From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1424219AbcFMPJT (ORCPT ); Mon, 13 Jun 2016 11:09:19 -0400 Received: from gum.cmpxchg.org ([85.214.110.215]:59302 "EHLO gum.cmpxchg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422835AbcFMPJR (ORCPT ); Mon, 13 Jun 2016 11:09:17 -0400 Date: Mon, 13 Jun 2016 11:06:53 -0400 From: Johannes Weiner To: Minchan Kim Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Rik van Riel , Sangwoo Park Subject: Re: [PATCH v1 3/3] mm: per-process reclaim Message-ID: <20160613150653.GA30642@cmpxchg.org> References: <1465804259-29345-1-git-send-email-minchan@kernel.org> <1465804259-29345-4-git-send-email-minchan@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1465804259-29345-4-git-send-email-minchan@kernel.org> User-Agent: Mutt/1.6.1 (2016-04-27) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Minchan, On Mon, Jun 13, 2016 at 04:50:58PM +0900, Minchan Kim wrote: > These day, there are many platforms available in the embedded market > and sometime, they has more hints about workingset than kernel so > they want to involve memory management more heavily like android's > lowmemory killer and ashmem or user-daemon with lowmemory notifier. > > This patch adds add new method for userspace to manage memory > efficiently via knob "/proc//reclaim" so platform can reclaim > any process anytime. Cgroups are our canonical way to control system resources on a per process or group-of-processes level. I don't like the idea of adding ad-hoc interfaces for single-use cases like this. For this particular case, you can already stick each app into its own cgroup and use memory.force_empty to target-reclaim them. Or better yet, set the soft limits / memory.low to guide physical memory pressure, once it actually occurs, toward the least-important apps? We usually prefer doing work on-demand rather than proactively. The one-cgroup-per-app model would give Android much more control and would also remove a *lot* of overhead during task switches, see this: https://lkml.org/lkml/2014/12/19/358