From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755374AbZHCQDF (ORCPT ); Mon, 3 Aug 2009 12:03:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755342AbZHCQDE (ORCPT ); Mon, 3 Aug 2009 12:03:04 -0400 Received: from mx2.redhat.com ([66.187.237.31]:40850 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755341AbZHCQDC (ORCPT ); Mon, 3 Aug 2009 12:03:02 -0400 Message-ID: <4A7709A0.4060402@redhat.com> Date: Mon, 03 Aug 2009 19:00:32 +0300 From: Izik Eidus User-Agent: Thunderbird 2.0.0.22 (Windows/20090605) MIME-Version: 1.0 To: Hugh Dickins CC: Andrea Arcangeli , Rik van Riel , Chris Wright , Nick Piggin , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 4/12] ksm: break cow once unshared References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hugh Dickins wrote: > We kept agreeing not to bother about the unswappable shared KSM pages > which later become unshared by others: observation suggests they're not > a significant proportion. But they are disadvantageous, and it is easier > to break COW to replace them by swappable pages, than offer statistics > to show that they don't matter; then we can stop worrying about them. > > Doing this in ksm_do_scan, they don't go through cmp_and_merge_page on > this pass: give them a good chance of getting into the unstable tree > on the next pass, or back into the stable, by computing checksum now. > > Signed-off-by: Hugh Dickins > --- ACK