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authorJens Axboe <jaxboe@fusionio.com>2011-04-15 15:49:07 +0200
committerJens Axboe <jaxboe@fusionio.com>2011-04-15 15:49:07 +0200
commitf6603783f9f099bf7a83b3f6c689bbbf74f0e96e (patch)
tree450065f77e95b6cd0eee13c9d8f721016be79839
parent88b996cd0652280cc9b9fc70008fda15f14175e1 (diff)
block: only force kblockd unplugging from the schedule() path
For the explicit unplugging, we'd prefer to kick things off immediately and not pay the penalty of the latency to switch to kblockd. So let blk_finish_plug() do the run inline, while the implicit-on-schedule-out unplug will punt to kblockd. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
-rw-r--r--block/blk-core.c13
-rw-r--r--include/linux/blkdev.h4
2 files changed, 9 insertions, 8 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index b598fa7720d4..3c8121072507 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2662,16 +2662,17 @@ static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b)
return !(rqa->q <= rqb->q);
}
-static void queue_unplugged(struct request_queue *q, unsigned int depth)
+static void queue_unplugged(struct request_queue *q, unsigned int depth,
+ bool force_kblockd)
{
trace_block_unplug_io(q, depth);
- __blk_run_queue(q, true);
+ __blk_run_queue(q, force_kblockd);
if (q->unplugged_fn)
q->unplugged_fn(q);
}
-void blk_flush_plug_list(struct blk_plug *plug)
+void blk_flush_plug_list(struct blk_plug *plug, bool force_kblockd)
{
struct request_queue *q;
unsigned long flags;
@@ -2706,7 +2707,7 @@ void blk_flush_plug_list(struct blk_plug *plug)
BUG_ON(!rq->q);
if (rq->q != q) {
if (q) {
- queue_unplugged(q, depth);
+ queue_unplugged(q, depth, force_kblockd);
spin_unlock(q->queue_lock);
}
q = rq->q;
@@ -2727,7 +2728,7 @@ void blk_flush_plug_list(struct blk_plug *plug)
}
if (q) {
- queue_unplugged(q, depth);
+ queue_unplugged(q, depth, force_kblockd);
spin_unlock(q->queue_lock);
}
@@ -2737,7 +2738,7 @@ EXPORT_SYMBOL(blk_flush_plug_list);
void blk_finish_plug(struct blk_plug *plug)
{
- blk_flush_plug_list(plug);
+ blk_flush_plug_list(plug, false);
if (plug == current->plug)
current->plug = NULL;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index ffe48ff318f9..1c76506fcf11 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -865,14 +865,14 @@ struct blk_plug {
extern void blk_start_plug(struct blk_plug *);
extern void blk_finish_plug(struct blk_plug *);
-extern void blk_flush_plug_list(struct blk_plug *);
+extern void blk_flush_plug_list(struct blk_plug *, bool);
static inline void blk_flush_plug(struct task_struct *tsk)
{
struct blk_plug *plug = tsk->plug;
if (plug)
- blk_flush_plug_list(plug);
+ blk_flush_plug_list(plug, true);
}
static inline bool blk_needs_flush_plug(struct task_struct *tsk)

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