| // Copyright (c) 2005, 2007, Google Inc. |
| // All rights reserved. |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following disclaimer |
| // in the documentation and/or other materials provided with the |
| // distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived from |
| // this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| // --- |
| // Author: Sanjay Ghemawat |
| |
| #include "config.h" |
| #if !(defined(USE_SYSTEM_MALLOC) && USE_SYSTEM_MALLOC) |
| #include "TCSystemAlloc.h" |
| |
| #include "Assertions.h" |
| #include "TCSpinLock.h" |
| #include "UnusedParam.h" |
| #include "VMTags.h" |
| #include <algorithm> |
| #include <stdint.h> |
| |
| #if OS(WINDOWS) |
| #include "windows.h" |
| #else |
| #include <errno.h> |
| #include <unistd.h> |
| #include <sys/mman.h> |
| #endif |
| |
| #ifndef MAP_ANONYMOUS |
| #define MAP_ANONYMOUS MAP_ANON |
| #endif |
| |
| using namespace std; |
| |
| // Structure for discovering alignment |
| union MemoryAligner { |
| void* p; |
| double d; |
| size_t s; |
| }; |
| |
| static SpinLock spinlock = SPINLOCK_INITIALIZER; |
| |
| // Page size is initialized on demand |
| static size_t pagesize = 0; |
| |
| // Configuration parameters. |
| // |
| // if use_devmem is true, either use_sbrk or use_mmap must also be true. |
| // For 2.2 kernels, it looks like the sbrk address space (500MBish) and |
| // the mmap address space (1300MBish) are disjoint, so we need both allocators |
| // to get as much virtual memory as possible. |
| #ifndef WTF_CHANGES |
| static bool use_devmem = false; |
| static bool use_sbrk = false; |
| #endif |
| |
| #if HAVE(MMAP) |
| static bool use_mmap = true; |
| #endif |
| |
| #if HAVE(VIRTUALALLOC) |
| static bool use_VirtualAlloc = true; |
| #endif |
| |
| // Flags to keep us from retrying allocators that failed. |
| static bool devmem_failure = false; |
| static bool sbrk_failure = false; |
| static bool mmap_failure = false; |
| static bool VirtualAlloc_failure = false; |
| |
| #ifndef WTF_CHANGES |
| DEFINE_int32(malloc_devmem_start, 0, |
| "Physical memory starting location in MB for /dev/mem allocation." |
| " Setting this to 0 disables /dev/mem allocation"); |
| DEFINE_int32(malloc_devmem_limit, 0, |
| "Physical memory limit location in MB for /dev/mem allocation." |
| " Setting this to 0 means no limit."); |
| #else |
| static const int32_t FLAGS_malloc_devmem_start = 0; |
| static const int32_t FLAGS_malloc_devmem_limit = 0; |
| #endif |
| |
| #ifndef WTF_CHANGES |
| |
| static void* TrySbrk(size_t size, size_t *actual_size, size_t alignment) { |
| size = ((size + alignment - 1) / alignment) * alignment; |
| |
| // could theoretically return the "extra" bytes here, but this |
| // is simple and correct. |
| if (actual_size) |
| *actual_size = size; |
| |
| void* result = sbrk(size); |
| if (result == reinterpret_cast<void*>(-1)) { |
| sbrk_failure = true; |
| return NULL; |
| } |
| |
| // Is it aligned? |
| uintptr_t ptr = reinterpret_cast<uintptr_t>(result); |
| if ((ptr & (alignment-1)) == 0) return result; |
| |
| // Try to get more memory for alignment |
| size_t extra = alignment - (ptr & (alignment-1)); |
| void* r2 = sbrk(extra); |
| if (reinterpret_cast<uintptr_t>(r2) == (ptr + size)) { |
| // Contiguous with previous result |
| return reinterpret_cast<void*>(ptr + extra); |
| } |
| |
| // Give up and ask for "size + alignment - 1" bytes so |
| // that we can find an aligned region within it. |
| result = sbrk(size + alignment - 1); |
| if (result == reinterpret_cast<void*>(-1)) { |
| sbrk_failure = true; |
| return NULL; |
| } |
| ptr = reinterpret_cast<uintptr_t>(result); |
| if ((ptr & (alignment-1)) != 0) { |
| ptr += alignment - (ptr & (alignment-1)); |
| } |
| return reinterpret_cast<void*>(ptr); |
| } |
| |
| #endif /* ifndef(WTF_CHANGES) */ |
| |
| #if HAVE(MMAP) |
| |
