Commit 95175daf authored by Damien Le Moal's avatar Damien Le Moal Committed by Jaegeuk Kim
Browse files

f2fs: Reduce zoned block device memory usage 



For zoned block devices, an array of zone types for each device is
allocated and initialized in order to determine if a section is stored
on a sequential zone (zone reset needed) or a conventional zone (no
zone reset needed and regular discard applies). Considering this usage,
the zone types stored in memory can be replaced with a bitmap to
indicate an equivalent information, that is, if a zone is sequential or
not. This reduces the memory usage for each zoned device by roughly 8:
on a 14TB disk with zones of 256 MB, the zone type array consumes
13x4KB pages while the bitmap uses only 2x4KB pages.

This patch changes the f2fs_dev_info structure blkz_type field to the
bitmap blkz_seq. Access to this bitmap is done using the helper
function f2fs_blkz_is_seq(), which is a rewrite of the function
get_blkz_type().

Signed-off-by: default avatarDamien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: default avatarChao Yu <yuchao0@huawei.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 0916878d

fs/f2fs/f2fs.h

+5 −9
Original line number Diff line number Diff line
@@ -1069,7 +1069,7 @@ struct f2fs_dev_info { 
	block_t end_blk;

#ifdef CONFIG_BLK_DEV_ZONED

	unsigned int nr_blkz;		/* Total number of zones */

	u8 *blkz_type;				/* Array of zones type */

	unsigned long *blkz_seq;	/* Bitmap indicating sequential zones */

#endif

};
@@ -3542,16 +3542,12 @@ F2FS_FEATURE_FUNCS(lost_found, LOST_FOUND); 
F2FS_FEATURE_FUNCS(sb_chksum, SB_CHKSUM);



#ifdef CONFIG_BLK_DEV_ZONED

static inline int get_blkz_type(struct f2fs_sb_info *sbi,

			struct block_device *bdev, block_t blkaddr)

static inline bool f2fs_blkz_is_seq(struct f2fs_sb_info *sbi, int devi,

				    block_t blkaddr)

{

	unsigned int zno = blkaddr >> sbi->log_blocks_per_blkz;

	int i;



	for (i = 0; i < sbi->s_ndevs; i++)

		if (FDEV(i).bdev == bdev)

			return FDEV(i).blkz_type[zno];

	return -EINVAL;

	return test_bit(zno, FDEV(devi).blkz_seq);

}

#endif

fs/f2fs/segment.c

+16 −20
Original line number Diff line number Diff line
@@ -1735,40 +1735,36 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi, 


	if (f2fs_is_multi_device(sbi)) {

		devi = f2fs_target_device_index(sbi, blkstart);

		if (blkstart < FDEV(devi).start_blk ||

		    blkstart > FDEV(devi).end_blk) {

			f2fs_msg(sbi->sb, KERN_ERR, "Invalid block %x",

				 blkstart);

			return -EIO;

		}

		blkstart -= FDEV(devi).start_blk;

	}



	/*

	 * We need to know the type of the zone: for conventional zones,

	 * use regular discard if the drive supports it. For sequential

	 * zones, reset the zone write pointer.

	 */

	switch (get_blkz_type(sbi, bdev, blkstart)) {



	case BLK_ZONE_TYPE_CONVENTIONAL:

		if (!blk_queue_discard(bdev_get_queue(bdev)))

			return 0;

		return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);

	case BLK_ZONE_TYPE_SEQWRITE_REQ:

	case BLK_ZONE_TYPE_SEQWRITE_PREF:

	/* For sequential zones, reset the zone write pointer */

	if (f2fs_blkz_is_seq(sbi, devi, blkstart)) {

		sector = SECTOR_FROM_BLOCK(blkstart);

		nr_sects = SECTOR_FROM_BLOCK(blklen);



		if (sector & (bdev_zone_sectors(bdev) - 1) ||

				nr_sects != bdev_zone_sectors(bdev)) {

			f2fs_msg(sbi->sb, KERN_INFO,

				"(%d) %s: Unaligned discard attempted (block %x + %x)",

			f2fs_msg(sbi->sb, KERN_ERR,

				"(%d) %s: Unaligned zone reset attempted (block %x + %x)",

				devi, sbi->s_ndevs ? FDEV(devi).path: "",

				blkstart, blklen);

			return -EIO;

		}

		trace_f2fs_issue_reset_zone(bdev, blkstart);

		return blkdev_reset_zones(bdev, sector,

					  nr_sects, GFP_NOFS);

	default:

		/* Unknown zone type: broken device ? */

		return -EIO;

		return blkdev_reset_zones(bdev, sector, nr_sects, GFP_NOFS);

	}



	/* For conventional zones, use regular discard if supported */

	if (!blk_queue_discard(bdev_get_queue(bdev)))

		return 0;

	return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);

}

#endif

fs/f2fs/super.c

+8 −5
Original line number Diff line number Diff line
@@ -1024,7 +1024,7 @@ static void destroy_device_list(struct f2fs_sb_info *sbi) 
	for (i = 0; i < sbi->s_ndevs; i++) {

		blkdev_put(FDEV(i).bdev, FMODE_EXCL);

#ifdef CONFIG_BLK_DEV_ZONED

		kvfree(FDEV(i).blkz_type);

		kvfree(FDEV(i).blkz_seq);

#endif

	}

	kvfree(sbi->devs);
@@ -2798,9 +2798,11 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi) 
	if (nr_sectors & (bdev_zone_sectors(bdev) - 1))

		FDEV(devi).nr_blkz++;



	FDEV(devi).blkz_type = f2fs_kmalloc(sbi, FDEV(devi).nr_blkz,

	FDEV(devi).blkz_seq = f2fs_kzalloc(sbi,

					BITS_TO_LONGS(FDEV(devi).nr_blkz)

					* sizeof(unsigned long),

					GFP_KERNEL);

	if (!FDEV(devi).blkz_type)

	if (!FDEV(devi).blkz_seq)

		return -ENOMEM;



#define F2FS_REPORT_NR_ZONES   4096
@@ -2827,7 +2829,8 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi) 
		}



		for (i = 0; i < nr_zones; i++) {

			FDEV(devi).blkz_type[n] = zones[i].type;

			if (zones[i].type != BLK_ZONE_TYPE_CONVENTIONAL)

				set_bit(n, FDEV(devi).blkz_seq);

			sector += zones[i].len;

			n++;

		}

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