dm thin: reduce number of metadata commits
Reduce the number of metadata commits by using
dm_thin_changed_this_transaction to check if metadata was changed on a
per thin device granularity.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index bc9d08c..98c50f9 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -707,6 +707,12 @@
bio->bi_bdev = tc->origin_dev->bdev;
}
+static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
+{
+ return (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) &&
+ dm_thin_changed_this_transaction(tc->td);
+}
+
static void issue(struct thin_c *tc, struct bio *bio)
{
struct pool *pool = tc->pool;
@@ -716,7 +722,7 @@
* Batch together any FUA/FLUSH bios we find and then issue
* a single commit for them in process_deferred_bios().
*/
- if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) {
+ if (bio_triggers_commit(tc, bio)) {
spin_lock_irqsave(&pool->lock, flags);
bio_list_add(&pool->deferred_flush_bios, bio);
spin_unlock_irqrestore(&pool->lock, flags);