File: memfs_malloc.cc

package info (click to toggle)
google-perftools 2.7-1
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, buster, sid
  • size: 7,284 kB
  • sloc: cpp: 27,869; ansic: 9,534; sh: 4,799; perl: 4,116; makefile: 1,101; asm: 128
file content (272 lines) | stat: -rw-r--r-- 9,887 bytes parent folder | download | duplicates (5)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
// -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*-
// 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>                      // for errno, EINVAL
#include <inttypes.h>                   // for PRId64
#include <limits.h>                     // for PATH_MAX
#include <stddef.h>                     // for size_t, NULL
#ifdef HAVE_STDINT_H
#include <stdint.h>                     // for int64_t, uintptr_t
#endif
#include <stdio.h>                      // for snprintf
#include <stdlib.h>                     // for mkstemp
#include <string.h>                     // for strerror
#include <sys/mman.h>                   // for mmap, MAP_FAILED, etc
#include <sys/statfs.h>                 // for fstatfs, statfs
#include <unistd.h>                     // for ftruncate, off_t, unlink
#include <new>                          // for operator new
#include <string>

#include <gperftools/malloc_extension.h>
#include "base/basictypes.h"
#include "base/googleinit.h"
#include "base/sysinfo.h"
#include "internal_logging.h"

// TODO(sanjay): Move the code below into the tcmalloc namespace
using tcmalloc::kLog;
using tcmalloc::kCrash;
using tcmalloc::Log;
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");
DEFINE_bool(memfs_malloc_map_private,
            EnvToBool("TCMALLOC_MEMFS_MAP_PRIVATE", false),
	    "Use MAP_PRIVATE with mmap");

// Hugetlbfs based allocator for tcmalloc
class HugetlbSysAllocator: public SysAllocator {
public:
  explicit HugetlbSysAllocator(SysAllocator* fallback)
    : failed_(true),  // To disable allocator until Initialize() is called.
      big_page_size_(0),
      hugetlb_fd_(-1),
      hugetlb_base_(0),
      fallback_(fallback) {
  }

  void* Alloc(size_t size, size_t *actual_size, size_t alignment);
  bool Initialize();

  bool failed_;          // Whether failed to allocate memory.

private:
  void* AllocInternal(size_t size, size_t *actual_size, size_t alignment);

  int64 big_page_size_;
  int hugetlb_fd_;       // file descriptor for hugetlb
  off_t hugetlb_base_;

  SysAllocator* fallback_;  // Default system allocator to fall back to.
};
static union {
  char buf[sizeof(HugetlbSysAllocator)];
  void *ptr;
} hugetlb_space;

// 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) {
  if (failed_) {
    return fallback_->Alloc(size, actual_size, alignment);
  }

  // We don't respond to allocation requests smaller than big_page_size_ unless
  // the caller is ok to take more than they asked for. Used by MetaDataAlloc.
  if (actual_size == NULL && size < big_page_size_) {
    return fallback_->Alloc(size, actual_size, alignment);
  }

  // Enforce huge page alignment.  Be careful to deal with overflow.
  size_t new_alignment = alignment;
  if (new_alignment < big_page_size_) new_alignment = big_page_size_;
  size_t aligned_size = ((size + new_alignment - 1) /
                         new_alignment) * new_alignment;
  if (aligned_size < size) {
    return fallback_->Alloc(size, actual_size, alignment);
  }

  void* result = AllocInternal(aligned_size, actual_size, new_alignment);
  if (result != NULL) {
    return result;
  }
  Log(kLog, __FILE__, __LINE__,
      "HugetlbSysAllocator: (failed, allocated)", failed_, hugetlb_base_);
  if (FLAGS_memfs_malloc_abort_on_fail) {
    Log(kCrash, __FILE__, __LINE__,
        "memfs_malloc_abort_on_fail is set");
  }
  return fallback_->Alloc(size, actual_size, alignment);
}

void* HugetlbSysAllocator::AllocInternal(size_t size, size_t* actual_size,
                                         size_t alignment) {
  // 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_) {
      Log(kLog, __FILE__, __LINE__, "reached memfs_malloc_limit_mb");
      failed_ = true;
    }
    else {
      Log(kLog, __FILE__, __LINE__,
          "alloc too large (size, bytes left)", size, limit-hugetlb_base_);
    }
    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) {
    Log(kLog, __FILE__, __LINE__,
        "ftruncate failed", strerror(errno));
    failed_ = true;
    return NULL;
  }

  // Note: size + extra does not overflow since:
  //            size + alignment < (1<<NBITS).
  // and        extra <= alignment
  // therefore  size + extra < (1<<NBITS)
  void *result;
  result = mmap(0, size + extra, PROT_WRITE|PROT_READ,
                FLAGS_memfs_malloc_map_private ? MAP_PRIVATE : MAP_SHARED,
                hugetlb_fd_, hugetlb_base_);
  if (result == reinterpret_cast<void*>(MAP_FAILED)) {
    if (!FLAGS_memfs_malloc_ignore_mmap_fail) {
      Log(kLog, __FILE__, __LINE__,
          "mmap failed (size, error)", size + extra, strerror(errno));
      failed_ = 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));
  }
  ptr += adjust;
  hugetlb_base_ += (size + extra);

  if (actual_size) {
    *actual_size = size + extra - adjust;
  }

  return reinterpret_cast<void*>(ptr);
}

bool HugetlbSysAllocator::Initialize() {
  char path[PATH_MAX];
  const int pathlen = FLAGS_memfs_malloc_path.size();
  if (pathlen + 8 > sizeof(path)) {
    Log(kCrash, __FILE__, __LINE__, "XX fatal: memfs_malloc_path too long");
    return false;
  }
  memcpy(path, FLAGS_memfs_malloc_path.data(), pathlen);
  memcpy(path + pathlen, ".XXXXXX", 8);  // Also copies terminating \0

  int hugetlb_fd = mkstemp(path);
  if (hugetlb_fd == -1) {
    Log(kLog, __FILE__, __LINE__,
        "warning: unable to create memfs_malloc_path",
        path, strerror(errno));
    return false;
  }

  // Cleanup memory on process exit
  if (unlink(path) == -1) {
    Log(kCrash, __FILE__, __LINE__,
        "fatal: error unlinking memfs_malloc_path", path, strerror(errno));
    return false;
  }

  // Use fstatfs to figure out the default page size for memfs
  struct statfs sfs;
  if (fstatfs(hugetlb_fd, &sfs) == -1) {
    Log(kCrash, __FILE__, __LINE__,
        "fatal: error fstatfs of memfs_malloc_path", strerror(errno));
    return false;
  }
  int64 page_size = sfs.f_bsize;

  hugetlb_fd_ = hugetlb_fd;
  big_page_size_ = page_size;
  failed_ = false;
  return true;
}

REGISTER_MODULE_INITIALIZER(memfs_malloc, {
  if (FLAGS_memfs_malloc_path.length()) {
    SysAllocator* alloc = MallocExtension::instance()->GetSystemAllocator();
    HugetlbSysAllocator* hp =
      new (hugetlb_space.buf) HugetlbSysAllocator(alloc);
    if (hp->Initialize()) {
      MallocExtension::instance()->SetSystemAllocator(hp);
    }
  }
});

#endif   /* ifdef __linux */