From: Mathieu Desnoyers Date: Fri, 1 Aug 2014 01:03:59 +0000 (-0400) Subject: wfcqueue: Implement mutex-free wfcqueue head with transparent union X-Git-Tag: v0.9.0~81 X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=f637f191d0939dccf3f5c9bab74bba70cfd45fc4;p=userspace-rcu.git wfcqueue: Implement mutex-free wfcqueue head with transparent union Tested-by: Eric Wong CC: "Paul E. McKenney" CC: "Lai Jiangshan" Signed-off-by: Mathieu Desnoyers --- diff --git a/urcu/static/wfcqueue.h b/urcu/static/wfcqueue.h index 62e003f..48b2625 100644 --- a/urcu/static/wfcqueue.h +++ b/urcu/static/wfcqueue.h @@ -106,6 +106,17 @@ static inline void _cds_wfcq_init(struct cds_wfcq_head *head, assert(!ret); } +/* + * __cds_wfcq_init: initialize wait-free queue. + */ +static inline void ___cds_wfcq_init(struct __cds_wfcq_head *head, + struct cds_wfcq_tail *tail) +{ + /* Set queue head and tail */ + _cds_wfcq_node_init(&head->node); + tail->p = &head->node; +} + /* * cds_wfcq_empty: return whether wait-free queue is empty. * @@ -118,9 +129,10 @@ static inline void _cds_wfcq_init(struct cds_wfcq_head *head, * make a queue appear empty if an enqueuer is preempted for a long time * between xchg() and setting the previous node's next pointer. */ -static inline bool _cds_wfcq_empty(struct cds_wfcq_head *head, +static inline bool _cds_wfcq_empty(cds_wfcq_head_ptr_t u_head, struct cds_wfcq_tail *tail) { + struct __cds_wfcq_head *head = u_head._h; /* * Queue is empty if no node is pointed by head->node.next nor * tail->p. Even though the tail->p check is sufficient to find @@ -150,11 +162,12 @@ static inline void _cds_wfcq_dequeue_unlock(struct cds_wfcq_head *head, assert(!ret); } -static inline bool ___cds_wfcq_append(struct cds_wfcq_head *head, +static inline bool ___cds_wfcq_append(cds_wfcq_head_ptr_t u_head, struct cds_wfcq_tail *tail, struct cds_wfcq_node *new_head, struct cds_wfcq_node *new_tail) { + struct __cds_wfcq_head *head = u_head._h; struct cds_wfcq_node *old_tail; /* @@ -190,7 +203,7 @@ static inline bool ___cds_wfcq_append(struct cds_wfcq_head *head, * Returns false if the queue was empty prior to adding the node. * Returns true otherwise. */ -static inline bool _cds_wfcq_enqueue(struct cds_wfcq_head *head, +static inline bool _cds_wfcq_enqueue(cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail, struct cds_wfcq_node *new_tail) { @@ -237,10 +250,11 @@ ___cds_wfcq_node_sync_next(struct cds_wfcq_node *node, int blocking) } static inline struct cds_wfcq_node * -___cds_wfcq_first(struct cds_wfcq_head *head, +___cds_wfcq_first(cds_wfcq_head_ptr_t u_head, struct cds_wfcq_tail *tail, int blocking) { + struct __cds_wfcq_head *head = u_head._h; struct cds_wfcq_node *node; if (_cds_wfcq_empty(head, tail)) @@ -266,7 +280,7 @@ ___cds_wfcq_first(struct cds_wfcq_head *head, * Returns NULL if queue is empty, first node otherwise. */ static inline struct cds_wfcq_node * -___cds_wfcq_first_blocking(struct cds_wfcq_head *head, +___cds_wfcq_first_blocking(cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail) { return ___cds_wfcq_first(head, tail, 1); @@ -280,14 +294,14 @@ ___cds_wfcq_first_blocking(struct cds_wfcq_head *head, * it needs to block. */ static inline struct cds_wfcq_node * -___cds_wfcq_first_nonblocking(struct