[f2fs-dev] [PATCH v3 0/2] f2fs: modify the calculation method of mtime

[f2fs-dev] [PATCH v3 0/2] f2fs: modify the calculation method of mtime

[liuderong--- via Linux-f2fs-devel]

From: liuderong <liuderong@oppo.com>

In cost-benefit GC algorithm, mtime will affect
the selection of victim segment.For a large section,
mtime should be the mean value of valid blocks,
in order to select correct victim segment,
it needs to modify the calculation method of mtime.

v3:
- add new define INVALID_MTIME and rename new API:f2fs_get_section_mtime

v2:
- modify new API:get_section_mtime

liuderong (2):
  f2fs: remove unused parameters
  f2fs: introduce f2fs_get_section_mtime

 fs/f2fs/f2fs.h    |  5 +++--
 fs/f2fs/gc.c      | 23 +++++++----------------
 fs/f2fs/segment.c | 38 +++++++++++++++++++++++++++++++-------
 fs/f2fs/segment.h |  6 ++++--
 4 files changed, 45 insertions(+), 27 deletions(-)

-- 
2.7.4



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[f2fs-dev] [PATCH v3 1/2] f2fs: remove unused parameters

[liuderong--- via Linux-f2fs-devel]

From: liuderong <liuderong@oppo.com>

Remove unused parameter segno from f2fs_usable_segs_in_sec.

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: liuderong <liuderong@oppo.com>
---
 fs/f2fs/f2fs.h    | 3 +--
 fs/f2fs/gc.c      | 6 +++---
 fs/f2fs/segment.c | 3 +--
 fs/f2fs/segment.h | 4 ++--
 4 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index ac19c61..4dcdcdd 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3759,8 +3759,7 @@ void f2fs_destroy_segment_manager_caches(void);
 int f2fs_rw_hint_to_seg_type(struct f2fs_sb_info *sbi, enum rw_hint hint);
 enum rw_hint f2fs_io_type_to_rw_hint(struct f2fs_sb_info *sbi,
 			enum page_type type, enum temp_type temp);
-unsigned int f2fs_usable_segs_in_sec(struct f2fs_sb_info *sbi,
-			unsigned int segno);
+unsigned int f2fs_usable_segs_in_sec(struct f2fs_sb_info *sbi);
 unsigned int f2fs_usable_blks_in_seg(struct f2fs_sb_info *sbi,
 			unsigned int segno);
 
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 724bbcb..6299639 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -339,7 +339,7 @@ static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
 	unsigned char age = 0;
 	unsigned char u;
 	unsigned int i;
-	unsigned int usable_segs_per_sec = f2fs_usable_segs_in_sec(sbi, segno);
+	unsigned int usable_segs_per_sec = f2fs_usable_segs_in_sec(sbi);
 
 	for (i = 0; i < usable_segs_per_sec; i++)
 		mtime += get_seg_entry(sbi, start + i)->mtime;
@@ -1707,7 +1707,7 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
 	 */
 	if (f2fs_sb_has_blkzoned(sbi))
 		end_segno -= SEGS_PER_SEC(sbi) -
-					f2fs_usable_segs_in_sec(sbi, segno);
+					f2fs_usable_segs_in_sec(sbi);
 
 	sanity_check_seg_type(sbi, get_seg_entry(sbi, segno)->type);
 
@@ -1881,7 +1881,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control)
 
 	total_freed += seg_freed;
 
-	if (seg_freed == f2fs_usable_segs_in_sec(sbi, segno)) {
+	if (seg_freed == f2fs_usable_segs_in_sec(sbi)) {
 		sec_freed++;
 		total_sec_freed++;
 	}
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 78c3198..6627394 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -5381,8 +5381,7 @@ unsigned int f2fs_usable_blks_in_seg(struct f2fs_sb_info *sbi,
 	return BLKS_PER_SEG(sbi);
 }
 
