Hi Chao,
This introduces another bitmap increasing memory footprint. Do we know how
much performance benefit with this?
On 04/11, Chao Yu wrote:
> 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 <c...@kernel.org>
> ---
> v2:
> - rebase to last dev-test branch.
> 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 6474b7338e81..af716925db19 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)) {
> @@ -4635,6 +4644,10 @@ 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)
> @@ -5453,6 +5466,7 @@ 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);
> }
> kfree(array);
> }
> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
> index e1c0f418aa11..10f3e44f036f 100644
> --- a/fs/f2fs/segment.h
> +++ b/fs/f2fs/segment.h
> @@ -292,6 +292,7 @@ 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
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