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