-unsigned int f2fs_usable_segs_in_sec(struct f2fs_sb_info *sbi,
-					unsigned int segno)
+unsigned int f2fs_usable_segs_in_sec(struct f2fs_sb_info *sbi)
 {
 	if (f2fs_sb_has_blkzoned(sbi))
 		return CAP_SEGS_PER_SEC(sbi);
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index bfc01a5..9e61ded 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -430,7 +430,7 @@ static inline void __set_free(struct f2fs_sb_info *sbi, unsigned int segno)
 	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
 	unsigned int start_segno = GET_SEG_FROM_SEC(sbi, secno);
 	unsigned int next;
-	unsigned int usable_segs = f2fs_usable_segs_in_sec(sbi, segno);
+	unsigned int usable_segs = f2fs_usable_segs_in_sec(sbi);
 
 	spin_lock(&free_i->segmap_lock);
 	clear_bit(segno, free_i->free_segmap);
@@ -464,7 +464,7 @@ static inline void __set_test_and_free(struct f2fs_sb_info *sbi,
 	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
 	unsigned int start_segno = GET_SEG_FROM_SEC(sbi, secno);
 	unsigned int next;
-	unsigned int usable_segs = f2fs_usable_segs_in_sec(sbi, segno);
+	unsigned int usable_segs = f2fs_usable_segs_in_sec(sbi);
 
 	spin_lock(&free_i->segmap_lock);
 	if (test_and_clear_bit(segno, free_i->free_segmap)) {
-- 
2.7.4



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[f2fs-dev] [PATCH v3 2/2] f2fs: introduce f2fs_get_section_mtime

[liuderong--- via Linux-f2fs-devel]

From: liuderong <liuderong@oppo.com>

When segs_per_sec is larger than 1, section may contain invalid segments,
mtime should be the average value of each valid blocks,
so introduce f2fs_get_section_mtime to
record the average mtime of all valid blocks in a section.

Signed-off-by: liuderong <liuderong@oppo.com>
---
 fs/f2fs/f2fs.h    |  2 ++
 fs/f2fs/gc.c      | 17 ++++-------------
 fs/f2fs/segment.c | 35 ++++++++++++++++++++++++++++++-----
 fs/f2fs/segment.h |  2 ++
 4 files changed, 38 insertions(+), 18 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 4dcdcdd..1c140ff 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3762,6 +3762,8 @@ enum rw_hint f2fs_io_type_to_rw_hint(struct f2fs_sb_info *sbi,
 unsigned int f2fs_usable_segs_in_sec(struct f2fs_sb_info *sbi);
 unsigned int f2fs_usable_blks_in_seg(struct f2fs_sb_info *sbi,
 			unsigned int segno);
+unsigned long long f2fs_get_section_mtime(struct f2fs_sb_info *sbi,
+			unsigned int segno);
 
 #define DEF_FRAGMENT_SIZE	4
 #define MIN_FRAGMENT_SIZE	1
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 6299639..9ca73bf 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -332,20 +332,15 @@ static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
 {
 	struct sit_info *sit_i = SIT_I(sbi);
-	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
-	unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
 	unsigned long long mtime = 0;
 	unsigned int vblocks;
 	unsigned char age = 0;
 	unsigned char u;
-	unsigned int i;
 	unsigned int usable_segs_per_sec = f2fs_usable_segs_in_sec(sbi);
 
-	for (i = 0; i < usable_segs_per_sec; i++)
-		mtime += get_seg_entry(sbi, start + i)->mtime;
+	mtime = f2fs_get_section_mtime(sbi, segno);
+	f2fs_bug_on(sbi, mtime == INVALID_MTIME);
 	vblocks = get_valid_blocks(sbi, segno, true);
-
-	mtime = div_u64(mtime, usable_segs_per_sec);
 	vblocks = div_u64(vblocks, usable_segs_per_sec);
 
 	u = BLKS_TO_SEGS(sbi, vblocks * 100);
@@ -485,10 +480,7 @@ static void add_victim_entry(struct f2fs_sb_info *sbi,
 				struct victim_sel_policy *p, unsigned int segno)
 {
 	struct sit_info *sit_i = SIT_I(sbi);
-	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
-	unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
 	unsigned long long mtime = 0;
-	unsigned int i;
 
 	if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
 		if (p->gc_mode == GC_AT &&
@@ -496,9 +488,8 @@ static void add_victim_entry(struct f2fs_sb_info *sbi,
 			return;
 	}
 
-	for (i = 0; i < SEGS_PER_SEC(sbi); i++)
-		mtime += get_seg_entry(sbi, start + i)->mtime;
-	mtime = div_u64(mtime, SEGS_PER_SEC(sbi));
+	mtime = f2fs_get_section_mtime(sbi, segno);
+	f2fs_bug_on(sbi, mtime == INVALID_MTIME);
 
 	/* Handle if the system time has changed by the user */
 	if (mtime < sit_i->min_mtime)
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 6627394..717cd15 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -5389,6 +5389,35 @@ unsigned int f2fs_usable_segs_in_sec(struct f2fs_sb_info *sbi)
 	return SEGS_PER_SEC(sbi);
 }
 
