From: Yunlong Song <yunlong.song@huawei.com>
To: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: <chao@kernel.org>, <yuchao0@huawei.com>,
<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: Tue, 7 Nov 2017 12:01:58 +0800 [thread overview]
Message-ID: <7433d584-b1e0-76e9-a6e4-8da1218dd71d@huawei.com> (raw)
In-Reply-To: <20171107032636.GB92599@jaegeuk-macbookpro.roam.corp.google.com>
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);
>
>> 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:[~2017-11-07 4:04 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 [this message]
2017-11-07 6:56 ` Chao Yu
2017-11-08 3:06 ` Yunlong Song
2017-11-09 17:59 ` Jaegeuk Kim
2017-11-10 2:11 ` Yunlong Song
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