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| 1 /* | 1 // Copyright (c) 2013 The Chromium Authors. All rights reserved. |
| 2 * Copyright (C) 2013 Google Inc. All rights reserved. | 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 * | 3 // found in the LICENSE file. |
| 4 * Redistribution and use in source and binary forms, with or without | |
| 5 * modification, are permitted provided that the following conditions are | |
| 6 * met: | |
| 7 * | |
| 8 * * Redistributions of source code must retain the above copyright | |
| 9 * notice, this list of conditions and the following disclaimer. | |
| 10 * * Redistributions in binary form must reproduce the above | |
| 11 * copyright notice, this list of conditions and the following disclaimer | |
| 12 * in the documentation and/or other materials provided with the | |
| 13 * distribution. | |
| 14 * * Neither the name of Google Inc. nor the names of its | |
| 15 * contributors may be used to endorse or promote products derived from | |
| 16 * this software without specific prior written permission. | |
| 17 * | |
| 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
| 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
| 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
| 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | |
| 22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
| 23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
| 24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
| 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
| 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
| 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
| 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 29 */ | |
| 30 | 4 |
| 31 #include "wtf/allocator/PageAllocator.h" | 5 #include "base/allocator/partition_allocator/page_allocator.h" |
| 32 | |
| 33 #include "wtf/Assertions.h" | |
| 34 #include "wtf/Atomics.h" | |
| 35 #include "wtf/allocator/AddressSpaceRandomization.h" | |
| 36 | 6 |
| 37 #include <limits.h> | 7 #include <limits.h> |
| 38 | 8 |
| 39 #if OS(POSIX) | 9 #include "base/allocator/partition_allocator/address_space_randomization.h" |
| 10 #include "base/atomicops.h" |
| 11 #include "base/logging.h" |
| 12 #include "build/build_config.h" |
| 13 |
| 14 #if defined(OS_POSIX) |
| 40 | 15 |
| 41 #include <errno.h> | 16 #include <errno.h> |
| 42 #include <sys/mman.h> | 17 #include <sys/mman.h> |
| 43 | 18 |
| 44 #ifndef MADV_FREE | 19 #ifndef MADV_FREE |
| 45 #define MADV_FREE MADV_DONTNEED | 20 #define MADV_FREE MADV_DONTNEED |
| 46 #endif | 21 #endif |
| 47 | 22 |
| 48 #ifndef MAP_ANONYMOUS | 23 #ifndef MAP_ANONYMOUS |
| 49 #define MAP_ANONYMOUS MAP_ANON | 24 #define MAP_ANONYMOUS MAP_ANON |
| 50 #endif | 25 #endif |
| 51 | 26 |
| 52 // On POSIX memmap uses a nearby address if the hint address is blocked. | 27 // On POSIX |mmap| uses a nearby address if the hint address is blocked. |
| 53 static const bool kHintIsAdvisory = true; | 28 static const bool kHintIsAdvisory = true; |
| 54 static uint32_t s_allocPageErrorCode = 0; | 29 static volatile base::subtle::Atomic32 s_allocPageErrorCode = 0; |
| 55 | 30 |
| 56 #elif OS(WIN) | 31 #elif defined(OS_WIN) |
| 57 | 32 |
| 58 #include <windows.h> | 33 #include <windows.h> |
| 59 | 34 |
| 60 // VirtualAlloc will fail if allocation at the hint address is blocked. | 35 // |VirtualAlloc| will fail if allocation at the hint address is blocked. |
| 61 static const bool kHintIsAdvisory = false; | 36 static const bool kHintIsAdvisory = false; |
