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

From	Jaegeuk Kim <jaegeuk@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [f2fs-dev] [PATCH 08/10] f2fs: relax async discard commands more
Date	2017-01-05 20:50 +0100
Message-ID	<sWmcW-7os-23@gated-at.bofh.it> (permalink)
References	<sUazf-86o-3@gated-at.bofh.it> <sUazf-86o-13@gated-at.bofh.it> <sVQd3-2M8-23@gated-at.bofh.it> <sW6Uy-5xP-23@gated-at.bofh.it>
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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 <jaegeuk@kernel.org>
> > 
> > Reviewed-by: Chao Yu <yuchao0@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 ?
> 
> 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,

Thread

Re: [f2fs-dev] [PATCH 08/10] f2fs: relax async discard commands more Chao Yu <yuchao0@huawei.com> - 2017-01-04 10:40 +0100
  Re: [f2fs-dev] [PATCH 08/10] f2fs: relax async discard commands more Chao Yu <yuchao0@huawei.com> - 2017-01-05 04:30 +0100
    Re: [f2fs-dev] [PATCH 08/10] f2fs: relax async discard commands more Chao Yu <yuchao0@huawei.com> - 2017-01-05 10:00 +0100
      Re: [f2fs-dev] [PATCH 08/10] f2fs: relax async discard commands more Jaegeuk Kim <jaegeuk@kernel.org> - 2017-01-05 21:10 +0100
    Re: [f2fs-dev] [PATCH 08/10] f2fs: relax async discard commands more Jaegeuk Kim <jaegeuk@kernel.org> - 2017-01-05 20:50 +0100
      Re: [f2fs-dev] [PATCH 08/10] f2fs: relax async discard commands more Chao Yu <yuchao0@huawei.com> - 2017-01-06 03:10 +0100
        Re: [f2fs-dev] [PATCH 08/10] f2fs: relax async discard commands more Jaegeuk Kim <jaegeuk@kernel.org> - 2017-01-06 03:50 +0100
          Re: [f2fs-dev] [PATCH 08/10] f2fs: relax async discard commands more Chao Yu <yuchao0@huawei.com> - 2017-01-06 04:40 +0100

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