third_party/tcmalloc/chromium/src/memfs_malloc.cc

   1 // Copyright (c) 2007, Google Inc.
   2 // All rights reserved.
   3 //
   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 // ---
  31 // Author: Arun Sharma
  32 //
  33 // A tcmalloc system allocator that uses a memory based filesystem such as
  34 // tmpfs or hugetlbfs
  35 //
  36 // Since these only exist on linux, we only register this allocator there.
  37
  38 #ifdef __linux
  39
  40 #include <config.h>
  41 #include <errno.h>                      // for errno, EINVAL
  42 #include <inttypes.h>                   // for PRId64
  43 #include <limits.h>                     // for PATH_MAX
  44 #include <stddef.h>                     // for size_t, NULL
  45 #ifdef HAVE_STDINT_H
  46 #include <stdint.h>                     // for int64_t, uintptr_t
  47 #endif
  48 #include <stdio.h>                      // for snprintf
  49 #include <stdlib.h>                     // for mkstemp
  50 #include <string.h>                     // for strerror
  51 #include <sys/mman.h>                   // for mmap, MAP_FAILED, etc
  52 #include <sys/statfs.h>                 // for fstatfs, statfs
  53 #include <unistd.h>                     // for ftruncate, off_t, unlink
  54 #include <new>                          // for operator new
  55 #include <string>
  56
  57 #include <gperftools/malloc_extension.h>
  58 #include "base/basictypes.h"
  59 #include "base/googleinit.h"
  60 #include "base/sysinfo.h"
  61 #include "internal_logging.h"
  62
  63 // TODO(sanjay): Move the code below into the tcmalloc namespace
  64 using tcmalloc::kLog;
  65 using tcmalloc::kCrash;
  66 using tcmalloc::Log;
  67 using std::string;
  68
  69 DEFINE_string(memfs_malloc_path, EnvToString("TCMALLOC_MEMFS_MALLOC_PATH", ""),
  70               "Path where hugetlbfs or tmpfs is mounted. The caller is "
  71               "responsible for ensuring that the path is unique and does "
  72               "not conflict with another process");
  73 DEFINE_int64(memfs_malloc_limit_mb,
  74              EnvToInt("TCMALLOC_MEMFS_LIMIT_MB", 0),
  75              "Limit total allocation size to the "
  76              "specified number of MiB.  0 == no limit.");
  77 DEFINE_bool(memfs_malloc_abort_on_fail,
  78             EnvToBool("TCMALLOC_MEMFS_ABORT_ON_FAIL", false),
  79             "abort whenever memfs_malloc fails to satisfy an allocation "
  80             "for any reason.");
  81 DEFINE_bool(memfs_malloc_ignore_mmap_fail,
  82             EnvToBool("TCMALLOC_MEMFS_IGNORE_MMAP_FAIL", false),
  83             "Ignore failures from mmap");
  84 DEFINE_bool(memfs_malloc_map_private,
  85             EnvToBool("TCMALLOC_MEMFS_MAP_PRIVATE", false),
  86             "Use MAP_PRIVATE with mmap");
  87
  88 // Hugetlbfs based allocator for tcmalloc
  89 class HugetlbSysAllocator: public SysAllocator {
  90 public:
  91   explicit HugetlbSysAllocator(SysAllocator* fallback)
  92     : failed_(true),  // To disable allocator until Initialize() is called.
  93       big_page_size_(0),
  94       hugetlb_fd_(-1),
  95       hugetlb_base_(0),
  96       fallback_(fallback) {
  97   }
  98
  99   void* Alloc(size_t size, size_t *actual_size, size_t alignment);
 100   bool Initialize();
 101
 102   bool failed_;          // Whether failed to allocate memory.
 103
 104 private:
 105   void* AllocInternal(size_t size, size_t *actual_size, size_t alignment);
 106
 107   int64 big_page_size_;
 108   int hugetlb_fd_;       // file descriptor for hugetlb
 109   off_t hugetlb_base_;
 110
 111   SysAllocator* fallback_;  // Default system allocator to fall back to.
 112 };
 113 static char hugetlb_space[sizeof(HugetlbSysAllocator)];
 114
 115 // No locking needed here since we assume that tcmalloc calls
 116 // us with an internal lock held (see tcmalloc/system-alloc.cc).
 117 void* HugetlbSysAllocator::Alloc(size_t size, size_t *actual_size,
 118                                  size_t alignment) {
 119   if (failed_) {
 120     return fallback_->Alloc(size, actual_size, alignment);
 121   }
 122
 123   // We don't respond to allocation requests smaller than big_page_size_ unless
 124   // the caller is ok to take more than they asked for. Used by MetaDataAlloc.
 125   if (actual_size == NULL && size < big_page_size_) {
 126     return fallback_->Alloc(size, actual_size, alignment);
 127   }
 128
 129   // Enforce huge page alignment.  Be careful to deal with overflow.
