[PATCH v5 1/2] f2fs: add a method for calculating the remaining blocks in the current segment in LFS mode.

[PATCH v5 1/2] f2fs: add a method for calculating the remaining blocks in the current segment in LFS mode.

[yohan.joung]

In LFS mode, the previous segment cannot use invalid blocks,
so the remaining blocks from the next_blkoff of the current segment
to the end of the section are calculated.

Signed-off-by: yohan.joung <yohan.joung@sk.com>
---
 fs/f2fs/segment.h | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 03c0f59be5a8..5777b385e7d2 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -102,6 +102,8 @@ static inline void sanity_check_seg_type(struct f2fs_sb_info *sbi,
 #define CAP_SEGS_PER_SEC(sbi)					\
 	(SEGS_PER_SEC(sbi) -					\
 	BLKS_TO_SEGS(sbi, (sbi)->unusable_blocks_per_sec))
+#define GET_START_SEG_FROM_SEC(sbi, segno)			\
+	(rounddown(segno, SEGS_PER_SEC(sbi)))
 #define GET_SEC_FROM_SEG(sbi, segno)				\
 	(((segno) == -1) ? -1 : (segno) / SEGS_PER_SEC(sbi))
 #define GET_SEG_FROM_SEC(sbi, secno)				\
@@ -582,8 +584,14 @@ static inline bool has_curseg_enough_space(struct f2fs_sb_info *sbi,
 		if (unlikely(segno == NULL_SEGNO))
 			return false;
 
-		left_blocks = CAP_BLKS_PER_SEC(sbi) -
-				get_ckpt_valid_blocks(sbi, segno, true);
+		if (f2fs_lfs_mode(sbi) && __is_large_section(sbi)) {
+			left_blocks = CAP_BLKS_PER_SEC(sbi) -
+				SEGS_TO_BLKS(sbi, (segno - GET_START_SEG_FROM_SEC(sbi, segno))) -
+				CURSEG_I(sbi, i)->next_blkoff;
+		} else {
+			left_blocks = CAP_BLKS_PER_SEC(sbi) -
+					get_ckpt_valid_blocks(sbi, segno, true);
+		}
 
 		blocks = i <= CURSEG_COLD_DATA ? data_blocks : node_blocks;
 		if (blocks > left_blocks)
@@ -596,8 +604,15 @@ static inline bool has_curseg_enough_space(struct f2fs_sb_info *sbi,
 	if (unlikely(segno == NULL_SEGNO))
 		return false;
 
-	left_blocks = CAP_BLKS_PER_SEC(sbi) -
-			get_ckpt_valid_blocks(sbi, segno, true);
+	if (f2fs_lfs_mode(sbi) && __is_large_section(sbi)) {
+		left_blocks = CAP_BLKS_PER_SEC(sbi) -
+				SEGS_TO_BLKS(sbi, (segno - GET_START_SEG_FROM_SEC(sbi, segno))) -
+				CURSEG_I(sbi, CURSEG_HOT_DATA)->next_blkoff;
+	} else {
+		left_blocks = CAP_BLKS_PER_SEC(sbi) -
+				get_ckpt_valid_blocks(sbi, segno, true);
+	}
+
 	if (dent_blocks > left_blocks)
 		return false;
 	return true;
-- 
2.33.0

[PATCH v5 2/2] f2fs: add ckpt_valid_blocks to the section entry

[yohan.joung]

when performing buffered writes in a large section,
overhead is incurred due to the iteration through
ckpt_valid_blocks within the section.
when SEGS_PER_SEC is 128, this overhead accounts for 20% within
the f2fs_write_single_data_page routine.
as the size of the section increases, the overhead also grows.
to handle this problem ckpt_valid_blocks is
added within the section entries.

Test
insmod null_blk.ko nr_devices=1 completion_nsec=1  submit_queues=8
hw_queue_depth=64 max_sectors=512 bs=4096 memory_backed=1
make_f2fs /dev/block/nullb0
make_f2fs -s 128 /dev/block/nullb0
fio --bs=512k --size=1536M --rw=write --name=1
--filename=/mnt/test_dir/seq_write
--ioengine=io_uring --iodepth=64 --end_fsync=1

before
SEGS_PER_SEC 1
2556MiB/s
SEGS_PER_SEC 128
2145MiB/s

after
SEGS_PER_SEC 1
2556MiB/s
SEGS_PER_SEC 128
2556MiB/s

Signed-off-by: yohan.joung <yohan.joung@sk.com>
---
 fs/f2fs/segment.c | 45 ++++++++++++++++++++++++++++++------
 fs/f2fs/segment.h | 58 ++++++++++++++++++++++++++++++++++++++---------
 2 files changed, 85 insertions(+), 18 deletions(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 671bc5a8fd4a..5ff0111ed974 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -2447,7 +2447,7 @@ static void update_segment_mtime(struct f2fs_sb_info *sbi, block_t blkaddr,
  * that the consecutive input blocks belong to the same segment.
  */
 static int update_sit_entry_for_release(struct f2fs_sb_info *sbi, struct seg_entry *se,
-				block_t blkaddr, unsigned int offset, int del)
+				unsigned int segno, block_t blkaddr, unsigned int offset, int del)
 {
 	bool exist;
 #ifdef CONFIG_F2FS_CHECK_FS
@@ -2492,15 +2492,21 @@ static int update_sit_entry_for_release(struct f2fs_sb_info *sbi, struct seg_ent
 				f2fs_test_and_clear_bit(offset + i, se->discard_map))
 			sbi->discard_blks++;
 
