diff options
Diffstat (limited to 'drivers/md/raid10.c')
| -rw-r--r-- | drivers/md/raid10.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 8427ff1c5af1..9496463ca5df 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -58,6 +58,12 @@ */ #define NR_RAID10_BIOS 256 +/* When there are this many requests queue to be written by + * the raid10 thread, we become 'congested' to provide back-pressure + * for writeback. + */ +static int max_queued_requests = 1024; + static void allow_barrier(struct r10conf *conf); static void lower_barrier(struct r10conf *conf); @@ -681,6 +687,10 @@ static int raid10_congested(void *data, int bits) struct r10conf *conf = mddev->private; int i, ret = 0; + if ((bits & (1 << BDI_async_congested)) && + conf->pending_count >= max_queued_requests) + return 1; + if (mddev_congested(mddev, bits)) return 1; rcu_read_lock(); @@ -706,10 +716,12 @@ static void flush_pending_writes(struct r10conf *conf) if (conf->pending_bio_list.head) { struct bio *bio; bio = bio_list_get(&conf->pending_bio_list); + conf->pending_count = 0; spin_unlock_irq(&conf->device_lock); /* flush any pending bitmap writes to disk * before proceeding w/ I/O */ bitmap_unplug(conf->mddev->bitmap); + wake_up(&conf->wait_barrier); while (bio) { /* submit pending writes */ struct bio *next = bio->bi_next; @@ -996,6 +1008,11 @@ read_again: /* * WRITE: */ + if (conf->pending_count >= max_queued_requests) { + md_wakeup_thread(mddev->thread); + wait_event(conf->wait_barrier, + conf->pending_count < max_queued_requests); + } /* first select target devices under rcu_lock and * inc refcount on their rdev. Record them by setting * bios[x] to bio @@ -1129,6 +1146,7 @@ retry_write: atomic_inc(&r10_bio->remaining); spin_lock_irqsave(&conf->device_lock, flags); bio_list_add(&conf->pending_bio_list, mbio); + conf->pending_count++; spin_unlock_irqrestore(&conf->device_lock, flags); } @@ -3086,3 +3104,5 @@ MODULE_DESCRIPTION("RAID10 (striped mirror) personality for MD"); MODULE_ALIAS("md-personality-9"); /* RAID10 */ MODULE_ALIAS("md-raid10"); MODULE_ALIAS("md-level-10"); + +module_param(max_queued_requests, int, S_IRUGO|S_IWUSR); |