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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>,
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	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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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!