[dm-devel] [PATCH] dm: dm_table_unplug_all optimization
Mike Anderson
andmike at linux.vnet.ibm.com
Tue Apr 8 18:21:00 UTC 2008
Performance optimization for high contention of the q->queue_lock under
certain workloads.
Signed-off-by: Mike Anderson <andmike at linux.vnet.ibm.com>
---
drivers/md/dm-table.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index e75b143..f4c8c1b 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1012,7 +1012,8 @@ void dm_table_unplug_all(struct dm_table *t)
list_for_each_entry(dd, devices, list) {
struct request_queue *q = bdev_get_queue(dd->bdev);
- blk_unplug(q);
+ if (blk_queue_plugged(q))
+ blk_unplug(q);
}
}
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