From: Daeho Jeong <daehoje...@google.com>

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: Daeho Jeong <daehoje...@google.com>
---
v2: use CAP_BLKS_PER_SEC instead of BLKS_PER_SEC
---
 Documentation/ABI/testing/sysfs-fs-f2fs |  8 ++++++++
 fs/f2fs/f2fs.h                          |  2 +-
 fs/f2fs/gc.c                            | 16 ++++++++++++----
 fs/f2fs/gc.h                            |  2 ++
 fs/f2fs/segment.c                       |  6 ++++--
 fs/f2fs/segment.h                       |  1 +
 fs/f2fs/sysfs.c                         |  2 ++
 7 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs 
b/Documentation/ABI/testing/sysfs-fs-f2fs
index f3c533b523cd..2fcb16ca10d3 100644
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -791,3 +791,11 @@ Contact:   "Daeho Jeong" <daehoje...@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" <daehoje...@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.
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 62880fbb9e20..2bfad046dc74 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3920,7 +3920,7 @@ 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
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 319b4b80ba72..d3e3104c4492 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -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 &&
diff --git a/fs/f2fs/gc.h b/fs/f2fs/gc.h
index c063310c8dde..2914b678bf8f 100644
--- a/fs/f2fs/gc.h
+++ b/fs/f2fs/gc.h
@@ -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 {
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 78c3198a6308..26f5abc62461 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -3052,7 +3052,8 @@ 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;
        }
@@ -3079,7 +3080,8 @@ 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;
                }
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index bfc01a521cb9..43db2d3e8c85 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -188,6 +188,7 @@ struct victim_sel_policy {
        unsigned int min_segno;         /* segment # having min. cost */
        unsigned long long age;         /* mtime of GCed section*/
        unsigned long long age_threshold;/* age threshold */
+       bool one_time_gc;               /* one time GC */
 };
 
 struct seg_entry {
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 60693ec39a03..83e52f6061d0 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -967,6 +967,7 @@ GC_THREAD_RW_ATTR(gc_max_sleep_time, max_sleep_time);
 GC_THREAD_RW_ATTR(gc_no_gc_sleep_time, no_gc_sleep_time);
 GC_THREAD_RW_ATTR(gc_no_zoned_gc_percent, no_zoned_gc_percent);
 GC_THREAD_RW_ATTR(gc_boost_zoned_gc_percent, boost_zoned_gc_percent);
+GC_THREAD_RW_ATTR(gc_valid_thresh_ratio, valid_thresh_ratio);
 
 /* SM_INFO ATTR */
 SM_INFO_RW_ATTR(reclaim_segments, rec_prefree_segments);
@@ -1127,6 +1128,7 @@ static struct attribute *f2fs_attrs[] = {
        ATTR_LIST(gc_no_gc_sleep_time),
        ATTR_LIST(gc_no_zoned_gc_percent),
        ATTR_LIST(gc_boost_zoned_gc_percent),
+       ATTR_LIST(gc_valid_thresh_ratio),
        ATTR_LIST(gc_idle),
        ATTR_LIST(gc_urgent),
        ATTR_LIST(reclaim_segments),
-- 
2.46.0.598.g6f2099f65c-goog



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