From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id BBE918D0040 for ; Fri, 4 Feb 2011 12:19:18 -0500 (EST) Received: from d01dlp02.pok.ibm.com (d01dlp02.pok.ibm.com [9.56.224.85]) by e4.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id p14GxPIh016291 for ; Fri, 4 Feb 2011 12:00:49 -0500 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by d01dlp02.pok.ibm.com (Postfix) with ESMTP id 810664DE8050 for ; Fri, 4 Feb 2011 12:18:35 -0500 (EST) Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p14HJEoL128004 for ; Fri, 4 Feb 2011 12:19:14 -0500 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p14HJEgf005134 for ; Fri, 4 Feb 2011 10:19:14 -0700 Subject: Re: [RFC][PATCH 2/6] pagewalk: only split huge pages when necessary From: Dave Hansen In-Reply-To: References: <20110201003357.D6F0BE0D@kernel> <20110201003359.8DDFF665@kernel> <1296768812.8299.1644.camel@nimitz> Content-Type: text/plain; charset="ANSI_X3.4-1968" Date: Fri, 04 Feb 2011 09:19:12 -0800 Message-ID: <1296839952.6737.2316.camel@nimitz> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: David Rientjes Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Michael J Wolf , Andrea Arcangeli On Thu, 2011-02-03 at 13:46 -0800, David Rientjes wrote: > > Probably, but we don't currently have any central documentation for it. > > Guess we could make some, or just ensure that all the users got updated. > > Any ideas where to put it other than the mm_walk struct? > > I think noting it where struct mm_walk is declared would be best (just a > "/* must handle pmd_trans_huge() */" would be sufficient) although > eventually it might be cleaner to add a ->pmd_huge_entry(). For code maintenance, I really like _not_ hiding this in the API somewhere. This way, we have a great, self-explanatory tag wherever code (possibly) hasn't properly dealt with THPs. We get a nice, greppable, cscope'able: split_huge_page_pmd() wherever we need to "teach" the code about THP. It's kinda like the BKL. :) -- Dave -- 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