From: Jaegeuk Kim <jaegeuk@kernel.org>
To: Yunlong Song <yunlong.song@huawei.com>
Cc: Chao Yu <yuchao0@huawei.com>,
chao@kernel.org, yunlong.song@icloud.com, miaoxie@huawei.com,
bintian.wang@huawei.com, linux-fsdevel@vger.kernel.org,
linux-f2fs-devel@lists.sourceforge.net,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] f2fs: add bug_on when f2fs_gc even fails to get one victim
Date: Thu, 9 Nov 2017 09:59:15 -0800 [thread overview]
Message-ID: <20171109175915.GC55844@jaegeuk-macbookpro.roam.corp.google.com> (raw)
In-Reply-To: <19eec8fd-e941-770a-9477-6ad2d266d475@huawei.com>
On 11/08, Yunlong Song wrote:
> So we should use f2fs_bug_on(sbi, !total_freed && !sync && gc_type ==
> FG_GC);
f2fs_bug_on(sbi, !total_freed && has_not_enough_free_secs(sbi, 0, 0)); ?
>
> On 2017/11/7 14:56, Chao Yu wrote:
> > On 2017/11/7 12:01, Yunlong Song wrote:
> > > Sorry, misunderstanding, because I think when sync == true, FG_GC does not
> > > check has_not_enough_free_secs, so maybe it does not have to do any gc
> > > at all.
> > > For example, if there are 100 segments for f2fs, and 20 segments are full or
> > > valid blocks over fggc_threshold, then it is correct to fail in get victim.
> > >
> > >
> > > On 2017/11/7 11:26, Jaegeuk Kim wrote:
> > > > On 11/07, Yunlong Song wrote:
> > > > > Because I find that some out-of-free problem is caused by the failure
> > > > > of get victim target. For example, chao has pointed out that he has
> > > > > found out a bug when adding this bug_on last week.
> > > > That's NOT what I asked. Why not checking FG_GC all the time like this?
> > > >
> > > > f2fs_bug_on(sbi, !total_freed && gc_type == FG_GC);
> > ioctl(F2FS_IOC_GARBAGE_COLLECT, &1) will simply trigger this bug_on, so we
> > have to check the conditon only when we run out-of-free-space?
> >
> > Thanks,
> >
> > > > > On 2017/11/7 10:40, Jaegeuk Kim wrote:
> > > > > > On 11/06, Jaegeuk Kim wrote:
> > > > > > > On 11/06, Yunlong Song wrote:
> > > > > > > > Agree.
> > > > > > > >
> > > > > > > > On 2017/11/3 11:44, Jaegeuk Kim wrote:
> > > > > > > > > On 10/13, Yunlong Song wrote:
> > > > > > > > > > This can help us to debug on some corner case.
> > > > > > > > > >
> > > > > > > > > > Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
> > > > > > > > > > Signed-off-by: Chao Yu <yuchao0@huawei.com>
> > > > > > > > > > ---
> > > > > > > > > > fs/f2fs/gc.c | 6 +++++-
> > > > > > > > > > 1 file changed, 5 insertions(+), 1 deletion(-)
> > > > > > > > > >
> > > > > > > > > > diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> > > > > > > > > > index 197ebf4..2b03202 100644
> > > > > > > > > > --- a/fs/f2fs/gc.c
> > > > > > > > > > +++ b/fs/f2fs/gc.c
> > > > > > > > > > @@ -986,6 +986,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
> > > > > > > > > > .ilist = LIST_HEAD_INIT(gc_list.ilist),
> > > > > > > > > > .iroot = RADIX_TREE_INIT(GFP_NOFS),
> > > > > > > > > > };
> > > > > > > > > > + bool need_fggc = false;
> > > > > > > > > > trace_f2fs_gc_begin(sbi->sb, sync, background,
> > > > > > > > > > get_pages(sbi, F2FS_DIRTY_NODES),
> > > > > > > > > > @@ -1018,8 +1019,10 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
> > > > > > > > > > if (ret)
> > > > > > > > > > goto stop;
> > > > > > > > > > }
> > > > > > > > > > - if (has_not_enough_free_secs(sbi, 0, 0))
> > > > > > > > > > + if (has_not_enough_free_secs(sbi, 0, 0)) {
> > > > > > > > > > gc_type = FG_GC;
> > > > > > > > > > + need_fggc = true;
> > > > > > > > > > + }
> > > > > > > > > > }
> > > > > > > > > > /* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
> > > > > > > > > > @@ -1028,6 +1031,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
> > > > > > > > > > goto stop;
> > > > > > > > > > }
> > > > > > > > > > if (!__get_victim(sbi, &segno, gc_type)) {
> > > > > > > > > > + f2fs_bug_on(sbi, !total_freed && need_fggc);
> > > > > > > > > Just like this?
> > > > > > > > That's OK.
> > > > > > > I'm not quite sure whether this is really a bug_on case.
> > > > > > > Let me make it WARN_ON() for debugging purpose first.
> > > > > > BTW, why is this the special case where BG_GC detects FG_GC?
> > > > > >
> > > > > > > Thanks,
> > > > > > >
> > > > > > > > > f2fs_bug_on(sbi, !total_freed && !sync && gc_type == FG_GC);
> > > > > > > > >
> > > > > > > > > > ret = -ENODATA;
> > > > > > > > > > goto stop;
> > > > > > > > > > }
> > > > > > > > > > --
> > > > > > > > > > 1.8.5.2
> > > > > > > > > .
> > > > > > > > >
> > > > > > > > --
> > > > > > > > Thanks,
> > > > > > > > Yunlong Song
> > > > > > > >
> > > > > > .
> > > > > >
> > > > > --
> > > > > Thanks,
> > > > > Yunlong Song
> > > > >
> > > > .
> > > >
> >
> > .
> >
>
> --
> Thanks,
> Yunlong Song
>
next prev parent reply other threads:[~2017-11-09 17:59 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-11 13:51 [PATCH] f2fs: add bug_on when f2fs_gc even fails to get one victim Yunlong Song
2017-10-12 23:23 ` Jaegeuk Kim
2017-10-13 1:09 ` Yunlong Song
2017-10-13 2:29 ` Jaegeuk Kim
2017-10-13 11:09 ` [f2fs-dev] " Chao Yu
2017-10-13 11:20 ` Yunlong Song
2017-10-13 12:24 ` Chao Yu
2017-10-13 13:31 ` [PATCH v2] " Yunlong Song
2017-10-14 0:17 ` [f2fs-dev] " Chao Yu
2017-10-14 12:34 ` Yunlong Song
2017-10-16 3:25 ` Chao Yu
2017-10-31 1:32 ` Yunlong Song
2017-10-31 3:17 ` Chao Yu
2017-10-31 3:30 ` Yunlong Song
2017-11-03 3:28 ` Yunlong Song
2017-11-03 3:44 ` Jaegeuk Kim
2017-11-03 15:08 ` 宋云龙
2017-11-06 1:12 ` Yunlong Song
2017-11-07 2:38 ` Jaegeuk Kim
2017-11-07 2:40 ` Jaegeuk Kim
2017-11-07 3:16 ` Yunlong Song
2017-11-07 3:26 ` Jaegeuk Kim
2017-11-07 4:01 ` Yunlong Song
2017-11-07 6:56 ` Chao Yu
2017-11-08 3:06 ` Yunlong Song
2017-11-09 17:59 ` Jaegeuk Kim [this message]
2017-11-10 2:11 ` Yunlong Song
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