From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f72.google.com (mail-wm0-f72.google.com [74.125.82.72]) by kanga.kvack.org (Postfix) with ESMTP id 8D8596B0388 for ; Thu, 23 Feb 2017 14:09:11 -0500 (EST) Received: by mail-wm0-f72.google.com with SMTP id e15so3950407wmd.6 for ; Thu, 23 Feb 2017 11:09:11 -0800 (PST) Received: from gum.cmpxchg.org (gum.cmpxchg.org. [85.214.110.215]) by mx.google.com with ESMTPS id p44si1469468wrb.57.2017.02.23.11.09.10 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 23 Feb 2017 11:09:10 -0800 (PST) Date: Thu, 23 Feb 2017 14:03:13 -0500 From: Johannes Weiner Subject: Re: [PATCH v2 2/2] mm/cgroup: delay soft limit data allocation Message-ID: <20170223190313.GB6088@cmpxchg.org> References: <1487856999-16581-1-git-send-email-ldufour@linux.vnet.ibm.com> <1487856999-16581-3-git-send-email-ldufour@linux.vnet.ibm.com> <20170223153107.GD29056@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170223153107.GD29056@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Laurent Dufour , Vladimir Davydov , Balbir Singh , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org On Thu, Feb 23, 2017 at 04:31:07PM +0100, Michal Hocko wrote: > On Thu 23-02-17 14:36:39, Laurent Dufour wrote: > > Until a soft limit is set to a cgroup, the soft limit data are useless > > so delay this allocation when a limit is set. > > Hmm, I am still undecided whether this is actually worth it. On one hand > distribution kernels tend to have quite large NUMA_SHIFT (e.g. SLES has > NUMA_SHIFT=10 and then we will save 8kB+12kB which is not hell of a lot > but always good if we can save that, especially for a rarely used > feature. The code grown on the other hand (it was in __init section > previously) which is a minus, on the other hand. > > What do you think Johannes? Hohumm, saving 5 pages on a NUMA machine vs. the additional complexity and the increased risk of memory problems when somebody sets up a soft limit after some uptime... I don't think I can give a strong yes or no on this one, so inertia wins for me; I'd just leave it alone. -- 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