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380 lines
7.1 KiB
380 lines
7.1 KiB
/*
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* Copyright 2011-2013 Samy Al Bahra.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef _CK_RWLOCK_H
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#define _CK_RWLOCK_H
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#include <ck_pr.h>
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#include <stdbool.h>
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#include <stddef.h>
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struct ck_rwlock {
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unsigned int writer;
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unsigned int n_readers;
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};
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typedef struct ck_rwlock ck_rwlock_t;
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#define CK_RWLOCK_INITIALIZER {0, 0}
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CK_CC_INLINE static void
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ck_rwlock_init(struct ck_rwlock *rw)
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{
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rw->writer = 0;
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rw->n_readers = 0;
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ck_pr_fence_memory();
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return;
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}
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CK_CC_INLINE static void
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ck_rwlock_write_unlock(ck_rwlock_t *rw)
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{
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ck_pr_fence_memory();
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ck_pr_store_uint(&rw->writer, 0);
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return;
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}
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#ifdef CK_F_PR_RTM
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CK_CC_INLINE static void
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ck_rwlock_write_unlock_rtm(ck_rwlock_t *rw)
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{
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if (ck_pr_load_uint(&rw->writer) == 0) {
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ck_pr_rtm_end();
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return;
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}
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ck_rwlock_write_unlock(rw);
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return;
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}
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#endif /* CK_F_PR_RTM */
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CK_CC_INLINE static void
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ck_rwlock_write_downgrade(ck_rwlock_t *rw)
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{
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ck_pr_inc_uint(&rw->n_readers);
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ck_rwlock_write_unlock(rw);
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return;
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}
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#ifdef CK_F_PR_RTM
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CK_CC_INLINE static void
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ck_rwlock_write_downgrade_rtm(ck_rwlock_t *rw)
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{
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if (ck_pr_load_uint(&rw->writer) != 0) {
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ck_rwlock_write_downgrade(rw);
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return;
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}
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/*
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* Both reader and writer counters are in read-set. A transactional
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* abort will occur in the presence of another writer. Inner-most
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* read_unlock call will attempt a transactional commit.
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*/
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return;
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}
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#endif /* CK_F_PR_RTM */
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CK_CC_INLINE static bool
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ck_rwlock_write_trylock(ck_rwlock_t *rw)
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{
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if (ck_pr_fas_uint(&rw->writer, 1) != 0)
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return false;
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ck_pr_fence_memory();
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if (ck_pr_load_uint(&rw->n_readers) != 0) {
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ck_rwlock_write_unlock(rw);
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return false;
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}
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return true;
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}
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#ifdef CK_F_PR_RTM
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CK_CC_INLINE static bool
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ck_rwlock_write_trylock_rtm(ck_rwlock_t *rw)
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{
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bool r;
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if (ck_pr_rtm_begin() != CK_PR_RTM_STARTED)
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return false;
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r = ck_pr_load_uint(&rw->writer) != 0;
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ck_pr_fence_load();
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if (r | (ck_pr_load_uint(&rw->n_readers) != 0))
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ck_pr_rtm_abort(0);
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return true;
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}
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#endif /* CK_F_PR_RTM */
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CK_CC_INLINE static void
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ck_rwlock_write_lock(ck_rwlock_t *rw)
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{
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while (ck_pr_fas_uint(&rw->writer, 1) != 0)
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ck_pr_stall();
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ck_pr_fence_memory();
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while (ck_pr_load_uint(&rw->n_readers) != 0)
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ck_pr_stall();
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return;
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}
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#ifdef CK_F_PR_RTM
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CK_CC_INLINE static void
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ck_rwlock_write_lock_rtm(ck_rwlock_t *rw)
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{
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bool r;
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if (ck_pr_rtm_begin() != CK_PR_RTM_STARTED) {
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ck_rwlock_write_lock(rw);
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return;
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}
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r = ck_pr_load_uint(&rw->writer) != 0;
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ck_pr_fence_load();
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if (r | (ck_pr_load_uint(&rw->n_readers) != 0))
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ck_pr_rtm_abort(0);
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return;
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}
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#endif /* CK_F_PR_RTM */
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CK_CC_INLINE static bool
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ck_rwlock_read_trylock(ck_rwlock_t *rw)
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{
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if (ck_pr_load_uint(&rw->writer) != 0)
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return false;
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ck_pr_inc_uint(&rw->n_readers);
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/*
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* Serialize with respect to concurrent write
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* lock operation.
