Not convinced this is a faster approach, and it does look IRQs off
longer than otherwise. With mq+scheduling, it's a problem since
it forces us to offload the queue running. If we get rid of it,
we can run the queue without the queue lock held.
Signed-off-by: Jens Axboe <ax...@fb.com>
---
block/blk-core.c | 32 ++++++++++++++------------------
1 file changed, 14 insertions(+), 18 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 8be12ba91f8e..2c61d2020c3f 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -3204,18 +3204,21 @@ static int plug_rq_cmp(void *priv, struct list_head *a,
struct list_head *b)
* plugger did not intend it.
*/
static void queue_unplugged(struct request_queue *q, unsigned int depth,
- bool from_schedule)
+ bool from_schedule, unsigned long flags)
__releases(q->queue_lock)
{
trace_block_unplug(q, depth, !from_schedule);
- if (q->mq_ops)
- blk_mq_run_hw_queues(q, true);
- else if (from_schedule)
- blk_run_queue_async(q);
- else
- __blk_run_queue(q);
- spin_unlock(q->queue_lock);
+ if (q->mq_ops) {
+ spin_unlock_irqrestore(q->queue_lock, flags);
+ blk_mq_run_hw_queues(q, from_schedule);
+ } else {
+ if (from_schedule)
+ blk_run_queue_async(q);
+ else
+ __blk_run_queue(q);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+ }
}
static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule)
@@ -3283,11 +3286,6 @@ void blk_flush_plug_list(struct blk_plug *plug, bool
from_schedule)
q = NULL;
depth = 0;
- /*
- * Save and disable interrupts here, to avoid doing it for every
- * queue lock we have to take.
- */
- local_irq_save(flags);
while (!list_empty(&list)) {
rq = list_entry_rq(list.next);
list_del_init(&rq->queuelist);
@@ -3297,10 +3295,10 @@ void blk_flush_plug_list(struct blk_plug *plug, bool
from_schedule)
* This drops the queue lock
*/
if (q)
- queue_unplugged(q, depth, from_schedule);
+ queue_unplugged(q, depth, from_schedule, flags);
q = rq->q;
depth = 0;
- spin_lock(q->queue_lock);
+ spin_lock_irqsave(q->queue_lock, flags);
}
/*
@@ -3329,9 +3327,7 @@ void blk_flush_plug_list(struct blk_plug *plug, bool
from_schedule)
* This drops the queue lock
*/
if (q)
- queue_unplugged(q, depth, from_schedule);
-
- local_irq_restore(flags);
+ queue_unplugged(q, depth, from_schedule, flags);
}
void blk_finish_plug(struct blk_plug *plug)
--
2.7.4
--
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