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

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Message-ID: <20190806073624.GD11812@dhcp22.suse.cz>
Date:   Tue, 6 Aug 2019 09:36:24 +0200
From:   Michal Hocko <mhocko@...nel.org>
To:     Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
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 Tue 06-08-19 10:19:49, Konstantin Khlebnikov wrote:
> 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.

Fine with me.

-- 
Michal Hocko
SUSE Labs