From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta7.messagelabs.com (mail6.bemta7.messagelabs.com [216.82.255.55]) by kanga.kvack.org (Postfix) with ESMTP id D34BA6B0069 for ; Fri, 18 Nov 2011 07:50:03 -0500 (EST) Date: Fri, 18 Nov 2011 13:52:02 +0100 From: Stanislaw Gruszka Subject: Re: [PATCH] mm,x86: remove debug_pagealloc_enabled Message-ID: <20111118125201.GC2203@redhat.com> References: <1321458232-6823-1-git-send-email-sgruszka@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1321458232-6823-1-git-send-email-sgruszka@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org, x86@kernel.org Cc: linux-kernel@vger.kernel.org, Mel Gorman , Andrew Morton , Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner On Wed, Nov 16, 2011 at 04:43:52PM +0100, Stanislaw Gruszka wrote: > When (no)bootmem finish operation, it pass pages to buddy allocator. > Since debug_pagealloc_enabled is not set, we will do not protect pages, > what is not what we want with CONFIG_DEBUG_PAGEALLOC=y. > > To fix remove debug_pagealloc_enabled. That variable was introduced by > commit 12d6f21e "x86: do not PSE on CONFIG_DEBUG_PAGEALLOC=y" to get > more CPA (change page attribude) code testing. But currently we have > CONFIG_CPA_DEBUG, which test CPA. Note this is more like fix than cleanup. Without patch, pages are not protected until they are allocated and then freed again, what may not happen if system is not used intensively. If that patch can not be accepted, I think we should just go through all free pages and mark then as not-presen in enable_debug_pagealloc() Stanislaw -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org