mirror of https://github.com/facebook/rocksdb.git
44 lines
1.6 KiB
C++
44 lines
1.6 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#include "memory/concurrent_arena.h"
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#include <thread>
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#include "port/port.h"
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#include "util/random.h"
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namespace ROCKSDB_NAMESPACE {
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thread_local size_t ConcurrentArena::tls_cpuid = 0;
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namespace {
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// If the shard block size is too large, in the worst case, every core
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// allocates a block without populate it. If the shared block size is
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// 1MB, 64 cores will quickly allocate 64MB, and may quickly trigger a
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// flush. Cap the size instead.
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const size_t kMaxShardBlockSize = size_t{128 * 1024};
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} // namespace
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ConcurrentArena::ConcurrentArena(size_t block_size, AllocTracker* tracker,
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size_t huge_page_size)
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: shard_block_size_(std::min(kMaxShardBlockSize, block_size / 8)),
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shards_(),
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arena_(block_size, tracker, huge_page_size) {
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Fixup();
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}
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ConcurrentArena::Shard* ConcurrentArena::Repick() {
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auto shard_and_index = shards_.AccessElementAndIndex();
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// even if we are cpu 0, use a non-zero tls_cpuid so we can tell we
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// have repicked
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tls_cpuid = shard_and_index.second | shards_.Size();
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return shard_and_index.first;
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}
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} // namespace ROCKSDB_NAMESPACE
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