md/md-bitmap: add a new helper to unplug bitmap asynchrously

If bitmap is enabled, bitmap must update before submitting write io, this
is why unplug callback must move these io to 'conf->pending_io_list' if
'current->bio_list' is not empty, which will suffer performance
degradation.

A new helper md_bitmap_unplug_async() is introduced to submit bitmap io
in a kworker, so that submit bitmap io in raid10_unplug() doesn't require
that 'current->bio_list' is empty.

This patch prepare to limit the number of plugged bio.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230529131106.2123367-6-yukuai1@huaweicloud.com
This commit is contained in:
Yu Kuai 2023-05-29 21:11:04 +08:00 committed by Song Liu
parent 7db922bae3
commit a022325ab9
4 changed files with 40 additions and 0 deletions

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@ -1054,6 +1054,35 @@ void md_bitmap_unplug(struct bitmap *bitmap)
}
EXPORT_SYMBOL(md_bitmap_unplug);
struct bitmap_unplug_work {
struct work_struct work;
struct bitmap *bitmap;
struct completion *done;
};
static void md_bitmap_unplug_fn(struct work_struct *work)
{
struct bitmap_unplug_work *unplug_work =
container_of(work, struct bitmap_unplug_work, work);
md_bitmap_unplug(unplug_work->bitmap);
complete(unplug_work->done);
}
void md_bitmap_unplug_async(struct bitmap *bitmap)
{
DECLARE_COMPLETION_ONSTACK(done);
struct bitmap_unplug_work unplug_work;
INIT_WORK_ONSTACK(&unplug_work.work, md_bitmap_unplug_fn);
unplug_work.bitmap = bitmap;
unplug_work.done = &done;
queue_work(md_bitmap_wq, &unplug_work.work);
wait_for_completion(&done);
}
EXPORT_SYMBOL(md_bitmap_unplug_async);
static void md_bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
/* * bitmap_init_from_disk -- called at bitmap_create time to initialize
* the in-memory bitmap from the on-disk bitmap -- also, sets up the

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@ -264,6 +264,7 @@ void md_bitmap_sync_with_cluster(struct mddev *mddev,
sector_t new_lo, sector_t new_hi);
void md_bitmap_unplug(struct bitmap *bitmap);
void md_bitmap_unplug_async(struct bitmap *bitmap);
void md_bitmap_daemon_work(struct mddev *mddev);
int md_bitmap_resize(struct bitmap *bitmap, sector_t blocks,

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@ -83,6 +83,7 @@ static struct module *md_cluster_mod;
static DECLARE_WAIT_QUEUE_HEAD(resync_wait);
static struct workqueue_struct *md_wq;
static struct workqueue_struct *md_misc_wq;
struct workqueue_struct *md_bitmap_wq;
static int remove_and_add_spares(struct mddev *mddev,
struct md_rdev *this);
@ -9637,6 +9638,11 @@ static int __init md_init(void)
if (!md_misc_wq)
goto err_misc_wq;
md_bitmap_wq = alloc_workqueue("md_bitmap", WQ_MEM_RECLAIM | WQ_UNBOUND,
0);
if (!md_bitmap_wq)
goto err_bitmap_wq;
ret = __register_blkdev(MD_MAJOR, "md", md_probe);
if (ret < 0)
goto err_md;
@ -9655,6 +9661,8 @@ static int __init md_init(void)
err_mdp:
unregister_blkdev(MD_MAJOR, "md");
err_md:
destroy_workqueue(md_bitmap_wq);
err_bitmap_wq:
destroy_workqueue(md_misc_wq);
err_misc_wq:
destroy_workqueue(md_wq);
@ -9951,6 +9959,7 @@ static __exit void md_exit(void)
spin_unlock(&all_mddevs_lock);
destroy_workqueue(md_misc_wq);
destroy_workqueue(md_bitmap_wq);
destroy_workqueue(md_wq);
}

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@ -852,6 +852,7 @@ struct mdu_array_info_s;
struct mdu_disk_info_s;
extern int mdp_major;
extern struct workqueue_struct *md_bitmap_wq;
void md_autostart_arrays(int part);
int md_set_array_info(struct mddev *mddev, struct mdu_array_info_s *info);
int md_add_new_disk(struct mddev *mddev, struct mdu_disk_info_s *info);