Revision ec711b23152ca4e426057557784af322a2065fbc authored by mrambacher on 17 July 2020, 02:04:44 UTC, committed by Facebook GitHub Bot on 17 July 2020, 02:06:31 UTC
Summary: This PR does a few things: - The "compression_opts" and "bottom_compression_opts" can now be read/written as name/value pairs of options (instead of only a colon-separated list; - These options can now be read/written to the Options file; - The parallel_threads value can now be set (either in the colon or name-value format). The compression options are now stored and treated as a OptionTypeInfo::Struct by the options system, meaning they can be read and written like the other structs. This change allows them to be read/written easily to the options file. Additionally, the colon-format was extended to allow support for setting parallel threads. Tests were added to test all of the option settings via the optional parameters in the colon format. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6817 Reviewed By: ajkr Differential Revision: D22396004 Pulled By: zhichao-cao fbshipit-source-id: 38bcf74b7e9cd5bc2a84540fac2e9ba4f765b2c8
1 parent c5ddece
thread_local.h
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#pragma once
#include <atomic>
#include <functional>
#include <memory>
#include <unordered_map>
#include <vector>
#include "util/autovector.h"
#include "port/port.h"
namespace ROCKSDB_NAMESPACE {
// Cleanup function that will be called for a stored thread local
// pointer (if not NULL) when one of the following happens:
// (1) a thread terminates
// (2) a ThreadLocalPtr is destroyed
//
// Warning: this function is called while holding a global mutex. The same mutex
// is used (at least in some cases) by most methods of ThreadLocalPtr, and it's
// shared across all instances of ThreadLocalPtr. Thereforere extra care
// is needed to avoid deadlocks. In particular, the handler shouldn't lock any
// mutexes and shouldn't call any methods of any ThreadLocalPtr instances,
// unless you know what you're doing.
typedef void (*UnrefHandler)(void* ptr);
// ThreadLocalPtr stores only values of pointer type. Different from
// the usual thread-local-storage, ThreadLocalPtr has the ability to
// distinguish data coming from different threads and different
// ThreadLocalPtr instances. For example, if a regular thread_local
// variable A is declared in DBImpl, two DBImpl objects would share
// the same A. However, a ThreadLocalPtr that is defined under the
// scope of DBImpl can avoid such confliction. As a result, its memory
// usage would be O(# of threads * # of ThreadLocalPtr instances).
class ThreadLocalPtr {
public:
explicit ThreadLocalPtr(UnrefHandler handler = nullptr);
ThreadLocalPtr(const ThreadLocalPtr&) = delete;
ThreadLocalPtr& operator=(const ThreadLocalPtr&) = delete;
~ThreadLocalPtr();
// Return the current pointer stored in thread local
void* Get() const;
// Set a new pointer value to the thread local storage.
void Reset(void* ptr);
// Atomically swap the supplied ptr and return the previous value
void* Swap(void* ptr);
// Atomically compare the stored value with expected. Set the new
// pointer value to thread local only if the comparison is true.
// Otherwise, expected returns the stored value.
// Return true on success, false on failure
bool CompareAndSwap(void* ptr, void*& expected);
// Reset all thread local data to replacement, and return non-nullptr
// data for all existing threads
void Scrape(autovector<void*>* ptrs, void* const replacement);
typedef std::function<void(void*, void*)> FoldFunc;
// Update res by applying func on each thread-local value. Holds a lock that
// prevents unref handler from running during this call, but clients must
// still provide external synchronization since the owning thread can
// access the values without internal locking, e.g., via Get() and Reset().
void Fold(FoldFunc func, void* res);
// Add here for testing
// Return the next available Id without claiming it
static uint32_t TEST_PeekId();
// Initialize the static singletons of the ThreadLocalPtr.
//
// If this function is not called, then the singletons will be
// automatically initialized when they are used.
//
// Calling this function twice or after the singletons have been
// initialized will be no-op.
static void InitSingletons();
class StaticMeta;
private:
static StaticMeta* Instance();
const uint32_t id_;
};
} // namespace ROCKSDB_NAMESPACE
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