2013-09-03 06:28:13

by Jaegeuk Kim

Subject: [PATCH 1/2] f2fs: trigger GC when there are prefree segments

Previously, f2fs conducts SSR when free_sections() < overprovision_sections.
But, even though there are a lot of prefree segments, it can consider SSR only.
So, let's consider the number of prefree segments too for triggering SSR.

Signed-off-by: Jaegeuk Kim <[email protected]>
---
fs/f2fs/segment.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 062424a..cd9bd93 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -453,7 +453,8 @@ static inline int reserved_sections(struct f2fs_sb_info *sbi)

static inline bool need_SSR(struct f2fs_sb_info *sbi)
{
- return (free_sections(sbi) < overprovision_sections(sbi));
+ return ((prefree_segments(sbi) / sbi->segs_per_sec)
+ + free_sections(sbi) < overprovision_sections(sbi));
}

static inline bool has_not_enough_free_secs(struct f2fs_sb_info *sbi, int freed)
--
1.8.3.1.437.g0dbd812

2013-09-03 06:28:15

by Jaegeuk Kim

Subject: [PATCH 2/2] f2fs: avoid an overflow during utilization calculation

The current f2fs uses all the block counts with 32 bit numbers, which is able to
cover about 15TB volume.

But in calculation of utilization, f2fs multiplies the count by 100 which can
induce overflow.
This patch fixes this.

Signed-off-by: Jaegeuk Kim <[email protected]>
---
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 cd9bd93..e0d6d3a 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -471,7 +471,7 @@ static inline bool has_not_enough_free_secs(struct f2fs_sb_info *sbi, int freed)

static inline int utilization(struct f2fs_sb_info *sbi)
{
- return div_u64(valid_user_blocks(sbi) * 100, sbi->user_block_count);
+ return div_u64((u64)valid_user_blocks(sbi) * 100, sbi->user_block_count);
}

/*
--
1.8.3.1.437.g0dbd812