cds_wfcq_head *head, +___cds_wfcq_first_nonblocking(cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail) { return ___cds_wfcq_first(head, tail, 0); } static inline struct cds_wfcq_node * -___cds_wfcq_next(struct cds_wfcq_head *head, +___cds_wfcq_next(cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail, struct cds_wfcq_node *node, int blocking) @@ -328,7 +342,7 @@ ___cds_wfcq_next(struct cds_wfcq_head *head, * otherwise. */ static inline struct cds_wfcq_node * -___cds_wfcq_next_blocking(struct cds_wfcq_head *head, +___cds_wfcq_next_blocking(cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail, struct cds_wfcq_node *node) { @@ -342,7 +356,7 @@ ___cds_wfcq_next_blocking(struct cds_wfcq_head *head, * it needs to block. */ static inline struct cds_wfcq_node * -___cds_wfcq_next_nonblocking(struct cds_wfcq_head *head, +___cds_wfcq_next_nonblocking(cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail, struct cds_wfcq_node *node) { @@ -350,11 +364,12 @@ ___cds_wfcq_next_nonblocking(struct cds_wfcq_head *head, } static inline struct cds_wfcq_node * -___cds_wfcq_dequeue_with_state(struct cds_wfcq_head *head, +___cds_wfcq_dequeue_with_state(cds_wfcq_head_ptr_t u_head, struct cds_wfcq_tail *tail, int *state, int blocking) { + struct __cds_wfcq_head *head = u_head._h; struct cds_wfcq_node *node, *next; if (state) @@ -422,7 +437,7 @@ ___cds_wfcq_dequeue_with_state(struct cds_wfcq_head *head, * caller. */ static inline struct cds_wfcq_node * -___cds_wfcq_dequeue_with_state_blocking(struct cds_wfcq_head *head, +___cds_wfcq_dequeue_with_state_blocking(cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail, int *state) { return ___cds_wfcq_dequeue_with_state(head, tail, state, 1); @@ -435,7 +450,7 @@ ___cds_wfcq_dequeue_with_state_blocking(struct cds_wfcq_head *head, * state. */ static inline struct cds_wfcq_node * -___cds_wfcq_dequeue_blocking(struct cds_wfcq_head *head, +___cds_wfcq_dequeue_blocking(cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail) { return ___cds_wfcq_dequeue_with_state_blocking(head, tail, NULL); @@ -448,7 +463,7 @@ ___cds_wfcq_dequeue_blocking(struct cds_wfcq_head *head, * if it needs to block. */ static inline struct cds_wfcq_node * -___cds_wfcq_dequeue_with_state_nonblocking(struct cds_wfcq_head *head, +___cds_wfcq_dequeue_with_state_nonblocking(cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail, int *state) { return ___cds_wfcq_dequeue_with_state(head, tail, state, 0); @@ -461,7 +476,7 @@ ___cds_wfcq_dequeue_with_state_nonblocking(struct cds_wfcq_head *head, * state. */ static inline struct cds_wfcq_node * -___cds_wfcq_dequeue_nonblocking(struct cds_wfcq_head *head, +___cds_wfcq_dequeue_nonblocking(cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail) { return ___cds_wfcq_dequeue_with_state_nonblocking(head, tail, NULL); @@ -479,12 +494,14 @@ ___cds_wfcq_dequeue_nonblocking(struct cds_wfcq_head *head, */ static inline enum cds_wfcq_ret ___cds_wfcq_splice( - struct cds_wfcq_head *dest_q_head, + cds_wfcq_head_ptr_t u_dest_q_head, struct cds_wfcq_tail *dest_q_tail, - struct cds_wfcq_head *src_q_head, + cds_wfcq_head_ptr_t u_src_q_head, struct cds_wfcq_tail *src_q_tail, int blocking) { + struct __cds_wfcq_head *dest_q_head = u_dest_q_head._h; + struct __cds_wfcq_head *src_q_head = u_src_q_head._h; struct cds_wfcq_node *head, *tail; int attempt = 0; @@ -540,9 +557,9 @@ ___cds_wfcq_splice( */ static inline enum cds_wfcq_ret ___cds_wfcq_splice_blocking( - struct cds_wfcq_head *dest_q_head, + cds_wfcq_head_ptr_t dest_q_head, struct cds_wfcq_tail *dest_q_tail, - struct cds_wfcq_head *src_q_head, + cds_wfcq_head_ptr_t src_q_head, struct cds_wfcq_tail *src_q_tail) { return ___cds_wfcq_splice(dest_q_head, dest_q_tail, @@ -557,9 +574,9 @@ ___cds_wfcq_splice_blocking( */ static inline enum cds_wfcq_ret ___cds_wfcq_splice_nonblocking( - struct cds_wfcq_head *dest_q_head, + cds_wfcq_head_ptr_t dest_q_head, struct cds_wfcq_tail *dest_q_tail, - struct cds_wfcq_head *src_q_head, + cds_wfcq_head_ptr_t src_q_head, struct cds_wfcq_tail *src_q_tail) { return ___cds_wfcq_splice(dest_q_head, dest_q_tail, diff --git a/urcu/wfcqueue.h b/urcu/wfcqueue.h index 4e83660..df26e33 100644 --- a/urcu/wfcqueue.h +++ b/urcu/wfcqueue.h @@ -65,11 +65,25 @@ struct cds_wfcq_node { * enqueue/dequeue are expected from many CPUs. This eliminates * false-sharing between enqueue and dequeue. */ +struct __cds_wfcq_head { + struct cds_wfcq_node node; +}; + struct cds_wfcq_head { struct cds_wfcq_node node; pthread_mutex_t lock; }; +/* + * The transparent union allows calling functions that work on both + * struct cds_wfcq_head and struct __cds_wfcq_head on any of those two + * types. + */ +typedef union __attribute__((__transparent_union__)) { + struct __cds_wfcq_head *_h; + struct cds_wfcq_head *h; +} cds_wfcq_head_ptr_t; + struct cds_wfcq_tail { struct cds_wfcq_node *p; }; @@ -163,12 +177,18 @@ extern void cds_wfcq_node_init(struct cds_wfcq_node *node); extern void cds_wfcq_init(struct cds_wfcq_head *head, struct cds_wfcq_tail *tail); +/* + * __cds_wfcq_init: initialize wait-free queue. + */ +extern void __cds_wfcq_init(struct __cds_wfcq_head *head, + struct cds_wfcq_tail *tail); + /* * cds_wfcq_empty: return whether wait-free queue is empty. * * No memory barrier is issued. No mutual exclusion is required. */ -extern bool cds_wfcq_empty(struct cds_wfcq_head *head, +extern bool cds_wfcq_empty(cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail); /* @@ -192,7 +212,7 @@ extern void cds_wfcq_dequeue_unlock(struct cds_wfcq_head *head, * Returns false if the queue was empty prior to adding the node. * Returns true otherwise. */ -extern bool cds_wfcq_enqueue(struct cds_wfcq_head *head, +extern bool cds_wfcq_enqueue(cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail, struct cds_wfcq_node *node); @@ -249,7 +269,7 @@ extern enum cds_wfcq_ret cds_wfcq_splice_blocking( * caller. */ extern struct cds_wfcq_node *__cds_wfcq_dequeue_blocking( - struct cds_wfcq_head *head, + cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail); /* @@ -259,7 +279,7 @@ extern struct cds_wfcq_node *__cds_wfcq_dequeue_blocking( * last node of the queue into state (CDS_WFCQ_STATE_LAST). */ extern struct cds_wfcq_node *__cds_wfcq_dequeue_with_state_blocking( - struct cds_wfcq_head *head, + cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail, int *state); @@ -270,7 +290,7 @@ extern struct cds_wfcq_node *__cds_wfcq_dequeue_with_state_blocking( * if it needs to block. */ extern struct cds_wfcq_node *__cds_wfcq_dequeue_nonblocking( - struct cds_wfcq_head *head, + cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail); /* @@ -280,7 +300,7 @@ extern struct cds_wfcq_node *__cds_wfcq_dequeue_nonblocking( * the last node of the queue into state (CDS_WFCQ_STATE_LAST). */ extern struct cds_wfcq_node *__cds_wfcq_dequeue_with_state_nonblocking( - struct cds_wfcq_head *head, + cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail, int *state); @@ -295,9 +315,9 @@ extern struct cds_wfcq_node *__cds_wfcq_dequeue_with_state_nonblocking( * dest queue. Never returns CDS_WFCQ_RET_WOULDBLOCK. */ extern enum cds_wfcq_ret __cds_wfcq_splice_blocking( - struct cds_wfcq_head *dest_q_head, + cds_wfcq_head_ptr_t dest_q_head, struct cds_wfcq_tail *dest_q_tail, - struct cds_wfcq_head *src_q_head, + cds_wfcq_head_ptr_t src_q_head, struct cds_wfcq_tail *src_q_tail); /* @@ -307,9 +327,9 @@ extern enum cds_wfcq_ret __cds_wfcq_splice_blocking( * CDS_WFCQ_RET_WOULDBLOCK if it needs to block. */ extern enum cds_wfcq_ret __cds_wfcq_splice_nonblocking( - struct cds_wfcq_head *dest_q_head, + cds_wfcq_head_ptr_t dest_q_head, struct cds_wfcq_tail *dest_q_tail, - struct cds_wfcq_head *src_q_head, + cds_wfcq_head_ptr_t src_q_head, struct cds_wfcq_tail *src_q_tail); /* @@ -327,7 +347,7 @@ extern enum cds_wfcq_ret __cds_wfcq_splice_nonblocking( * Returns NULL if queue is empty, first node otherwise. */ extern struct cds_wfcq_node *__cds_wfcq_first_blocking( - struct cds_wfcq_head *head, + cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail); /* @@ -337,7 +357,7 @@ extern struct cds_wfcq_node *__cds_wfcq_first_blocking( * it needs to block. */ extern struct cds_wfcq_node *__cds_wfcq_first_nonblocking( - struct cds_wfcq_head *head, + cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail); /* @@ -356,7 +376,7 @@ extern struct cds_wfcq_node *__cds_wfcq_first_nonblocking( * otherwise. */ extern struct cds_wfcq_node *__cds_wfcq_next_blocking( - struct cds_wfcq_head *head, + cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail, struct cds_wfcq_node *node); @@ -367,7 +387,7 @@ extern struct cds_wfcq_node *__cds_wfcq_next_blocking( * it needs to block. */ extern struct cds_wfcq_node *__cds_wfcq_next_nonblocking( - struct cds_wfcq_head *head, + cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail, struct cds_wfcq_node *node); @@ -376,7 +396,7 @@ extern struct cds_wfcq_node *__cds_wfcq_next_nonblocking( /* * __cds_wfcq_for_each_blocking: Iterate over all nodes in a queue, * without dequeuing them. - * @head: head of the queue (struct cds_wfcq_head pointer). + * @head: head of the queue (struct cds_wfcq_head or __cds_wfcq_head pointer). * @tail: tail of the queue (struct cds_wfcq_tail pointer). * @node: iterator on the queue (struct cds_wfcq_node pointer). * @@ -393,7 +413,7 @@ extern struct cds_wfcq_node *__cds_wfcq_next_nonblocking( /* * __cds_wfcq_for_each_blocking_safe: Iterate over all nodes in a queue, * without dequeuing them. Safe against deletion. - * @head: head of the queue (struct cds_wfcq_head pointer). + * @head: head of the queue (struct cds_wfcq_head or __cds_wfcq_head pointer). * @tail: tail of the queue (struct cds_wfcq_tail pointer). * @node: iterator on the queue (struct cds_wfcq_node pointer). * @n: struct