Commit e791d00b authored by Daeho Jeong's avatar Daeho Jeong Committed by Jaegeuk Kim
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f2fs: add valid block ratio not to do excessive GC for one time GC 



We need to introduce a valid block ratio threshold not to trigger
excessive GC for zoned deivces. The initial value of it is 95%. So, F2FS
will stop the thread from intiating GC for sections having valid blocks
exceeding the ratio.

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 9a481a1c

Documentation/ABI/testing/sysfs-fs-f2fs

+8 −0
Original line number Diff line number Diff line
@@ -811,3 +811,11 @@ Contact: "Daeho Jeong" <daehojeong@google.com> 
Description:	If the percentage of free sections over total sections is under this

		number, F2FS boosts garbage collection for zoned devices through the

		background GC thread. the default number is "25".



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

Date:		September 2024

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

Description:	It controls the valid block ratio threshold not to trigger excessive GC

		for zoned deivces. The initial value of it is 95(%). F2FS will stop the

		background GC thread from intiating GC for sections having valid blocks

		exceeding the ratio.

fs/f2fs/f2fs.h

+1 −1
Original line number Diff line number Diff line
@@ -3922,7 +3922,7 @@ void f2fs_destroy_garbage_collection_cache(void); 
/* victim selection function for cleaning and SSR */

int f2fs_get_victim(struct f2fs_sb_info *sbi, unsigned int *result,

			int gc_type, int type, char alloc_mode,

			unsigned long long age);

			unsigned long long age, bool one_time);



/*

 * recovery.c

fs/f2fs/gc.c

+12 −4
Original line number Diff line number Diff line
@@ -196,6 +196,7 @@ int f2fs_start_gc_thread(struct f2fs_sb_info *sbi) 
		return -ENOMEM;



	gc_th->urgent_sleep_time = DEF_GC_THREAD_URGENT_SLEEP_TIME;

	gc_th->valid_thresh_ratio = DEF_GC_THREAD_VALID_THRESH_RATIO;



	if (f2fs_sb_has_blkzoned(sbi)) {

		gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME_ZONED;
@@ -396,6 +397,11 @@ static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi, 
	if (p->alloc_mode == SSR)

		return get_seg_entry(sbi, segno)->ckpt_valid_blocks;



	if (p->one_time_gc && (get_valid_blocks(sbi, segno, true) >=

		CAP_BLKS_PER_SEC(sbi) * sbi->gc_thread->valid_thresh_ratio /

		100))

		return UINT_MAX;



	/* alloc_mode == LFS */

	if (p->gc_mode == GC_GREEDY)

		return get_valid_blocks(sbi, segno, true);
@@ -770,7 +776,7 @@ static int f2fs_gc_pinned_control(struct inode *inode, int gc_type, 
 */

int f2fs_get_victim(struct f2fs_sb_info *sbi, unsigned int *result,

			int gc_type, int type, char alloc_mode,

			unsigned long long age)

			unsigned long long age, bool one_time)

{

	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);

	struct sit_info *sm = SIT_I(sbi);
@@ -787,6 +793,7 @@ int f2fs_get_victim(struct f2fs_sb_info *sbi, unsigned int *result, 
	p.alloc_mode = alloc_mode;

	p.age = age;

	p.age_threshold = sbi->am.age_threshold;

	p.one_time_gc = one_time;



retry:

	select_policy(sbi, gc_type, type, &p);
@@ -1698,13 +1705,14 @@ static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum, 
}



static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,

			int gc_type)

			int gc_type, bool one_time)

{

	struct sit_info *sit_i = SIT_I(sbi);

	int ret;



	down_write(&sit_i->sentry_lock);

	ret = f2fs_get_victim(sbi, victim, gc_type, NO_CHECK_TYPE, LFS, 0);

	ret = f2fs_get_victim(sbi, victim, gc_type, NO_CHECK_TYPE,

			LFS, 0, one_time);

	up_write(&sit_i->sentry_lock);

	return ret;

}
@@ -1911,7 +1919,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control) 
		goto stop;

	}

retry:

	ret = __get_victim(sbi, &segno, gc_type);

	ret = __get_victim(sbi, &segno, gc_type, gc_control->one_time);

	if (ret) {

		/* allow to search victim from sections has pinned data */

		if (ret == -ENODATA && gc_type == FG_GC &&

fs/f2fs/gc.h

+2 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#define DEF_GC_THREAD_CANDIDATE_RATIO		20	/* select 20% oldest sections as candidates */

#define DEF_GC_THREAD_MAX_CANDIDATE_COUNT	10	/* select at most 10 sections as candidates */

#define DEF_GC_THREAD_AGE_WEIGHT		60	/* age weight */

#define DEF_GC_THREAD_VALID_THRESH_RATIO	95	/* do not GC over 95% valid block ratio for one time GC */

#define DEFAULT_ACCURACY_CLASS			10000	/* accuracy class */



#define LIMIT_INVALID_BLOCK	40 /* percentage over total user space */
@@ -65,6 +66,7 @@ struct f2fs_gc_kthread { 
	/* for gc control for zoned devices */

	unsigned int no_zoned_gc_percent;

	unsigned int boost_zoned_gc_percent;

	unsigned int valid_thresh_ratio;

};



struct gc_inode_list {

fs/f2fs/segment.c

+4 −2
Original line number Diff line number Diff line
@@ -3090,7 +3090,8 @@ static int get_ssr_segment(struct f2fs_sb_info *sbi, int type, 
	sanity_check_seg_type(sbi, seg_type);



	/* f2fs_need_SSR() already forces to do this */

	if (!f2fs_get_victim(sbi, &segno, BG_GC, seg_type, alloc_mode, age)) {

	if (!f2fs_get_victim(sbi, &segno, BG_GC, seg_type,

				alloc_mode, age, false)) {

		curseg->next_segno = segno;

		return 1;

	}
@@ -3117,7 +3118,8 @@ static int get_ssr_segment(struct f2fs_sb_info *sbi, int type, 
	for (; cnt-- > 0; reversed ? i-- : i++) {

		if (i == seg_type)

			continue;

		if (!f2fs_get_victim(sbi, &segno, BG_GC, i, alloc_mode, age)) {

		if (!f2fs_get_victim(sbi, &segno, BG_GC, i,

					alloc_mode, age, false)) {

			curseg->next_segno = segno;

			return 1;

		}