| 62 static uint32_t s_allocPageErrorCode = ERROR_SUCCESS; | 37 static base::subtle::Atomic32 s_allocPageErrorCode = ERROR_SUCCESS; |
| 63 | 38 |
| 64 #else | 39 #else |
| 65 #error Unknown OS | 40 #error Unknown OS |
| 66 #endif // OS(POSIX) | 41 #endif // defined(OS_POSIX) |
| 67 | 42 |
| 68 namespace WTF { | 43 namespace base { |
| 69 | 44 |
| 70 // This internal function wraps the OS-specific page allocation call. The | 45 // This internal function wraps the OS-specific page allocation call: |
| 71 // behavior of the hint address is determined by the kHintIsAdvisory constant. | 46 // |VirtualAlloc| on Windows, and |mmap| on POSIX. |
| 72 // If true, a non-zero hint is advisory and the returned address may differ from | |
| 73 // the hint. If false, the hint is mandatory and a successful allocation will | |
| 74 // not differ from the hint. | |
| 75 static void* systemAllocPages( | 47 static void* systemAllocPages( |
| 76 void* hint, | 48 void* hint, |
| 77 size_t len, | 49 size_t len, |
| 78 PageAccessibilityConfiguration pageAccessibility) { | 50 PageAccessibilityConfiguration pageAccessibility) { |
| 79 ASSERT(!(len & kPageAllocationGranularityOffsetMask)); | 51 DCHECK(!(len & kPageAllocationGranularityOffsetMask)); |
| 80 ASSERT(!(reinterpret_cast<uintptr_t>(hint) & | 52 DCHECK(!(reinterpret_cast<uintptr_t>(hint) & |
| 81 kPageAllocationGranularityOffsetMask)); | 53 kPageAllocationGranularityOffsetMask)); |
| 82 void* ret; | 54 void* ret; |
| 83 #if OS(WIN) | 55 #if defined(OS_WIN) |
| 84 DWORD accessFlag = | 56 DWORD accessFlag = |
| 85 pageAccessibility == PageAccessible ? PAGE_READWRITE : PAGE_NOACCESS; | 57 pageAccessibility == PageAccessible ? PAGE_READWRITE : PAGE_NOACCESS; |
| 86 ret = VirtualAlloc(hint, len, MEM_RESERVE | MEM_COMMIT, accessFlag); | 58 ret = VirtualAlloc(hint, len, MEM_RESERVE | MEM_COMMIT, accessFlag); |
| 87 if (!ret) | 59 if (!ret) |
| 88 releaseStore(&s_allocPageErrorCode, GetLastError()); | 60 base::subtle::Release_Store(&s_allocPageErrorCode, GetLastError()); |
| 89 #else | 61 #else |
| 90 int accessFlag = pageAccessibility == PageAccessible | 62 int accessFlag = pageAccessibility == PageAccessible |
| 91 ? (PROT_READ | PROT_WRITE) | 63 ? (PROT_READ | PROT_WRITE) |
| 92 : PROT_NONE; | 64 : PROT_NONE; |
| 93 ret = mmap(hint, len, accessFlag, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); | 65 ret = mmap(hint, len, accessFlag, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); |
| 94 if (ret == MAP_FAILED) { | 66 if (ret == MAP_FAILED) { |
| 95 releaseStore(&s_allocPageErrorCode, errno); | 67 base::subtle::Release_Store(&s_allocPageErrorCode, errno); |
| 96 ret = 0; | 68 ret = 0; |
| 97 } | 69 } |
| 98 #endif | 70 #endif |
| 99 return ret; | 71 return ret; |
| 100 } | 72 } |
| 101 | 73 |
| 102 // Trims base to given length and alignment. Windows returns null on failure and | 74 // Trims base to given length and alignment. Windows returns null on failure and |
| 103 // frees base. | 75 // frees base. |
| 104 static void* trimMapping(void* base, | 76 static void* trimMapping(void* base, |
| 105 size_t baseLen, | 77 size_t baseLen, |
| 106 size_t trimLen, | 78 size_t trimLen, |
| 107 uintptr_t align, | 79 uintptr_t align, |
| 108 PageAccessibilityConfiguration pageAccessibility) { | 80 PageAccessibilityConfiguration pageAccessibility) { |
| 109 size_t preSlack = reinterpret_cast<uintptr_t>(base) & (align - 1); | 81 size_t preSlack = reinterpret_cast<uintptr_t>(base) & (align - 1); |
