From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id 668F86B005A for ; Mon, 20 Jul 2009 14:11:16 -0400 (EDT) Message-ID: <4A64B342.8070002@redhat.com> Date: Mon, 20 Jul 2009 14:11:14 -0400 From: Rik van Riel MIME-Version: 1.0 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: owner-linux-mm@kvack.org 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 List-ID: 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org