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*/
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ck_pr_fence_memory();
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if (ck_pr_load_uint(&rw->writer) == 0) {
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ck_pr_fence_load();
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return true;
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}
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ck_pr_dec_uint(&rw->n_readers);
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return false;
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}
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#ifdef CK_F_PR_RTM
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CK_CC_INLINE static bool
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ck_rwlock_read_trylock_rtm(ck_rwlock_t *rw)
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{
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if (ck_pr_rtm_begin() != CK_PR_RTM_STARTED)
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return false;
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if (ck_pr_load_uint(&rw->writer) == 0)
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return true;
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ck_pr_rtm_abort(0);
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return false;
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}
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#endif /* CK_F_PR_RTM */
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CK_CC_INLINE static void
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ck_rwlock_read_lock(ck_rwlock_t *rw)
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{
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for (;;) {
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while (ck_pr_load_uint(&rw->writer) != 0)
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ck_pr_stall();
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ck_pr_inc_uint(&rw->n_readers);
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/*
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* Serialize with respect to concurrent write
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* lock operation.
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*/
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ck_pr_fence_atomic_load();
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if (ck_pr_load_uint(&rw->writer) == 0)
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break;
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ck_pr_dec_uint(&rw->n_readers);
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}
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/* Acquire semantics are necessary. */
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ck_pr_fence_load();
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return;
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}
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#ifdef CK_F_PR_RTM
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CK_CC_INLINE static void
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ck_rwlock_read_lock_rtm(ck_rwlock_t *rw)
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{
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if (ck_pr_rtm_begin() == CK_PR_RTM_STARTED) {
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if (ck_pr_load_uint(&rw->writer) != 0)
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ck_pr_rtm_abort(0);
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return;
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}
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ck_rwlock_read_lock(rw);
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return;
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}
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#endif /* CK_F_PR_RTM */
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CK_CC_INLINE static void
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ck_rwlock_read_unlock(ck_rwlock_t *rw)
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{
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ck_pr_fence_memory();
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ck_pr_dec_uint(&rw->n_readers);
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return;
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}
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#ifdef CK_F_PR_RTM
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CK_CC_INLINE static void
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ck_rwlock_read_unlock_rtm(ck_rwlock_t *rw)
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{
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if (ck_pr_load_uint(&rw->n_readers) == 0) {
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ck_pr_rtm_end();
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} else {
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ck_rwlock_read_unlock(rw);
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}
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return;
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}
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#endif /* CK_F_PR_RTM */
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/*
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* Recursive writer reader-writer lock implementation.
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*/
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struct ck_rwlock_recursive {
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struct ck_rwlock rw;
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unsigned int wc;
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};
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typedef struct ck_rwlock_recursive ck_rwlock_recursive_t;
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#define CK_RWLOCK_RECURSIVE_INITIALIZER {CK_RWLOCK_INITIALIZER, 0}
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CK_CC_INLINE static void
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ck_rwlock_recursive_write_lock(ck_rwlock_recursive_t *rw, unsigned int tid)
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{
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unsigned int o;
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o = ck_pr_load_uint(&rw->rw.writer);
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if (o == tid)
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goto leave;
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while (ck_pr_cas_uint(&rw->rw.writer, 0, tid) == false)
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ck_pr_stall();
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ck_pr_fence_memory();
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while (ck_pr_load_uint(&rw->rw.n_readers) != 0)
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ck_pr_stall();
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leave:
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rw->wc++;
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return;
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}
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CK_CC_INLINE static bool
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ck_rwlock_recursive_write_trylock(ck_rwlock_recursive_t *rw, unsigned int tid)
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{
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unsigned int o;
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o = ck_pr_load_uint(&rw->rw.writer);
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if (o == tid)
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goto leave;
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if (ck_pr_cas_uint(&rw->rw.writer, 0, tid) == false)
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return false;
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ck_pr_fence_memory();
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if (ck_pr_load_uint(&rw->rw.n_readers) != 0) {
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ck_pr_store_uint(&rw->rw.writer, 0);
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return false;
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}
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leave:
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rw->wc++;
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return true;
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}
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CK_CC_INLINE static void
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ck_rwlock_recursive_write_unlock(ck_rwlock_recursive_t *rw)
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{
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if (--rw->wc == 0) {
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ck_pr_fence_memory();
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ck_pr_store_uint(&rw->rw.writer, 0);
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}
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return;
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}
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CK_CC_INLINE static void
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ck_rwlock_recursive_read_lock(ck_rwlock_recursive_t *rw)
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{
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ck_rwlock_read_lock(&rw->rw);
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return;
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}
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CK_CC_INLINE static bool
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ck_rwlock_recursive_read_trylock(ck_rwlock_recursive_t *rw)
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{
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return ck_rwlock_read_trylock(&rw->rw);
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}
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CK_CC_INLINE static void
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ck_rwlock_recursive_read_unlock(ck_rwlock_recursive_t *rw)
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{
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ck_rwlock_read_unlock(&rw->rw);
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return;
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}
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#endif /* _CK_RWLOCK_H */
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