2 * Copyright 2017 Facebook, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 // http://www.canonware.com/download/jemalloc/jemalloc-latest/doc/jemalloc.html
21 #include <folly/portability/Config.h>
23 #ifdef FOLLY_HAVE_LIBJEMALLOC
25 #include <folly/portability/SysMman.h>
26 #include <jemalloc/jemalloc.h>
28 #if (JEMALLOC_VERSION_MAJOR > 3) && defined(MADV_DONTDUMP)
29 #define FOLLY_JEMALLOC_NODUMP_ALLOCATOR_SUPPORTED 1
30 #if (JEMALLOC_VERSION_MAJOR == 4)
31 #define FOLLY_JEMALLOC_NODUMP_ALLOCATOR_CHUNK
32 #define JEMALLOC_CHUNK_OR_EXTENT chunk
34 #define FOLLY_JEMALLOC_NODUMP_ALLOCATOR_EXTENT
35 #define JEMALLOC_CHUNK_OR_EXTENT extent
39 #endif // FOLLY_HAVE_LIBJEMALLOC
46 * An allocator which uses Jemalloc to create an dedicated arena to allocate
47 * memory from. The only special property set on the allocated memory is that
48 * the memory is not dump-able.
50 * This is done by setting MADV_DONTDUMP using the `madvise` system call. A
51 * custom hook installed which is called when allocating a new chunk / extent of
52 * memory. All it does is call the original jemalloc hook to allocate the
53 * memory and then set the advise on it before returning the pointer to the
54 * allocated memory. Jemalloc does not use allocated chunks / extents across
55 * different arenas, without `munmap`-ing them first, and the advises are not
56 * sticky i.e. they are unset if `munmap` is done. Also this arena can't be used
57 * by any other part of the code by just calling `malloc`.
59 * If target system doesn't support MADV_DONTDUMP or jemalloc doesn't support
60 * custom arena hook, JemallocNodumpAllocator would fall back to using malloc /
61 * free. Such behavior can be identified by using
62 * !defined(FOLLY_JEMALLOC_NODUMP_ALLOCATOR_SUPPORTED).
64 * Similarly, if binary isn't linked with jemalloc, the logic would fall back to
67 class JemallocNodumpAllocator {
74 // To be used as IOBuf::FreeFunction, userData should be set to
75 // reinterpret_cast<void*>(getFlags()).
76 static void deallocate(void* p, void* userData);
78 explicit JemallocNodumpAllocator(State state = State::ENABLED);
80 void* allocate(size_t size);
81 void* reallocate(void* p, size_t size);
82 void deallocate(void* p);
84 unsigned getArenaIndex() const { return arena_index_; }
85 int getFlags() const { return flags_; }
88 #ifdef FOLLY_JEMALLOC_NODUMP_ALLOCATOR_SUPPORTED
89 #ifdef FOLLY_JEMALLOC_NODUMP_ALLOCATOR_CHUNK
90 static chunk_alloc_t* original_alloc_;
94 static extent_hooks_t extent_hooks_;
95 static extent_alloc_t* original_alloc_;
97 extent_hooks_t* extent,
105 #endif // FOLLY_JEMALLOC_NODUMP_ALLOCATOR_SUPPORTED
107 bool extend_and_setup_arena();
109 unsigned arena_index_{0};
114 * JemallocNodumpAllocator singleton.
116 JemallocNodumpAllocator& globalJemallocNodumpAllocator();