From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f46.google.com (mail-wm0-f46.google.com [74.125.82.46]) by kanga.kvack.org (Postfix) with ESMTP id 412AC828DF for ; Fri, 11 Mar 2016 02:55:18 -0500 (EST) Received: by mail-wm0-f46.google.com with SMTP id p65so7045419wmp.1 for ; Thu, 10 Mar 2016 23:55:18 -0800 (PST) Received: from mail-wm0-f43.google.com (mail-wm0-f43.google.com. [74.125.82.43]) by mx.google.com with ESMTPS id b71si1271464wmd.66.2016.03.10.23.55.17 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 10 Mar 2016 23:55:17 -0800 (PST) Received: by mail-wm0-f43.google.com with SMTP id l68so7151893wml.0 for ; Thu, 10 Mar 2016 23:55:17 -0800 (PST) Date: Fri, 11 Mar 2016 08:55:15 +0100 From: Michal Hocko Subject: Re: [PATCH] mm: memcontrol: reclaim when shrinking memory.high below usage Message-ID: <20160311075514.GB27701@dhcp22.suse.cz> References: <1457643015-8828-1-git-send-email-hannes@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1457643015-8828-1-git-send-email-hannes@cmpxchg.org> Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner Cc: Andrew Morton , Vladimir Davydov , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com On Thu 10-03-16 15:50:13, Johannes Weiner wrote: > When setting memory.high below usage, nothing happens until the next > charge comes along, and then it will only reclaim its own charge and > not the now potentially huge excess of the new memory.high. This can > cause groups to stay in excess of their memory.high indefinitely. > > To fix that, when shrinking memory.high, kick off a reclaim cycle that > goes after the delta. This has been the case since the knob was introduce but I wouldn't bother with the CC: stable # 4.0+ as this was still in experimental mode. I guess we want to have it in 4.5 or put it to 4.5 stable. > > Signed-off-by: Johannes Weiner Acked-by: Michal Hocko Thanks! > --- > mm/memcontrol.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 8615b066b642..f7c9b4cbdf01 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -4992,6 +4992,7 @@ static ssize_t memory_high_write(struct kernfs_open_file *of, > char *buf, size_t nbytes, loff_t off) > { > struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); > + unsigned long nr_pages; > unsigned long high; > int err; > > @@ -5002,6 +5003,11 @@ static ssize_t memory_high_write(struct kernfs_open_file *of, > > memcg->high = high; > > + nr_pages = page_counter_read(&memcg->memory); > + if (nr_pages > high) > + try_to_free_mem_cgroup_pages(memcg, nr_pages - high, > + GFP_KERNEL, true); > + > memcg_wb_domain_size_changed(memcg); > return nbytes; > } > -- > 2.7.2 -- Michal Hocko SUSE Labs -- 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