Commit 8c890c4c authored by Daeho Jeong's avatar Daeho Jeong Committed by Jaegeuk Kim
Browse files

f2fs: introduce migration_window_granularity 



We can control the scanning window granularity for GC migration. For
more frequent scanning and GC on zoned devices, we need a fine grained
control knob for it.

Signed-off-by: default avatarDaeho Jeong <daehojeong@google.com>
Reviewed-by: default avatarChao Yu <chao@kernel.org>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 5062b5be

Documentation/ABI/testing/sysfs-fs-f2fs

+8 −0
Original line number Diff line number Diff line
@@ -783,3 +783,11 @@ Description: The zone UFS we are currently using consists of two parts: 
		blkzone_alloc_policy = 1  Only allow writing to sequential zones

		blkzone_alloc_policy = 2  Prioritize writing to conventional zones

		========================  =========================================



What:		/sys/fs/f2fs/<disk>/migration_window_granularity

Date:		September 2024

Contact:	"Daeho Jeong" <daehojeong@google.com>

Description:	Controls migration window granularity of garbage collection on large

		section. it can control the scanning window granularity for GC migration

		in a unit of segment, while migration_granularity controls the number

		of segments which can be migrated at the same turn.

fs/f2fs/f2fs.h

+2 −0
Original line number Diff line number Diff line
@@ -1696,6 +1696,8 @@ struct f2fs_sb_info { 
	unsigned int max_victim_search;

	/* migration granularity of garbage collection, unit: segment */

	unsigned int migration_granularity;

	/* migration window granularity of garbage collection, unit: segment */

	unsigned int migration_window_granularity;



	/*

	 * for stat information.

fs/f2fs/gc.c

+21 −10
Original line number Diff line number Diff line
@@ -1708,24 +1708,34 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi, 
	struct blk_plug plug;

	unsigned int segno = start_segno;

	unsigned int end_segno = start_segno + SEGS_PER_SEC(sbi);

	unsigned int sec_end_segno;

	int seg_freed = 0, migrated = 0;

	unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?

						SUM_TYPE_DATA : SUM_TYPE_NODE;

	unsigned char data_type = (type == SUM_TYPE_DATA) ? DATA : NODE;

	int submitted = 0;



	if (__is_large_section(sbi))

		end_segno = rounddown(end_segno, SEGS_PER_SEC(sbi));

	if (__is_large_section(sbi)) {

		sec_end_segno = rounddown(end_segno, SEGS_PER_SEC(sbi));



		/*

		 * zone-capacity can be less than zone-size in zoned devices,

		 * resulting in less than expected usable segments in the zone,

	 * calculate the end segno in the zone which can be garbage collected

		 * calculate the end segno in the zone which can be garbage

		 * collected

		 */

		if (f2fs_sb_has_blkzoned(sbi))

		end_segno -= SEGS_PER_SEC(sbi) -

			sec_end_segno -= SEGS_PER_SEC(sbi) -

					f2fs_usable_segs_in_sec(sbi, segno);



		if (gc_type == BG_GC)

			end_segno = start_segno +

				sbi->migration_window_granularity;



		if (end_segno > sec_end_segno)

			end_segno = sec_end_segno;

	}



	sanity_check_seg_type(sbi, get_seg_entry(sbi, segno)->type);



	/* readahead multi ssa blocks those have contiguous address */
@@ -1803,7 +1813,8 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi, 


		if (__is_large_section(sbi))

			sbi->next_victim_seg[gc_type] =

				(segno + 1 < end_segno) ? segno + 1 : NULL_SEGNO;

				(segno + 1 < sec_end_segno) ?

					segno + 1 : NULL_SEGNO;

skip:

		f2fs_put_page(sum_page, 0);

	}

fs/f2fs/gc.h

+1 −0
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ 


#define LIMIT_NO_ZONED_GC	60 /* percentage over total user space of no gc for zoned devices */

#define LIMIT_BOOST_ZONED_GC	25 /* percentage over total user space of boosted gc for zoned devices */

#define DEF_MIGRATION_WINDOW_GRANULARITY_ZONED	3



#define DEF_GC_FAILED_PINNED_FILES	2048

#define MAX_GC_FAILED_PINNED_FILES	USHRT_MAX

fs/f2fs/super.c

+2 −0
Original line number Diff line number Diff line
@@ -3807,6 +3807,8 @@ static void init_sb_info(struct f2fs_sb_info *sbi) 
	sbi->next_victim_seg[FG_GC] = NULL_SEGNO;

	sbi->max_victim_search = DEF_MAX_VICTIM_SEARCH;

	sbi->migration_granularity = SEGS_PER_SEC(sbi);

	sbi->migration_window_granularity = f2fs_sb_has_blkzoned(sbi) ?

		DEF_MIGRATION_WINDOW_GRANULARITY_ZONED : SEGS_PER_SEC(sbi);

	sbi->seq_file_ra_mul = MIN_RA_MUL;

	sbi->max_fragment_chunk = DEF_FRAGMENT_SIZE;

	sbi->max_fragment_hole = DEF_FRAGMENT_SIZE;