On 2017/1/6 3:46, Jaegeuk Kim wrote:
> On 01/05, Chao Yu wrote:
>> On 2017/1/4 17:29, Chao Yu wrote:
>>> On 2016/12/31 2:51, Jaegeuk Kim wrote:
>>>> This patch relaxes async discard commands to avoid waiting its end_io
>>>> during
>>>> checkpoint.
>>>> Instead of waiting them during checkpoint, it will be done when actually
>>>> reusing
>>>> them.
>>>>
>>>> Test on initial partition of nvme drive.
>>>>
>>>> # time fstrim /mnt/test
>>>>
>>>> Before : 6.158s
>>>> After : 4.822s
>>>>
>>>> Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org>
>>>
>>> Reviewed-by: Chao Yu <yuch...@huawei.com>
>>>
>>> One comment below,
>>
>> I still have a comment on this patch.
>>
>>>> -void f2fs_wait_all_discard_bio(struct f2fs_sb_info *sbi)
>>>> +/* This should be covered by global mutex, &sit_i->sentry_lock */
>>>> +void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, unsigned int segno)
>>>> {
>>>> struct list_head *wait_list = &(SM_I(sbi)->wait_list);
>>>> struct bio_entry *be, *tmp;
>>>> @@ -646,7 +650,15 @@ void f2fs_wait_all_discard_bio(struct f2fs_sb_info
>>>> *sbi)
>>>> struct bio *bio = be->bio;
>>>> int err;
>>>>
>>>> - wait_for_completion_io(&be->event);
>>>> + if (!completion_done(&be->event)) {
>>>> + if ((be->start_segno >= segno &&
>>>> + be->end_segno <= segno) ||
>>>
>>> segno >= be->start_segno && segno < be->end_segno ?
Still can not understand this judgment condition, we should wait completion of
discard command only when segno is locate in range of [start_segno, end_segno]?
But now, this condition can be true only when segno, start_segno, end_segno have
equal value.
Please correct me if I'm wrong.
Thanks,
>>
>> Can you check this?
>
> The be->start_segno and be->end_segno are assigned by:
>
> unsigned int start_segno = GET_SEGNO(sbi, blkstart);
> unsigned int end_segno = GET_SEGNO(sbi, blkstart + blklen);
>
> in __f2fs_issue_discard_async().
>
> So, the problem comes when, for example, blkstart = 0 and blklen = 512.
>
> I should have got the end_segno by:
>
> unsigned int end_segno = GET_SEGNO(sbi, blkstart + blklen - 1);
>
> Thanks,
>
> .
>
