From: Joe Thornber <ejt@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
---
drivers/md/dm-thin.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 73a1c96..fffdebc 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);
--
1.8.3.1
--
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