Re: [PATCH] f2fs: clear get_ssr_cost

From: Chao Yu
Date: Sun Sep 03 2017 - 22:49:09 EST


On 2017/9/4 9:54, Yunlong Song wrote:
> The update_sit_entry provides this:
> ...
> 1658 if (!f2fs_test_bit(offset, se->ckpt_valid_map))
> 1659 se->ckpt_valid_blocks += del;
> ...
> As a result, the ckpt_valid_blocks is always larger than valid_blocks.
> If not correct, can you provide
> the case valid_blocks larger than ckpt_valid_blocks?

Oh, I just nit-pick, :), how about using 'se->ckpt_valid_blocks will never be
smaller than se->valid_blocks' instead?

And could you just revert Yunlei's patch and add above commit log?

Thanks,

>
> On 2017/9/4 9:17, Chao Yu wrote:
>> On 2017/9/1 20:14, Yunlong Song wrote:
>>> se->ckpt_valid_blocks is always larger than se->valid_blocks, so
>>> get_ssr_cost can be cleared.
>> I think this is not correct.
>>
>> Thanks,
>>
>>> Signed-off-by: Yunlong Song <yunlong.song@xxxxxxxxxx>
>>> ---
>>> fs/f2fs/gc.c | 11 +----------
>>> 1 file changed, 1 insertion(+), 10 deletions(-)
>>>
>>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
>>> index cd147e7..b226760 100644
>>> --- a/fs/f2fs/gc.c
>>> +++ b/fs/f2fs/gc.c
>>> @@ -277,20 +277,11 @@ static unsigned int get_greedy_cost(struct f2fs_sb_info *sbi,
>>> valid_blocks * 2 : valid_blocks;
>>> }
>>>
>>> -static unsigned int get_ssr_cost(struct f2fs_sb_info *sbi,
>>> - unsigned int segno)
>>> -{
>>> - struct seg_entry *se = get_seg_entry(sbi, segno);
>>> -
>>> - return se->ckpt_valid_blocks > se->valid_blocks ?
>>> - se->ckpt_valid_blocks : se->valid_blocks;
>>> -}
>>> -
>>> static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
>>> unsigned int segno, struct victim_sel_policy *p)
>>> {
>>> if (p->alloc_mode == SSR)
>>> - return get_ssr_cost(sbi, segno);
>>> + return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
>>>
>>> /* alloc_mode == LFS */
>>> if (p->gc_mode == GC_GREEDY)
>>>
>>
>> .
>>
>