| 110 if (preSlack) | 82 if (preSlack) |
| 111 preSlack = align - preSlack; | 83 preSlack = align - preSlack; |
| 112 size_t postSlack = baseLen - preSlack - trimLen; | 84 size_t postSlack = baseLen - preSlack - trimLen; |
| 113 ASSERT(baseLen >= trimLen || preSlack || postSlack); | 85 DCHECK(baseLen >= trimLen || preSlack || postSlack); |
| 114 ASSERT(preSlack < baseLen); | 86 DCHECK(preSlack < baseLen); |
| 115 ASSERT(postSlack < baseLen); | 87 DCHECK(postSlack < baseLen); |
| 116 void* ret = base; | 88 void* ret = base; |
| 117 | 89 |
| 118 #if OS(POSIX) // On POSIX we can resize the allocation run. | 90 #if defined(OS_POSIX) // On POSIX we can resize the allocation run. |
| 119 (void)pageAccessibility; | 91 (void)pageAccessibility; |
| 120 if (preSlack) { | 92 if (preSlack) { |
| 121 int res = munmap(base, preSlack); | 93 int res = munmap(base, preSlack); |
| 122 RELEASE_ASSERT(!res); | 94 CHECK(!res); |
| 123 ret = reinterpret_cast<char*>(base) + preSlack; | 95 ret = reinterpret_cast<char*>(base) + preSlack; |
| 124 } | 96 } |
| 125 if (postSlack) { | 97 if (postSlack) { |
| 126 int res = munmap(reinterpret_cast<char*>(ret) + trimLen, postSlack); | 98 int res = munmap(reinterpret_cast<char*>(ret) + trimLen, postSlack); |
| 127 RELEASE_ASSERT(!res); | 99 CHECK(!res); |
| 128 } | 100 } |
| 129 #else // On Windows we can't resize the allocation run. | 101 #else // On Windows we can't resize the allocation run. |
| 130 if (preSlack || postSlack) { | 102 if (preSlack || postSlack) { |
| 131 ret = reinterpret_cast<char*>(base) + preSlack; | 103 ret = reinterpret_cast<char*>(base) + preSlack; |
| 132 freePages(base, baseLen); | 104 freePages(base, baseLen); |
| 133 ret = systemAllocPages(ret, trimLen, pageAccessibility); | 105 ret = systemAllocPages(ret, trimLen, pageAccessibility); |
| 134 } | 106 } |
| 135 #endif | 107 #endif |
| 136 | 108 |
| 137 return ret; | 109 return ret; |
| 138 } | 110 } |
| 139 | 111 |
| 140 void* allocPages(void* addr, | 112 void* allocPages(void* addr, |
| 141 size_t len, | 113 size_t len, |
| 142 size_t align, | 114 size_t align, |
| 143 PageAccessibilityConfiguration pageAccessibility) { | 115 PageAccessibilityConfiguration pageAccessibility) { |
| 144 ASSERT(len >= kPageAllocationGranularity); | 116 DCHECK(len >= kPageAllocationGranularity); |
| 145 ASSERT(!(len & kPageAllocationGranularityOffsetMask)); | 117 DCHECK(!(len & kPageAllocationGranularityOffsetMask)); |
| 146 ASSERT(align >= kPageAllocationGranularity); | 118 DCHECK(align >= kPageAllocationGranularity); |
| 147 ASSERT(!(align & kPageAllocationGranularityOffsetMask)); | 119 DCHECK(!(align & kPageAllocationGranularityOffsetMask)); |
| 148 ASSERT(!(reinterpret_cast<uintptr_t>(addr) & | 120 DCHECK(!(reinterpret_cast<uintptr_t>(addr) & |
| 149 kPageAllocationGranularityOffsetMask)); | 121 kPageAllocationGranularityOffsetMask)); |
| 150 uintptr_t alignOffsetMask = align - 1; | 122 uintptr_t alignOffsetMask = align - 1; |
| 151 uintptr_t alignBaseMask = ~alignOffsetMask; | 123 uintptr_t alignBaseMask = ~alignOffsetMask; |
| 152 ASSERT(!(reinterpret_cast<uintptr_t>(addr) & alignOffsetMask)); | 124 DCHECK(!(reinterpret_cast<uintptr_t>(addr) & alignOffsetMask)); |
| 153 | 125 |
| 154 // If the client passed null as the address, choose a good one. | 126 // If the client passed null as the address, choose a good one. |
| 155 if (!addr) { | 127 if (!addr) { |
| 156 addr = getRandomPageBase(); | 128 addr = getRandomPageBase(); |
