Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751062AbaKXXjm (ORCPT ); Mon, 24 Nov 2014 18:39:42 -0500 Received: from lgeamrelo04.lge.com ([156.147.1.127]:62778 "EHLO lgeamrelo04.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750784AbaKXXjl (ORCPT ); Mon, 24 Nov 2014 18:39:41 -0500 X-Original-SENDERIP: 10.177.222.213 X-Original-MAILFROM: iamjoonsoo.kim@lge.com Date: Tue, 25 Nov 2014 08:42:37 +0900 From: Joonsoo Kim To: Andrew Morton Cc: Mel Gorman , Johannes Weiner , Minchan Kim , Dave Hansen , Michal Nazarewicz , Jungsoo Son , Ingo Molnar , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 3/8] mm/debug-pagealloc: make debug-pagealloc boottime configurable Message-ID: <20141124234237.GA7824@js1304-P5Q-DELUXE> References: <1416816926-7756-1-git-send-email-iamjoonsoo.kim@lge.com> <1416816926-7756-4-git-send-email-iamjoonsoo.kim@lge.com> <20141124145542.08b97076.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141124145542.08b97076.akpm@linux-foundation.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 24, 2014 at 02:55:42PM -0800, Andrew Morton wrote: > On Mon, 24 Nov 2014 17:15:21 +0900 Joonsoo Kim wrote: > > > Now, we have prepared to avoid using debug-pagealloc in boottime. So > > introduce new kernel-parameter to disable debug-pagealloc in boottime, > > and makes related functions to be disabled in this case. > > > > Only non-intuitive part is change of guard page functions. Because > > guard page is effective only if debug-pagealloc is enabled, turning off > > according to debug-pagealloc is reasonable thing to do. > > > > ... > > > > --- a/Documentation/kernel-parameters.txt > > +++ b/Documentation/kernel-parameters.txt > > @@ -858,6 +858,14 @@ bytes respectively. Such letter suffixes can also be entirely omitted. > > causing system reset or hang due to sending > > INIT from AP to BSP. > > > > + disable_debug_pagealloc > > + [KNL] When CONFIG_DEBUG_PAGEALLOC is set, this > > + parameter allows user to disable it at boot time. > > + With this parameter, we can avoid allocating huge > > + chunk of memory for debug pagealloc and then > > + the system will work mostly same with the kernel > > + built without CONFIG_DEBUG_PAGEALLOC. > > + > > Weren't we going to make this default to "off", require a boot option > to turn debug_pagealloc on? Hello, Andrew. I'm afraid that changing default to "off" confuses some old users. They would expect that it is default "on". But, it is just debug feature, so, it may be no problem. If you prefer to change default, I will rework this patch. Please let me know your decision. Thanks. -- 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/