You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
117 lines
3.6 KiB
117 lines
3.6 KiB
/*
|
|
* Copyright 2010-2015 Samy Al Bahra.
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
#ifndef CK_SPINLOCK_CLH_H
|
|
#define CK_SPINLOCK_CLH_H
|
|
|
|
#include <ck_cc.h>
|
|
#include <ck_limits.h>
|
|
#include <ck_pr.h>
|
|
#include <stdbool.h>
|
|
#include <stddef.h>
|
|
|
|
#ifndef CK_F_SPINLOCK_CLH
|
|
#define CK_F_SPINLOCK_CLH
|
|
|
|
struct ck_spinlock_clh {
|
|
unsigned int wait;
|
|
struct ck_spinlock_clh *previous;
|
|
};
|
|
typedef struct ck_spinlock_clh ck_spinlock_clh_t;
|
|
|
|
CK_CC_INLINE static void
|
|
ck_spinlock_clh_init(struct ck_spinlock_clh **lock, struct ck_spinlock_clh *unowned)
|
|
{
|
|
|
|
unowned->previous = NULL;
|
|
unowned->wait = false;
|
|
*lock = unowned;
|
|
ck_pr_barrier();
|
|
return;
|
|
}
|
|
|
|
CK_CC_INLINE static bool
|
|
ck_spinlock_clh_locked(struct ck_spinlock_clh **queue)
|
|
{
|
|
struct ck_spinlock_clh *head;
|
|
|
|
ck_pr_fence_load();
|
|
head = ck_pr_load_ptr(queue);
|
|
ck_pr_fence_load();
|
|
return ck_pr_load_uint(&head->wait);
|
|
}
|
|
|
|
CK_CC_INLINE static void
|
|
ck_spinlock_clh_lock(struct ck_spinlock_clh **queue, struct ck_spinlock_clh *thread)
|
|
{
|
|
struct ck_spinlock_clh *previous;
|
|
|
|
/* Indicate to the next thread on queue that they will have to block. */
|
|
thread->wait = true;
|
|
ck_pr_fence_store_atomic();
|
|
|
|
/* Mark current request as last request. Save reference to previous request. */
|
|
previous = ck_pr_fas_ptr(queue, thread);
|
|
thread->previous = previous;
|
|
|
|
/* Wait until previous thread is done with lock. */
|
|
ck_pr_fence_load();
|
|
while (ck_pr_load_uint(&previous->wait) == true)
|
|
ck_pr_stall();
|
|
|
|
ck_pr_fence_acquire();
|
|
return;
|
|
}
|
|
|
|
CK_CC_INLINE static void
|
|
ck_spinlock_clh_unlock(struct ck_spinlock_clh **thread)
|
|
{
|
|
struct ck_spinlock_clh *previous;
|
|
|
|
/*
|
|
* If there are waiters, they are spinning on the current node wait
|
|
* flag. The flag is cleared so that the successor may complete an
|
|
* acquisition. If the caller is pre-empted then the predecessor field
|
|
* may be updated by a successor's lock operation. In order to avoid
|
|
* this, save a copy of the predecessor before setting the flag.
|
|
*/
|
|
previous = thread[0]->previous;
|
|
|
|
/* We have to pay this cost anyways, use it as a compiler barrier too. */
|
|
ck_pr_fence_release();
|
|
ck_pr_store_uint(&(*thread)->wait, false);
|
|
|
|
/*
|
|
* Predecessor is guaranteed not to be spinning on previous request,
|
|
* so update caller to use previous structure. This allows successor
|
|
* all the time in the world to successfully read updated wait flag.
|
|
*/
|
|
*thread = previous;
|
|
return;
|
|
}
|
|
#endif /* CK_F_SPINLOCK_CLH */
|
|
#endif /* CK_SPINLOCK_CLH_H */
|