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Commit 40c57f47 authored by Joe Thornber's avatar Joe Thornber Committed by Mike Snitzer
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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: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 41d35d25

drivers/md/persistent-data/dm-space-map-disk.c

+1 −17
Original line number Diff line number Diff line
@@ -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)