From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Hocko Subject: Re: [PATCH v1] mm:memcg: skip memcg of current in mem_cgroup_soft_limit_reclaim Date: Fri, 3 Aug 2018 08:18:17 +0200 Message-ID: <20180803061817.GC27245@dhcp22.suse.cz> References: <1533275285-12387-1-git-send-email-zhaoyang.huang@spreadtrum.com> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Zhaoyang Huang Cc: Steven Rostedt , Ingo Molnar , Johannes Weiner , Vladimir Davydov , "open list:MEMORY MANAGEMENT" , cgroups@vger.kernel.org, LKML , kernel-patch-test@lists.linaro.org On Fri 03-08-18 14:11:26, Zhaoyang Huang wrote: > On Fri, Aug 3, 2018 at 1:48 PM Zhaoyang Huang wrote: > > > > for the soft_limit reclaim has more directivity than global reclaim, we40960 > > have current memcg be skipped to avoid potential page thrashing. > > > The patch is tested in our android system with 2GB ram. The case > mainly focus on the smooth slide of pictures on a gallery, which used > to stall on the direct reclaim for over several hundred > millionseconds. By further debugging, we find that the direct reclaim > spend most of time to reclaim pages on its own with softlimit set to > 40960KB. I add a ftrace event to verify that the patch can help > escaping such scenario. Furthermore, we also measured the major fault > of this process(by dumpsys of android). The result is the patch can > help to reduce 20% of the major fault during the test. I have asked already asked. Why do you use the soft limit in the first place? It is known to cause excessive reclaim and long stalls. -- Michal Hocko SUSE Labs