dm zoned: start reclaim with sequential zones

Sequential zones perform better for reclaim, so start off using
them and only use random zones as a fallback when cache zones are
present.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/dm-zoned-reclaim.c b/drivers/md/dm-zoned-reclaim.c
index bd62245d4556af1f261b95b92222de46d212f2ff..d62f6890b92cd797b6a8941bf326f1b55ed8725c 100644 (file)
--- a/drivers/md/dm-zoned-reclaim.c
+++ b/drivers/md/dm-zoned-reclaim.c
@@ -281,15 +281,16 @@ static int dmz_reclaim_rnd_data(struct dmz_reclaim *zrc, struct dm_zone *dzone)
        struct dm_zone *szone = NULL;
        struct dmz_metadata *zmd = zrc->metadata;
        int ret;
-       int alloc_flags = dmz_nr_cache_zones(zmd) ?
-               DMZ_ALLOC_RND : DMZ_ALLOC_SEQ;
+       int alloc_flags = DMZ_ALLOC_SEQ;
 
-       /* Always use sequential zones to reclaim random zones */
-       if (dmz_is_rnd(dzone))
-               alloc_flags = DMZ_ALLOC_SEQ;
        /* Get a free random or sequential zone */
        dmz_lock_map(zmd);
+again:
        szone = dmz_alloc_zone(zmd, alloc_flags | DMZ_ALLOC_RECLAIM);
+       if (!szone && alloc_flags == DMZ_ALLOC_SEQ && dmz_nr_cache_zones(zmd)) {
+               alloc_flags = DMZ_ALLOC_RND;
+               goto again;
+       }
        dmz_unlock_map(zmd);
        if (!szone)
                return -ENOSPC;