[PATCH] f2fs: fix to correct no_fggc_candidate

From: Chao Yu
Date: Tue Oct 17 2017 - 11:01:52 EST


From: Chao Yu <yuchao0@xxxxxxxxxx>

There may be extreme case as below:

For one section contains one segment, and there are total 100 segments
with 10% over-privision ratio in f2fs partition, fggc_threshold will
be rounded down to 460 instead of 460.8 as below caclulation:

sbi->fggc_threshold = div_u64((u64)(main_count - ovp_count) *
BLKS_PER_SEC(sbi), (main_count - resv_count));

If section usage is as:

As valid block number in all sections is large than fggc_threshold, so
none of them will be chosen as candidate due to incorrect fggc_threshold.

Let's just soften the term of choosing foreground GC candidates.

Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
---
fs/f2fs/segment.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 5a1f7b9c8a72..8d93652d5b6a 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -731,7 +731,7 @@ static inline block_t sum_blk_addr(struct f2fs_sb_info *sbi, int base, int type)
static inline bool no_fggc_candidate(struct f2fs_sb_info *sbi,
unsigned int secno)
{
- if (get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true) >=
+ if (get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true) >
sbi->fggc_threshold)
return true;
return false;
--
2.14.1.145.gb3622a4ee