Commit a022325a authored by Yu Kuai's avatar Yu Kuai Committed by Song Liu
Browse files

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: default avatarYu Kuai <yukuai3@huawei.com>
Signed-off-by: default avatarSong Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230529131106.2123367-6-yukuai1@huaweicloud.com
parent 7db922ba

drivers/md/md-bitmap.c

+29 −0
Original line number Diff line number Diff line
@@ -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

drivers/md/md-bitmap.h

+1 −0
Original line number Diff line number Diff line
@@ -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,

drivers/md/md.c

+9 −0
Original line number Diff line number Diff line
@@ -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);

}

drivers/md/md.h

+1 −0
Original line number Diff line number Diff line
@@ -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);