From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756805AbaDPVe2 (ORCPT ); Wed, 16 Apr 2014 17:34:28 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:46563 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756643AbaDPVe0 (ORCPT ); Wed, 16 Apr 2014 17:34:26 -0400 Date: Wed, 16 Apr 2014 14:34:25 -0700 From: Andrew Morton To: Johannes Weiner Cc: Michal Hocko , Tejun Heo , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [patch] mm: memcontrol: remove hierarchy restrictions for swappiness and oom_control Message-Id: <20140416143425.c2b6f511cf4c6cd7336134b3@linux-foundation.org> In-Reply-To: <1397682798-22906-1-git-send-email-hannes@cmpxchg.org> References: <1397682798-22906-1-git-send-email-hannes@cmpxchg.org> X-Mailer: Sylpheed 3.2.0beta5 (GTK+ 2.24.10; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 16 Apr 2014 17:13:18 -0400 Johannes Weiner wrote: > Per-memcg swappiness and oom killing can currently not be tweaked on a > memcg that is part of a hierarchy, but not the root of that hierarchy. > Users have complained that they can't configure this when they turned > on hierarchy mode. In fact, with hierarchy mode becoming the default, > this restriction disables the tunables entirely. > > But there is no good reason for this restriction. The settings for > swappiness and OOM killing are taken from whatever memcg whose limit > triggered reclaim and OOM invocation, regardless of its position in > the hierarchy tree. > > Allow setting swappiness on any group. The knob on the root memcg > already reads the global VM swappiness, make it writable as well. > > Allow disabling the OOM killer on any non-root memcg. Documentation/cgroups/memory.txt needs updates?