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authorShaohua Li <shli@fb.com>2017-02-11 03:18:09 +0300
committerShaohua Li <shli@fb.com>2017-02-13 20:20:05 +0300
commite33fbb9cc73d6502e69eaf1c178e0c39059763ea (patch)
tree3a75c9e524eab2facb854a41e970dfb86fc538c1 /drivers/md/raid5-cache.c
parente8fd52eec2cd25b917983b3f3aa738b722522376 (diff)
downloadlinux-e33fbb9cc73d6502e69eaf1c178e0c39059763ea.tar.xz
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 <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md/raid5-cache.c')
-rw-r--r--drivers/md/raid5-cache.c14
1 files changed, 12 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);
}
}