diff options
| -rw-r--r-- | drivers/md/raid1.c | 56 | ||||
| -rw-r--r-- | drivers/md/raid1.h | 1 |
2 files changed, 50 insertions, 7 deletions
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index d9869f2..7aa958e 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -504,6 +504,7 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect unsigned int min_pending; struct md_rdev *rdev; int choose_first; + int choose_next_idle; rcu_read_lock(); /* @@ -520,6 +521,7 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect min_pending = UINT_MAX; best_good_sectors = 0; has_nonrot_disk = 0; + choose_next_idle = 0; if (conf->mddev->recovery_cp < MaxSector && (this_sector + sectors >= conf->next_resync)) @@ -532,6 +534,7 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect sector_t first_bad; int bad_sectors; unsigned int pending; + bool nonrot; rdev = rcu_dereference(conf->mirrors[disk].rdev); if (r1_bio->bios[disk] == IO_BLOCKED @@ -590,18 +593,52 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect } else best_good_sectors = sectors; - has_nonrot_disk |= blk_queue_nonrot(bdev_get_queue(rdev->bdev)); + nonrot = blk_queue_nonrot(bdev_get_queue(rdev->bdev)); + has_nonrot_disk |= nonrot; pending = atomic_read(&rdev->nr_pending); dist = abs(this_sector - conf->mirrors[disk].head_position); - if (choose_first - /* Don't change to another disk for sequential reads */ - || conf->mirrors[disk].next_seq_sect == this_sector - || dist == 0 - /* If device is idle, use it */ - || pending == 0) { + if (choose_first) { best_disk = disk; break; } + /* Don't change to another disk for sequential reads */ + if (conf->mirrors[disk].next_seq_sect == this_sector + || dist == 0) { + int opt_iosize = bdev_io_opt(rdev->bdev) >> 9; + struct raid1_info *mirror = &conf->mirrors[disk]; + + best_disk = disk; + /* + * If buffered sequential IO size exceeds optimal + * iosize, check if there is idle disk. If yes, choose + * the idle disk. read_balance could already choose an + * idle disk before noticing it's a sequential IO in + * this disk. This doesn't matter because this disk + * will idle, next time it will be utilized after the + * first disk has IO size exceeds optimal iosize. In + * this way, iosize of the first disk will be optimal + * iosize at least. iosize of the second disk might be + * small, but not a big deal since when the second disk + * starts IO, the first disk is likely still busy. + */ + if (nonrot && opt_iosize > 0 && + mirror->seq_start != MaxSector && + mirror->next_seq_sect > opt_iosize && + mirror->next_seq_sect - opt_iosize >= + mirror->seq_start) { + choose_next_idle = 1; + continue; + } + break; + } + /* If device is idle, use it */ + if (pending == 0) { + best_disk = disk; + break; + } + + if (choose_next_idle) + continue; if (min_pending > pending) { min_pending = pending; @@ -640,6 +677,10 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect goto retry; } sectors = best_good_sectors; + + if (conf->mirrors[best_disk].next_seq_sect != this_sector) + conf->mirrors[best_disk].seq_start = this_sector; + conf->mirrors[best_disk].next_seq_sect = this_sector + sectors; } rcu_read_unlock(); @@ -2605,6 +2646,7 @@ static struct r1conf *setup_conf(struct mddev *mddev) mddev->merge_check_needed = 1; disk->head_position = 0; + disk->seq_start = MaxSector; } conf->raid_disks = mddev->raid_disks; conf->mddev = mddev; diff --git a/drivers/md/raid1.h b/drivers/md/raid1.h index 3770b4a..0ff3715 100644 --- a/drivers/md/raid1.h +++ b/drivers/md/raid1.h @@ -9,6 +9,7 @@ struct raid1_info { * we try to keep sequential reads one the same device */ sector_t next_seq_sect; + sector_t seq_start; }; /* |
