1 // Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
2 // This source code is licensed under both the GPLv2 (found in the
3 // COPYING file in the root directory) and Apache 2.0 License
4 // (found in the LICENSE.Apache file in the root directory).
5 //
6 // Copyright (c) 2011 The LevelDB Authors. All rights reserved.
7 // Use of this source code is governed by a BSD-style license that can be
8 // found in the LICENSE file. See the AUTHORS file for names of contributors.
9
10 #include "memory/concurrent_arena.h"
11 #include <thread>
12 #include "port/port.h"
13 #include "util/random.h"
14
15 namespace rocksdb {
16
17 #ifdef ROCKSDB_SUPPORT_THREAD_LOCAL
18 __thread size_t ConcurrentArena::tls_cpuid = 0;
19 #endif
20
21 namespace {
22 // If the shard block size is too large, in the worst case, every core
23 // allocates a block without populate it. If the shared block size is
24 // 1MB, 64 cores will quickly allocate 64MB, and may quickly trigger a
25 // flush. Cap the size instead.
26 const size_t kMaxShardBlockSize = size_t{128 * 1024};
27 } // namespace
28
ConcurrentArena(size_t block_size,AllocTracker * tracker,size_t huge_page_size)29 ConcurrentArena::ConcurrentArena(size_t block_size, AllocTracker* tracker,
30 size_t huge_page_size)
31 : shard_block_size_(std::min(kMaxShardBlockSize, block_size / 8)),
32 shards_(),
33 arena_(block_size, tracker, huge_page_size) {
34 Fixup();
35 }
36
Repick()37 ConcurrentArena::Shard* ConcurrentArena::Repick() {
38 auto shard_and_index = shards_.AccessElementAndIndex();
39 #ifdef ROCKSDB_SUPPORT_THREAD_LOCAL
40 // even if we are cpu 0, use a non-zero tls_cpuid so we can tell we
41 // have repicked
42 tls_cpuid = shard_and_index.second | shards_.Size();
43 #endif
44 return shard_and_index.first;
45 }
46
47 } // namespace rocksdb
48