mirror of
https://github.com/matrix-construct/construct
synced 2024-11-17 15:30:52 +01:00
51 lines
1.7 KiB
C++
51 lines
1.7 KiB
C++
// Matrix Construct
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//
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// Copyright (C) Matrix Construct Developers, Authors & Contributors
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// Copyright (C) 2016-2019 Jason Volk <jason@zemos.net>
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice is present in all copies. The
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// full license for this software is available in the LICENSE file.
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#if __has_include("db/write_thread.h")
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#define ROCKSDB_PLATFORM_POSIX
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#include "db/write_thread.h"
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#endif
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#ifndef STORAGE_ROCKSDB_INCLUDE_DB_H_
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#warning "The RocksDB source code is not available. Cannot interpose bugfixes for db/write_thread.h."
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#endif
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#ifdef STORAGE_ROCKSDB_INCLUDE_DB_H_
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uint8_t
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__attribute__((externally_visible))
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rocksdb::WriteThread::BlockingAwaitState(Writer *const w,
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uint8_t goal_mask)
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{
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// Create the class member mutex and cv where it's expected by
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// rocksdb callers
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w->CreateMutex();
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auto state(w->state.load(std::memory_order_acquire));
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assert(state != STATE_LOCKED_WAITING);
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if((state & goal_mask) == 0 && w->state.compare_exchange_strong(state, STATE_LOCKED_WAITING))
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{
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size_t yields(0);
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while((state = w->state.load(std::memory_order_relaxed)) == STATE_LOCKED_WAITING)
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{
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ircd::ctx::yield();
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++yields;
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}
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// Since we're using a coarse ctx::yield() it's theoretically possible
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// that our loop can spin out of control. That is highly unlikely,
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// and there is usually not even more than one iteration. Nevertheless
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// we assert to be sure this is working within reason.
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assert(yields < 32);
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}
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assert((state & goal_mask) != 0);
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return state;
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}
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#endif STORAGE_ROCKSDB_INCLUDE_DB_H_
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