From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f71.google.com (mail-wm0-f71.google.com [74.125.82.71]) by kanga.kvack.org (Postfix) with ESMTP id 05DE36B0006 for ; Wed, 30 May 2018 09:04:44 -0400 (EDT) Received: by mail-wm0-f71.google.com with SMTP id v2-v6so12964777wmc.0 for ; Wed, 30 May 2018 06:04:43 -0700 (PDT) Received: from gum.cmpxchg.org (gum.cmpxchg.org. [85.214.110.215]) by mx.google.com with ESMTPS id g42-v6si1319234edg.360.2018.05.30.06.04.42 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 30 May 2018 06:04:42 -0700 (PDT) Date: Wed, 30 May 2018 09:06:48 -0400 From: Johannes Weiner Subject: Re: [PATCH 05/13] swap,blkcg: issue swap io with the appropriate context Message-ID: <20180530130648.GA4035@cmpxchg.org> References: <20180529211724.4531-1-josef@toxicpanda.com> <20180529211724.4531-6-josef@toxicpanda.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180529211724.4531-6-josef@toxicpanda.com> Sender: owner-linux-mm@kvack.org List-ID: To: Josef Bacik Cc: axboe@kernel.dk, kernel-team@fb.com, linux-block@vger.kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, tj@kernel.org, linux-fsdevel@vger.kernel.org On Tue, May 29, 2018 at 05:17:16PM -0400, Josef Bacik wrote: > From: Tejun Heo > > For backcharging we need to know who the page belongs to when swapping > it out. > > Signed-off-by: Tejun Heo > Signed-off-by: Josef Bacik > --- > mm/page_io.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/mm/page_io.c b/mm/page_io.c > index a552cb37e220..61e1268e5dbc 100644 > --- a/mm/page_io.c > +++ b/mm/page_io.c > @@ -339,6 +339,16 @@ int __swap_writepage(struct page *page, struct writeback_control *wbc, > goto out; > } > bio->bi_opf = REQ_OP_WRITE | REQ_SWAP | wbc_to_write_flags(wbc); > +#if defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP) > + if (page->mem_cgroup) { > + struct cgroup_subsys_state *blkcg_css; > + > + blkcg_css = cgroup_get_e_css(page->mem_cgroup->css.cgroup, > + &io_cgrp_subsys); > + bio_associate_blkcg(bio, blkcg_css); > + css_put(blkcg_css); > + } > +#endif This looks reasonable, but it probably warrants a helper function. bio_associate_blkcg_from_page() or something?