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@xxxxxxxxxx>
>>>>>>>> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
>>>>>>>> ---
>>>>>>>> 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
>>>
>> .
>>
>
