Re: [f2fs-dev] [PATCH v2 1/2] f2fs: use per-log target_bitmap to improve lookup performace of ssr allocation

[Chao Yu <chao@kernel.org>]

On 2024/5/31 9:10, Chao Yu wrote:
> On 2024/5/31 7:39, Jaegeuk Kim wrote:
>> On 05/29, Chao Yu wrote:
>>> Ping,
> 
> Jaegeuk,
> 
>>
>> Chao, sorry, I might need some time to take a look at the change cautiously.
> 
> No problem, I've done some tests on this patch, though, I will keeping this in
> my queue, and do test base on the queue whenever it comes new patches.

Jaegeuk,

Any progress on this patchset?

Thanks,

> 
> Thanks,
> 
>>
>>>
>>> On 2024/4/23 10:07, Chao Yu wrote:
>>>> Jaegeuk, any comments for this serials?
>>>>
>>>> On 2024/4/11 16:23, 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 <chao@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 */
>>>>
>>>>
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