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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 {
uint32_t head;
uint32_t tail;
struct message_queue ** queue;
// We use a separated flag array to ensure the mq is pushed.
// See the comments below.
struct message_queue *list;
struct message_queue *head;
struct message_queue *tail;
int lock;
};
static struct global_queue *Q = NULL;
@@ -51,57 +48,33 @@ void
skynet_globalmq_push(struct message_queue * queue) {
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)
if (!__sync_bool_compare_and_swap(&q->queue[tail], NULL, queue)) {
// The queue may full seldom, save queue in list
assert(queue->next == NULL);
struct message_queue * last;
do {
last = q->list;
queue->next = last;
} while(!__sync_bool_compare_and_swap(&q->list, last, queue));
return;
LOCK(q)
assert(queue->next == NULL);
if(q->tail) {
q->tail->next = queue;
q->tail = queue;
} else {
q->head = q->tail = queue;
}
UNLOCK(q)
}
struct message_queue *
skynet_globalmq_pop() {
struct global_queue *q = Q;
uint32_t head = q->head;
if (head == q->tail) {
// The queue is empty.
return NULL;
}
uint32_t head_ptr = GP(head);
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);
LOCK(q)
struct message_queue *mq = q->head;
if(mq) {
q->head = mq->next;
if(q->head == NULL) {
assert(mq == q->tail);
q->tail = NULL;
}
mq->next = NULL;
}
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;
}
UNLOCK(q)
return mq;
}
@@ -243,8 +216,6 @@ void
skynet_mq_init() {
struct global_queue *q = skynet_malloc(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;
}

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)