From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f182.google.com (mail-pd0-f182.google.com [209.85.192.182]) by kanga.kvack.org (Postfix) with ESMTP id 3A4EC6B0035 for ; Mon, 6 Jan 2014 18:24:01 -0500 (EST) Received: by mail-pd0-f182.google.com with SMTP id v10so18745796pde.13 for ; Mon, 06 Jan 2014 15:24:00 -0800 (PST) Received: from e23smtp07.au.ibm.com (e23smtp07.au.ibm.com. [202.81.31.140]) by mx.google.com with ESMTPS id ob10si56338887pbb.37.2014.01.06.15.23.58 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Mon, 06 Jan 2014 15:23:59 -0800 (PST) Received: from /spool/local by e23smtp07.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 7 Jan 2014 09:23:54 +1000 Received: from d23relay04.au.ibm.com (d23relay04.au.ibm.com [9.190.234.120]) by d23dlp01.au.ibm.com (Postfix) with ESMTP id 1DD6D2CE8053 for ; Tue, 7 Jan 2014 10:23:51 +1100 (EST) Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by d23relay04.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s06N55CC48693454 for ; Tue, 7 Jan 2014 10:05:06 +1100 Received: from d23av04.au.ibm.com (localhost [127.0.0.1]) by d23av04.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s06NNn4b020170 for ; Tue, 7 Jan 2014 10:23:49 +1100 Date: Tue, 7 Jan 2014 07:23:48 +0800 From: Wanpeng Li Subject: Re: [PATCH] sched/auto_group: fix consume memory even if add 'noautogroup' in the cmdline Message-ID: <52cb3b0f.2a82440a.5285.ffff9642SMTPIN_ADDED_BROKEN@mx.google.com> Reply-To: Wanpeng Li References: <1388139751-19632-1-git-send-email-liwanp@linux.vnet.ibm.com> <20140106121719.GH31570@twins.programming.kicks-ass.net> <1389016976.5536.10.camel@marge.simpson.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1389016976.5536.10.camel@marge.simpson.net> Sender: owner-linux-mm@kvack.org List-ID: To: Mike Galbraith Cc: Peter Zijlstra , Ingo Molnar , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Mon, Jan 06, 2014 at 03:02:56PM +0100, Mike Galbraith wrote: >On Mon, 2014-01-06 at 13:17 +0100, Peter Zijlstra wrote: >> On Fri, Dec 27, 2013 at 06:22:31PM +0800, Wanpeng Li wrote: >> > We have a server which have 200 CPUs and 8G memory, there is auto_group creation >> >> I'm hoping that is 8T, otherwise that's a severely under provisioned >> system, that's a mere 40M per cpu, does that even work? >> >> > which will almost consume 12MB memory even if add 'noautogroup' in the kernel >> > boot parameter. In addtion, SLUB per cpu partial caches freeing that is local to >> > a processor which requires the taking of locks at the price of more indeterminism >> > in the latency of the free. This patch fix it by check noautogroup earlier to avoid >> > free after unnecessary memory consumption. >> >> That's just a bad changelog. It fails to explain the actual problem and >> it babbles about unrelated things like SLUB details. >> >> Also, I'm not entirely sure what the intention was of this code, I've so >> far tried to ignore the entire autogroup fest... >> >> It looks like it creates and maintains the entire autogroup hierarchy, >> such that if you at runtime enable the sysclt and move tasks 'back' to >> the root cgroup you get the autogroup behaviour. >> >> Was this intended? Mike? > >Yeah, it was intended that autogroups always exist if you config it in. >We could make is such that noautogroup makes it irreversibly off/dead. > >People with 200 ram starved CPUs can turn it off in their .config too :) Thanks for your great explaination. Regards, Wanpeng Li > >-Mike > >-- >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 -- 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