Commit 8a01a6af authored by Joe Thornber's avatar Joe Thornber Committed by Mike Snitzer
Browse files

dm thin: prefetch missing metadata pages 



Prefetch metadata at the start of the worker thread and then again every
128th bio processed from the deferred list.

Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 4646015d

drivers/md/dm-thin-metadata.c

+5 −0
Original line number Diff line number Diff line
@@ -1809,3 +1809,8 @@ bool dm_pool_metadata_needs_check(struct dm_pool_metadata *pmd) 


	return needs_check;

}



void dm_pool_issue_prefetches(struct dm_pool_metadata *pmd)

{

	dm_tm_issue_prefetches(pmd->tm);

}

drivers/md/dm-thin-metadata.h

+5 −0
Original line number Diff line number Diff line
@@ -213,6 +213,11 @@ int dm_pool_register_metadata_threshold(struct dm_pool_metadata *pmd, 
int dm_pool_metadata_set_needs_check(struct dm_pool_metadata *pmd);

bool dm_pool_metadata_needs_check(struct dm_pool_metadata *pmd);



/*

 * Issue any prefetches that may be useful.

 */

void dm_pool_issue_prefetches(struct dm_pool_metadata *pmd);



/*----------------------------------------------------------------*/



#endif

drivers/md/dm-thin.c

+6 −4
Original line number Diff line number Diff line
@@ -1526,6 +1526,7 @@ static void process_thin_deferred_bios(struct thin_c *tc) 
	struct bio *bio;

	struct bio_list bios;

	struct blk_plug plug;

	unsigned count = 0;



	if (tc->requeue_mode) {

		requeue_bio_list(tc, &tc->deferred_bio_list);
@@ -1567,6 +1568,10 @@ static void process_thin_deferred_bios(struct thin_c *tc) 
			pool->process_discard(tc, bio);

		else

			pool->process_bio(tc, bio);



		if ((count++ & 127) == 0) {

			dm_pool_issue_prefetches(pool->pmd);

		}

	}

	blk_finish_plug(&plug);

}
@@ -1652,6 +1657,7 @@ static void do_worker(struct work_struct *ws) 
{

	struct pool *pool = container_of(ws, struct pool, worker);



	dm_pool_issue_prefetches(pool->pmd);

	process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);

	process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);

	process_deferred_bios(pool);
@@ -1996,10 +2002,6 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio) 
		/* fall through */



	case -EWOULDBLOCK:

		/*

		 * In future, the failed dm_thin_find_block above could

		 * provide the hint to load the metadata into cache.

		 */

		thin_defer_bio(tc, bio);

		cell_defer_no_holder_no_free(tc, &cell1);

		return DM_MAPIO_SUBMITTED;