From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vlastimil Babka Subject: Re: [PATCH/RFC 3/3] s390: query dynamic DEBUG_PAGEALLOC setting Date: Wed, 27 Jan 2016 13:41:57 +0100 Message-ID: <56A8BB15.9070305@suse.cz> References: <1453799905-10941-1-git-send-email-borntraeger@de.ibm.com> <1453799905-10941-4-git-send-email-borntraeger@de.ibm.com> <20160126181903.GB4671@osiris> <20160127001918.GA7089@js1304-P5Q-DELUXE> <20160127005920.GB7089@js1304-P5Q-DELUXE> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: Received: from mx2.suse.de ([195.135.220.15]:36981 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932318AbcA0MmA (ORCPT ); Wed, 27 Jan 2016 07:42:00 -0500 In-Reply-To: <20160127005920.GB7089@js1304-P5Q-DELUXE> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Joonsoo Kim , David Rientjes Cc: Heiko Carstens , Christian Borntraeger , linux-kernel@vger.kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, x86@kernel.org On 01/27/2016 01:59 AM, Joonsoo Kim wrote: > On Tue, Jan 26, 2016 at 04:36:11PM -0800, David Rientjes wrote: >> >> If we can convert existing users that only check for >> CONFIG_DEBUG_PAGEALLOC to rather check for debug_pagealloc_enabled() and >> agree that it is only enabled for debug_pagealloc=on, then this would seem >> fine. However, I think we should at least consult with those users before >> removing an artifact from the kernel log that could be useful in debugging >> why a particular BUG() happened. > > Yes, at least, non-architecture dependent code (vmalloc, SLAB, SLUB) should > be changed first. If Christian doesn't mind, I will try to fix above 3 > things. I think it might be worth also to convert debug_pagealloc_enabled() to be based on static key, like I did for page_owner [1]. That should help make it possible to have virtually no overhead when compiling kernel with CONFIG_DEBUG_PAGEALLOC without enabling it boot-time. I assume it's one of the goals here? [1] http://www.spinics.net/lists/linux-mm/msg100795.html > Thanks. > > -- > 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 >