| 157 addr = reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(addr) & | 129 addr = reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(addr) & |
| 158 alignBaseMask); | 130 alignBaseMask); |
| 159 } | 131 } |
| 160 | 132 |
| 161 // First try to force an exact-size, aligned allocation from our random base. | 133 // First try to force an exact-size, aligned allocation from our random base. |
| 162 for (int count = 0; count < 3; ++count) { | 134 for (int count = 0; count < 3; ++count) { |
| 163 void* ret = systemAllocPages(addr, len, pageAccessibility); | 135 void* ret = systemAllocPages(addr, len, pageAccessibility); |
| 164 if (kHintIsAdvisory || ret) { | 136 if (kHintIsAdvisory || ret) { |
| 165 // If the alignment is to our liking, we're done. | 137 // If the alignment is to our liking, we're done. |
| 166 if (!(reinterpret_cast<uintptr_t>(ret) & alignOffsetMask)) | 138 if (!(reinterpret_cast<uintptr_t>(ret) & alignOffsetMask)) |
| 167 return ret; | 139 return ret; |
| 168 freePages(ret, len); | 140 freePages(ret, len); |
| 169 #if CPU(32BIT) | 141 #if defined(ARCH_CPU_32_BITS) |
| 170 addr = reinterpret_cast<void*>( | 142 addr = reinterpret_cast<void*>( |
| 171 (reinterpret_cast<uintptr_t>(ret) + align) & alignBaseMask); | 143 (reinterpret_cast<uintptr_t>(ret) + align) & alignBaseMask); |
| 172 #endif | 144 #endif |
| 173 } else if (!addr) { // We know we're OOM when an unhinted allocation fails. | 145 } else if (!addr) { // We know we're OOM when an unhinted allocation fails. |
| 174 return nullptr; | 146 return nullptr; |
| 175 | 147 |
| 176 } else { | 148 } else { |
| 177 #if CPU(32BIT) | 149 #if defined(ARCH_CPU_32_BITS) |
| 178 addr = reinterpret_cast<char*>(addr) + align; | 150 addr = reinterpret_cast<char*>(addr) + align; |
| 179 #endif | 151 #endif |
| 180 } | 152 } |
| 181 | 153 |
| 182 #if !CPU(32BIT) | 154 #if !defined(ARCH_CPU_32_BITS) |
| 183 // Keep trying random addresses on systems that have a large address space. | 155 // Keep trying random addresses on systems that have a large address space. |
| 184 addr = getRandomPageBase(); | 156 addr = getRandomPageBase(); |
| 185 addr = reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(addr) & | 157 addr = reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(addr) & |
| 186 alignBaseMask); | 158 alignBaseMask); |
| 187 #endif | 159 #endif |
| 188 } | 160 } |
| 189 | 161 |
| 190 // Map a larger allocation so we can force alignment, but continue randomizing | 162 // Map a larger allocation so we can force alignment, but continue randomizing |
| 191 // only on 64-bit POSIX. | 163 // only on 64-bit POSIX. |
| 192 size_t tryLen = len + (align - kPageAllocationGranularity); | 164 size_t tryLen = len + (align - kPageAllocationGranularity); |
| 193 RELEASE_ASSERT(tryLen >= len); | 165 CHECK(tryLen >= len); |
| 194 void* ret; | 166 void* ret; |
| 195 | 167 |
| 196 do { | 168 do { |
| 197 // Don't continue to burn cycles on mandatory hints (Windows). | 169 // Don't continue to burn cycles on mandatory hints (Windows). |
| 198 addr = kHintIsAdvisory ? getRandomPageBase() : nullptr; | 170 addr = kHintIsAdvisory ? getRandomPageBase() : nullptr; |
| 199 ret = systemAllocPages(addr, tryLen, pageAccessibility); | 171 ret = systemAllocPages(addr, tryLen, pageAccessibility); |
| 200 // The retries are for Windows, where a race can steal our mapping on | 172 // The retries are for Windows, where a race can steal our mapping on |
| 201 // resize. | 173 // resize. |