 130   size_t new_alignment = alignment;
 131   if (new_alignment < big_page_size_) new_alignment = big_page_size_;
 132   size_t aligned_size = ((size + new_alignment - 1) /
 133                          new_alignment) * new_alignment;
 134   if (aligned_size < size) {
 135     return fallback_->Alloc(size, actual_size, alignment);
 136   }
 137
 138   void* result = AllocInternal(aligned_size, actual_size, new_alignment);
 139   if (result != NULL) {
 140     return result;
 141   }
 142   Log(kLog, __FILE__, __LINE__,
 143       "HugetlbSysAllocator: (failed, allocated)", failed_, hugetlb_base_);
 144   if (FLAGS_memfs_malloc_abort_on_fail) {
 145     Log(kCrash, __FILE__, __LINE__,
 146         "memfs_malloc_abort_on_fail is set");
 147   }
 148   return fallback_->Alloc(size, actual_size, alignment);
 149 }
 150
 151 void* HugetlbSysAllocator::AllocInternal(size_t size, size_t* actual_size,
 152                                          size_t alignment) {
 153   // Ask for extra memory if alignment > pagesize
 154   size_t extra = 0;
 155   if (alignment > big_page_size_) {
 156     extra = alignment - big_page_size_;
 157   }
 158
 159   // Test if this allocation would put us over the limit.
 160   off_t limit = FLAGS_memfs_malloc_limit_mb*1024*1024;
 161   if (limit > 0 && hugetlb_base_ + size + extra > limit) {
 162     // Disable the allocator when there's less than one page left.
 163     if (limit - hugetlb_base_ < big_page_size_) {
 164       Log(kLog, __FILE__, __LINE__, "reached memfs_malloc_limit_mb");
 165       failed_ = true;
 166     }
 167     else {
 168       Log(kLog, __FILE__, __LINE__,
 169           "alloc too large (size, bytes left)", size, limit-hugetlb_base_);
 170     }
 171     return NULL;
 172   }
 173
 174   // This is not needed for hugetlbfs, but needed for tmpfs.  Annoyingly
 175   // hugetlbfs returns EINVAL for ftruncate.
 176   int ret = ftruncate(hugetlb_fd_, hugetlb_base_ + size + extra);
 177   if (ret != 0 && errno != EINVAL) {
 178     Log(kLog, __FILE__, __LINE__,
 179         "ftruncate failed", strerror(errno));
 180     failed_ = true;
 181     return NULL;
 182   }
 183
 184   // Note: size + extra does not overflow since:
 185   //            size + alignment < (1<<NBITS).
 186   // and        extra <= alignment
 187   // therefore  size + extra < (1<<NBITS)
 188   void *result;
 189   result = mmap(0, size + extra, PROT_WRITE|PROT_READ,
 190                 FLAGS_memfs_malloc_map_private ? MAP_PRIVATE : MAP_SHARED,
 191                 hugetlb_fd_, hugetlb_base_);
 192   if (result == reinterpret_cast<void*>(MAP_FAILED)) {
 193     if (!FLAGS_memfs_malloc_ignore_mmap_fail) {
 194       Log(kLog, __FILE__, __LINE__,
 195           "mmap failed (size, error)", size + extra, strerror(errno));
 196       failed_ = true;
 197     }
 198     return NULL;
 199   }
 200   uintptr_t ptr = reinterpret_cast<uintptr_t>(result);
 201
 202   // Adjust the return memory so it is aligned
 203   size_t adjust = 0;
 204   if ((ptr & (alignment - 1)) != 0) {
 205     adjust = alignment - (ptr & (alignment - 1));
 206   }
 207   ptr += adjust;
 208   hugetlb_base_ += (size + extra);
 209
 210   if (actual_size) {
 211     *actual_size = size + extra - adjust;
 212   }
 213
 214   return reinterpret_cast<void*>(ptr);
 215 }
 216
 217 bool HugetlbSysAllocator::Initialize() {
 218   char path[PATH_MAX];
 219   const int pathlen = FLAGS_memfs_malloc_path.size();
 220   if (pathlen + 8 > sizeof(path)) {
 221     Log(kCrash, __FILE__, __LINE__, "XX fatal: memfs_malloc_path too long");
 222     return false;
 223   }
 224   memcpy(path, FLAGS_memfs_malloc_path.data(), pathlen);
 225   memcpy(path + pathlen, ".XXXXXX", 8);  // Also copies terminating \0
 226
 227   int hugetlb_fd = mkstemp(path);
 228   if (hugetlb_fd == -1) {
 229     Log(kLog, __FILE__, __LINE__,
 230         "warning: unable to create memfs_malloc_path",
 231         path, strerror(errno));
 232     return false;
 233   }
 234
 235   // Cleanup memory on process exit
 236   if (unlink(path) == -1) {
 237     Log(kCrash, __FILE__, __LINE__,
 238         "fatal: error unlinking memfs_malloc_path", path, strerror(errno));
 239     return false;
 240   }
 241
 242   // Use fstatfs to figure out the default page size for memfs
 243   struct statfs sfs;
 244   if (fstatfs(hugetlb_fd, &sfs) == -1) {
 245     Log(kCrash, __FILE__, __LINE__,
 246         "fatal: error fstatfs of memfs_malloc_path", strerror(errno));
 247     return false;
 248   }
 249   int64 page_size = sfs.f_bsize;
 250
 251   hugetlb_fd_ = hugetlb_fd;
 252   big_page_size_ = page_size;
 253   failed_ = false;
 254   return true;
 255 }
 256
 257 REGISTER_MODULE_INITIALIZER(memfs_malloc, {
 258   if (FLAGS_memfs_malloc_path.length()) {
 259     SysAllocator* alloc = MallocExtension::instance()->GetSystemAllocator();
 260     HugetlbSysAllocator* hp = new (hugetlb_space) HugetlbSysAllocator(alloc);
 261     if (hp->Initialize()) {
 262       MallocExtension::instance()->SetSystemAllocator(hp);
 263     }
 264   }
 265 });
 266
 267 #endif   /* ifdef __linux */