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throttle-groups: do not use qemu_co_enter_next 

Prepare for removing this function; always restart throttled requests
from coroutine context.  This will matter when restarting throttled
requests will have to acquire a CoMutex.

Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20170605123908.18777-9-pbonzini@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
This commit is contained in:
Paolo Bonzini 2017-06-05 14:38:57 +02:00 committed by Fam Zheng
parent 7258ed930c
commit 3b170dc867
1 changed files with 37 additions and 5 deletions
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42
block/throttle-groups.c
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@ -260,6 +260,20 @@ static bool throttle_group_schedule_timer(BlockBackend *blk, bool is_write)
return must_wait;
}
/* Start the next pending I/O request for a BlockBackend. Return whether
* any request was actually pending.
*
* @blk: the current BlockBackend
* @is_write: the type of operation (read/write)
*/
static bool coroutine_fn throttle_group_co_restart_queue(BlockBackend *blk,
bool is_write)
{
BlockBackendPublic *blkp = blk_get_public(blk);
return qemu_co_queue_next(&blkp->throttled_reqs[is_write]);
}
/* Look for the next pending I/O request and schedule it.
*
* This assumes that tg->lock is held.
@ -287,7 +301,7 @@ static void schedule_next_request(BlockBackend *blk, bool is_write)
if (!must_wait) {
/* Give preference to requests from the current blk */
if (qemu_in_coroutine() &&
qemu_co_queue_next(&blkp->throttled_reqs[is_write])) {
throttle_group_co_restart_queue(blk, is_write)) {
token = blk;
} else {
ThrottleTimers *tt = &blk_get_public(token)->throttle_timers;
@ -340,15 +354,21 @@ void coroutine_fn throttle_group_co_io_limits_intercept(BlockBackend *blk,
qemu_mutex_unlock(&tg->lock);
}
static void throttle_group_restart_queue(BlockBackend *blk, bool is_write)
typedef struct {
BlockBackend *blk;
bool is_write;
} RestartData;
static void coroutine_fn throttle_group_restart_queue_entry(void *opaque)
{
RestartData *data = opaque;
BlockBackend *blk = data->blk;
bool is_write = data->is_write;
BlockBackendPublic *blkp = blk_get_public(blk);
ThrottleGroup *tg = container_of(blkp->throttle_state, ThrottleGroup, ts);
bool empty_queue;
aio_context_acquire(blk_get_aio_context(blk));
empty_queue = !qemu_co_enter_next(&blkp->throttled_reqs[is_write]);
aio_context_release(blk_get_aio_context(blk));
empty_queue = !throttle_group_co_restart_queue(blk, is_write);
/* If the request queue was empty then we have to take care of
* scheduling the next one */
@ -359,6 +379,18 @@ static void throttle_group_restart_queue(BlockBackend *blk, bool is_write)
}
}
static void throttle_group_restart_queue(BlockBackend *blk, bool is_write)
{
Coroutine *co;
RestartData rd = {
.blk = blk,
.is_write = is_write
};
co = qemu_coroutine_create(throttle_group_restart_queue_entry, &rd);
aio_co_enter(blk_get_aio_context(blk), co);
}
void throttle_group_restart_blk(BlockBackend *blk)
{
BlockBackendPublic *blkp = blk_get_public(blk);