Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751322AbWHRJ3F (ORCPT ); Fri, 18 Aug 2006 05:29:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751323AbWHRJ3F (ORCPT ); Fri, 18 Aug 2006 05:29:05 -0400 Received: from mailhub.sw.ru ([195.214.233.200]:3250 "EHLO relay.sw.ru") by vger.kernel.org with ESMTP id S1751322AbWHRJ3E (ORCPT ); Fri, 18 Aug 2006 05:29:04 -0400 Message-ID: <44E588F0.40502@sw.ru> Date: Fri, 18 Aug 2006 13:31:28 +0400 From: Kirill Korotaev User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.13) Gecko/20060417 X-Accept-Language: en-us, en, ru MIME-Version: 1.0 To: Dave Hansen CC: rohitseth@google.com, Rik van Riel , ckrm-tech@lists.sourceforge.net, Linux Kernel Mailing List , Andi Kleen , Christoph Hellwig , Andrey Savochkin , devel@openvz.org, hugh@veritas.com, Ingo Molnar , Alan Cox , Pavel Emelianov Subject: Re: [ckrm-tech] [RFC][PATCH 5/7] UBC: kernel memory accounting (core) References: <44E33893.6020700@sw.ru> <44E33C8A.6030705@sw.ru> <1155752693.22595.76.camel@galaxy.corp.google.com> <44E46ED3.7000201@sw.ru> <1155825493.9274.42.camel@localhost.localdomain> In-Reply-To: <1155825493.9274.42.camel@localhost.localdomain> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1375 Lines: 36 Dave Hansen wrote: > On Thu, 2006-08-17 at 17:27 +0400, Kirill Korotaev wrote: > >>charged kernel objects can't be _reclaimed_. how do you propose >>to reclaim tasks page tables or files or task struct or vma or etc.? > > > Do you have any statistics on which of these objects are the most > troublesome? If it _is_ pagetables, for instance, it is quite > conceivable that we could reclaim them. they all are troublesome :/ user can create lots of vmas, w/o page tables. lots of fdsets, ipcids. These are not reclaimable. Also consider the following scenario with reclaimable page tables. e.g. user hit kmemsize limit due to fat page tables. kernel reclaims some of the page tables and frees user kenerl memory. after that user creates some uncreclaimable objects like fdsets or ipcs and then accesses memory with reclaimed page tables. Sooner or later we kill user with SIGSEGV from page fault due to no memory. This is worse then returning ENOMEM from poll() or mmap() where user allocates kernel objects. > This one probably deserves a big, fat comment, though. ;) tell me where to write it and what? :) Thanks, Kirill - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/