path: root/drivers/md/dm-thin.c
diff options
authorJoe Thornber <ejt@redhat.com>2014-09-12 11:34:01 +0100
committerMike Snitzer <snitzer@redhat.com>2014-11-10 15:25:27 -0500
commit7a7e97ca580b944d2c89b59bc74a7b9ddd044705 (patch)
tree93ce0a65769205e6330ccf0691777eeaf51011fa /drivers/md/dm-thin.c
parent36f12aeb714fc04752997d6c07b6afb2fa0ac947 (diff)
dm thin: performance improvement to discard processing
When processing a discard bio, if the block is already quiesced do the discard immediately rather than adding the mapping to a list for the next iteration of the worker thread. Discarding a fully provisioned 100G thin volume with 64k block size goes from 860s to 95s with this change. Clearly there's something wrong with the worker architecture, more investigation needed. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-thin.c')
1 files changed, 3 insertions, 7 deletions
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 068607828691..8c3d048dd319 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -1194,7 +1194,6 @@ static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *c
static void process_discard(struct thin_c *tc, struct bio *bio)
int r;
- unsigned long flags;
struct pool *pool = tc->pool;
struct dm_bio_prison_cell *cell, *cell2;
struct dm_cell_key key, key2;
@@ -1235,12 +1234,9 @@ static void process_discard(struct thin_c *tc, struct bio *bio)
m->cell2 = cell2;
m->bio = bio;
- if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list)) {
- spin_lock_irqsave(&pool->lock, flags);
- list_add_tail(&m->list, &pool->prepared_discards);
- spin_unlock_irqrestore(&pool->lock, flags);
- wake_worker(pool);
- }
+ if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list))
+ pool->process_prepared_discard(m);
} else {
inc_all_io_entry(pool, bio);
cell_defer_no_holder(tc, cell);