From 40c57f475f416ab241124e1e6a593b2f982eaae3 Mon Sep 17 00:00:00 2001
From: Joe Thornber <ejt@redhat.com>
Date: Fri, 9 Aug 2013 14:19:32 +0100
Subject: [PATCH] dm space map disk: optimise sm_disk_dec_block
Don't waste time spotting blocks that have been allocated and then freed
in the same transaction.
The extra lookup is expensive, and I don't think it really gives us much.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---
drivers/md/persistent-data/dm-space-map-disk.c | 18 +-----------------
1 file changed, 1 insertion(+), 17 deletions(-)
diff --git a/drivers/md/persistent-data/dm-space-map-disk.c b/drivers/md/persistent-data/dm-space-map-disk.c
index e735a6d5a793..cfbf9617e465 100644
--- a/drivers/md/persistent-data/dm-space-map-disk.c
+++ b/drivers/md/persistent-data/dm-space-map-disk.c
@@ -140,26 +140,10 @@ static int sm_disk_inc_block(struct dm_space_map *sm, dm_block_t b)
static int sm_disk_dec_block(struct dm_space_map *sm, dm_block_t b)
{
- int r;
- uint32_t old_count;
enum allocation_event ev;
struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
- r = sm_ll_dec(&smd->ll, b, &ev);
- if (!r && (ev == SM_FREE)) {
- /*
- * It's only free if it's also free in the last
- * transaction.
- */
- r = sm_ll_lookup(&smd->old_ll, b, &old_count);
- if (r)
- return r;
-
- if (!old_count)
- smd->nr_allocated_this_transaction--;
- }
-
- return r;
+ return sm_ll_dec(&smd->ll, b, &ev);
}
static int sm_disk_new_block(struct dm_space_map *sm, dm_block_t *b)