| 202 } while (ret && | 174 } while (ret && |
| 203 !(ret = trimMapping(ret, tryLen, len, align, pageAccessibility))); | 175 !(ret = trimMapping(ret, tryLen, len, align, pageAccessibility))); |
| 204 | 176 |
| 205 return ret; | 177 return ret; |
| 206 } | 178 } |
| 207 | 179 |
| 208 void freePages(void* addr, size_t len) { | 180 void freePages(void* addr, size_t len) { |
| 209 ASSERT(!(reinterpret_cast<uintptr_t>(addr) & | 181 DCHECK(!(reinterpret_cast<uintptr_t>(addr) & |
| 210 kPageAllocationGranularityOffsetMask)); | 182 kPageAllocationGranularityOffsetMask)); |
| 211 ASSERT(!(len & kPageAllocationGranularityOffsetMask)); | 183 DCHECK(!(len & kPageAllocationGranularityOffsetMask)); |
| 212 #if OS(POSIX) | 184 #if defined(OS_POSIX) |
| 213 int ret = munmap(addr, len); | 185 int ret = munmap(addr, len); |
| 214 RELEASE_ASSERT(!ret); | 186 CHECK(!ret); |
| 215 #else | 187 #else |
| 216 BOOL ret = VirtualFree(addr, 0, MEM_RELEASE); | 188 BOOL ret = VirtualFree(addr, 0, MEM_RELEASE); |
| 217 RELEASE_ASSERT(ret); | 189 CHECK(ret); |
| 218 #endif | 190 #endif |
| 219 } | 191 } |
| 220 | 192 |
| 221 void setSystemPagesInaccessible(void* addr, size_t len) { | 193 void setSystemPagesInaccessible(void* addr, size_t len) { |
| 222 ASSERT(!(len & kSystemPageOffsetMask)); | 194 DCHECK(!(len & kSystemPageOffsetMask)); |
| 223 #if OS(POSIX) | 195 #if defined(OS_POSIX) |
| 224 int ret = mprotect(addr, len, PROT_NONE); | 196 int ret = mprotect(addr, len, PROT_NONE); |
| 225 RELEASE_ASSERT(!ret); | 197 CHECK(!ret); |
| 226 #else | 198 #else |
| 227 BOOL ret = VirtualFree(addr, len, MEM_DECOMMIT); | 199 BOOL ret = VirtualFree(addr, len, MEM_DECOMMIT); |
| 228 RELEASE_ASSERT(ret); | 200 CHECK(ret); |
| 229 #endif | 201 #endif |
| 230 } | 202 } |
| 231 | 203 |
| 232 bool setSystemPagesAccessible(void* addr, size_t len) { | 204 bool setSystemPagesAccessible(void* addr, size_t len) { |
| 233 ASSERT(!(len & kSystemPageOffsetMask)); | 205 DCHECK(!(len & kSystemPageOffsetMask)); |
| 234 #if OS(POSIX) | 206 #if defined(OS_POSIX) |
| 235 return !mprotect(addr, len, PROT_READ | PROT_WRITE); | 207 return !mprotect(addr, len, PROT_READ | PROT_WRITE); |
| 236 #else | 208 #else |
| 237 return !!VirtualAlloc(addr, len, MEM_COMMIT, PAGE_READWRITE); | 209 return !!VirtualAlloc(addr, len, MEM_COMMIT, PAGE_READWRITE); |
| 238 #endif | 210 #endif |
| 239 } | 211 } |
| 240 | 212 |
| 241 void decommitSystemPages(void* addr, size_t len) { | 213 void decommitSystemPages(void* addr, size_t len) { |
| 242 ASSERT(!(len & kSystemPageOffsetMask)); | 214 DCHECK(!(len & kSystemPageOffsetMask)); |
| 243 #if OS(POSIX) | 215 #if defined(OS_POSIX) |
| 244 int ret = madvise(addr, len, MADV_FREE); | 216 int ret = madvise(addr, len, MADV_FREE); |
| 245 RELEASE_ASSERT(!ret); | 217 CHECK(!ret); |
| 246 #else | 218 #else |
| 247 setSystemPagesInaccessible(addr, len); | 219 setSystemPagesInaccessible(addr, len); |
| 248 #endif | 220 #endif |
| 249 } | 221 } |
| 250 | 222 |
| 251 void recommitSystemPages(void* addr, size_t len) { | 223 void recommitSystemPages(void* addr, size_t len) { |
| 252 ASSERT(!(len & kSystemPageOffsetMask)); | 224 DCHECK(!(len & kSystemPageOffsetMask)); |
| 253 #if OS(POSIX) | 225 #if defined(OS_POSIX) |
| 254 (void)addr; | 226 (void)addr; |
| 255 #else | 227 #else |
| 256 RELEASE_ASSERT(setSystemPagesAccessible(addr, len)); | 228 CHECK(setSystemPagesAccessible(addr, len)); |
| 257 #endif | 229 #endif |
| 258 } | 230 } |
| 259 | 231 |
