[PATCH 1/2] f2fs: use per-log target_bitmap to improve lookup performace of ssr allocation

Chao Yu
2024-04-07T13:02:01Z

After commit 899fee36fac0 ("f2fs: fix to avoid data corruption by
forbidding SSR overwrite"), valid block bitmap of current openned
segment is fixed, let's introduce a per-log bitmap instead of temp
bitmap to avoid unnecessary calculation overhead whenever allocating
free slot w/ SSR allocator.

Signed-off-by: Chao Yu <chao@kernel.org>
---
fs/f2fs/segment.c | 30 ++++++++++++++++++++++--------
fs/f2fs/segment.h | 1 +
2 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 4a3cf2888faf..ecb9ee80d5e0 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -2840,31 +2840,39 @@ static int new_curseg(struct f2fs_sb_info *sbi, int type, bool new_sec)
return 0;
}

-static int __next_free_blkoff(struct f2fs_sb_info *sbi,
- int segno, block_t start)
+static void __get_segment_bitmap(struct f2fs_sb_info *sbi,
+ unsigned long *target_map,
+ int segno)
{
struct seg_entry *se = get_seg_entry(sbi, segno);
int entries = SIT_VBLOCK_MAP_SIZE / sizeof(unsigned long);
- unsigned long *target_map = SIT_I(sbi)->tmp_map;
unsigned long *ckpt_map = (unsigned long *)se->ckpt_valid_map;
unsigned long *cur_map = (unsigned long *)se->cur_valid_map;
int i;

for (i = 0; i < entries; i++)
target_map[i] = ckpt_map[i] | cur_map[i];
+}
+
+static int __next_free_blkoff(struct f2fs_sb_info *sbi, unsigned long *bitmap,
+ int segno, block_t start)
+{
+ __get_segment_bitmap(sbi, bitmap, segno);

- return __find_rev_next_zero_bit(target_map, BLKS_PER_SEG(sbi), start);
+ return __find_rev_next_zero_bit(bitmap, BLKS_PER_SEG(sbi), start);
}

static int f2fs_find_next_ssr_block(struct f2fs_sb_info *sbi,
- struct curseg_info *seg)
+ struct curseg_info *seg)
{
- return __next_free_blkoff(sbi, seg->segno, seg->next_blkoff + 1);
+ return __find_rev_next_zero_bit(seg->target_map,
+ BLKS_PER_SEG(sbi), seg->next_blkoff + 1);
}

bool f2fs_segment_has_free_slot(struct f2fs_sb_info *sbi, int segno)
{
- return __next_free_blkoff(sbi, segno, 0) < BLKS_PER_SEG(sbi);
+ return __next_free_blkoff(sbi, SIT_I(sbi)->tmp_map, segno, 0) <
+ BLKS_PER_SEG(sbi);
}

/*
@@ -2890,7 +2898,8 @@ static int change_curseg(struct f2fs_sb_info *sbi, int type)

reset_curseg(sbi, type, 1);
curseg->alloc_type = SSR;
- curseg->next_blkoff = __next_free_blkoff(sbi, curseg->segno, 0);
+ curseg->next_blkoff = __next_free_blkoff(sbi, curseg->target_map,
+ curseg->segno, 0);

sum_page = f2fs_get_sum_page(sbi, new_segno);
if (IS_ERR(sum_page)) {
@@ -4652,6 +4661,10 @@ static int build_curseg(struct f2fs_sb_info *sbi)
sizeof(struct f2fs_journal), GFP_KERNEL);
if (!array[i].journal)
return -ENOMEM;
+ array[i].target_map = f2fs_kzalloc(sbi, SIT_VBLOCK_MAP_SIZE,
+ GFP_KERNEL);
+ if (!array[i].target_map)
+ return -ENOMEM;
if (i < NR_PERSISTENT_LOG)
array[i].seg_type = CURSEG_HOT_DATA + i;
else if (i == CURSEG_COLD_DATA_PINNED)
@@ -5470,6 +5483,7 @@ static void destroy_curseg(struct f2fs_sb_info *sbi)
for (i = 0; i < NR_CURSEG_TYPE; i++) {
kfree(array[i].sum_blk);
kfree(array[i].journal);
+ kfree(array[i].target_map);

#ifdef CONFIG_BLK_DEV_ZONED
if (f2fs_sb_has_blkzoned(sbi)) {
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 855978ca869f..08d667e6a36f 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -293,6 +293,7 @@ struct curseg_info {
struct f2fs_summary_block *sum_blk; /* cached summary block */
struct rw_semaphore journal_rwsem; /* protect journal area */
struct f2fs_journal *journal; /* cached journal info */
+ unsigned long *target_map; /* bitmap for SSR allocator */
unsigned char alloc_type; /* current allocation type */
unsigned short seg_type; /* segment type like CURSEG_XXX_TYPE */
unsigned int segno; /* current segment number */
--
2.40.1