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Diffstat (limited to 'trunk/src/memfs_malloc.cc')
| -rw-r--r-- | trunk/src/memfs_malloc.cc | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/trunk/src/memfs_malloc.cc b/trunk/src/memfs_malloc.cc new file mode 100644 index 0000000..9df4cad --- /dev/null +++ b/trunk/src/memfs_malloc.cc @@ -0,0 +1,234 @@ +// Copyright (c) 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: Arun Sharma +// +// A tcmalloc system allocator that uses a memory based filesystem such as +// tmpfs or hugetlbfs +// +// Since these only exist on linux, we only register this allocator there. + +#ifdef __linux + +#include <config.h> +#include <errno.h> +#include <fcntl.h> +#include <unistd.h> +#include <inttypes.h> +#include <sys/mman.h> +#include <sys/param.h> +#include <sys/types.h> +#include <sys/vfs.h> // for statfs +#include <string> + +#include "base/basictypes.h" +#include "base/googleinit.h" +#include "base/sysinfo.h" +#include "system-alloc.h" +#include "internal_logging.h" + +using std::string; + +DEFINE_string(memfs_malloc_path, EnvToString("TCMALLOC_MEMFS_MALLOC_PATH", ""), + "Path where hugetlbfs or tmpfs is mounted. The caller is " + "responsible for ensuring that the path is unique and does " + "not conflict with another process"); +DEFINE_int64(memfs_malloc_limit_mb, + EnvToInt("TCMALLOC_MEMFS_LIMIT_MB", 0), + "Limit total allocation size to the " + "specified number of MiB. 0 == no limit."); +DEFINE_bool(memfs_malloc_abort_on_fail, + EnvToBool("TCMALLOC_MEMFS_ABORT_ON_FAIL", false), + "abort() whenever memfs_malloc fails to satisfy an allocation " + "for any reason."); +DEFINE_bool(memfs_malloc_ignore_mmap_fail, + EnvToBool("TCMALLOC_MEMFS_IGNORE_MMAP_FAIL", false), + "Ignore failures from mmap"); + +// Hugetlbfs based allocator for tcmalloc +class HugetlbSysAllocator: public SysAllocator { +public: + HugetlbSysAllocator(int fd, int page_size) + : big_page_size_(page_size), + hugetlb_fd_(fd), + hugetlb_base_(0) { + } + + void* Alloc(size_t size, size_t *actual_size, size_t alignment); + + void DumpStats(TCMalloc_Printer* printer); + +private: + int64 big_page_size_; + int hugetlb_fd_; // file descriptor for hugetlb + off_t hugetlb_base_; +}; + +void HugetlbSysAllocator::DumpStats(TCMalloc_Printer* printer) { + printer->printf("HugetlbSysAllocator: failed_=%d allocated=%"PRId64"\n", + failed_, static_cast<int64_t>(hugetlb_base_)); +} + +// No locking needed here since we assume that tcmalloc calls +// us with an internal lock held (see tcmalloc/system-alloc.cc). +void* HugetlbSysAllocator::Alloc(size_t size, size_t *actual_size, + size_t alignment) { + + // don't go any further if we haven't opened the backing file + if (hugetlb_fd_ == -1) { + return NULL; + } + + // We don't respond to allocation requests smaller than big_page_size_ unless + // the caller is willing to take more than they asked for. + if (actual_size == NULL && size < big_page_size_) { + return NULL; + } + + // Enforce huge page alignment. Be careful to deal with overflow. + if (alignment < big_page_size_) alignment = big_page_size_; + size_t aligned_size = ((size + alignment - 1) / alignment) * alignment; + if (aligned_size < size) { + return NULL; + } + size = aligned_size; + + // Ask for extra memory if alignment > pagesize + size_t extra = 0; + if (alignment > big_page_size_) { + extra = alignment - big_page_size_; + } + + // Test if this allocation would put us over the limit. + off_t limit = FLAGS_memfs_malloc_limit_mb*1024*1024; + if (limit > 0 && hugetlb_base_ + size + extra > limit) { + // Disable the allocator when there's less than one page left. + if (limit - hugetlb_base_ < big_page_size_) { + TCMalloc_MESSAGE(__FILE__, __LINE__, "reached memfs_malloc_limit_mb\n"); + failed_ = true; + } + else { + TCMalloc_MESSAGE(__FILE__, __LINE__, "alloc size=%"PRIuS + " too large while %"PRId64" bytes remain\n", + size, static_cast<int64_t>(limit - hugetlb_base_)); + } + if (FLAGS_memfs_malloc_abort_on_fail) { + CRASH("memfs_malloc_abort_on_fail is set\n"); + } + return NULL; + } + + // This is not needed for hugetlbfs, but needed for tmpfs. Annoyingly + // hugetlbfs returns EINVAL for ftruncate. + int ret = ftruncate(hugetlb_fd_, hugetlb_base_ + size + extra); + if (ret != 0 && errno != EINVAL) { + TCMalloc_MESSAGE(__FILE__, __LINE__, "ftruncate failed: %s\n", + strerror(errno)); + failed_ = true; + if (FLAGS_memfs_malloc_abort_on_fail) { + CRASH("memfs_malloc_abort_on_fail is set\n"); + } + return NULL; + } + + // Note: size + extra does not overflow since: + // size + alignment < (1<<NBITS). + // and extra <= alignment + // therefore size + extra < (1<<NBITS) + void *result = mmap(0, size + extra, PROT_WRITE|PROT_READ, + MAP_SHARED, hugetlb_fd_, hugetlb_base_); + if (result == reinterpret_cast<void*>(MAP_FAILED)) { + if (!FLAGS_memfs_malloc_ignore_mmap_fail) { + TCMalloc_MESSAGE(__FILE__, __LINE__, "mmap of size %"PRIuS" failed: %s\n", + size + extra, strerror(errno)); + failed_ = true; + if (FLAGS_memfs_malloc_abort_on_fail) { + CRASH("memfs_malloc_abort_on_fail is set\n"); + } + } + 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)); + } + ptr += adjust; + hugetlb_base_ += (size + extra); + + if (actual_size) { + *actual_size = size + extra - adjust; + } + + return reinterpret_cast<void*>(ptr); +} + +static void InitSystemAllocator() { + if (FLAGS_memfs_malloc_path.length()) { + char path[PATH_MAX]; + int rc = snprintf(path, sizeof(path), "%s.XXXXXX", + FLAGS_memfs_malloc_path.c_str()); + if (rc < 0 || rc >= sizeof(path)) { + CRASH("XX fatal: memfs_malloc_path too long\n"); + } + + int hugetlb_fd = mkstemp(path); + if (hugetlb_fd == -1) { + TCMalloc_MESSAGE(__FILE__, __LINE__, + "warning: unable to create memfs_malloc_path %s: %s\n", + path, strerror(errno)); + return; + } + + // Cleanup memory on process exit + if (unlink(path) == -1) { + CRASH("fatal: error unlinking memfs_malloc_path %s: %s\n", + path, strerror(errno)); + } + + // Use fstatfs to figure out the default page size for memfs + struct statfs sfs; + if (fstatfs(hugetlb_fd, &sfs) == -1) { + CRASH("fatal: error fstatfs of memfs_malloc_path: %s\n", + strerror(errno)); + } + int64 page_size = sfs.f_bsize; + + SysAllocator *alloc = new HugetlbSysAllocator(hugetlb_fd, page_size); + // Register ourselves with tcmalloc + RegisterSystemAllocator(alloc, 0); + } +} + +REGISTER_MODULE_INITIALIZER(memfs_malloc, { InitSystemAllocator(); }); + +#endif /* ifdef __linux */ |