From: Yu Kuai <yukuai3@xxxxxxxxxx>
For raid1/raid10, each read will iterate all the rdevs from conf and
check if any rdev is non-rotational, then choose rdev with minimal IO
inflight if so, or rdev with closest distance otherwise.
Disk nonrot info can be changed through sysfs entry:
/sys/block/[disk_name]/queue/rotational
However, consider that this should only be used for testing, and user
really shouldn't do this in real life. Record the number of non-rotational
disks in mddev, to avoid checking each rdev in IO fast path and simplify
read_balance() a little bit.
Co-developed-by: Paul Luse <paul.e.luse@xxxxxxxxxxxxxxx>
Signed-off-by: Paul Luse <paul.e.luse@xxxxxxxxxxxxxxx>
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
drivers/md/md.c | 28 ++++++++++++++++++++++++++--
drivers/md/md.h | 2 ++
drivers/md/raid1.c | 9 ++-------
drivers/md/raid10.c | 8 ++------
4 files changed, 32 insertions(+), 15 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index e2a5f513dbb7..9e671eec9309 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -146,6 +146,24 @@ static inline int speed_max(struct mddev *mddev)
mddev->sync_speed_max : sysctl_speed_limit_max;
}
+static void rdev_update_nonrot(struct md_rdev *rdev)
+{
+ if (!bdev_nonrot(rdev->bdev))
+ return;
+
+ set_bit(Nonrot, &rdev->flags);
+ WRITE_ONCE(rdev->mddev->nonrot_disks, rdev->mddev->nonrot_disks + 1);
+}
+
+static void rdev_clear_nonrot(struct md_rdev *rdev)
+{
+ if (!test_bit(Nonrot, &rdev->flags))
+ return;
+
+ clear_bit(Nonrot, &rdev->flags);
+ WRITE_ONCE(rdev->mddev->nonrot_disks, rdev->mddev->nonrot_disks - 1);
+}
+
static void rdev_uninit_serial(struct md_rdev *rdev)
{
if (!test_and_clear_bit(CollisionCheck, &rdev->flags))
@@ -2922,6 +2940,8 @@ static int add_bound_rdev(struct md_rdev *rdev)
md_kick_rdev_from_array(rdev);
return err;
}
+
+ rdev_update_nonrot(rdev);
}
sysfs_notify_dirent_safe(rdev->sysfs_state);
@@ -3271,8 +3291,10 @@ slot_store(struct md_rdev *rdev, const char *buf, size_t len)
if (err) {
rdev->raid_disk = -1;
return err;
- } else
- sysfs_notify_dirent_safe(rdev->sysfs_state);
+ }
+
+ rdev_update_nonrot(rdev);
+ sysfs_notify_dirent_safe(rdev->sysfs_state);
/* failure here is OK */;
sysfs_link_rdev(rdev->mddev, rdev);
/* don't wakeup anyone, leave that to userspace. */
@@ -9266,6 +9288,7 @@ static int remove_and_add_spares(struct mddev *mddev,
rdev_for_each(rdev, mddev) {
if ((this == NULL || rdev == this) && rdev_removeable(rdev) &&
!mddev->pers->hot_remove_disk(mddev, rdev)) {
+ rdev_clear_nonrot(rdev);
sysfs_unlink_rdev(mddev, rdev);
rdev->saved_raid_disk = rdev->raid_disk;
rdev->raid_disk = -1;
@@ -9289,6 +9312,7 @@ static int remove_and_add_spares(struct mddev *mddev,
if (!test_bit(Journal, &rdev->flags))
rdev->recovery_offset = 0;
if (mddev->pers->hot_add_disk(mddev, rdev) == 0) {
+ rdev_update_nonrot(rdev);
/* failure here is OK */
sysfs_link_rdev(mddev, rdev);
if (!test_bit(Journal, &rdev->flags))
diff --git a/drivers/md/md.h b/drivers/md/md.h
index a49ab04ab707..54aa951f2bba 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -207,6 +207,7 @@ enum flag_bits {
* check if there is collision between raid1
* serial bios.
*/
+ Nonrot, /* non-rotational device (SSD) */
};
static inline int is_badblock(struct md_rdev *rdev, sector_t s, int sectors,
@@ -312,6 +313,7 @@ struct mddev {
unsigned long flags;
unsigned long sb_flags;
+ int nonrot_disks;
int suspended;
struct mutex suspend_mutex;
struct percpu_ref active_io;
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index a145fe48b9ce..c60ea58ae8c5 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -599,7 +599,6 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
int sectors;
int best_good_sectors;
int best_disk, best_dist_disk, best_pending_disk;
- int has_nonrot_disk;
int disk;
sector_t best_dist;
unsigned int min_pending;
@@ -620,7 +619,6 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
best_pending_disk = -1;
min_pending = UINT_MAX;
best_good_sectors = 0;
- has_nonrot_disk = 0;
choose_next_idle = 0;
clear_bit(R1BIO_FailFast, &r1_bio->state);
@@ -637,7 +635,6 @@ 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 = conf->mirrors[disk].rdev;
if (r1_bio->bios[disk] == IO_BLOCKED
@@ -703,8 +700,6 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
/* At least two disks to choose from so failfast is OK */
set_bit(R1BIO_FailFast, &r1_bio->state);
- nonrot = bdev_nonrot(rdev->bdev);
- has_nonrot_disk |= nonrot;
pending = atomic_read(&rdev->nr_pending);
dist = abs(this_sector - conf->mirrors[disk].head_position);
if (choose_first) {
@@ -731,7 +726,7 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
* 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 &&
+ if (test_bit(Nonrot, &rdev->flags) && opt_iosize > 0 &&
mirror->seq_start != MaxSector &&
mirror->next_seq_sect > opt_iosize &&
mirror->next_seq_sect - opt_iosize >=
@@ -763,7 +758,7 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
* mixed ratation/non-rotational disks depending on workload.
*/
if (best_disk == -1) {
- if (has_nonrot_disk || min_pending == 0)
+ if (conf->mddev->nonrot_disks || min_pending == 0)
best_disk = best_pending_disk;
else
best_disk = best_dist_disk;
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index d5a7a621f0f0..1f6693e40e12 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -735,7 +735,6 @@ static struct md_rdev *read_balance(struct r10conf *conf,
struct md_rdev *best_dist_rdev, *best_pending_rdev, *rdev = NULL;
int do_balance;
int best_dist_slot, best_pending_slot;
- bool has_nonrot_disk = false;
unsigned int min_pending;
struct geom *geo = &conf->geo;
@@ -766,7 +765,6 @@ static struct md_rdev *read_balance(struct r10conf *conf,
int bad_sectors;
sector_t dev_sector;
unsigned int pending;
- bool nonrot;
if (r10_bio->devs[slot].bio == IO_BLOCKED)
continue;
@@ -818,10 +816,8 @@ static struct md_rdev *read_balance(struct r10conf *conf,
if (!do_balance)
break;
- nonrot = bdev_nonrot(rdev->bdev);
- has_nonrot_disk |= nonrot;
pending = atomic_read(&rdev->nr_pending);
- if (min_pending > pending && nonrot) {
+ if (min_pending > pending && test_bit(Nonrot, &rdev->flags)) {
min_pending = pending;
best_pending_slot = slot;
best_pending_rdev = rdev;
@@ -851,7 +847,7 @@ static struct md_rdev *read_balance(struct r10conf *conf,
}
}
if (slot >= conf->copies) {
- if (has_nonrot_disk) {
+ if (conf->mddev->nonrot_disks) {
slot = best_pending_slot;
rdev = best_pending_rdev;
} else {
--
2.39.2
