Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753582AbZGTSL1 (ORCPT ); Mon, 20 Jul 2009 14:11:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753022AbZGTSL0 (ORCPT ); Mon, 20 Jul 2009 14:11:26 -0400 Received: from mx2.redhat.com ([66.187.237.31]:44443 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751489AbZGTSLZ (ORCPT ); Mon, 20 Jul 2009 14:11:25 -0400 Message-ID: <4A64B342.8070002@redhat.com> Date: Mon, 20 Jul 2009 14:11:14 -0400 From: Rik van Riel Organization: Red Hat, Inc User-Agent: Thunderbird 2.0.0.17 (X11/20080915) MIME-Version: 1.0 To: Izik Eidus CC: akpm@linux-foundation.org, hugh.dickins@tiscali.co.uk, aarcange@redhat.com, chrisw@redhat.com, avi@redhat.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, nickpiggin@yahoo.com.au, Nick Piggin Subject: Re: [PATCH 05/10] ksm: no debug in page_dup_rmap() References: <1247851850-4298-1-git-send-email-ieidus@redhat.com> <1247851850-4298-2-git-send-email-ieidus@redhat.com> <1247851850-4298-3-git-send-email-ieidus@redhat.com> <1247851850-4298-4-git-send-email-ieidus@redhat.com> <1247851850-4298-5-git-send-email-ieidus@redhat.com> <1247851850-4298-6-git-send-email-ieidus@redhat.com> In-Reply-To: <1247851850-4298-6-git-send-email-ieidus@redhat.com> 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 Content-Length: 949 Lines: 22 Izik Eidus wrote: > From: Hugh Dickins > > page_dup_rmap(), used on each mapped page when forking, was originally > just an inline atomic_inc of mapcount. 2.6.22 added CONFIG_DEBUG_VM > out-of-line checks to it, which would need to be ever-so-slightly > complicated to allow for the PageKsm() we're about to define. > > But I think these checks never caught anything. And if it's coding > errors we're worried about, such checks should be in page_remove_rmap() > too, not just when forking; whereas if it's pagetable corruption we're > worried about, then they shouldn't be limited to CONFIG_DEBUG_VM. Acked-by: Rik van Riel -- All rights reversed. -- 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/