basically a hook for being 5310 // able to use structured exception handling (thread-local exception filters) 5311 // on, e.g., Win32. 5312 void 5313 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method, 5314 JavaCallArguments* args, Thread* thread) { 5315 f(value, method, args, thread); 5316 } 5317 5318 void os::print_statistics() { 5319 } 5320 5321 bool os::message_box(const char* title, const char* message) { 5322 int i; 5323 fdStream err(defaultStream::error_fd()); 5324 for (i = 0; i < 78; i++) err.print_raw("="); 5325 err.cr(); 5326 err.print_raw_cr(title); 5327 for (i = 0; i < 78; i++) err.print_raw("-"); 5328 err.cr(); 5329 err.print_raw_cr(message); 5330 for (i = 0; i < 78; i++) err.print_raw("="); 5331 err.cr(); 5332 5333 char buf[16]; 5334 // Prevent process from exiting upon "read error" without consuming all CPU 5335 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 5336 5337 return buf[0] == 'y' || buf[0] == 'Y'; 5338 } 5339 5340 // Is a (classpath) directory empty? 5341 bool os::dir_is_empty(const char* path) { 5342 DIR *dir = NULL; 5343 struct dirent *ptr; 5344 5345 dir = opendir(path); 5346 if (dir == NULL) return true; 5347 5348 // Scan the directory 5349 bool result = true; 5350 while (result && (ptr = readdir(dir)) != NULL) { 5351 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 5352 result = false; 5353 } 5354 } 5355 closedir(dir); 5356 return result; 5357 } 5358 5359 // This code originates from JDK's sysOpen and open64_w 5360 // from src/solaris/hpi/src/system_md.c 5361 5362 int os::open(const char *path, int oflag, int mode) { 5363 if (strlen(path) > MAX_PATH - 1) { 5364 errno = ENAMETOOLONG; 5365 return -1; 5366 } 5367 5368 // All file descriptors that are opened in the Java process and not 5369 // specifically destined for a subprocess should have the close-on-exec 5370 // flag set. If we don't set it, then careless 3rd party native code 5371 // might fork and exec without closing all appropriate file descriptors 5372 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in 5373 // turn might: 5374 // 5375 // - cause end-of-file to fail to be detected on some file 5376 // descriptors, resulting in mysterious hangs, or 5377 // 5378 // - might cause an fopen in the subprocess to fail on a system 5379 // suffering from bug 1085341. 5380 // 5381 // (Yes, the default setting of the close-on-exec flag is a Unix 5382 // design flaw) 5383 // 5384 // See: 5385 // 1085341: 32-bit stdio routines should support file descriptors >255 5386 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed 5387 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 5388 // 5389 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open(). 5390 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor 5391 // because it saves a system call and removes a small window where the flag 5392 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored 5393 // and we fall back to using FD_CLOEXEC (see below). 5394 #ifdef O_CLOEXEC 5395 oflag |= O_CLOEXEC; 5396 #endif 5397 5398 int fd = ::open64(path, oflag, mode); 5399 if (fd == -1) return -1; 5400 5401 //If the open succeeded, the file might still be a directory 5402 { 5403 struct stat64 buf64; 5404 int ret = ::fstat64(fd, &buf64); 5405 int st_mode = buf64.st_mode; 5406 5407 if (ret != -1) { 5408 if ((st_mode & S_IFMT) == S_IFDIR) { 5409 errno = EISDIR; 5410 ::close(fd); 5411 return -1; 5412 } 5413 } else { 5414 ::close(fd); 5415 return -1; 5416 } 5417 } 5418 5419 #ifdef FD_CLOEXEC 5420 // Validate that the use of the O_CLOEXEC flag on open above worked. 5421 // With recent kernels, we will perform this check exactly once. 5422 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0; 5423 if (!O_CLOEXEC_is_known_to_work) { 5424 int flags = ::fcntl(fd, F_GETFD); 5425 if (flags != -1) { 5426 if ((flags & FD_CLOEXEC) != 0) 5427 O_CLOEXEC_is_known_to_work = 1; 5428 else 5429 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 5430 } 5431 } 5432 #endif 5433 5434 return fd; 5435 } 5436 5437 5438 // create binary file, rewriting existing file if required 5439 int os::create_binary_file(const char* path, bool rewrite_existing) { 5440 int oflags = O_WRONLY | O_CREAT; 5441 if (!rewrite_existing) { 5442 oflags |= O_EXCL; 5443 } 5444 return ::open64(path, oflags, S_IREAD | S_IWRITE); 5445 } 5446 5447 // return current position of file pointer 5448 jlong os::current_file_offset(int fd) { 5449 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 5450 } 5451 5452 // move file pointer to the specified offset 5453 jlong os::seek_to_file_offset(int fd, jlong offset) { 5454 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 5455 } 5456 5457 // This code originates from JDK's sysAvailable 5458 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c 5459 5460 int os::available(int fd, jlong *bytes) { 5461 jlong cur, end; 5462 int mode; 5463 struct stat64 buf64; 5464 5465 if (::fstat64(fd, &buf64) >= 0) { 5466 mode = buf64.st_mode; 5467 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 5468 int n; 5469 if (::ioctl(fd, FIONREAD, &n) >= 0) { 5470 *bytes = n; 5471 return 1; 5472 } 5473 } 5474 } 5475 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 5476 return 0; 5477 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 5478 return 0; 5479 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 5480 return 0; 5481 } 5482 *bytes = end - cur; 5483 return 1; 5484 } 5485 5486 // Map a block of memory. 5487 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset, 5488 char *addr, size_t bytes, bool read_only, 5489 bool allow_exec) { 5490 int prot; 5491 int flags = MAP_PRIVATE; 5492 5493 if (read_only) { 5494 prot = PROT_READ; 5495 } else { 5496 prot = PROT_READ | PROT_WRITE; 5497 } 5498 5499 if (allow_exec) { 5500 prot |= PROT_EXEC; 5501 } 5502 5503 if (addr != NULL) { 5504 flags |= MAP_FIXED; 5505 } 5506 5507 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 5508 fd, file_offset); 5509 if (mapped_address == MAP_FAILED) { 5510 return NULL; 5511 } 5512 return mapped_address; 5513 } 5514 5515 5516 // Remap a block of memory. 5517 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, 5518 char *addr, size_t bytes, bool read_only, 5519 bool allow_exec) { 5520 // same as map_memory() on this OS 5521 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 5522 allow_exec); 5523 } 5524 5525 5526 // Unmap a block of memory. 5527 bool os::pd_unmap_memory(char* addr, size_t bytes) { 5528 return munmap(addr, bytes) == 0; 5529 } 5530 5531 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 5532 5533 static jlong fast_cpu_time(Thread *thread) { 5534 clockid_t clockid; 5535 int rc = os::Linux::pthread_getcpuclockid(thread->osthread()->pthread_id(), 5536 &clockid); 5537 if (rc == 0) { 5538 return os::Linux::fast_thread_cpu_time(clockid); 5539 } else { 5540 // It's possible to encounter a terminated native thread that failed 5541 // to detach itself from the VM - which should result in ESRCH. 5542 assert_status(rc == ESRCH, rc, "pthread_getcpuclockid failed"); 5543 return -1; 5544 } 5545 } 5546 5547 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 5548 // are used by JVM M&M and JVMTI to get user+sys or user CPU time 5549 // of a thread. 5550 // 5551 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns 5552 // the fast estimate available on the platform. 5553 5554 jlong os::current_thread_cpu_time() { 5555 if (os::Linux::supports_fast_thread_cpu_time()) { 5556 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5557 } else { 5558 // return user + sys since the cost is the same 5559 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 5560 } 5561 } 5562 5563 jlong os::thread_cpu_time(Thread* thread) { 5564 // consistent with what current_thread_cpu_time() returns 5565 if (os::Linux::supports_fast_thread_cpu_time()) { 5566 return fast_cpu_time(thread); 5567 } else { 5568 return slow_thread_cpu_time(thread, true /* user + sys */); 5569 } 5570 } 5571 5572 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 5573 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5574 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5575 } else { 5576 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 5577 } 5578 } 5579 5580 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5581 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5582 return fast_cpu_time(thread); 5583 } else { 5584 return slow_thread_cpu_time(thread, user_sys_cpu_time); 5585 } 5586 } 5587 5588 // -1 on error. 