diff options
| -rw-r--r-- | drivers/md/raid1.c | 167 | ||||
| -rw-r--r-- | include/linux/raid/raid1.h | 4 |
2 files changed, 91 insertions, 80 deletions
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 229d7b204297..f5204149ab65 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -51,6 +51,8 @@ static mdk_personality_t raid1_personality; static void unplug_slaves(mddev_t *mddev); +static void allow_barrier(conf_t *conf); +static void lower_barrier(conf_t *conf); static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data) { @@ -160,20 +162,13 @@ static void put_all_bios(conf_t *conf, r1bio_t *r1_bio) static inline void free_r1bio(r1bio_t *r1_bio) { - unsigned long flags; - conf_t *conf = mddev_to_conf(r1_bio->mddev); /* * Wake up any possible resync thread that waits for the device * to go idle. */ - spin_lock_irqsave(&conf->resync_lock, flags); - if (!--conf->nr_pending) { - wake_up(&conf->wait_idle); - wake_up(&conf->wait_resume); - } - spin_unlock_irqrestore(&conf->resync_lock, flags); + allow_barrier(conf); put_all_bios(conf, r1_bio); mempool_free(r1_bio, conf->r1bio_pool); @@ -182,22 +177,10 @@ static inline void free_r1bio(r1bio_t *r1_bio) static inline void put_buf(r1bio_t *r1_bio) { conf_t *conf = mddev_to_conf(r1_bio->mddev); - unsigned long flags; mempool_free(r1_bio, conf->r1buf_pool); - spin_lock_irqsave(&conf->resync_lock, flags); - if (!conf->barrier) - BUG(); - --conf->barrier; - wake_up(&conf->wait_resume); - wake_up(&conf->wait_idle); - - if (!--conf->nr_pending) { - wake_up(&conf->wait_idle); - wake_up(&conf->wait_resume); - } - spin_unlock_irqrestore(&conf->resync_lock, flags); + lower_barrier(conf); } static void reschedule_retry(r1bio_t *r1_bio) @@ -210,6 +193,7 @@ static void reschedule_retry(r1bio_t *r1_bio) list_add(&r1_bio->retry_list, &conf->retry_list); spin_unlock_irqrestore(&conf->device_lock, flags); + wake_up(&conf->wait_barrier); md_wakeup_thread(mddev->thread); } @@ -593,30 +577,83 @@ static int raid1_issue_flush(request_queue_t *q, struct gendisk *disk, return ret; } -/* - * Throttle resync depth, so that we can both get proper overlapping of - * requests, but are still able to handle normal requests quickly. +/* Barriers.... + * Sometimes we need to suspend IO while we do something else, + * either some resync/recovery, or reconfigure the array. + * To do this we raise a 'barrier'. + * The 'barrier' is a counter that can be raised multiple times + * to count how many activities are happening which preclude + * normal IO. + * We can only raise the barrier if there is no pending IO. + * i.e. if nr_pending == 0. + * We choose only to raise the barrier if no-one is waiting for the + * barrier to go down. This means that as soon as an IO request + * is ready, no other operations which require a barrier will start + * until the IO request has had a chance. + * + * So: regular IO calls 'wait_barrier'. When that returns there + * is no backgroup IO happening, It must arrange to call + * allow_barrier when it has finished its IO. + * backgroup IO calls must call raise_barrier. Once that returns + * there is no normal IO happeing. It must arrange to call + * lower_barrier when the particular background IO completes. */ #define RESYNC_DEPTH 32 -static void device_barrier(conf_t *conf, sector_t sect) +static void raise_barrier(conf_t *conf) { spin_lock_irq(&conf->resync_lock); - wait_event_lock_irq(conf->wait_idle, !waitqueue_active(&conf->wait_resume), - conf->resync_lock, raid1_unplug(conf->mddev->queue)); - - if (!conf->barrier++) { - wait_event_lock_irq(conf->wait_idle, !conf->nr_pending, - conf->resync_lock, raid1_unplug(conf->mddev->queue)); - if (conf->nr_pending) - BUG(); + + /* Wait until no block IO is waiting */ + wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting, + conf->resync_lock, + raid1_unplug(conf->mddev->queue)); + + /* block any new IO from starting */ + conf->barrier++; + + /* No wait for all pending IO to complete */ + wait_event_lock_irq(conf->wait_barrier, + !conf->nr_pending && conf->barrier < RESYNC_DEPTH, + conf->resync_lock, + raid1_unplug(conf->mddev->queue)); + + spin_unlock_irq(&conf->resync_lock); +} + +static void lower_barrier(conf_t *conf) +{ + unsigned long flags; + spin_lock_irqsave(&conf->resync_lock, flags); + conf->barrier--; + spin_unlock_irqrestore(&conf->resync_lock, flags); + wake_up(&conf->wait_barrier); +} + +static void wait_barrier(conf_t *conf) +{ + spin_lock_irq(&conf->resync_lock); + if (conf->barrier) { + conf->nr_waiting++; + wait_event_lock_irq(conf->wait_barrier, !conf->barrier, + conf->resync_lock, + raid1_unplug(conf->mddev->queue)); + conf->nr_waiting--; } - wait_event_lock_irq(conf->wait_resume, conf->barrier < RESYNC_DEPTH, - conf->resync_lock, raid1_unplug(conf->mddev->queue)); - conf->next_resync = sect; + conf->nr_pending++; spin_unlock_irq(&conf->resync_lock); } +static void allow_barrier(conf_t *conf) +{ + unsigned long flags; + spin_lock_irqsave(&conf->resync_lock, flags); + conf->nr_pending--; + spin_unlock_irqrestore(&conf->resync_lock, flags); + wake_up(&conf->wait_barrier); +} + + /* duplicate the data pages for behind I/O */ static struct page **alloc_behind_pages(struct bio *bio) { @@ -678,10 +715,7 @@ static int make_request(request_queue_t *q, struct bio * bio) */ md_write_start(mddev, bio); /* wait on superblock update early */ - spin_lock_irq(&conf->resync_lock); - wait_event_lock_irq(conf->wait_resume, !conf->barrier, conf->resync_lock, ); - conf->nr_pending++; - spin_unlock_irq(&conf->resync_lock); + wait_barrier(conf); disk_stat_inc(mddev->gendisk, ios[rw]); disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio)); @@ -909,13 +943,8 @@ static void print_conf(conf_t *conf) static void close_sync(conf_t *conf) { - spin_lock_irq(&conf->resync_lock); - wait_event_lock_irq(conf->wait_resume, !conf->barrier, - conf->resync_lock, raid1_unplug(conf->mddev->queue)); - spin_unlock_irq(&conf->resync_lock); - - if (conf->barrier) BUG(); - if (waitqueue_active(&conf->wait_idle)) BUG(); + wait_barrier(conf); + allow_barrier(conf); mempool_destroy(conf->r1buf_pool); conf->r1buf_pool = NULL; @@ -1317,12 +1346,16 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i return sync_blocks; } /* - * If there is non-resync activity waiting for us then - * put in a delay to throttle resync. + * If there is non-resync activity waiting for a turn, + * and resync is going fast enough, + * then let it though before starting on this new sync request. */ - if (!go_faster && waitqueue_active(&conf->wait_resume)) + if (!go_faster && conf->nr_waiting) msleep_interruptible(1000); - device_barrier(conf, sector_nr + RESYNC_SECTORS); + + raise_barrier(conf); + + conf->next_resync = sector_nr; /* * If reconstructing, and >1 working disc, @@ -1355,10 +1388,6 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO); - spin_lock_irq(&conf->resync_lock); - conf->nr_pending++; - spin_unlock_irq(&conf->resync_lock); - r1_bio->mddev = mddev; r1_bio->sector = sector_nr; r1_bio->state = 0; @@ -1542,8 +1571,7 @@ static int run(mddev_t *mddev) mddev->recovery_cp = MaxSector; spin_lock_init(&conf->resync_lock); - init_waitqueue_head(&conf->wait_idle); - init_waitqueue_head(&conf->wait_resume); + init_waitqueue_head(&conf->wait_barrier); bio_list_init(&conf->pending_bio_list); bio_list_init(&conf->flushing_bio_list); @@ -1714,11 +1742,7 @@ static int raid1_reshape(mddev_t *mddev, int raid_disks) } memset(newmirrors, 0, sizeof(struct mirror_info)*raid_disks); - spin_lock_irq(&conf->resync_lock); - conf->barrier++; - wait_event_lock_irq(conf->wait_idle, !conf->nr_pending, - conf->resync_lock, raid1_unplug(mddev->queue)); - spin_unlock_irq(&conf->resync_lock); + raise_barrier(conf); /* ok, everything is stopped */ oldpool = conf->r1bio_pool; @@ -1738,12 +1762,7 @@ static int raid1_reshape(mddev_t *mddev, int raid_disks) conf->raid_disks = mddev->raid_disks = raid_disks; conf->last_used = 0; /* just make sure it is in-range */ - spin_lock_irq(&conf->resync_lock); - conf->barrier--; - spin_unlock_irq(&conf->resync_lock); - wake_up(&conf->wait_resume); - wake_up(&conf->wait_idle); - + lower_barrier(conf); set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); md_wakeup_thread(mddev->thread); @@ -1758,18 +1777,10 @@ static void raid1_quiesce(mddev_t *mddev, int state) switch(state) { case 1: - spin_lock_irq(&conf->resync_lock); - conf->barrier++; - wait_event_lock_irq(conf->wait_idle, !conf->nr_pending, - conf->resync_lock, raid1_unplug(mddev->queue)); - spin_unlock_irq(&conf->resync_lock); + raise_barrier(conf); break; case 0: - spin_lock_irq(&conf->resync_lock); - conf->barrier--; - spin_unlock_irq(&conf->resync_lock); - wake_up(&conf->wait_resume); - wake_up(&conf->wait_idle); + lower_barrier(conf); break; } if (mddev->thread) { diff --git a/include/linux/raid/raid1.h b/include/linux/raid/raid1.h index 292b98f2b408..c55674252533 100644 --- a/include/linux/raid/raid1.h +++ b/include/linux/raid/raid1.h @@ -45,6 +45,7 @@ struct r1_private_data_s { spinlock_t resync_lock; int nr_pending; + int nr_waiting; int barrier; sector_t next_resync; int fullsync; /* set to 1 if a full sync is needed, @@ -52,8 +53,7 @@ struct r1_private_data_s { * Cleared when a sync completes. */ - wait_queue_head_t wait_idle; - wait_queue_head_t wait_resume; + wait_queue_head_t wait_barrier; struct pool_info *poolinfo; |