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// 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 */
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