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coroutines: Use one global bottom half for CoQueue 

Now that AsyncContexts don't exist any more, we can use one global bottom half
for restarting coroutines instead of allocating a new one every time (before
removing AsyncContexts, the problem with having a global BH was that it had to
belong to a single AsyncContexts and wouldn't be executed in a different one -
which leads to deadlocks)

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Kevin Wolf 2011-07-13 15:42:52 +02:00
parent 384acbf46b
commit e680cfa7e2
1 changed files with 6 additions and 13 deletions
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19
qemu-coroutine-lock.c
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@ -30,14 +30,10 @@
static QTAILQ_HEAD(, Coroutine) unlock_bh_queue = static QTAILQ_HEAD(, Coroutine) unlock_bh_queue =
QTAILQ_HEAD_INITIALIZER(unlock_bh_queue); QTAILQ_HEAD_INITIALIZER(unlock_bh_queue);
static QEMUBH* unlock_bh;
struct unlock_bh {
QEMUBH *bh;
};
static void qemu_co_queue_next_bh(void *opaque) static void qemu_co_queue_next_bh(void *opaque)
{ {
struct unlock_bh *unlock_bh = opaque;
Coroutine *next; Coroutine *next;
trace_qemu_co_queue_next_bh(); trace_qemu_co_queue_next_bh();
@ -45,14 +41,15 @@ static void qemu_co_queue_next_bh(void *opaque)
QTAILQ_REMOVE(&unlock_bh_queue, next, co_queue_next); QTAILQ_REMOVE(&unlock_bh_queue, next, co_queue_next);
qemu_coroutine_enter(next, NULL); qemu_coroutine_enter(next, NULL);
} }
qemu_bh_delete(unlock_bh->bh);
qemu_free(unlock_bh);
} }
void qemu_co_queue_init(CoQueue *queue) void qemu_co_queue_init(CoQueue *queue)
{ {
QTAILQ_INIT(&queue->entries); QTAILQ_INIT(&queue->entries);
if (!unlock_bh) {
unlock_bh = qemu_bh_new(qemu_co_queue_next_bh, NULL);
}
} }
void coroutine_fn qemu_co_queue_wait(CoQueue *queue) void coroutine_fn qemu_co_queue_wait(CoQueue *queue)
@ -65,7 +62,6 @@ void coroutine_fn qemu_co_queue_wait(CoQueue *queue)
bool qemu_co_queue_next(CoQueue *queue) bool qemu_co_queue_next(CoQueue *queue)
{ {
struct unlock_bh *unlock_bh;
Coroutine *next; Coroutine *next;
next = QTAILQ_FIRST(&queue->entries); next = QTAILQ_FIRST(&queue->entries);
@ -73,10 +69,7 @@ bool qemu_co_queue_next(CoQueue *queue)
QTAILQ_REMOVE(&queue->entries, next, co_queue_next); QTAILQ_REMOVE(&queue->entries, next, co_queue_next);
QTAILQ_INSERT_TAIL(&unlock_bh_queue, next, co_queue_next); QTAILQ_INSERT_TAIL(&unlock_bh_queue, next, co_queue_next);
trace_qemu_co_queue_next(next); trace_qemu_co_queue_next(next);
qemu_bh_schedule(unlock_bh);
unlock_bh = qemu_malloc(sizeof(*unlock_bh));
unlock_bh->bh = qemu_bh_new(qemu_co_queue_next_bh, unlock_bh);
qemu_bh_schedule(unlock_bh->bh);
} }
return (next != NULL); return (next != NULL);