linux-kernel - Re: [PATCH RFC] mm/memcontrol: reclaim severe usage over high limit in get_user

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Message-ID: <c6b2c864-985a-2565-95e7-3af9e3e015f8@yandex-team.ru>
Date:   Tue, 6 Aug 2019 10:19:49 +0300
From:   Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
To:     Michal Hocko <mhocko@...nel.org>
Cc:     Johannes Weiner <hannes@...xchg.org>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, cgroups@...r.kernel.org,
        Vladimir Davydov <vdavydov.dev@...il.com>
Subject: Re: [PATCH RFC] mm/memcontrol: reclaim severe usage over high limit
 in get_user_pages loop

On 8/6/19 10:07 AM, Michal Hocko wrote:
> On Fri 02-08-19 13:44:38, Michal Hocko wrote:
> [...]
>>>> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
>>>> index ba9138a4a1de..53a35c526e43 100644
>>>> --- a/mm/memcontrol.c
>>>> +++ b/mm/memcontrol.c
>>>> @@ -2429,8 +2429,12 @@ static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
>>>>    				schedule_work(&memcg->high_work);
>>>>    				break;
>>>>    			}
>>>> -			current->memcg_nr_pages_over_high += batch;
>>>> -			set_notify_resume(current);
>>>> +			if (gfpflags_allow_blocking(gfp_mask)) {
>>>> +				reclaim_high(memcg, nr_pages, GFP_KERNEL);
>>
>> ups, this should be s@..._KERNEL@..._mask@
>>
>>>> +			} else {
>>>> +				current->memcg_nr_pages_over_high += batch;
>>>> +				set_notify_resume(current);
>>>> +			}
>>>>    			break;
>>>>    		}
>>>>    	} while ((memcg = parent_mem_cgroup(memcg)));
>>>>
> 
> Should I send an official patch for this?
> 

I prefer to keep it as is while we have no better solution.