[patch 5/9] blk: branch hints

[Nick Piggin]

5/9

--
SUSE Labs, Novell Inc.

Sprinkle around a few branch hints in the block layer.

Signed-off-by: Nick Piggin <[EMAIL PROTECTED]>

Index: linux-2.6/drivers/block/ll_rw_blk.c
===================================================================
--- linux-2.6.orig/drivers/block/ll_rw_blk.c    2005-04-12 22:26:13.000000000 
+1000
+++ linux-2.6/drivers/block/ll_rw_blk.c 2005-04-12 22:26:13.000000000 +1000
@@ -1450,7 +1450,7 @@ EXPORT_SYMBOL(blk_remove_plug);
  */
 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))
@@ -1749,7 +1749,7 @@ EXPORT_SYMBOL(blk_init_queue);
 
 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;
        }
@@ -2577,7 +2577,7 @@ static int __make_request(request_queue_
        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;
        }
@@ -2678,7 +2678,7 @@ get_rq:
        /*
         * REQ_BARRIER implies no merging, but lets make it explicit
         */
-       if (barrier)
+       if (unlikely(barrier))
                req->flags |= (REQ_HARDBARRIER | REQ_NOMERGE);
 
        req->errors = 0;
@@ -2802,7 +2802,7 @@ static inline void block_wait_queue_runn
 {
        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,
@@ -2911,7 +2911,7 @@ end_io:
                        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);