5589 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5590 pid_t tid = thread->osthread()->thread_id(); 5591 char *s; 5592 char stat[2048]; 5593 int statlen; 5594 char proc_name[64]; 5595 int count; 5596 long sys_time, user_time; 5597 char cdummy; 5598 int idummy; 5599 long ldummy; 5600 FILE *fp; 5601 5602 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid); 5603 fp = fopen(proc_name, "r"); 5604 if (fp == NULL) return -1; 5605 statlen = fread(stat, 1, 2047, fp); 5606 stat[statlen] = '\0'; 5607 fclose(fp); 5608 5609 // Skip pid and the command string. Note that we could be dealing with 5610 // weird command names, e.g. user could decide to rename java launcher 5611 // to "java 1.4.2 :)", then the stat file would look like 5612 // 1234 (java 1.4.2 :)) R ... ... 5613 // We don't really need to know the command string, just find the last 5614 // occurrence of ")" and then start parsing from there. See bug 4726580. 5615 s = strrchr(stat, ')'); 5616 if (s == NULL) return -1; 5617 5618 // Skip blank chars 5619 do { s++; } while (s && isspace(*s)); 5620 5621 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 5622 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 5623 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 5624 &user_time, &sys_time); 5625 if (count != 13) return -1; 5626 if (user_sys_cpu_time) { 5627 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 5628 } else { 5629 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 5630 } 5631 } 5632 5633 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5634 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5635 info_ptr->may_skip_backward = false; // elapsed time not wall time 5636 info_ptr->may_skip_forward = false; // elapsed time not wall time 5637 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5638 } 5639 5640 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5641 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5642 info_ptr->may_skip_backward = false; // elapsed time not wall time 5643 info_ptr->may_skip_forward = false; // elapsed time not wall time 5644 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5645 } 5646 5647 bool os::is_thread_cpu_time_supported() { 5648 return true; 5649 } 5650 5651 // System loadavg support. Returns -1 if load average cannot be obtained. 5652 // Linux doesn't yet have a (official) notion of processor sets, 5653 // so just return the system wide load average. 5654 int os::loadavg(double loadavg[], int nelem) { 5655 return ::getloadavg(loadavg, nelem); 5656 } 5657 5658 void os::pause() { 5659 char filename[MAX_PATH]; 5660 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 5661 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile); 5662 } else { 5663 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 5664 } 5665 5666 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 5667 if (fd != -1) { 5668 struct stat buf; 5669 ::close(fd); 5670 while (::stat(filename, &buf) == 0) { 5671 (void)::poll(NULL, 0, 100); 5672 } 5673 } else { 5674 jio_fprintf(stderr, 5675 "Could not open pause file '%s', continuing immediately.\n", filename); 5676 } 5677 } 5678 5679 extern char** environ; 5680 5681 // Run the specified command in a separate process. Return its exit value, 5682 // or -1 on failure (e.g. can't fork a new process). 5683 // Unlike system(), this function can be called from signal handler. It 5684 // doesn't block SIGINT et al. 5685 int os::fork_and_exec(char* cmd, bool use_vfork_if_available) { 5686 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5687 5688 pid_t pid ; 5689 5690 if (use_vfork_if_available) { 5691 pid = vfork(); 5692 } else { 5693 pid = fork(); 5694 } 5695 5696 if (pid < 0) { 5697 // fork failed 5698 return -1; 5699 5700 } else if (pid == 0) { 5701 // child process 5702 5703 execve("/bin/sh", (char* const*)argv, environ); 5704 5705 // execve failed 5706 _exit(-1); 5707 5708 } else { 5709 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5710 // care about the actual exit code, for now. 5711 5712 int status; 5713 5714 // Wait for the child process to exit. This returns immediately if 5715 // the child has already exited. */ 5716 while (waitpid(pid, &status, 0) < 0) { 5717 switch (errno) { 5718 case ECHILD: return 0; 5719 case EINTR: break; 5720 default: return -1; 5721 } 5722 } 5723 5724 if (WIFEXITED(status)) { 5725 // The child exited normally; get its exit code. 5726 return WEXITSTATUS(status); 5727 } else if (WIFSIGNALED(status)) { 5728 // The child exited because of a signal 5729 // The best value to return is 0x80 + signal number, 5730 // because that is what all Unix shells do, and because 5731 // it allows callers to distinguish between process exit and 5732 // process death by signal. 