Re: [PATCH v6 0/3] Directed kmem charging

From: Shakeel Butt <shakeelb@google.com>
To: Johannes Weiner <hannes@cmpxchg.org>
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>
Subject: Re: [PATCH v6 0/3] Directed kmem charging
Date: Tue, 19 Jun 2018 15:58:38 -0700	[thread overview]
Message-ID: <CALvZod56hRAjCE25Wc-+O-rc+v_t6a9n3JrD4gTRaFotkcrMCQ@mail.gmail.com> (raw)
In-Reply-To: <20180619161149.GA27423@cmpxchg.org>

On Tue, Jun 19, 2018 at 9:09 AM Johannes Weiner <hannes@cmpxchg.org> wrote:
>
> Hi Shakeel,
>
> this looks generally reasonable to me.
>
> However, patch 1 introduces API that isn't used until patch 2 and 3,
> which makes reviewing harder since you have to jump back and forth
> between emails. Please fold patch 1 and introduce API along with the
> users.
>

Thanks a lot for the review. Ack, I will do as you suggested in next version.

> On Mon, Jun 18, 2018 at 10:13:24PM -0700, Shakeel Butt wrote:
> > This patchset introduces memcg variant memory allocation functions.  The
> > caller can explicitly pass the memcg to charge for kmem allocations.
> > Currently the kernel, for __GFP_ACCOUNT memory allocation requests,
> > extract the memcg of the current task to charge for the kmem allocation.
> > This patch series introduces kmem allocation functions where the caller
> > can pass the pointer to the remote memcg.  The remote memcg will be
> > charged for the allocation instead of the memcg of the caller.  However
> > the caller must have a reference to the remote memcg.  This patch series
> > also introduces scope API for targeted memcg charging. So, all the
> > __GFP_ACCOUNT alloctions within the specified scope will be charged to
> > the given target memcg.
>
> Can you open with the rationale for the series, i.e. the problem
> statement (fsnotify and bh memory footprint), *then* follow with the
> proposed solution?
>

Sure.

thanks,
Shakeel