1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- 2 * vim: sw=2 ts=4 et : 3 */ 4 /* This Source Code Form is subject to the terms of the Mozilla Public 5 * License, v. 2.0. If a copy of the MPL was not distributed with this 6 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ 7 8 #include "mozilla/mozalloc_abort.h" 9 #include "mozilla/mozalloc_oom.h" 10 #include "mozilla/Assertions.h" 11 12 #define OOM_MSG_LEADER "out of memory: 0x" 13 #define OOM_MSG_DIGITS "0000000000000000" // large enough for 2^64 14 #define OOM_MSG_TRAILER " bytes requested" 15 #define OOM_MSG_FIRST_DIGIT_OFFSET sizeof(OOM_MSG_LEADER) - 1 16 #define OOM_MSG_LAST_DIGIT_OFFSET \ 17 sizeof(OOM_MSG_LEADER) + sizeof(OOM_MSG_DIGITS) - 3 18 19 MFBT_DATA size_t gOOMAllocationSize = 0; 20 21 static const char* hex = "0123456789ABCDEF"; 22 mozalloc_handle_oom(size_t size)23void mozalloc_handle_oom(size_t size) { 24 char oomMsg[] = OOM_MSG_LEADER OOM_MSG_DIGITS OOM_MSG_TRAILER; 25 size_t i; 26 27 // NB: this is handle_oom() stage 1, which simply aborts on OOM. 28 // we might proceed to a stage 2 in which an attempt is made to 29 // reclaim memory 30 // Warning: when stage 2 is done by, for example, notifying 31 // "memory-pressure" synchronously, please audit all 32 // nsExpirationTrackers and ensure that the actions they take 33 // on memory-pressure notifications (via NotifyExpired) are safe. 34 // Note that Document::SelectorCache::NotifyExpired is _known_ 35 // to not be safe: it will delete the selector it's caching, 36 // which might be in use at the time under querySelector or 37 // querySelectorAll. 38 39 gOOMAllocationSize = size; 40 41 static_assert(OOM_MSG_FIRST_DIGIT_OFFSET > 0, 42 "Loop below will never terminate (i can't go below 0)"); 43 44 // Insert size into the diagnostic message using only primitive operations 45 for (i = OOM_MSG_LAST_DIGIT_OFFSET; size && i >= OOM_MSG_FIRST_DIGIT_OFFSET; 46 i--) { 47 oomMsg[i] = hex[size % 16]; 48 size /= 16; 49 } 50 51 mozalloc_abort(oomMsg); 52 } 53