| static void* TryMmap(size_t size, size_t *actual_size, size_t alignment) { |
| // Enforce page alignment |
| if (pagesize == 0) pagesize = getpagesize(); |
| if (alignment < pagesize) alignment = pagesize; |
| size = ((size + alignment - 1) / alignment) * alignment; |
| |
| // could theoretically return the "extra" bytes here, but this |
| // is simple and correct. |
| if (actual_size) |
| *actual_size = size; |
| |
| // Ask for extra memory if alignment > pagesize |
| size_t extra = 0; |
| if (alignment > pagesize) { |
| extra = alignment - pagesize; |
| } |
| void* result = mmap(NULL, size + extra, |
| PROT_READ | PROT_WRITE, |
| MAP_PRIVATE|MAP_ANONYMOUS, |
| VM_TAG_FOR_TCMALLOC_MEMORY, 0); |
| if (result == reinterpret_cast<void*>(MAP_FAILED)) { |
| mmap_failure = true; |
| return NULL; |
| } |
| |
| // Adjust the return memory so it is aligned |
| uintptr_t ptr = reinterpret_cast<uintptr_t>(result); |
| size_t adjust = 0; |
| if ((ptr & (alignment - 1)) != 0) { |
| adjust = alignment - (ptr & (alignment - 1)); |
| } |
| |
| // Return the unused memory to the system |
| if (adjust > 0) { |
| munmap(reinterpret_cast<void*>(ptr), adjust); |
| } |
| if (adjust < extra) { |
| munmap(reinterpret_cast<void*>(ptr + adjust + size), extra - adjust); |
| } |
| |
| ptr += adjust; |
| return reinterpret_cast<void*>(ptr); |
| } |
| |
| #endif /* HAVE(MMAP) */ |
| |
| #if HAVE(VIRTUALALLOC) |
| |
| static void* TryVirtualAlloc(size_t size, size_t *actual_size, size_t alignment) { |
| // Enforce page alignment |
| if (pagesize == 0) { |
| SYSTEM_INFO system_info; |
| GetSystemInfo(&system_info); |
| pagesize = system_info.dwPageSize; |
| } |
| |
| if (alignment < pagesize) alignment = pagesize; |
| size = ((size + alignment - 1) / alignment) * alignment; |
| |
| // could theoretically return the "extra" bytes here, but this |
| // is simple and correct. |
| if (actual_size) |
| *actual_size = size; |
| |
| // Ask for extra memory if alignment > pagesize |
| size_t extra = 0; |
| if (alignment > pagesize) { |
| extra = alignment - pagesize; |
| } |
| void* result = VirtualAlloc(NULL, size + extra, |
| MEM_RESERVE | MEM_COMMIT | MEM_TOP_DOWN, |
| PAGE_READWRITE); |
| |
| if (result == NULL) { |
| VirtualAlloc_failure = true; |
| return NULL; |
| } |
| |
| // Adjust the return memory so it is aligned |
| uintptr_t ptr = reinterpret_cast<uintptr_t>(result); |
| size_t adjust = 0; |
| if ((ptr & (alignment - 1)) != 0) { |
| adjust = alignment - (ptr & (alignment - 1)); |
| } |
| |
| // Return the unused memory to the system - we'd like to release but the best we can do |
| // is decommit, since Windows only lets you free the whole allocation. |
| if (adjust > 0) { |
| VirtualFree(reinterpret_cast<void*>(ptr), adjust, MEM_DECOMMIT); |
| } |
| if (adjust < extra) { |
| VirtualFree(reinterpret_cast<void*>(ptr + adjust + size), extra-adjust, MEM_DECOMMIT); |
| } |
| |
| ptr += adjust; |
| return reinterpret_cast<void*>(ptr); |
| } |
| |
| #endif /* HAVE(MMAP) */ |
| |
| #ifndef WTF_CHANGES |
| static void* TryDevMem(size_t size, size_t *actual_size, size_t alignment) { |
| static bool initialized = false; |
| static off_t physmem_base; // next physical memory address to allocate |
| static off_t physmem_limit; // maximum physical address allowed |
| static int physmem_fd; // file descriptor for /dev/mem |
| |
| // Check if we should use /dev/mem allocation. Note that it may take |
| // a while to get this flag initialized, so meanwhile we fall back to |
| // the next allocator. (It looks like 7MB gets allocated before |
| // this flag gets initialized -khr.) |
| if (FLAGS_malloc_devmem_start == 0) { |
| // NOTE: not a devmem_failure - we'd like TCMalloc_SystemAlloc to |
| // try us again next time. |
| return NULL; |
| } |
| |
| if (!initialized) { |
| physmem_fd = open("/dev/mem", O_RDWR); |