| 260 void discardSystemPages(void* addr, size_t len) { | 232 void discardSystemPages(void* addr, size_t len) { |
| 261 ASSERT(!(len & kSystemPageOffsetMask)); | 233 DCHECK(!(len & kSystemPageOffsetMask)); |
| 262 #if OS(POSIX) | 234 #if defined(OS_POSIX) |
| 263 // On POSIX, the implementation detail is that discard and decommit are the | 235 // On POSIX, the implementation detail is that discard and decommit are the |
| 264 // same, and lead to pages that are returned to the system immediately and | 236 // same, and lead to pages that are returned to the system immediately and |
| 265 // get replaced with zeroed pages when touched. So we just call | 237 // get replaced with zeroed pages when touched. So we just call |
| 266 // decommitSystemPages() here to avoid code duplication. | 238 // decommitSystemPages() here to avoid code duplication. |
| 267 decommitSystemPages(addr, len); | 239 decommitSystemPages(addr, len); |
| 268 #else | 240 #else |
| 269 // On Windows discarded pages are not returned to the system immediately and | 241 // On Windows discarded pages are not returned to the system immediately and |
| 270 // not guaranteed to be zeroed when returned to the application. | 242 // not guaranteed to be zeroed when returned to the application. |
| 271 using DiscardVirtualMemoryFunction = | 243 using DiscardVirtualMemoryFunction = |
| 272 DWORD(WINAPI*)(PVOID virtualAddress, SIZE_T size); | 244 DWORD(WINAPI*)(PVOID virtualAddress, SIZE_T size); |
| 273 static DiscardVirtualMemoryFunction discardVirtualMemory = | 245 static DiscardVirtualMemoryFunction discardVirtualMemory = |
| 274 reinterpret_cast<DiscardVirtualMemoryFunction>(-1); | 246 reinterpret_cast<DiscardVirtualMemoryFunction>(-1); |
| 275 if (discardVirtualMemory == | 247 if (discardVirtualMemory == |
| 276 reinterpret_cast<DiscardVirtualMemoryFunction>(-1)) | 248 reinterpret_cast<DiscardVirtualMemoryFunction>(-1)) |
| 277 discardVirtualMemory = | 249 discardVirtualMemory = |
| 278 reinterpret_cast<DiscardVirtualMemoryFunction>(GetProcAddress( | 250 reinterpret_cast<DiscardVirtualMemoryFunction>(GetProcAddress( |
| 279 GetModuleHandle(L"Kernel32.dll"), "DiscardVirtualMemory")); | 251 GetModuleHandle(L"Kernel32.dll"), "DiscardVirtualMemory")); |
| 280 // Use DiscardVirtualMemory when available because it releases faster than | 252 // Use DiscardVirtualMemory when available because it releases faster than |
| 281 // MEM_RESET. | 253 // MEM_RESET. |
| 282 DWORD ret = 1; | 254 DWORD ret = 1; |
| 283 if (discardVirtualMemory) | 255 if (discardVirtualMemory) |
| 284 ret = discardVirtualMemory(addr, len); | 256 ret = discardVirtualMemory(addr, len); |
| 285 // DiscardVirtualMemory is buggy in Win10 SP0, so fall back to MEM_RESET on | 257 // DiscardVirtualMemory is buggy in Win10 SP0, so fall back to MEM_RESET on |
| 286 // failure. | 258 // failure. |
| 287 if (ret) { | 259 if (ret) { |
| 288 void* ret = VirtualAlloc(addr, len, MEM_RESET, PAGE_READWRITE); | 260 void* ret = VirtualAlloc(addr, len, MEM_RESET, PAGE_READWRITE); |
| 289 RELEASE_ASSERT(ret); | 261 CHECK(ret); |
| 290 } | 262 } |
| 291 #endif | 263 #endif |
| 292 } | 264 } |
| 293 | 265 |
| 294 uint32_t getAllocPageErrorCode() { | 266 uint32_t getAllocPageErrorCode() { |
| 295 return acquireLoad(&s_allocPageErrorCode); | 267 return base::subtle::Acquire_Load(&s_allocPageErrorCode); |
| 296 } | 268 } |
| 297 | 269 |
| 298 } // namespace WTF | 270 } // namespace base |
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