Commit f40c153a authored by Jens Axboe's avatar Jens Axboe
Browse files

Merge tag 'md-next-2023-04-28' of... 

Merge tag 'md-next-2023-04-28' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md into for-6.4/block

Pull MD fixes from Song:

"1. Improve raid5 sequential IO performance on spinning disks, which fixes
    a regression since v6.0, by Jan Kara.
 2. Fix bitmap offset types, which fixes an issue introduced in this merge
    window, by Jonathan Derrick."

* tag 'md-next-2023-04-28' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md:
  md: Fix bitmap offset type in sb writer
  md/raid5: Improve performance for sequential IO
parents 952aa344 b1211978

drivers/md/md-bitmap.c

+3 −3
Original line number Diff line number Diff line
@@ -219,7 +219,7 @@ static unsigned int optimal_io_size(struct block_device *bdev, 
}



static unsigned int bitmap_io_size(unsigned int io_size, unsigned int opt_size,

				   sector_t start, sector_t boundary)

				   loff_t start, loff_t boundary)

{

	if (io_size != opt_size &&

	    start + opt_size / SECTOR_SIZE <= boundary)
@@ -237,8 +237,8 @@ static int __write_sb_page(struct md_rdev *rdev, struct bitmap *bitmap, 
	struct block_device *bdev;

	struct mddev *mddev = bitmap->mddev;

	struct bitmap_storage *store = &bitmap->storage;

	sector_t offset = mddev->bitmap_info.offset;

	sector_t ps, sboff, doff;

	loff_t sboff, offset = mddev->bitmap_info.offset;

	sector_t ps, doff;

	unsigned int size = PAGE_SIZE;

	unsigned int opt_size = PAGE_SIZE;

drivers/md/raid5.c

+44 −1
Original line number Diff line number Diff line
@@ -6079,6 +6079,38 @@ static enum stripe_result make_stripe_request(struct mddev *mddev, 
	return ret;

}



/*

 * If the bio covers multiple data disks, find sector within the bio that has

 * the lowest chunk offset in the first chunk.

 */

static sector_t raid5_bio_lowest_chunk_sector(struct r5conf *conf,

					      struct bio *bi)

{

	int sectors_per_chunk = conf->chunk_sectors;

	int raid_disks = conf->raid_disks;

	int dd_idx;

	struct stripe_head sh;

	unsigned int chunk_offset;

	sector_t r_sector = bi->bi_iter.bi_sector & ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);

	sector_t sector;



	/* We pass in fake stripe_head to get back parity disk numbers */

	sector = raid5_compute_sector(conf, r_sector, 0, &dd_idx, &sh);

	chunk_offset = sector_div(sector, sectors_per_chunk);

	if (sectors_per_chunk - chunk_offset >= bio_sectors(bi))

		return r_sector;

	/*

	 * Bio crosses to the next data disk. Check whether it's in the same

	 * chunk.

	 */

	dd_idx++;

	while (dd_idx == sh.pd_idx || dd_idx == sh.qd_idx)

		dd_idx++;

	if (dd_idx >= raid_disks)

		return r_sector;

	return r_sector + sectors_per_chunk - chunk_offset;

}



static bool raid5_make_request(struct mddev *mddev, struct bio * bi)

{

	DEFINE_WAIT_FUNC(wait, woken_wake_function);
@@ -6150,6 +6182,17 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi) 
	}

	md_account_bio(mddev, &bi);



	/*

	 * Lets start with the stripe with the lowest chunk offset in the first

	 * chunk. That has the best chances of creating IOs adjacent to

	 * previous IOs in case of sequential IO and thus creates the most

	 * sequential IO pattern. We don't bother with the optimization when

	 * reshaping as the performance benefit is not worth the complexity.

	 */

	if (likely(conf->reshape_progress == MaxSector))

		logical_sector = raid5_bio_lowest_chunk_sector(conf, bi);

	s = (logical_sector - ctx.first_sector) >> RAID5_STRIPE_SHIFT(conf);



	add_wait_queue(&conf->wait_for_overlap, &wait);

	while (1) {

		res = make_stripe_request(mddev, conf, &ctx, logical_sector,
@@ -6178,7 +6221,7 @@ static bool raid5_make_request(struct mddev *mddev, struct bio * bi) 
			continue;

		}



		s = find_first_bit(ctx.sectors_to_do, stripe_cnt);

		s = find_next_bit_wrap(ctx.sectors_to_do, stripe_cnt, s);

		if (s == stripe_cnt)

			break;