| if (physmem_fd < 0) { |
| devmem_failure = true; |
| return NULL; |
| } |
| physmem_base = FLAGS_malloc_devmem_start*1024LL*1024LL; |
| physmem_limit = FLAGS_malloc_devmem_limit*1024LL*1024LL; |
| initialized = true; |
| } |
| |
| // Enforce page alignment |
| if (pagesize == 0) pagesize = getpagesize(); |
| if (alignment < pagesize) alignment = pagesize; |
| size = ((size + alignment - 1) / alignment) * alignment; |
| |
| // could theoretically return the "extra" bytes here, but this |
| // is simple and correct. |
| if (actual_size) |
| *actual_size = size; |
| |
| // Ask for extra memory if alignment > pagesize |
| size_t extra = 0; |
| if (alignment > pagesize) { |
| extra = alignment - pagesize; |
| } |
| |
| // check to see if we have any memory left |
| if (physmem_limit != 0 && physmem_base + size + extra > physmem_limit) { |
| devmem_failure = true; |
| return NULL; |
| } |
| void *result = mmap(0, size + extra, PROT_READ | PROT_WRITE, |
| MAP_SHARED, physmem_fd, physmem_base); |
| if (result == reinterpret_cast<void*>(MAP_FAILED)) { |
| devmem_failure = true; |
| return NULL; |
| } |
| uintptr_t ptr = reinterpret_cast<uintptr_t>(result); |
| |
| // Adjust the return memory so it is aligned |
| size_t adjust = 0; |
| if ((ptr & (alignment - 1)) != 0) { |
| adjust = alignment - (ptr & (alignment - 1)); |
| } |
| |
| // Return the unused virtual memory to the system |
| if (adjust > 0) { |
| munmap(reinterpret_cast<void*>(ptr), adjust); |
| } |
| if (adjust < extra) { |
| munmap(reinterpret_cast<void*>(ptr + adjust + size), extra - adjust); |
| } |
| |
| ptr += adjust; |
| physmem_base += adjust + size; |
| |
| return reinterpret_cast<void*>(ptr); |
| } |
| #endif |
| |
| void* TCMalloc_SystemAlloc(size_t size, size_t *actual_size, size_t alignment) { |
| // Discard requests that overflow |
| if (size + alignment < size) return NULL; |
| |
| SpinLockHolder lock_holder(&spinlock); |
| |
| // Enforce minimum alignment |
| if (alignment < sizeof(MemoryAligner)) alignment = sizeof(MemoryAligner); |
| |
| // Try twice, once avoiding allocators that failed before, and once |
| // more trying all allocators even if they failed before. |
| for (int i = 0; i < 2; i++) { |
| |
| #ifndef WTF_CHANGES |
| if (use_devmem && !devmem_failure) { |
| void* result = TryDevMem(size, actual_size, alignment); |
| if (result != NULL) return result; |
| } |
| |
| if (use_sbrk && !sbrk_failure) { |
| void* result = TrySbrk(size, actual_size, alignment); |
| if (result != NULL) return result; |
| } |
| #endif |
| |
| #if HAVE(MMAP) |
| if (use_mmap && !mmap_failure) { |
| void* result = TryMmap(size, actual_size, alignment); |
| if (result != NULL) return result; |
| } |
| #endif |
| |
| #if HAVE(VIRTUALALLOC) |
| if (use_VirtualAlloc && !VirtualAlloc_failure) { |
| void* result = TryVirtualAlloc(size, actual_size, alignment); |
| if (result != NULL) return result; |
| } |
| #endif |
| |
| // nothing worked - reset failure flags and try again |
| devmem_failure = false; |
| sbrk_failure = false; |
| mmap_failure = false; |
| VirtualAlloc_failure = false; |
| } |
| return NULL; |
| } |
| |
| #if HAVE(MADV_FREE_REUSE) |
| |
| void TCMalloc_SystemRelease(void* start, size_t length) |
| { |
| int madviseResult; |
| |
| while ((madviseResult = madvise(start, length, MADV_FREE_REUSABLE)) == -1 && errno == EAGAIN) { } |
| |
| // Although really advisory, if madvise fail, we want to know about it. |
| ASSERT_UNUSED(madviseResult, madviseResult != -1); |
| } |
| |
| #elif HAVE(MADV_FREE) || HAVE(MADV_DONTNEED) |
| |
| void TCMalloc_SystemRelease(void* start, size_t length) |
| { |
| // MADV_FREE clears the modified bit on pages, which allows |
| // them to be discarded immediately. |
| #if HAVE(MADV_FREE) |
| const int advice = MADV_FREE; |
| #else |
| const int advice = MADV_DONTNEED; |
| #endif |
