Re: [BUGFIX][PATCH 1/4] memcg: fix limit estimation at reclaim for hugepage

[Minchan Kim]

On Fri, Jan 28, 2011 at 5:24 PM, KAMEZAWA Hiroyuki
<kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
> On Fri, 28 Jan 2011 17:04:16 +0900
> Minchan Kim <minchan.kim@xxxxxxxxx> wrote:
>
>> Hi Kame,
>>
>> On Fri, Jan 28, 2011 at 1:58 PM, KAMEZAWA Hiroyuki
>> <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
>> > How about this ?
>> > ==
>> > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
>> >
>> > Current memory cgroup's code tends to assume page_size == PAGE_SIZE
>> > and arrangement for THP is not enough yet.
>> >
>> > This is one of fixes for supporing THP. This adds
>> > mem_cgroup_check_margin() and checks whether there are required amount of
>> > free resource after memory reclaim. By this, THP page allocation
>> > can know whether it really succeeded or not and avoid infinite-loop
>> > and hangup.
>> >
>> > Total fixes for do_charge()/reclaim memory will follow this patch.
>>
>> If this patch is only related to THP, I think patch order isn't good.
>> Before applying [2/4], huge page allocation will retry without
>> reclaiming and loop forever by below part.
>>
>> @@ -1854,9 +1858,6 @@ static int __mem_cgroup_do_charge(struct
>> Â Â Â } else
>> Â Â Â Â Â Â Â mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
>>
>> - Â Â if (csize > PAGE_SIZE) /* change csize and retry */
>> - Â Â Â Â Â Â return CHARGE_RETRY;
>> -
>> Â Â Â if (!(gfp_mask & __GFP_WAIT))
>> Â Â Â Â Â Â Â return CHARGE_WOULDBLOCK;
>>
>> Am I missing something?
>>
>
> You're right. But
> Â- This patch oder doesn't affect bi-sect of the bug. because
> Â 2 bugs seems to be the same.
> Â- This patch implements a leaf function for the real fix.
>
> Then, I think patch order is not problem here.
>
> Thank you for pointing out.

Okay. I understand Hannes and your opinion.
In my opinion, my suggestion can enhance the patch readability in this
series as just only my viewpoint. :)
Anyway, I don't mind it.

Reviewed-by: Minchan Kim <minchan.kim@xxxxxxxxx>

Thanks!!

>
> Thanks,
> -Kame
>
>
>
>
>



-- 
Kind regards,
Minchan Kim
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