linux-kernel - Re: [f2fs-dev] [PATCH 08/10] f2fs: relax async discard commands more

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Date:   Thu, 5 Jan 2017 16:17:52 +0800
From:   Chao Yu <yuchao0@...wei.com>
To:     Jaegeuk Kim <jaegeuk@...nel.org>, <linux-kernel@...r.kernel.org>,
        <linux-fsdevel@...r.kernel.org>,
        <linux-f2fs-devel@...ts.sourceforge.net>
Subject: Re: [f2fs-dev] [PATCH 08/10] f2fs: relax async discard commands more

Hi Jaegeuk,

I can see patch named ("f2fs: call f2fs_wait_all_discard_bio for an error case")
was merged in dev-test, but I think it's no needed to change error case handling
like this since f2fs_wait_all_discard_bio should always be called after
clear_prefree_segments.

Thanks,

On 2017/1/5 11:19, 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 <jaegeuk@...nel.org>
>>
>> Reviewed-by: Chao Yu <yuchao0@...wei.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 ?
> 
> Can you check this?
> 
> Thanks,
>