[PATCH] blk: branch hints
Sprinkle around a few branch hints in the block layer.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/block/ll_rw_blk.c b/drivers/block/ll_rw_blk.c
index 265de85..1e84715 100644
--- a/drivers/block/ll_rw_blk.c
+++ b/drivers/block/ll_rw_blk.c
@@ -1439,7 +1439,7 @@
*/
void __generic_unplug_device(request_queue_t *q)
{
- if (test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags))
+ if (unlikely(test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags)))
return;
if (!blk_remove_plug(q))
@@ -1763,7 +1763,7 @@
int blk_get_queue(request_queue_t *q)
{
- if (!test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
+ if (likely(!test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) {
atomic_inc(&q->refcnt);
return 0;
}
@@ -2584,7 +2584,7 @@
spin_lock_prefetch(q->queue_lock);
barrier = bio_barrier(bio);
- if (barrier && (q->ordered == QUEUE_ORDERED_NONE)) {
+ if (unlikely(barrier) && (q->ordered == QUEUE_ORDERED_NONE)) {
err = -EOPNOTSUPP;
goto end_io;
}
@@ -2685,7 +2685,7 @@
/*
* REQ_BARRIER implies no merging, but lets make it explicit
*/
- if (barrier)
+ if (unlikely(barrier))
req->flags |= (REQ_HARDBARRIER | REQ_NOMERGE);
req->errors = 0;
@@ -2809,7 +2809,7 @@
{
DEFINE_WAIT(wait);
- while (test_bit(QUEUE_FLAG_DRAIN, &q->queue_flags)) {
+ while (unlikely(test_bit(QUEUE_FLAG_DRAIN, &q->queue_flags))) {
struct request_list *rl = &q->rq;
prepare_to_wait_exclusive(&rl->drain, &wait,
@@ -2918,7 +2918,7 @@
goto end_io;
}
- if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))
+ if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)))
goto end_io;
block_wait_queue_running(q);