diff options
Diffstat (limited to 'drivers/md/raid1.c')
| -rw-r--r-- | drivers/md/raid1.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index e023a25acf54..d8957d74fd25 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -45,6 +45,11 @@ */ #define NR_RAID1_BIOS 256 +/* When there are this many requests queue to be written by + * the raid1 thread, we become 'congested' to provide back-pressure + * for writeback. + */ +static int max_queued_requests = 1024; static void allow_barrier(struct r1conf *conf); static void lower_barrier(struct r1conf *conf); @@ -598,6 +603,10 @@ int md_raid1_congested(struct mddev *mddev, int bits) struct r1conf *conf = mddev->private; int i, ret = 0; + if ((bits & (1 << BDI_async_congested)) && + conf->pending_count >= max_queued_requests) + return 1; + rcu_read_lock(); for (i = 0; i < mddev->raid_disks; i++) { struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev); @@ -638,10 +647,12 @@ static void flush_pending_writes(struct r1conf *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; @@ -945,6 +956,11 @@ 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 @@ -1108,6 +1124,7 @@ read_again: atomic_inc(&r1_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); } /* Mustn't call r1_bio_write_done before this next test, @@ -2418,6 +2435,7 @@ static struct r1conf *setup_conf(struct mddev *mddev) init_waitqueue_head(&conf->wait_barrier); bio_list_init(&conf->pending_bio_list); + conf->pending_count = 0; conf->last_used = -1; for (i = 0; i < conf->raid_disks; i++) { @@ -2776,3 +2794,5 @@ MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD"); MODULE_ALIAS("md-personality-3"); /* RAID1 */ MODULE_ALIAS("md-raid1"); MODULE_ALIAS("md-level-1"); + +module_param(max_queued_requests, int, S_IRUGO|S_IWUSR); |