dm bio prison: switch to using a red black tree
Previously it was using a fixed sized hash table. There are times
when very many concurrent cells are held (such as when processing a very
large discard). When this happens the hash table performance becomes
very poor.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
diff --git a/drivers/md/dm-bio-prison.h b/drivers/md/dm-bio-prison.h
index 6805a14..997a439 100644
--- a/drivers/md/dm-bio-prison.h
+++ b/drivers/md/dm-bio-prison.h
@@ -10,8 +10,8 @@
#include "persistent-data/dm-block-manager.h" /* FIXME: for dm_block_t */
#include "dm-thin-metadata.h" /* FIXME: for dm_thin_id */
-#include <linux/list.h>
#include <linux/bio.h>
+#include <linux/rbtree.h>
/*----------------------------------------------------------------*/
@@ -35,13 +35,14 @@
* themselves.
*/
struct dm_bio_prison_cell {
- struct hlist_node list;
+ struct rb_node node;
+
struct dm_cell_key key;
struct bio *holder;
struct bio_list bios;
};
-struct dm_bio_prison *dm_bio_prison_create(unsigned nr_cells);
+struct dm_bio_prison *dm_bio_prison_create(void);
void dm_bio_prison_destroy(struct dm_bio_prison *prison);
/*