From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: [PATCH v3 3/6] memcg: Simplify mem_cgroup_force_empty_list error handling Date: Wed, 31 Oct 2012 14:30:47 -0700 Message-ID: <20121031143047.95587bff.akpm@linux-foundation.org> References: <1351251453-6140-1-git-send-email-mhocko@suse.cz> <1351251453-6140-4-git-send-email-mhocko@suse.cz> <508E8B95.406@parallels.com> <20121029150022.a595b866.akpm@linux-foundation.org> <20121030103559.GA7394@dhcp22.suse.cz> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20121030103559.GA7394-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Michal Hocko Cc: Glauber Costa , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Tejun Heo , Li Zefan , Johannes Weiner , KAMEZAWA Hiroyuki , Balbir Singh On Tue, 30 Oct 2012 11:35:59 +0100 Michal Hocko wrote: > > If the kernel is uniprocessor and the caller is SCHED_FIFO: ad infinitum! > > ... > > Can we consider this as a corner case (it is much easier to kill a > machine with SCHED_FIFO than this anyway) or the concern is really > strong and we should come with a solution before this can get merged? Sure. SCHED_FIFO can be used to permanently block all kernel threads which pretty quickly results in a very sick kernel. My observation was just a general moan about the SCHED_FIFO wontfix problem :) From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx160.postini.com [74.125.245.160]) by kanga.kvack.org (Postfix) with SMTP id 7ED716B0062 for ; Wed, 31 Oct 2012 17:30:49 -0400 (EDT) Date: Wed, 31 Oct 2012 14:30:47 -0700 From: Andrew Morton Subject: Re: [PATCH v3 3/6] memcg: Simplify mem_cgroup_force_empty_list error handling Message-Id: <20121031143047.95587bff.akpm@linux-foundation.org> In-Reply-To: <20121030103559.GA7394@dhcp22.suse.cz> References: <1351251453-6140-1-git-send-email-mhocko@suse.cz> <1351251453-6140-4-git-send-email-mhocko@suse.cz> <508E8B95.406@parallels.com> <20121029150022.a595b866.akpm@linux-foundation.org> <20121030103559.GA7394@dhcp22.suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Glauber Costa , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Tejun Heo , Li Zefan , Johannes Weiner , KAMEZAWA Hiroyuki , Balbir Singh On Tue, 30 Oct 2012 11:35:59 +0100 Michal Hocko wrote: > > If the kernel is uniprocessor and the caller is SCHED_FIFO: ad infinitum! > > ... > > Can we consider this as a corner case (it is much easier to kill a > machine with SCHED_FIFO than this anyway) or the concern is really > strong and we should come with a solution before this can get merged? Sure. SCHED_FIFO can be used to permanently block all kernel threads which pretty quickly results in a very sick kernel. My observation was just a general moan about the SCHED_FIFO wontfix problem :) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760714Ab2JaVau (ORCPT ); Wed, 31 Oct 2012 17:30:50 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:37611 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751527Ab2JaVat (ORCPT ); Wed, 31 Oct 2012 17:30:49 -0400 Date: Wed, 31 Oct 2012 14:30:47 -0700 From: Andrew Morton To: Michal Hocko Cc: Glauber Costa , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Tejun Heo , Li Zefan , Johannes Weiner , KAMEZAWA Hiroyuki , Balbir Singh Subject: Re: [PATCH v3 3/6] memcg: Simplify mem_cgroup_force_empty_list error handling Message-Id: <20121031143047.95587bff.akpm@linux-foundation.org> In-Reply-To: <20121030103559.GA7394@dhcp22.suse.cz> References: <1351251453-6140-1-git-send-email-mhocko@suse.cz> <1351251453-6140-4-git-send-email-mhocko@suse.cz> <508E8B95.406@parallels.com> <20121029150022.a595b866.akpm@linux-foundation.org> <20121030103559.GA7394@dhcp22.suse.cz> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; 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 Tue, 30 Oct 2012 11:35:59 +0100 Michal Hocko wrote: > > If the kernel is uniprocessor and the caller is SCHED_FIFO: ad infinitum! > > ... > > Can we consider this as a corner case (it is much easier to kill a > machine with SCHED_FIFO than this anyway) or the concern is really > strong and we should come with a solution before this can get merged? Sure. SCHED_FIFO can be used to permanently block all kernel threads which pretty quickly results in a very sick kernel. My observation was just a general moan about the SCHED_FIFO wontfix problem :)