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104 lines
3.3 KiB
C++
104 lines
3.3 KiB
C++
/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- */
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// vim: ft=cpp:expandtab:ts=8:sw=4:softtabstop=4:
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#ident "$Id$"
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/*======
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This file is part of PerconaFT.
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Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved.
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PerconaFT is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License, version 2,
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as published by the Free Software Foundation.
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PerconaFT is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with PerconaFT. If not, see <http://www.gnu.org/licenses/>.
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----------------------------------------
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PerconaFT is free software: you can redistribute it and/or modify
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it under the terms of the GNU Affero General Public License, version 3,
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as published by the Free Software Foundation.
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PerconaFT is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Affero General Public License for more details.
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You should have received a copy of the GNU Affero General Public License
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along with PerconaFT. If not, see <http://www.gnu.org/licenses/>.
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======= */
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#ident "Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved."
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#pragma once
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#include "rwlock.h"
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//Use case:
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// General purpose non blocking mutex with properties:
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// 1. one writer at a time
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// An external mutex must be locked when using these functions. An alternate
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// design would bury a mutex into the nb_mutex itself. While this may
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// increase parallelism at the expense of single thread performance, we
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// are experimenting with a single higher level lock.
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typedef struct nb_mutex *NB_MUTEX;
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struct nb_mutex {
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struct rwlock lock;
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};
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// initialize an nb mutex
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static __attribute__((__unused__))
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void
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nb_mutex_init(NB_MUTEX nb_mutex) {
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rwlock_init(&nb_mutex->lock);
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}
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// destroy a read write lock
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static __attribute__((__unused__))
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void
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nb_mutex_destroy(NB_MUTEX nb_mutex) {
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rwlock_destroy(&nb_mutex->lock);
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}
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// obtain a write lock
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// expects: mutex is locked
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static inline void nb_mutex_lock(NB_MUTEX nb_mutex, toku_mutex_t *mutex) {
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rwlock_write_lock(&nb_mutex->lock, mutex);
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}
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// release a write lock
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// expects: mutex is locked
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static inline void nb_mutex_unlock(NB_MUTEX nb_mutex) {
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rwlock_write_unlock(&nb_mutex->lock);
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}
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static inline void nb_mutex_wait_for_users(NB_MUTEX nb_mutex, toku_mutex_t *mutex) {
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rwlock_wait_for_users(&nb_mutex->lock, mutex);
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}
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// returns: the number of writers who are waiting for the lock
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static inline int nb_mutex_blocked_writers(NB_MUTEX nb_mutex) {
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return rwlock_blocked_writers(&nb_mutex->lock);
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}
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// returns: the number of writers
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static inline int nb_mutex_writers(NB_MUTEX nb_mutex) {
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return rwlock_writers(&nb_mutex->lock);
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}
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// returns: the sum of the number of readers, pending readers,
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// writers, and pending writers
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static inline int nb_mutex_users(NB_MUTEX nb_mutex) {
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return rwlock_users(&nb_mutex->lock);
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}
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