| if (FLAGS_malloc_devmem_start) { |
| // It's not safe to use MADV_DONTNEED if we've been mapping |
| // /dev/mem for heap memory |
| return; |
| } |
| if (pagesize == 0) pagesize = getpagesize(); |
| const size_t pagemask = pagesize - 1; |
| |
| size_t new_start = reinterpret_cast<size_t>(start); |
| size_t end = new_start + length; |
| size_t new_end = end; |
| |
| // Round up the starting address and round down the ending address |
| // to be page aligned: |
| new_start = (new_start + pagesize - 1) & ~pagemask; |
| new_end = new_end & ~pagemask; |
| |
| ASSERT((new_start & pagemask) == 0); |
| ASSERT((new_end & pagemask) == 0); |
| ASSERT(new_start >= reinterpret_cast<size_t>(start)); |
| ASSERT(new_end <= end); |
| |
| if (new_end > new_start) { |
| // Note -- ignoring most return codes, because if this fails it |
| // doesn't matter... |
| while (madvise(reinterpret_cast<char*>(new_start), new_end - new_start, |
| advice) == -1 && |
| errno == EAGAIN) { |
| // NOP |
| } |
| } |
| } |
| |
| #elif HAVE(MMAP) |
| |
| void TCMalloc_SystemRelease(void* start, size_t length) |
| { |
| void* newAddress = mmap(start, length, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0); |
| // If the mmap failed then that's ok, we just won't return the memory to the system. |
| ASSERT_UNUSED(newAddress, newAddress == start || newAddress == reinterpret_cast<void*>(MAP_FAILED)); |
| } |
| |
| #elif HAVE(VIRTUALALLOC) |
| |
| void TCMalloc_SystemRelease(void* start, size_t length) |
| { |
| if (VirtualFree(start, length, MEM_DECOMMIT)) |
| return; |
| |
| // The decommit may fail if the memory region consists of allocations |
| // from more than one call to VirtualAlloc. In this case, fall back to |
| // using VirtualQuery to retrieve the allocation boundaries and decommit |
| // them each individually. |
| |
| char* ptr = static_cast<char*>(start); |
| char* end = ptr + length; |
| MEMORY_BASIC_INFORMATION info; |
| while (ptr < end) { |
| size_t resultSize = VirtualQuery(ptr, &info, sizeof(info)); |
| ASSERT_UNUSED(resultSize, resultSize == sizeof(info)); |
| |
| size_t decommitSize = min<size_t>(info.RegionSize, end - ptr); |
| BOOL success = VirtualFree(ptr, decommitSize, MEM_DECOMMIT); |
| ASSERT_UNUSED(success, success); |
| ptr += decommitSize; |
| } |
| } |
| |
| #else |
| |
| // Platforms that don't support returning memory use an empty inline version of TCMalloc_SystemRelease |
| // declared in TCSystemAlloc.h |
| |
| #endif |
| |
| #if HAVE(MADV_FREE_REUSE) |
| |
| void TCMalloc_SystemCommit(void* start, size_t length) |
| { |
| while (madvise(start, length, MADV_FREE_REUSE) == -1 && errno == EAGAIN) { } |
| } |
| |
| #elif HAVE(VIRTUALALLOC) |
| |
| void TCMalloc_SystemCommit(void* start, size_t length) |
| { |
| if (VirtualAlloc(start, length, MEM_COMMIT, PAGE_READWRITE) == start) |
| return; |
| |
| // The commit may fail if the memory region consists of allocations |
| // from more than one call to VirtualAlloc. In this case, fall back to |
| // using VirtualQuery to retrieve the allocation boundaries and commit them |
| // each individually. |
| |
| char* ptr = static_cast<char*>(start); |
| char* end = ptr + length; |
| MEMORY_BASIC_INFORMATION info; |
| while (ptr < end) { |
| size_t resultSize = VirtualQuery(ptr, &info, sizeof(info)); |
| ASSERT_UNUSED(resultSize, resultSize == sizeof(info)); |
| |
| size_t commitSize = min<size_t>(info.RegionSize, end - ptr); |
| void* newAddress = VirtualAlloc(ptr, commitSize, MEM_COMMIT, PAGE_READWRITE); |
| ASSERT_UNUSED(newAddress, newAddress == ptr); |
| ptr += commitSize; |
| } |
| } |
| |
| #else |
| |
| // Platforms that don't need to explicitly commit memory use an empty inline version of TCMalloc_SystemCommit |
| // declared in TCSystemAlloc.h |
| |
| #endif |
| |
| #endif // #if !(defined(USE_SYSTEM_MALLOC) && USE_SYSTEM_MALLOC) |
| |