Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754886AbaDGHGI (ORCPT ); Mon, 7 Apr 2014 03:06:08 -0400 Received: from gate.crashing.org ([63.228.1.57]:42534 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750922AbaDGHGC (ORCPT ); Mon, 7 Apr 2014 03:06:02 -0400 Message-ID: <1396849534.3671.35.camel@pasglop> Subject: Re: [PATCH V2 1/2] mm: move FAULT_AROUND_ORDER to arch/ From: Benjamin Herrenschmidt To: Dave Hansen Cc: Madhavan Srinivasan , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, x86@kernel.org, paulus@samba.org, kirill.shutemov@linux.intel.com, rusty@rustcorp.com.au, akpm@linux-foundation.org, riel@redhat.com, mgorman@suse.de, ak@linux.intel.com, peterz@infradead.org, mingo@kernel.org Date: Mon, 07 Apr 2014 15:45:34 +1000 In-Reply-To: <533EDB63.8090909@intel.com> References: <1396592835-24767-1-git-send-email-maddy@linux.vnet.ibm.com> <1396592835-24767-2-git-send-email-maddy@linux.vnet.ibm.com> <533EDB63.8090909@intel.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.11.90 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2014-04-04 at 09:18 -0700, Dave Hansen wrote: > On 04/03/2014 11:27 PM, Madhavan Srinivasan wrote: > > This patch creates infrastructure to move the FAULT_AROUND_ORDER > > to arch/ using Kconfig. This will enable architecture maintainers > > to decide on suitable FAULT_AROUND_ORDER value based on > > performance data for that architecture. Patch also adds > > FAULT_AROUND_ORDER Kconfig element in arch/X86. > > Please don't do it this way. > > In mm/Kconfig, put > > config FAULT_AROUND_ORDER > int > default 1234 if POWERPC > default 4 > > The way you have it now, every single architecture that needs to enable > this has to go put that in their Kconfig. That's madness. This way, > you only put it in one place, and folks only have to care if they want > to change the default to be something other than 4. Also does it have to be a constant ? Maddy here tested on our POWER servers. The "Sweet spot" value might be VERY different on an embedded chip or even on a future generation of server chip. Cheers, Ben. -- 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/