5733 return 0x80 + WTERMSIG(status); 5734 } else { 5735 // Unknown exit code; pass it through 5736 return status; 5737 } 5738 } 5739 } 5740 5741 // Get the default path to the core file 5742 // Returns the length of the string 5743 int os::get_core_path(char* buffer, size_t bufferSize) { 5744 /* 5745 * Max length of /proc/sys/kernel/core_pattern is 128 characters. 5746 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt 5747 */ 5748 const int core_pattern_len = 129; 5749 char core_pattern[core_pattern_len] = {0}; 5750 5751 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY); 5752 if (core_pattern_file == -1) { 5753 return -1; 5754 } 5755 5756 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len); 5757 ::close(core_pattern_file); 5758 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') { 5759 return -1; 5760 } 5761 if (core_pattern[ret-1] == '\n') { 5762 core_pattern[ret-1] = '\0'; 5763 } else { 5764 core_pattern[ret] = '\0'; 5765 } 5766 5767 // Replace the %p in the core pattern with the process id. NOTE: we do this 5768 // only if the pattern doesn't start with "|", and we support only one %p in 5769 // the pattern. 5770 char *pid_pos = strstr(core_pattern, "%p"); 5771 const char* tail = (pid_pos != NULL) ? (pid_pos + 2) : ""; // skip over the "%p" 5772 int written; 5773 5774 if (core_pattern[0] == '/') { 5775 if (pid_pos != NULL) { 5776 *pid_pos = '\0'; 5777 written = jio_snprintf(buffer, bufferSize, "%s%d%s", core_pattern, 5778 current_process_id(), tail); 5779 } else { 5780 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern); 5781 } 5782 } else { 5783 char cwd[PATH_MAX]; 5784 5785 const char* p = get_current_directory(cwd, PATH_MAX); 5786 if (p == NULL) { 5787 return -1; 5788 } 5789 5790 if (core_pattern[0] == '|') { 5791 written = jio_snprintf(buffer, bufferSize, 5792 "\"%s\" (or dumping to %s/core.%d)", 5793 &core_pattern[1], p, current_process_id()); 5794 } else if (pid_pos != NULL) { 5795 *pid_pos = '\0'; 5796 written = jio_snprintf(buffer, bufferSize, "%s/%s%d%s", p, core_pattern, 5797 current_process_id(), tail); 5798 } else { 5799 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern); 5800 } 5801 } 5802 5803 if (written < 0) { 5804 return -1; 5805 } 5806 5807 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) { 5808 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY); 5809 5810 if (core_uses_pid_file != -1) { 5811 char core_uses_pid = 0; 5812 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1); 5813 ::close(core_uses_pid_file); 5814 5815 if (core_uses_pid == '1') { 5816 jio_snprintf(buffer + written, bufferSize - written, 5817 ".%d", current_process_id()); 5818 } 5819 } 5820 } 5821 5822 return strlen(buffer); 5823 } 5824 5825 bool os::start_debugging(char *buf, int buflen) { 5826 int len = (int)strlen(buf); 5827 char *p = &buf[len]; 5828 5829 jio_snprintf(p, buflen-len, 5830 "\n\n" 5831 "Do you want to debug the problem?\n\n" 5832 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n" 5833 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n" 5834 "Otherwise, press RETURN to abort...", 5835 os::current_process_id(), os::current_process_id(), 5836 os::current_thread_id(), os::current_thread_id()); 5837 5838 bool yes = os::message_box("Unexpected Error", buf); 5839 5840 if (yes) { 5841 // yes, user asked VM to launch debugger 5842 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d", 5843 os::current_process_id(), os::current_process_id()); 5844 5845 os::fork_and_exec(buf); 5846 yes = false; 5847 } 5848 return yes; 5849 } 5850 5851 5852 // Java/Compiler thread: 5853 // 5854 // Low memory addresses 5855 // P0 +------------------------+ 5856 // | |\ Java thread created by VM does not have glibc 5857 // | glibc guard page | - guard page, attached Java thread usually has 5858 // | |/ 1 glibc guard page. 5859 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 5860 // | |\ 5861 // | HotSpot Guard Pages | - red, yellow and reserved pages 5862 // | |/ 5863 // +------------------------+ JavaThread::stack_reserved_zone_base() 5864 // | |\ 5865 // | Normal Stack | - 5866 // | |/ 5867 // P2 +------------------------+ Thread::stack_base() 5868 // 5869 // Non-Java thread: 5870 // 5871 // Low memory addresses 5872 // P0 +------------------------+ 5873 // | |\ 5874 // | glibc guard page | - usually 1 page 5875 // | |/ 5876 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 5877 // | |\ 5878 // | Normal Stack | - 5879 // | |/ 5880 // P2 +------------------------+ Thread::stack_base() 5881 // 5882 // ** P1 (aka bottom) and size (P2 = P1 - size) are the address and stack size 5883 // returned from pthread_attr_getstack(). 5884 // ** Due to NPTL implementation error, linux takes the glibc guard page out 5885 // of the stack size given in pthread_attr. We work around this for 5886 // threads created by the VM. (We adapt bottom to be P1 and size accordingly.) 5887 // 5888 #ifndef ZERO 5889 static void current_stack_region(address * bottom, size_t * size) { 5890 if (os::is_primordial_thread()) { 5891 // primordial thread needs special handling because pthread_getattr_np() 5892 // may return bogus value. 5893 *bottom = os::Linux::initial_thread_stack_bottom(); 5894 *size = os::Linux::initial_thread_stack_size(); 5895 } else { 5896 pthread_attr_t attr; 5897 5898 int rslt = pthread_getattr_np(pthread_self(), &attr); 5899 5900 // JVM needs to know exact stack location, abort if it fails 5901 if (rslt != 0) { 5902 if (rslt == ENOMEM) { 5903 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np"); 5904 } else { 5905 fatal("pthread_getattr_np failed with error = %d", rslt); 5906 } 5907 } 5908 5909 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) { 5910 fatal("Cannot locate current stack attributes!"); 5911 } 5912 5913 // Work around NPTL stack guard error. 5914 size_t guard_size = 0; 5915 rslt = pthread_attr_getguardsize(&attr, &guard_size); 5916 if (rslt != 0) { 5917 fatal("pthread_attr_getguardsize failed with error = %d", rslt); 5918 } 5919 *bottom += guard_size; 5920 *size -= guard_size; 5921 5922 pthread_attr_destroy(&attr); 5923 5924 } 5925 assert(os::current_stack_pointer() >= *bottom && 5926 os::current_stack_pointer() < *bottom + *size, "just checking"); 5927 } 5928 5929 address os::current_stack_base() { 5930 address bottom; 5931 size_t size; 5932 current_stack_region(&bottom, &size); 5933 return (bottom + size); 5934 } 5935 5936 size_t os::current_stack_size() { 5937 // This stack size includes the usable stack and HotSpot guard pages 5938 // (for the threads that have Hotspot guard pages). 5939 address bottom; 5940 size_t size; 5941 current_stack_region(&bottom, &size); 5942 return size; 5943 } 5944 #endif 5945 5946 static inline struct timespec get_mtime(const char* filename) { 5947 struct stat st; 5948 int ret = os::stat(filename, &st); 5949 assert(ret == 0, "failed to stat() file '%s': %s", filename, strerror(errno)); 5950 return st.st_mtim; 5951 } 5952 5953 int os::compare_file_modified_times(const char* file1, const char* file2) { 5954 struct timespec filetime1 = get_mtime(file1); 5955 struct timespec filetime2 = get_mtime(file2); 5956 int diff = filetime1.tv_sec - filetime2.tv_sec; 5957 if (diff == 0) { 5958 return filetime1.tv_nsec - filetime2.tv_nsec; 5959 } 5960 return diff; 5961 } 5962 5963 /////////////// Unit tests /////////////// 5964 5965 #ifndef PRODUCT 5966 5967 class TestReserveMemorySpecial : AllStatic { 5968 public: 5969 static void small_page_write(void* addr, size_t size) { 5970 size_t page_size = os::vm_page_size(); 5971 5972 char* end = (char*)addr + size; 5973 for (char* p = (char*)addr; p < end; p += page_size) { 5974 *p = 1; 5975 } 5976 } 5977 5978 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) { 5979 if (!UseHugeTLBFS) { 5980 return; 5981 } 5982 5983 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false); 5984 5985 if (addr != NULL) { 5986 small_page_write(addr, size); 5987 5988 os::Linux::release_memory_special_huge_tlbfs(addr, size); 5989 } 5990 } 5991 5992 static void test_reserve_memory_special_huge_tlbfs_only() { 5993 if (!UseHugeTLBFS) { 5994 return; 5995 } 5996 5997 size_t lp = os::large_page_size(); 5998 5999 for (size_t size = lp; size <= lp * 10; size += lp) { 6000 test_reserve_memory_special_huge_tlbfs_only(size); 