diff options
author | Shaohua Li <shli@kernel.org> | 2012-07-19 08:01:31 +0200 |
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committer | NeilBrown <neilb@suse.de> | 2012-07-19 08:01:31 +0200 |
commit | 4eb788df670ef30a19b7ea15b107ea440544bc80 (patch) | |
tree | 6a99872db014f67e43312afd4a93b3bcffe64506 /drivers/md/raid5.c | |
parent | md/raid1: close some possible races on write errors during resync (diff) | |
download | linux-4eb788df670ef30a19b7ea15b107ea440544bc80.tar.xz linux-4eb788df670ef30a19b7ea15b107ea440544bc80.zip |
raid5: reduce chance release_stripe() taking device_lock
release_stripe() is a place conf->device_lock is heavily contended. We take the
lock even stripe count isn't 1, which isn't required.
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Diffstat (limited to '')
-rw-r--r-- | drivers/md/raid5.c | 75 |
1 files changed, 41 insertions, 34 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 04348d76bb30..848034666342 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -190,49 +190,56 @@ static int stripe_operations_active(struct stripe_head *sh) test_bit(STRIPE_COMPUTE_RUN, &sh->state); } -static void __release_stripe(struct r5conf *conf, struct stripe_head *sh) -{ - if (atomic_dec_and_test(&sh->count)) { - BUG_ON(!list_empty(&sh->lru)); - BUG_ON(atomic_read(&conf->active_stripes)==0); - if (test_bit(STRIPE_HANDLE, &sh->state)) { - if (test_bit(STRIPE_DELAYED, &sh->state) && - !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) - list_add_tail(&sh->lru, &conf->delayed_list); - else if (test_bit(STRIPE_BIT_DELAY, &sh->state) && - sh->bm_seq - conf->seq_write > 0) - list_add_tail(&sh->lru, &conf->bitmap_list); - else { - clear_bit(STRIPE_DELAYED, &sh->state); - clear_bit(STRIPE_BIT_DELAY, &sh->state); - list_add_tail(&sh->lru, &conf->handle_list); - } - md_wakeup_thread(conf->mddev->thread); - } else { - BUG_ON(stripe_operations_active(sh)); - if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) - if (atomic_dec_return(&conf->preread_active_stripes) - < IO_THRESHOLD) - md_wakeup_thread(conf->mddev->thread); - atomic_dec(&conf->active_stripes); - if (!test_bit(STRIPE_EXPANDING, &sh->state)) { - list_add_tail(&sh->lru, &conf->inactive_list); - wake_up(&conf->wait_for_stripe); - if (conf->retry_read_aligned) - md_wakeup_thread(conf->mddev->thread); - } +static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh) +{ + BUG_ON(!list_empty(&sh->lru)); + BUG_ON(atomic_read(&conf->active_stripes)==0); + if (test_bit(STRIPE_HANDLE, &sh->state)) { + if (test_bit(STRIPE_DELAYED, &sh->state) && + !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) + list_add_tail(&sh->lru, &conf->delayed_list); + else if (test_bit(STRIPE_BIT_DELAY, &sh->state) && + sh->bm_seq - conf->seq_write > 0) + list_add_tail(&sh->lru, &conf->bitmap_list); + else { + clear_bit(STRIPE_DELAYED, &sh->state); + clear_bit(STRIPE_BIT_DELAY, &sh->state); + list_add_tail(&sh->lru, &conf->handle_list); + } + md_wakeup_thread(conf->mddev->thread); + } else { + BUG_ON(stripe_operations_active(sh)); + if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) + if (atomic_dec_return(&conf->preread_active_stripes) + < IO_THRESHOLD) + md_wakeup_thread(conf->mddev->thread); + atomic_dec(&conf->active_stripes); + if (!test_bit(STRIPE_EXPANDING, &sh->state)) { + list_add_tail(&sh->lru, &conf->inactive_list); + wake_up(&conf->wait_for_stripe); + if (conf->retry_read_aligned) + md_wakeup_thread(conf->mddev->thread); } } } +static void __release_stripe(struct r5conf *conf, struct stripe_head *sh) +{ + if (atomic_dec_and_test(&sh->count)) + do_release_stripe(conf, sh); +} + static void release_stripe(struct stripe_head *sh) { struct r5conf *conf = sh->raid_conf; unsigned long flags; - spin_lock_irqsave(&conf->device_lock, flags); - __release_stripe(conf, sh); - spin_unlock_irqrestore(&conf->device_lock, flags); + local_irq_save(flags); + if (atomic_dec_and_lock(&sh->count, &conf->device_lock)) { + do_release_stripe(conf, sh); + spin_unlock(&conf->device_lock); + } + local_irq_restore(flags); } static inline void remove_hash(struct stripe_head *sh) |