From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754048Ab2HTLRt (ORCPT ); Mon, 20 Aug 2012 07:17:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57138 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753412Ab2HTLRq (ORCPT ); Mon, 20 Aug 2012 07:17:46 -0400 Message-ID: <50321CD3.5050501@redhat.com> Date: Mon, 20 Aug 2012 07:17:39 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120717 Thunderbird/14.0 MIME-Version: 1.0 To: Michel Lespinasse CC: Hugh Dickins , Daniel Forrest , Andrea Arcangeli , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: Repeated fork() causes SLAB to grow without bound References: <20120816024610.GA5350@evergreen.ssec.wisc.edu> <502D42E5.7090403@redhat.com> <20120818000312.GA4262@evergreen.ssec.wisc.edu> <502F100A.1080401@redhat.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/20/2012 05:39 AM, Michel Lespinasse wrote: > I would still prefer if we could just remove the anon_vma_chain stuff, though. If only we could. That simply replaces a medium issue at fork time, with the potential for a catastrophic issue at page reclaim time, in any workload with heavily forking server software. Without the anon_vma_chains, we end up scanning every single one of the child processes (and the parent) for every COWed page, which can be a real issue when the VM runs into 1000 such pages, for 1000 child processes. Unfortunately, we have seen this happen... -- All rights reversed