cds_wfcq_node pointer holding the next pointer (used diff --git a/wfcqueue.c b/wfcqueue.c index 4950c10..e28d51a 100644 --- a/wfcqueue.c +++ b/wfcqueue.c @@ -40,14 +40,20 @@ void cds_wfcq_init(struct cds_wfcq_head *head, _cds_wfcq_init(head, tail); } -bool cds_wfcq_empty(struct cds_wfcq_head *head, +void __cds_wfcq_init(struct __cds_wfcq_head *head, + struct cds_wfcq_tail *tail) +{ + ___cds_wfcq_init(head, tail); +} + +bool cds_wfcq_empty(cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail) { return _cds_wfcq_empty(head, tail); } -bool cds_wfcq_enqueue(struct cds_wfcq_head *head, +bool cds_wfcq_enqueue(cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail, struct cds_wfcq_node *node) { @@ -92,14 +98,14 @@ enum cds_wfcq_ret cds_wfcq_splice_blocking( } struct cds_wfcq_node *__cds_wfcq_dequeue_blocking( - struct cds_wfcq_head *head, + cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail) { return ___cds_wfcq_dequeue_blocking(head, tail); } struct cds_wfcq_node *__cds_wfcq_dequeue_with_state_blocking( - struct cds_wfcq_head *head, + cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail, int *state) { @@ -107,14 +113,14 @@ struct cds_wfcq_node *__cds_wfcq_dequeue_with_state_blocking( } struct cds_wfcq_node *__cds_wfcq_dequeue_nonblocking( - struct cds_wfcq_head *head, + cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail) { return ___cds_wfcq_dequeue_nonblocking(head, tail); } struct cds_wfcq_node *__cds_wfcq_dequeue_with_state_nonblocking( - struct cds_wfcq_head *head, + cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail, int *state) { @@ -122,9 +128,9 @@ struct cds_wfcq_node *__cds_wfcq_dequeue_with_state_nonblocking( } enum cds_wfcq_ret __cds_wfcq_splice_blocking( - struct cds_wfcq_head *dest_q_head, + cds_wfcq_head_ptr_t dest_q_head, struct cds_wfcq_tail *dest_q_tail, - struct cds_wfcq_head *src_q_head, + cds_wfcq_head_ptr_t src_q_head, struct cds_wfcq_tail *src_q_tail) { return ___cds_wfcq_splice_blocking(dest_q_head, dest_q_tail, @@ -132,9 +138,9 @@ enum cds_wfcq_ret __cds_wfcq_splice_blocking( } enum cds_wfcq_ret __cds_wfcq_splice_nonblocking( - struct cds_wfcq_head *dest_q_head, + cds_wfcq_head_ptr_t dest_q_head, struct cds_wfcq_tail *dest_q_tail, - struct cds_wfcq_head *src_q_head, + cds_wfcq_head_ptr_t src_q_head, struct cds_wfcq_tail *src_q_tail) { return ___cds_wfcq_splice_nonblocking(dest_q_head, dest_q_tail, @@ -142,21 +148,21 @@ enum cds_wfcq_ret __cds_wfcq_splice_nonblocking( } struct cds_wfcq_node *__cds_wfcq_first_blocking( - struct cds_wfcq_head *head, + cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail) { return ___cds_wfcq_first_blocking(head, tail); } struct cds_wfcq_node *__cds_wfcq_first_nonblocking( - struct cds_wfcq_head *head, + cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail) { return ___cds_wfcq_first_nonblocking(head, tail); } struct cds_wfcq_node *__cds_wfcq_next_blocking( - struct cds_wfcq_head *head, + cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail, struct cds_wfcq_node *node) { @@ -164,7 +170,7 @@ struct cds_wfcq_node *__cds_wfcq_next_blocking( } struct cds_wfcq_node *__cds_wfcq_next_nonblocking( - struct cds_wfcq_head *head, + cds_wfcq_head_ptr_t head, struct cds_wfcq_tail *tail, struct cds_wfcq_node *node) {