diff options
Diffstat (limited to 'drivers/md/raid1.c')
| -rw-r--r-- | drivers/md/raid1.c | 32 |
1 files changed, 22 insertions, 10 deletions
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index de6ea87d4d24..fa86d9fdb16f 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -598,13 +598,12 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect const sector_t this_sector = r1_bio->sector; int sectors; int best_good_sectors; - int best_disk, best_dist_disk, best_pending_disk; + int best_disk, best_dist_disk, best_pending_disk, sequential_disk; int disk; sector_t best_dist; unsigned int min_pending; struct md_rdev *rdev; int choose_first; - int choose_next_idle; /* * Check if we can balance. We can balance on the whole @@ -615,11 +614,11 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect sectors = r1_bio->sectors; best_disk = -1; best_dist_disk = -1; + sequential_disk = -1; best_dist = MaxSector; best_pending_disk = -1; min_pending = UINT_MAX; best_good_sectors = 0; - choose_next_idle = 0; clear_bit(R1BIO_FailFast, &r1_bio->state); if ((conf->mddev->recovery_cp < this_sector + sectors) || @@ -712,7 +711,6 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect 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 @@ -731,15 +729,22 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect mirror->next_seq_sect > opt_iosize && mirror->next_seq_sect - opt_iosize >= mirror->seq_start) { - choose_next_idle = 1; - continue; + /* + * Add 'pending' to avoid choosing this disk if + * there is other idle disk. + */ + pending++; + /* + * If there is no other idle disk, this disk + * will be chosen. + */ + sequential_disk = disk; + } else { + best_disk = disk; + break; } - break; } - if (choose_next_idle) - continue; - if (min_pending > pending) { min_pending = pending; best_pending_disk = disk; @@ -752,6 +757,13 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect } /* + * sequential IO size exceeds optimal iosize, however, there is no other + * idle disk, so choose the sequential disk. + */ + if (best_disk == -1 && min_pending != 0) + best_disk = sequential_disk; + + /* * If all disks are rotational, choose the closest disk. If any disk is * non-rotational, choose the disk with less pending request even the * disk is rotational, which might/might not be optimal for raids with |