6001 } 6002 } 6003 6004 static void test_reserve_memory_special_huge_tlbfs_mixed() { 6005 size_t lp = os::large_page_size(); 6006 size_t ag = os::vm_allocation_granularity(); 6007 6008 // sizes to test 6009 const size_t sizes[] = { 6010 lp, lp + ag, lp + lp / 2, lp * 2, 6011 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2, 6012 lp * 10, lp * 10 + lp / 2 6013 }; 6014 const int num_sizes = sizeof(sizes) / sizeof(size_t); 6015 6016 // For each size/alignment combination, we test three scenarios: 6017 // 1) with req_addr == NULL 6018 // 2) with a non-null req_addr at which we expect to successfully allocate 6019 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we 6020 // expect the allocation to either fail or to ignore req_addr 6021 6022 // Pre-allocate two areas; they shall be as large as the largest allocation 6023 // and aligned to the largest alignment we will be testing. 6024 const size_t mapping_size = sizes[num_sizes - 1] * 2; 6025 char* const mapping1 = (char*) ::mmap(NULL, mapping_size, 6026 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6027 -1, 0); 6028 assert(mapping1 != MAP_FAILED, "should work"); 6029 6030 char* const mapping2 = (char*) ::mmap(NULL, mapping_size, 6031 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6032 -1, 0); 6033 assert(mapping2 != MAP_FAILED, "should work"); 6034 6035 // Unmap the first mapping, but leave the second mapping intact: the first 6036 // mapping will serve as a value for a "good" req_addr (case 2). The second 6037 // mapping, still intact, as "bad" req_addr (case 3). 6038 ::munmap(mapping1, mapping_size); 6039 6040 // Case 1 6041 for (int i = 0; i < num_sizes; i++) { 6042 const size_t size = sizes[i]; 6043 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6044 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false); 6045 if (p != NULL) { 6046 assert(is_aligned(p, alignment), "must be"); 6047 small_page_write(p, size); 6048 os::Linux::release_memory_special_huge_tlbfs(p, size); 6049 } 6050 } 6051 } 6052 6053 // Case 2 6054 for (int i = 0; i < num_sizes; i++) { 6055 const size_t size = sizes[i]; 6056 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6057 char* const req_addr = align_up(mapping1, alignment); 6058 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6059 if (p != NULL) { 6060 assert(p == req_addr, "must be"); 6061 small_page_write(p, size); 6062 os::Linux::release_memory_special_huge_tlbfs(p, size); 6063 } 6064 } 6065 } 6066 6067 // Case 3 6068 for (int i = 0; i < num_sizes; i++) { 6069 const size_t size = sizes[i]; 6070 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6071 char* const req_addr = align_up(mapping2, alignment); 6072 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6073 // as the area around req_addr contains already existing mappings, the API should always 6074 // return NULL (as per contract, it cannot return another address) 6075 assert(p == NULL, "must be"); 6076 } 6077 } 6078 6079 ::munmap(mapping2, mapping_size); 6080 6081 } 6082 6083 static void test_reserve_memory_special_huge_tlbfs() { 6084 if (!UseHugeTLBFS) { 6085 return; 6086 } 6087 6088 test_reserve_memory_special_huge_tlbfs_only(); 6089 test_reserve_memory_special_huge_tlbfs_mixed(); 6090 } 6091 6092 static void test_reserve_memory_special_shm(size_t size, size_t alignment) { 6093 if (!UseSHM) { 6094 return; 6095 } 6096 6097 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false); 6098 6099 if (addr != NULL) { 6100 assert(is_aligned(addr, alignment), "Check"); 6101 assert(is_aligned(addr, os::large_page_size()), "Check"); 6102 6103 small_page_write(addr, size); 6104 6105 os::Linux::release_memory_special_shm(addr, size); 6106 } 6107 } 6108 6109 static void test_reserve_memory_special_shm() { 6110 size_t lp = os::large_page_size(); 6111 size_t ag = os::vm_allocation_granularity(); 6112 6113 for (size_t size = ag; size < lp * 3; size += ag) { 6114 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) { 6115 test_reserve_memory_special_shm(size, alignment); 6116 } 6117 } 6118 } 6119 6120 static void test() { 6121 test_reserve_memory_special_huge_tlbfs(); 6122 test_reserve_memory_special_shm(); 6123 } 6124 }; 6125 6126 void TestReserveMemorySpecial_test() { 6127 TestReserveMemorySpecial::test(); 6128 } 6129 6130 #endif