On 1/7/2026 9:15 PM, liujinbao1 wrote:
From: liujinbao1 <[email protected]>
During the f2fs_get_victim process, when the f2fs_need_rand_seg is enabled in
select_policy,
p->offset is a random value, and the search range is from p->offset to
MAIN_SECS.
When segno >= last_segment, the loop breaks and exits directly without searching
the range from 0 to p->offset.This results in an incomplete search when the
random
offset is not zero.
What about updating sm->last_victim[p.gc_mode] as well when p->offset is not
zero
in select_policy()?
select_policy()
...
/* let's select beginning hot/small space first. */
if (f2fs_need_rand_seg(sbi)) {
p->offset = get_random_u32_below(MAIN_SECS(sbi) *
SEGS_PER_SEC(sbi));
if (p->offset)
sm->last_victim[p.gc_mode] = p->offset;
}
Then we can expect p->offset being reset to zero, and last_segment being reset
to
sm->last_victim[p.gc_mode] in below logic?
if (segno >= last_segment) {
if (sm->last_victim[p.gc_mode]) {
last_segment =
sm->last_victim[p.gc_mode];
sm->last_victim[p.gc_mode] = 0;
p.offset = 0;
continue;
}
break;
}
Thanks,
Signed-off-by: liujinbao1 <[email protected]>
---
fs/f2fs/gc.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 384fa7e2085b..100b8fc3e65a 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -781,6 +781,7 @@ int f2fs_get_victim(struct f2fs_sb_info *sbi, unsigned int
*result,
unsigned int valid_thresh_ratio = 100;
bool is_atgc;
int ret = 0;
+ unsigned int original_offset;
mutex_lock(&dirty_i->seglist_lock);
last_segment = MAIN_SECS(sbi) * SEGS_PER_SEC(sbi);
@@ -799,6 +800,7 @@ int f2fs_get_victim(struct f2fs_sb_info *sbi, unsigned int
*result,
p.min_segno = NULL_SEGNO;
p.oldest_age = 0;
p.min_cost = get_max_cost(sbi, &p);
+ original_offset = p.offset;
is_atgc = (p.gc_mode == GC_AT || p.alloc_mode == AT_SSR);
nsearched = 0;
@@ -859,11 +861,11 @@ int f2fs_get_victim(struct f2fs_sb_info *sbi, unsigned
int *result,
p.offset / p.ofs_unit);
segno = unit_no * p.ofs_unit;
if (segno >= last_segment) {
- if (sm->last_victim[p.gc_mode]) {
- last_segment =
- sm->last_victim[p.gc_mode];
- sm->last_victim[p.gc_mode] = 0;
+ if (original_offset != 0) {
+ last_segment = original_offset;
p.offset = 0;
+ if (sm->last_victim[p.gc_mode])
+ sm->last_victim[p.gc_mode] = 0;
continue;
}
break;
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