-		if (!f2fs_test_bit(offset + i, se->ckpt_valid_map))
+		if (!f2fs_test_bit(offset + i, se->ckpt_valid_map)) {
 			se->ckpt_valid_blocks -= 1;
+			if (__is_large_section(sbi))
+				get_sec_entry(sbi, segno)->ckpt_valid_blocks -= 1;
+		}
 	}
 
+	if (__is_large_section(sbi))
+		sanity_check_valid_blocks(sbi, segno);
+
 	return del;
 }
 
 static int update_sit_entry_for_alloc(struct f2fs_sb_info *sbi, struct seg_entry *se,
-				block_t blkaddr, unsigned int offset, int del)
+				unsigned int segno, block_t blkaddr, unsigned int offset, int del)
 {
 	bool exist;
 #ifdef CONFIG_F2FS_CHECK_FS
@@ -2533,12 +2539,21 @@ static int update_sit_entry_for_alloc(struct f2fs_sb_info *sbi, struct seg_entry
 	 * or newly invalidated.
 	 */
 	if (!is_sbi_flag_set(sbi, SBI_CP_DISABLED)) {
-		if (!f2fs_test_and_set_bit(offset, se->ckpt_valid_map))
+		if (!f2fs_test_and_set_bit(offset, se->ckpt_valid_map)) {
 			se->ckpt_valid_blocks++;
+			if (__is_large_section(sbi))
+				get_sec_entry(sbi, segno)->ckpt_valid_blocks++;
+		}
 	}
 
-	if (!f2fs_test_bit(offset, se->ckpt_valid_map))
+	if (!f2fs_test_bit(offset, se->ckpt_valid_map)) {
 		se->ckpt_valid_blocks += del;
+		if (__is_large_section(sbi))
+			get_sec_entry(sbi, segno)->ckpt_valid_blocks += del;
+	}
+
+	if (__is_large_section(sbi))
+		sanity_check_valid_blocks(sbi, segno);
 
 	return del;
 }
@@ -2569,9 +2584,9 @@ static void update_sit_entry(struct f2fs_sb_info *sbi, block_t blkaddr, int del)
 
 	/* Update valid block bitmap */
 	if (del > 0) {
-		del = update_sit_entry_for_alloc(sbi, se, blkaddr, offset, del);
+		del = update_sit_entry_for_alloc(sbi, se, segno, blkaddr, offset, del);
 	} else {
-		del = update_sit_entry_for_release(sbi, se, blkaddr, offset, del);
+		del = update_sit_entry_for_release(sbi, se, segno, blkaddr, offset, del);
 	}
 
 	__mark_sit_entry_dirty(sbi, segno);
@@ -4708,6 +4723,12 @@ void f2fs_flush_sit_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 						&raw_sit->entries[sit_offset]);
 			}
 
+			/* update ckpt_valid_block */
+			if (__is_large_section(sbi)) {
+				set_ckpt_valid_blocks(sbi, segno);
+				sanity_check_valid_blocks(sbi, segno);
+			}
+
 			__clear_bit(segno, bitmap);
 			sit_i->dirty_sentries--;
 			ses->entry_cnt--;
@@ -5029,6 +5050,16 @@ static int build_sit_entries(struct f2fs_sb_info *sbi)
 	}
 	up_read(&curseg->journal_rwsem);
 
+	/* update ckpt_valid_block */
+	if (__is_large_section(sbi)) {
+		unsigned int segno;
+
+		for (segno = 0; segno < MAIN_SEGS(sbi); segno += SEGS_PER_SEC(sbi))
+			set_ckpt_valid_blocks(sbi, segno);
+
+		sanity_check_valid_blocks(sbi, segno);
+	}
+
 	if (err)
 		return err;
 
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 5777b385e7d2..db619fd2f51a 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -211,6 +211,7 @@ struct seg_entry {
 
 struct sec_entry {
 	unsigned int valid_blocks;	/* # of valid blocks in a section */
+	unsigned int ckpt_valid_blocks; /* # of valid blocks last cp in a section */
 };
 
 #define MAX_SKIP_GC_COUNT			16
@@ -347,22 +348,57 @@ static inline unsigned int get_valid_blocks(struct f2fs_sb_info *sbi,
 static inline unsigned int get_ckpt_valid_blocks(struct f2fs_sb_info *sbi,
 				unsigned int segno, bool use_section)
 {
-	if (use_section && __is_large_section(sbi)) {
-		unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
-		unsigned int start_segno = GET_SEG_FROM_SEC(sbi, secno);
-		unsigned int blocks = 0;
-		int i;
+	if (use_section && __is_large_section(sbi))
+		return get_sec_entry(sbi, segno)->ckpt_valid_blocks;
+	else
+		return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
+}
 
