From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932273AbcCJUvi (ORCPT ); Thu, 10 Mar 2016 15:51:38 -0500 Received: from gum.cmpxchg.org ([85.214.110.215]:45696 "EHLO gum.cmpxchg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932088AbcCJUvh (ORCPT ); Thu, 10 Mar 2016 15:51:37 -0500 From: Johannes Weiner To: Andrew Morton Cc: Michal Hocko , Vladimir Davydov , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: [PATCH] mm: memcontrol: reclaim when shrinking memory.high below usage Date: Thu, 10 Mar 2016 15:50:13 -0500 Message-Id: <1457643015-8828-1-git-send-email-hannes@cmpxchg.org> X-Mailer: git-send-email 2.7.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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