From: Ken Chen <[email protected]>
In function __generic_unplug_device(), kernel can use a cheaper function
elv_queue_empty() instead of more expensive elv_next_request to find
whether the queue is empty or not. blk_run_queue can also made conditional
on whether queue's emptiness before calling request_fn().
Signed-off-by: Jens Axboe <[email protected]>
Signed-off-by: Ken Chen <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---
25-akpm/drivers/block/ll_rw_blk.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletion(-)
diff -puN drivers/block/ll_rw_blk.c~use-cheaper-elv_queue_empty-when-unplug-a-device drivers/block/ll_rw_blk.c
--- 25/drivers/block/ll_rw_blk.c~use-cheaper-elv_queue_empty-when-unplug-a-device 2005-04-12 03:21:34.394908080 -0700
+++ 25-akpm/drivers/block/ll_rw_blk.c 2005-04-12 03:21:34.399907320 -0700
@@ -1589,7 +1589,8 @@ void blk_run_queue(struct request_queue
spin_lock_irqsave(q->queue_lock, flags);
blk_remove_plug(q);
- q->request_fn(q);
+ if (!elv_queue_empty(q))
+ q->request_fn(q);
spin_unlock_irqrestore(q->queue_lock, flags);
}
EXPORT_SYMBOL(blk_run_queue);
_
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
