From e33fbb9cc73d6502e69eaf1c178e0c39059763ea Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Fri, 10 Feb 2017 16:18:09 -0800 Subject: [PATCH] md/raid5-cache: exclude reclaiming stripes in reclaim check stripes which are being reclaimed are still accounted into cached stripes. The reclaim takes time. r5c_do_reclaim isn't aware of the stripes and does unnecessary stripe reclaim. In practice, I saw one stripe is reclaimed one time. This will cause bad IO pattern. Fixing this by excluding the reclaing stripes in the check. Cc: Song Liu Signed-off-by: Shaohua Li --- drivers/md/raid5-cache.c | 14 ++++++++++++-- drivers/md/raid5.c | 2 ++ drivers/md/raid5.h | 2 ++ 3 files changed, 16 insertions(+), 2 deletions(-) diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c index a01f4daeb390..3f307be01b10 100644 --- a/drivers/md/raid5-cache.c +++ b/drivers/md/raid5-cache.c @@ -1327,6 +1327,10 @@ static void r5c_flush_stripe(struct r5conf *conf, struct stripe_head *sh) atomic_inc(&conf->active_stripes); r5c_make_stripe_write_out(sh); + if (test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) + atomic_inc(&conf->r5c_flushing_partial_stripes); + else + atomic_inc(&conf->r5c_flushing_full_stripes); raid5_release_stripe(sh); } @@ -1369,12 +1373,16 @@ static void r5c_do_reclaim(struct r5conf *conf) unsigned long flags; int total_cached; int stripes_to_flush; + int flushing_partial, flushing_full; if (!r5c_is_writeback(log)) return; + flushing_partial = atomic_read(&conf->r5c_flushing_partial_stripes); + flushing_full = atomic_read(&conf->r5c_flushing_full_stripes); total_cached = atomic_read(&conf->r5c_cached_partial_stripes) + - atomic_read(&conf->r5c_cached_full_stripes); + atomic_read(&conf->r5c_cached_full_stripes) - + flushing_full - flushing_partial; if (total_cached > conf->min_nr_stripes * 3 / 4 || atomic_read(&conf->empty_inactive_list_nr) > 0) @@ -1384,7 +1392,7 @@ static void r5c_do_reclaim(struct r5conf *conf) */ stripes_to_flush = R5C_RECLAIM_STRIPE_GROUP; else if (total_cached > conf->min_nr_stripes * 1 / 2 || - atomic_read(&conf->r5c_cached_full_stripes) > + atomic_read(&conf->r5c_cached_full_stripes) - flushing_full > R5C_FULL_STRIPE_FLUSH_BATCH) /* * if stripe cache pressure moderate, or if there is many full @@ -2601,11 +2609,13 @@ void r5c_finish_stripe_write_out(struct r5conf *conf, if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) { BUG_ON(atomic_read(&conf->r5c_cached_partial_stripes) == 0); + atomic_dec(&conf->r5c_flushing_partial_stripes); atomic_dec(&conf->r5c_cached_partial_stripes); } if (test_and_clear_bit(STRIPE_R5C_FULL_STRIPE, &sh->state)) { BUG_ON(atomic_read(&conf->r5c_cached_full_stripes) == 0); + atomic_dec(&conf->r5c_flushing_full_stripes); atomic_dec(&conf->r5c_cached_full_stripes); } } diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index b0d1345c832c..e2fa88fc6a1b 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -6838,6 +6838,8 @@ static struct r5conf *setup_conf(struct mddev *mddev) INIT_LIST_HEAD(&conf->r5c_full_stripe_list); atomic_set(&conf->r5c_cached_partial_stripes, 0); INIT_LIST_HEAD(&conf->r5c_partial_stripe_list); + atomic_set(&conf->r5c_flushing_full_stripes, 0); + atomic_set(&conf->r5c_flushing_partial_stripes, 0); conf->level = mddev->new_level; conf->chunk_sectors = mddev->new_chunk_sectors; diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h index c0687df5ba06..4bb27b97bf6b 100644 --- a/drivers/md/raid5.h +++ b/drivers/md/raid5.h @@ -663,6 +663,8 @@ struct r5conf { struct list_head r5c_full_stripe_list; atomic_t r5c_cached_partial_stripes; struct list_head r5c_partial_stripe_list; + atomic_t r5c_flushing_full_stripes; + atomic_t r5c_flushing_partial_stripes; atomic_t empty_inactive_list_nr; struct llist_head released_stripes; -- 2.20.1