-		for (i = 0; i < SEGS_PER_SEC(sbi); i++, start_segno++) {
-			struct seg_entry *se = get_seg_entry(sbi, start_segno);
+static inline void set_ckpt_valid_blocks(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 blocks = 0;
+	int i;
 
-			blocks += se->ckpt_valid_blocks;
-		}
-		return blocks;
+	for (i = 0; i < SEGS_PER_SEC(sbi); i++, start_segno++) {
+		struct seg_entry *se = get_seg_entry(sbi, start_segno);
+
+		blocks += se->ckpt_valid_blocks;
 	}
-	return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
+	get_sec_entry(sbi, segno)->ckpt_valid_blocks = blocks;
 }
 
+#ifdef CONFIG_F2FS_CHECK_FS
+static inline void sanity_check_valid_blocks(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 blocks = 0;
+	int i;
+
+	for (i = 0; i < SEGS_PER_SEC(sbi); i++, start_segno++) {
+		struct seg_entry *se = get_seg_entry(sbi, start_segno);
+
+		blocks += se->ckpt_valid_blocks;
+	}
+
+	if (blocks != get_sec_entry(sbi, segno)->ckpt_valid_blocks) {
+		f2fs_err(sbi,
+			"Inconsistent ckpt valid blocks: "
+			"seg entry(%d) vs sec entry(%d) at secno %d",
+			blocks, get_sec_entry(sbi, segno)->ckpt_valid_blocks, secno);
+		f2fs_bug_on(sbi, 1);
+	}
+}
+#else
+static inline void sanity_check_valid_blocks(struct f2fs_sb_info *sbi,
+			unsigned int segno)
+{
+}
+#endif
 static inline void seg_info_from_raw_sit(struct seg_entry *se,
 					struct f2fs_sit_entry *rs)
 {
-- 
2.33.0

Re: [PATCH v5 2/2] f2fs: add ckpt_valid_blocks to the section entry

[Chao Yu]

On 5/12/25 15:36, yohan.joung wrote:
> when performing buffered writes in a large section,
> overhead is incurred due to the iteration through
> ckpt_valid_blocks within the section.
> when SEGS_PER_SEC is 128, this overhead accounts for 20% within
> the f2fs_write_single_data_page routine.
> as the size of the section increases, the overhead also grows.
> to handle this problem ckpt_valid_blocks is
> added within the section entries.
> 
> Test
> insmod null_blk.ko nr_devices=1 completion_nsec=1  submit_queues=8
> hw_queue_depth=64 max_sectors=512 bs=4096 memory_backed=1
> make_f2fs /dev/block/nullb0
> make_f2fs -s 128 /dev/block/nullb0
> fio --bs=512k --size=1536M --rw=write --name=1
> --filename=/mnt/test_dir/seq_write
> --ioengine=io_uring --iodepth=64 --end_fsync=1
> 
> before
> SEGS_PER_SEC 1
> 2556MiB/s
> SEGS_PER_SEC 128
> 2145MiB/s
> 
> after
> SEGS_PER_SEC 1
> 2556MiB/s
> SEGS_PER_SEC 128
> 2556MiB/s
> 
> Signed-off-by: yohan.joung <yohan.joung@sk.com>

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

Thanks,

Re: [PATCH v5 1/2] f2fs: add a method for calculating the remaining blocks in the current segment in LFS mode.

[Chao Yu]

On 5/12/25 15:36, yohan.joung wrote:
> In LFS mode, the previous segment cannot use invalid blocks,
> so the remaining blocks from the next_blkoff of the current segment
> to the end of the section are calculated.
> 
> Signed-off-by: yohan.joung <yohan.joung@sk.com>

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

Thanks,

Re: [f2fs-dev] [PATCH v5 1/2] f2fs: add a method for calculating the remaining blocks in the current segment in LFS mode.

[patchwork-bot+f2fs]

Hello:

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

On Mon, 12 May 2025 16:36:09 +0900 you wrote:
> In LFS mode, the previous segment cannot use invalid blocks,
> so the remaining blocks from the next_blkoff of the current segment
> to the end of the section are calculated.
> 
> Signed-off-by: yohan.joung <yohan.joung@sk.com>
> ---
>  fs/f2fs/segment.h | 23 +++++++++++++++++++----
>  1 file changed, 19 insertions(+), 4 deletions(-)

Here is the summary with links:
  - [f2fs-dev,v5,1/2] f2fs: add a method for calculating the remaining blocks in the current segment in LFS mode.
    https://git.kernel.org/jaegeuk/f2fs/c/91b11bd8152c
  - [f2fs-dev,v5,2/2] f2fs: add ckpt_valid_blocks to the section entry
    https://git.kernel.org/jaegeuk/f2fs/c/313d10d79a82

You are awesome, thank you!
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