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Date:   Wed, 20 Jun 2018 11:22:35 -0400
From:   Johannes Weiner <hannes@cmpxchg.org>
To:     Shakeel Butt <shakeelb@google.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Michal Hocko <mhocko@kernel.org>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Jan Kara <jack@suse.com>, Greg Thelen <gthelen@google.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Cgroups <cgroups@vger.kernel.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        Linux MM <linux-mm@kvack.org>, Jan Kara <jack@suse.cz>,
        Amir Goldstein <amir73il@gmail.com>,
        Christoph Lameter <cl@linux.com>,
        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Mel Gorman <mgorman@suse.de>, Vlastimil Babka <vbabka@suse.cz>,
        Alexander Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH 1/3] mm: memcg: remote memcg charging for kmem allocations
Message-ID: <20180620152235.GB2441@cmpxchg.org>
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 <20180619162429.GB27423@cmpxchg.org>
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On Tue, Jun 19, 2018 at 04:31:18PM -0700, Shakeel Butt wrote:
> On Tue, Jun 19, 2018 at 9:22 AM Johannes Weiner <hannes@cmpxchg.org> wrote:
> >
> > On Mon, Jun 18, 2018 at 10:13:25PM -0700, Shakeel Butt wrote:
> > > @@ -248,6 +248,30 @@ static inline void memalloc_noreclaim_restore(unsigned int flags)
> > >       current->flags = (current->flags & ~PF_MEMALLOC) | flags;
> > >  }
> > >
> > > +#ifdef CONFIG_MEMCG
> > > +static inline struct mem_cgroup *memalloc_memcg_save(struct mem_cgroup *memcg)
> > > +{
> > > +     struct mem_cgroup *old_memcg = current->target_memcg;
> > > +
> > > +     current->target_memcg = memcg;
> > > +     return old_memcg;
> > > +}
> > > +
> > > +static inline void memalloc_memcg_restore(struct mem_cgroup *memcg)
> > > +{
> > > +     current->target_memcg = memcg;
> > > +}
> >
> > The use_mm() and friends naming scheme would be better here:
> > memalloc_use_memcg(), memalloc_unuse_memcg(), current->active_memcg
> >
> 
> Ack. Though do you still think <linux/sched/mm.h> is the right place
> for these functions?

Yeah, since it has the memalloc_* prefix, we should keep it there.

If we did use_memcg(), unuse_memcg(), I'd put it into memcontrol.h,
but it seems a little terse; memalloc adds valuable context, IMO.

Thanks Shakeel!