diff options
Diffstat (limited to 'drivers/md/raid10.c')
| -rw-r--r-- | drivers/md/raid10.c | 135 |
1 files changed, 79 insertions, 56 deletions
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 713dc9c2c73..50bd7b152f2 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -47,6 +47,9 @@ static void unplug_slaves(mddev_t *mddev); +static void allow_barrier(conf_t *conf); +static void lower_barrier(conf_t *conf); + static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data) { conf_t *conf = data; @@ -175,20 +178,13 @@ static void put_all_bios(conf_t *conf, r10bio_t *r10_bio) static inline void free_r10bio(r10bio_t *r10_bio) { - unsigned long flags; - conf_t *conf = mddev_to_conf(r10_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, r10_bio); mempool_free(r10_bio, conf->r10bio_pool); @@ -197,22 +193,10 @@ static inline void free_r10bio(r10bio_t *r10_bio) static inline void put_buf(r10bio_t *r10_bio) { conf_t *conf = mddev_to_conf(r10_bio->mddev); - unsigned long flags; mempool_free(r10_bio, conf->r10buf_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(r10bio_t *r10_bio) @@ -640,30 +624,82 @@ static int raid10_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, unplug_slaves(conf->mddev)); - - if (!conf->barrier++) { - wait_event_lock_irq(conf->wait_idle, !conf->nr_pending, - conf->resync_lock, unplug_slaves(conf->mddev)); - 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, + raid10_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, + raid10_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, + raid10_unplug(conf->mddev->queue)); + conf->nr_waiting--; } - wait_event_lock_irq(conf->wait_resume, conf->barrier < RESYNC_DEPTH, - conf->resync_lock, unplug_slaves(conf->mddev)); - 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); +} + static int make_request(request_queue_t *q, struct bio * bio) { mddev_t *mddev = q->queuedata; @@ -719,10 +755,7 @@ static int make_request(request_queue_t *q, struct bio * bio) * thread has put up a bar for new requests. * Continue immediately if no resync is active currently. */ - 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)); @@ -897,13 +930,8 @@ 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, unplug_slaves(conf->mddev)); - 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->r10buf_pool); conf->r10buf_pool = NULL; @@ -1395,9 +1423,10 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i * If there is non-resync activity waiting for us then * put in a delay to throttle resync. */ - 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; /* Again, very different code for resync and recovery. * Both must result in an r10bio with a list of bios that @@ -1427,7 +1456,6 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO); spin_lock_irq(&conf->resync_lock); - conf->nr_pending++; if (rb2) conf->barrier++; spin_unlock_irq(&conf->resync_lock); atomic_set(&r10_bio->remaining, 0); @@ -1500,10 +1528,6 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i int count = 0; r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO); - spin_lock_irq(&conf->resync_lock); - conf->nr_pending++; - spin_unlock_irq(&conf->resync_lock); - r10_bio->mddev = mddev; atomic_set(&r10_bio->remaining, 0); @@ -1713,8 +1737,7 @@ static int run(mddev_t *mddev) INIT_LIST_HEAD(&conf->retry_list); spin_lock_init(&conf->resync_lock); - init_waitqueue_head(&conf->wait_idle); - init_waitqueue_head(&conf->wait_resume); + init_waitqueue_head(&conf->wait_barrier); /* need to check that every block has at least one working mirror */ if (!enough(conf)) { |