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anderson.h
(4.61 KB)
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cas.h
(3.21 KB)
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clh.h
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dec.h
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fas.h
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hclh.h
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mcs.h
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ticket.h
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Editing: mcs.h
/* * 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_MCS_H #define CK_SPINLOCK_MCS_H #include <ck_cc.h> #include <ck_pr.h> #include <ck_stdbool.h> #include <ck_stddef.h> #ifndef CK_F_SPINLOCK_MCS #define CK_F_SPINLOCK_MCS struct ck_spinlock_mcs { unsigned int locked; struct ck_spinlock_mcs *next; }; typedef struct ck_spinlock_mcs * ck_spinlock_mcs_t; typedef struct ck_spinlock_mcs ck_spinlock_mcs_context_t; #define CK_SPINLOCK_MCS_INITIALIZER (NULL) CK_CC_INLINE static void ck_spinlock_mcs_init(struct ck_spinlock_mcs **queue) { *queue = NULL; ck_pr_barrier(); return; } CK_CC_INLINE static bool ck_spinlock_mcs_trylock(struct ck_spinlock_mcs **queue, struct ck_spinlock_mcs *node) { bool r; node->locked = true; node->next = NULL; ck_pr_fence_store_atomic(); r = ck_pr_cas_ptr(queue, NULL, node); ck_pr_fence_lock(); return r; } CK_CC_INLINE static bool ck_spinlock_mcs_locked(struct ck_spinlock_mcs **queue) { bool r; r = ck_pr_load_ptr(queue) != NULL; ck_pr_fence_acquire(); return r; } CK_CC_INLINE static void ck_spinlock_mcs_lock(struct ck_spinlock_mcs **queue, struct ck_spinlock_mcs *node) { struct ck_spinlock_mcs *previous; /* * In the case that there is a successor, let them know they must * wait for us to unlock. */ node->locked = true; node->next = NULL; ck_pr_fence_store_atomic(); /* * Swap current tail with current lock request. If the swap operation * returns NULL, it means the queue was empty. If the queue was empty, * then the operation is complete. */ previous = ck_pr_fas_ptr(queue, node); if (previous != NULL) { /* * Let the previous lock holder know that we are waiting on * them. */ ck_pr_store_ptr(&previous->next, node); while (ck_pr_load_uint(&node->locked) == true) ck_pr_stall(); } ck_pr_fence_lock(); return; } CK_CC_INLINE static void ck_spinlock_mcs_unlock(struct ck_spinlock_mcs **queue, struct ck_spinlock_mcs *node) { struct ck_spinlock_mcs *next; ck_pr_fence_unlock(); next = ck_pr_load_ptr(&node->next); if (next == NULL) { /* * If there is no request following us then it is a possibilty * that we are the current tail. In this case, we may just * mark the spinlock queue as empty. */ if (ck_pr_load_ptr(queue) == node && ck_pr_cas_ptr(queue, node, NULL) == true) { return; } /* * If the node is not the current tail then a lock operation * is in-progress. In this case, busy-wait until the queue is * in a consistent state to wake up the incoming lock * request. */ for (;;) { next = ck_pr_load_ptr(&node->next); if (next != NULL) break; ck_pr_stall(); } } /* Allow the next lock operation to complete. */ ck_pr_store_uint(&next->locked, false); return; } #endif /* CK_F_SPINLOCK_MCS */ #endif /* CK_SPINLOCK_MCS_H */
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