diff options
| author | Shaohua Li <shli@kernel.org> | 2012-08-02 08:33:00 +1000 |
|---|---|---|
| committer | NeilBrown <neilb@suse.de> | 2012-08-02 08:33:00 +1000 |
| commit | 8811b5968f6216e97ccb9fe7b9883af39e339921 (patch) | |
| tree | 9693073f6cb1bcd8743d429d7d3330018bc0ce6d /drivers/md | |
| parent | 74018dc3063a2c729fc73041c0a9f03aac995920 (diff) | |
| download | linux-3.10-8811b5968f6216e97ccb9fe7b9883af39e339921.tar.gz linux-3.10-8811b5968f6216e97ccb9fe7b9883af39e339921.tar.bz2 linux-3.10-8811b5968f6216e97ccb9fe7b9883af39e339921.zip | |
raid5: make_request use batch stripe release
make_request() does stripe release for every stripe and the stripe usually has
count 1, which makes previous release_stripe() optimization not work. In my
test, this release_stripe() becomes the heaviest pleace to take
conf->device_lock after previous patches applied.
Below patch makes stripe release batch. All the stripes will be released in
unplug. The STRIPE_ON_UNPLUG_LIST bit is to protect concurrent access stripe
lru.
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/raid5.c | 62 | ||||
| -rw-r--r-- | drivers/md/raid5.h | 1 |
2 files changed, 60 insertions, 3 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index bde9da2baa3..978ba9b7a3c 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -471,7 +471,8 @@ get_active_stripe(struct r5conf *conf, sector_t sector, } else { if (atomic_read(&sh->count)) { BUG_ON(!list_empty(&sh->lru) - && !test_bit(STRIPE_EXPANDING, &sh->state)); + && !test_bit(STRIPE_EXPANDING, &sh->state) + && !test_bit(STRIPE_ON_UNPLUG_LIST, &sh->state)); } else { if (!test_bit(STRIPE_HANDLE, &sh->state)) atomic_inc(&conf->active_stripes); @@ -3988,6 +3989,62 @@ static struct stripe_head *__get_priority_stripe(struct r5conf *conf) return sh; } +struct raid5_plug_cb { + struct blk_plug_cb cb; + struct list_head list; +}; + +static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule) +{ + struct raid5_plug_cb *cb = container_of( + blk_cb, struct raid5_plug_cb, cb); + struct stripe_head *sh; + struct mddev *mddev = cb->cb.data; + struct r5conf *conf = mddev->private; + + if (cb->list.next && !list_empty(&cb->list)) { + spin_lock_irq(&conf->device_lock); + while (!list_empty(&cb->list)) { + sh = list_first_entry(&cb->list, struct stripe_head, lru); + list_del_init(&sh->lru); + /* + * avoid race release_stripe_plug() sees + * STRIPE_ON_UNPLUG_LIST clear but the stripe + * is still in our list + */ + smp_mb__before_clear_bit(); + clear_bit(STRIPE_ON_UNPLUG_LIST, &sh->state); + __release_stripe(conf, sh); + } + spin_unlock_irq(&conf->device_lock); + } + kfree(cb); +} + +static void release_stripe_plug(struct mddev *mddev, + struct stripe_head *sh) +{ + struct blk_plug_cb *blk_cb = blk_check_plugged( + raid5_unplug, mddev, + sizeof(struct raid5_plug_cb)); + struct raid5_plug_cb *cb; + + if (!blk_cb) { + release_stripe(sh); + return; + } + + cb = container_of(blk_cb, struct raid5_plug_cb, cb); + + if (cb->list.next == NULL) + INIT_LIST_HEAD(&cb->list); + + if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST, &sh->state)) + list_add_tail(&sh->lru, &cb->list); + else + release_stripe(sh); +} + static void make_request(struct mddev *mddev, struct bio * bi) { struct r5conf *conf = mddev->private; @@ -4116,8 +4173,7 @@ static void make_request(struct mddev *mddev, struct bio * bi) if ((bi->bi_rw & REQ_SYNC) && !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) atomic_inc(&conf->preread_active_stripes); - mddev_check_plugged(mddev); - release_stripe(sh); + release_stripe_plug(mddev, sh); } else { /* cannot get stripe for read-ahead, just give-up */ clear_bit(BIO_UPTODATE, &bi->bi_flags); diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h index 2164021f3b5..9a7b36f0a42 100644 --- a/drivers/md/raid5.h +++ b/drivers/md/raid5.h @@ -319,6 +319,7 @@ enum { STRIPE_BIOFILL_RUN, STRIPE_COMPUTE_RUN, STRIPE_OPS_REQ_PENDING, + STRIPE_ON_UNPLUG_LIST, }; /* |