From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757534Ab3BVUjO (ORCPT ); Fri, 22 Feb 2013 15:39:14 -0500 Received: from mail-pb0-f43.google.com ([209.85.160.43]:46040 "EHLO mail-pb0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757435Ab3BVUjM (ORCPT ); Fri, 22 Feb 2013 15:39:12 -0500 Date: Fri, 22 Feb 2013 12:38:26 -0800 (PST) From: Hugh Dickins X-X-Sender: hugh@eggly.anvils To: Ric Mason cc: Andrew Morton , Mel Gorman , Petr Holasek , Andrea Arcangeli , Izik Eidus , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 0/7] ksm: responses to NUMA review In-Reply-To: <5126E987.7020809@gmail.com> Message-ID: References: <5126E987.7020809@gmail.com> User-Agent: Alpine 2.00 (LNX 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 22 Feb 2013, Ric Mason wrote: > On 02/21/2013 04:17 PM, Hugh Dickins wrote: > > Here's a second KSM series, based on mmotm 2013-02-19-17-20: partly in > > response to Mel's review feedback, partly fixes to issues that I found > > myself in doing more review and testing. None of the issues fixed are > > truly show-stoppers, though I would prefer them fixed sooner than later. > > Do you have any ideas ksm support page cache and tmpfs? No. It's only been asked as a hypothetical question: I don't know of anyone actually needing it, and I wouldn't have time to do it myself. It would be significantly more invasive than just dealing with anonymous memory: with anon, we already have the infrastructure for read-only pages, but we don't at present have any notion of read-only pagecache. Just doing it in tmpfs? Well, yes, that might be easier: since v3.1's radix_tree rework, shmem/tmpfs mostly goes through its own interfaces to pagecache, so read-only pagecache, and hence KSM, might be easier to implement there than more generally. Hugh