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authorShaohua Li <shli@kernel.org>2013-11-14 15:16:17 +1100
committerNeilBrown <neilb@suse.de>2013-11-19 15:18:22 +1100
commit4bda556aea1d2916260326c6afa77b84a1f1345a (patch)
tree5233a0470d29eb5976ec9f6296ef129adf097ed8
parent566c09c53455d7c4f1130928ef8071da1a24ea65 (diff)
downloadlinux-4bda556aea1d2916260326c6afa77b84a1f1345a.tar.bz2
raid5: relieve lock contention in get_active_stripe()
track empty inactive list count, so md_raid5_congested() can use it to make decision. Signed-off-by: Shaohua Li <shli@fusionio.com> Signed-off-by: NeilBrown <neilb@suse.de>
-rw-r--r--drivers/md/raid5.c8
-rw-r--r--drivers/md/raid5.h1
2 files changed, 8 insertions, 1 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 93090b2afab4..1fb28c56457a 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -356,6 +356,9 @@ static void release_inactive_stripe_list(struct r5conf *conf,
*/
if (!list_empty_careful(list)) {
spin_lock_irqsave(conf->hash_locks + hash, flags);
+ if (list_empty(conf->inactive_list + hash) &&
+ !list_empty(list))
+ atomic_dec(&conf->empty_inactive_list_nr);
list_splice_tail_init(list, conf->inactive_list + hash);
do_wakeup = true;
spin_unlock_irqrestore(conf->hash_locks + hash, flags);
@@ -477,6 +480,8 @@ static struct stripe_head *get_free_stripe(struct r5conf *conf, int hash)
remove_hash(sh);
atomic_inc(&conf->active_stripes);
BUG_ON(hash != sh->hash_lock_index);
+ if (list_empty(conf->inactive_list + hash))
+ atomic_inc(&conf->empty_inactive_list_nr);
out:
return sh;
}
@@ -4059,7 +4064,7 @@ int md_raid5_congested(struct mddev *mddev, int bits)
return 1;
if (conf->quiesce)
return 1;
- if (atomic_read(&conf->active_stripes) == conf->max_nr_stripes)
+ if (atomic_read(&conf->empty_inactive_list_nr))
return 1;
return 0;
@@ -5750,6 +5755,7 @@ static struct r5conf *setup_conf(struct mddev *mddev)
memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
+ atomic_set(&conf->empty_inactive_list_nr, NR_STRIPE_HASH_LOCKS);
if (grow_stripes(conf, NR_STRIPES)) {
printk(KERN_ERR
"md/raid:%s: couldn't allocate %dkB for buffers\n",
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index a9e443a1116f..e4407388670a 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -475,6 +475,7 @@ struct r5conf {
*/
atomic_t active_stripes;
struct list_head inactive_list[NR_STRIPE_HASH_LOCKS];
+ atomic_t empty_inactive_list_nr;
struct llist_head released_stripes;
wait_queue_head_t wait_for_stripe;
wait_queue_head_t wait_for_overlap;