From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id 8C72C6B02C3 for ; Wed, 30 Aug 2017 08:45:25 -0400 (EDT) Received: by mail-pg0-f71.google.com with SMTP id 85so1855533pge.9 for ; Wed, 30 Aug 2017 05:45:25 -0700 (PDT) Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com. [67.231.145.42]) by mx.google.com with ESMTPS id x124si4397119pfx.223.2017.08.30.05.45.24 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 30 Aug 2017 05:45:24 -0700 (PDT) Date: Wed, 30 Aug 2017 13:44:59 +0100 From: Roman Gushchin Subject: Re: [PATCH] mm: memcontrol: use per-cpu stocks for socket memory uncharging Message-ID: <20170830124459.GA10438@castle.DHCP.thefacebook.com> References: <20170829100150.4580-1-guro@fb.com> <20170830123655.6kce7yfkrhrhwubu@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20170830123655.6kce7yfkrhrhwubu@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: linux-mm@kvack.org, Johannes Weiner , Vladimir Davydov , cgroups@vger.kernel.org, kernel-team@fb.com, linux-kernel@vger.kernel.org On Wed, Aug 30, 2017 at 02:36:55PM +0200, Michal Hocko wrote: > On Tue 29-08-17 11:01:50, Roman Gushchin wrote: > [...] > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > > index b9cf3cf4a3d0..a69d23082abf 100644 > > --- a/mm/memcontrol.c > > +++ b/mm/memcontrol.c > > @@ -1792,6 +1792,9 @@ static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages) > > } > > stock->nr_pages += nr_pages; > > > > + if (stock->nr_pages > CHARGE_BATCH) > > + drain_stock(stock); > > + > > local_irq_restore(flags); > > } > > Why do we need this? In other words, why cannot we rely on draining we > already do? The existing draining depends on memory pressure, so to keep the accounting (which we expose to a user) reasonable accurate even without memory pressure, we need to limit the size of per-cpu stocks. Thanks! -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org