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使用spinlock，避免cas不能充分调度testdeadloop这样的用例

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This commit is contained in:
xjdrew
2014-12-04 15:50:19 +08:00
parent 6f6039c136
commit a0d2c7172c
2 changed files with 30 additions and 49 deletions
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69
skynet-src/skynet_mq.c
View File

@@ -32,12 +32,9 @@ struct message_queue {
}; };
struct global_queue { struct global_queue {
uint32_t head; struct message_queue *head;
uint32_t tail; struct message_queue *tail;
struct message_queue ** queue; int lock;
// We use a separated flag array to ensure the mq is pushed.
// See the comments below.
struct message_queue *list;
}; };
static struct global_queue *Q = NULL; static struct global_queue *Q = NULL;
@@ -51,57 +48,33 @@ void
skynet_globalmq_push(struct message_queue * queue) { skynet_globalmq_push(struct message_queue * queue) {
struct global_queue *q= Q; struct global_queue *q= Q;
uint32_t tail = GP(__sync_fetch_and_add(&q->tail,1));
// only one thread can set the slot (change q->queue[tail] from NULL to queue) // only one thread can set the slot (change q->queue[tail] from NULL to queue)
if (!__sync_bool_compare_and_swap(&q->queue[tail], NULL, queue)) { LOCK(q)
// The queue may full seldom, save queue in list assert(queue->next == NULL);
assert(queue->next == NULL); if(q->tail) {
struct message_queue * last; q->tail->next = queue;
do { q->tail = queue;
last = q->list; } else {
queue->next = last; q->head = q->tail = queue;
} while(!__sync_bool_compare_and_swap(&q->list, last, queue));
return;
} }
UNLOCK(q)
} }
struct message_queue * struct message_queue *
skynet_globalmq_pop() { skynet_globalmq_pop() {
struct global_queue *q = Q; struct global_queue *q = Q;
uint32_t head = q->head;
if (head == q->tail) { LOCK(q)
// The queue is empty. struct message_queue *mq = q->head;
return NULL; if(mq) {
} q->head = mq->next;
if(q->head == NULL) {
uint32_t head_ptr = GP(head); assert(mq == q->tail);
q->tail = NULL;
struct message_queue * list = q->list;
if (list) {
// If q->list is not empty, try to load it back to the queue
struct message_queue *newhead = list->next;
if (__sync_bool_compare_and_swap(&q->list, list, newhead)) {
// try load list only once, if success , push it back to the queue.
list->next = NULL;
skynet_globalmq_push(list);
} }
mq->next = NULL;
} }
UNLOCK(q)
struct message_queue * mq = q->queue[head_ptr];
if (mq == NULL) {
// globalmq push not complete
return NULL;
}
if (!__sync_bool_compare_and_swap(&q->head, head, head+1)) {
return NULL;
}
// only one thread can get the slot (change q->queue[head_ptr] to NULL)
if (!__sync_bool_compare_and_swap(&q->queue[head_ptr], mq, NULL)) {
return NULL;
}
return mq; return mq;
} }
@@ -243,8 +216,6 @@ void
skynet_mq_init() { skynet_mq_init() {
struct global_queue *q = skynet_malloc(sizeof(*q)); struct global_queue *q = skynet_malloc(sizeof(*q));
memset(q,0,sizeof(*q)); memset(q,0,sizeof(*q));
q->queue = skynet_malloc(MAX_GLOBAL_MQ * sizeof(struct message_queue *));
memset(q->queue, 0, sizeof(struct message_queue *) * MAX_GLOBAL_MQ);
Q=q; Q=q;
} }

10
test/testdeadloop.lua Normal file
View File

@@ -0,0 +1,10 @@
local skynet = require "skynet"
local function dead_loop()
while true do
skynet.sleep(0)
end
end
skynet.start(function()
skynet.fork(dead_loop)
end)