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Message-ID: <32521aa2-876e-0e87-975b-34ff00f9095c@huaweicloud.com>
Date: Mon, 26 Feb 2024 21:25:17 +0800
From: Yu Kuai <yukuai1@...weicloud.com>
To: Xiao Ni <xni@...hat.com>, Yu Kuai <yukuai1@...weicloud.com>
Cc: paul.e.luse@...ux.intel.com, song@...nel.org, neilb@...e.com,
shli@...com, linux-raid@...r.kernel.org, linux-kernel@...r.kernel.org,
yi.zhang@...wei.com, yangerkun@...wei.com, "yukuai (C)" <yukuai3@...wei.com>
Subject: Re: [PATCH md-6.9 02/10] md: record nonrot rdevs while
adding/removing rdevs to conf
Hi,
在 2024/02/26 21:12, Xiao Ni 写道:
> Hi Kuai
>
> I added some logs to check and add_bound_rdev can't be called when
> creating raid device. Maybe move rdev_update_nonrot to
> bind_rdev_to_array?
bind_rdev_to_array() is used to add new rdev to the array, then
'pers->hot_add_disk' is used to add the rdev to conf. For new spares,
bind_rdev_to_array() will be called while 'pers->hot_add_disk' won't.
Hence rdev_update_nonrot() is used where 'pers->hot_add_disk' succeed
in this patch.
Perhaps it's better to move related code to raid1/raid10_add_disk() and
the new counter in raid1/raid10 conf?
Thanks,
Kuai
>
> Regards
> Xiao
>
> On Thu, Feb 22, 2024 at 4:04 PM Yu Kuai <yukuai1@...weicloud.com> wrote:
>>
>> From: Yu Kuai <yukuai3@...wei.com>
>>
>> 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@...ux.intel.com>
>> Signed-off-by: Paul Luse <paul.e.luse@...ux.intel.com>
>> Signed-off-by: Yu Kuai <yukuai3@...wei.com>
>> ---
>> 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
>>
>>
>
> .
>
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