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authorJoe Thornber <ejt@redhat.com>2014-10-06 15:28:30 +0100
committerMike Snitzer <snitzer@redhat.com>2014-11-10 15:25:27 -0500
commit8a01a6af75f839ff8eb25dab69b49224e855bfa1 (patch)
tree6e0c31ce682332cd8af5d6f77037b56421507542 /drivers/md
parent4646015d7e4ca5a4dc19427fb0a0aeff15a4fd91 (diff)
downloadlinux-8a01a6af75f839ff8eb25dab69b49224e855bfa1.tar.gz
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: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/dm-thin-metadata.c5
-rw-r--r--drivers/md/dm-thin-metadata.h5
-rw-r--r--drivers/md/dm-thin.c10
3 files changed, 16 insertions, 4 deletions
diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index ee42d1c52387..43adbb863f5a 100644
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -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);
+}
diff --git a/drivers/md/dm-thin-metadata.h b/drivers/md/dm-thin-metadata.h
index efedd5a4cd8f..921d15ee56a0 100644
--- a/drivers/md/dm-thin-metadata.h
+++ b/drivers/md/dm-thin-metadata.h
@@ -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
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index eecfe7495232..97a7eb4d0412 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -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;