+unsigned long long f2fs_get_section_mtime(struct f2fs_sb_info *sbi,
+	unsigned int segno)
+{
+	unsigned int usable_segs_per_sec = f2fs_usable_segs_in_sec(sbi);
+	unsigned int secno = 0, start = 0;
+	unsigned int total_valid_blocks = 0;
+	unsigned long long mtime = 0;
+	unsigned int i = 0;
+
+	secno = GET_SEC_FROM_SEG(sbi, segno);
+	start = GET_SEG_FROM_SEC(sbi, secno);
+
+	if (!__is_large_section(sbi))
+		return get_seg_entry(sbi, start + i)->mtime;
+
+	for (i = 0; i < usable_segs_per_sec; i++) {
+		/* for large section, only check the mtime of valid segments */
+		struct seg_entry *se = get_seg_entry(sbi, start+i);
+
+		mtime += se->mtime * se->valid_blocks;
+		total_valid_blocks += se->valid_blocks;
+	}
+
+	if (total_valid_blocks == 0)
+		return INVALID_MTIME;
+
+	return div_u64(mtime, total_valid_blocks);
+}
+
 /*
  * Update min, max modified time for cost-benefit GC algorithm
  */
@@ -5402,13 +5431,9 @@ static void init_min_max_mtime(struct f2fs_sb_info *sbi)
 	sit_i->min_mtime = ULLONG_MAX;
 
 	for (segno = 0; segno < MAIN_SEGS(sbi); segno += SEGS_PER_SEC(sbi)) {
-		unsigned int i;
 		unsigned long long mtime = 0;
 
-		for (i = 0; i < SEGS_PER_SEC(sbi); i++)
-			mtime += get_seg_entry(sbi, segno + i)->mtime;
-
-		mtime = div_u64(mtime, SEGS_PER_SEC(sbi));
+		mtime = f2fs_get_section_mtime(sbi, segno);
 
 		if (sit_i->min_mtime > mtime)
 			sit_i->min_mtime = mtime;
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 9e61ded..e7ff51d 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -18,6 +18,8 @@
 #define F2FS_MIN_SEGMENTS	9 /* SB + 2 (CP + SIT + NAT) + SSA + MAIN */
 #define F2FS_MIN_META_SEGMENTS	8 /* SB + 2 (CP + SIT + NAT) + SSA */
 
+#define INVALID_MTIME ULLONG_MAX /* no valid blocks in a segment/section */
+
 /* L: Logical segment # in volume, R: Relative segment # in main area */
 #define GET_L2R_SEGNO(free_i, segno)	((segno) - (free_i)->start_segno)
 #define GET_R2L_SEGNO(free_i, segno)	((segno) + (free_i)->start_segno)
-- 
2.7.4



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Re: [f2fs-dev] [PATCH v3 2/2] f2fs: introduce f2fs_get_section_mtime

[Chao Yu via Linux-f2fs-devel]

On 2024/9/18 18:06, liuderong@oppo.com wrote:
> From: liuderong <liuderong@oppo.com>
> 
> When segs_per_sec is larger than 1, section may contain invalid segments,
> mtime should be the average value of each valid blocks,
> so introduce f2fs_get_section_mtime to
> record the average mtime of all valid blocks in a section.
> 
> Signed-off-by: liuderong <liuderong@oppo.com>

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,


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Re: [f2fs-dev] [PATCH v3 0/2] f2fs: modify the calculation method of mtime

[patchwork-bot+f2fs--- via Linux-f2fs-devel]

Hello:

This series was applied to jaegeuk/f2fs.git (dev)
by Jaegeuk Kim <jaegeuk@kernel.org>:

On Wed, 18 Sep 2024 18:06:18 +0800 you wrote:
> From: liuderong <liuderong@oppo.com>
> 
> In cost-benefit GC algorithm, mtime will affect
> the selection of victim segment.For a large section,
> mtime should be the mean value of valid blocks,
> in order to select correct victim segment,
> it needs to modify the calculation method of mtime.
> 
> [...]

Here is the summary with links:
  - [f2fs-dev,v3,1/2] f2fs: remove unused parameters
    (no matching commit)
  - [f2fs-dev,v3,2/2] f2fs: introduce f2fs_get_section_mtime
    https://git.kernel.org/jaegeuk/f2fs/c/b19ee7272208

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html




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