Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755507AbcDJU0e (ORCPT ); Sun, 10 Apr 2016 16:26:34 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:52374 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757698AbcDJSsc (ORCPT ); Sun, 10 Apr 2016 14:48:32 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Johannes Weiner , Michal Hocko , Vladimir Davydov , Andrew Morton , Linus Torvalds Subject: [PATCH 4.5 138/238] mm: memcontrol: reclaim when shrinking memory.high below usage Date: Sun, 10 Apr 2016 11:35:15 -0700 Message-Id: <20160410183504.162348441@linuxfoundation.org> X-Mailer: git-send-email 2.8.0 In-Reply-To: <20160410183456.398741366@linuxfoundation.org> References: <20160410183456.398741366@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1544 Lines: 50 4.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Johannes Weiner commit 588083bb37a3cea8533c392370a554417c8f29cb upstream. 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. Signed-off-by: Johannes Weiner Acked-by: Michal Hocko Cc: Vladimir Davydov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/memcontrol.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -5051,6 +5051,7 @@ static ssize_t memory_high_write(struct 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; @@ -5061,6 +5062,11 @@ static ssize_t memory_high_write(struct 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; }