From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d06nrmr1407.portsmouth.uk.ibm.com (d06nrmr1407.portsmouth.uk.ibm.com [9.149.38.185]) by mtagate1.uk.ibm.com (8.13.8/8.13.8) with ESMTP id m67HSBtQ267200 for ; Mon, 7 Jul 2008 17:28:11 GMT Received: from d06av01.portsmouth.uk.ibm.com (d06av01.portsmouth.uk.ibm.com [9.149.37.212]) by d06nrmr1407.portsmouth.uk.ibm.com (8.13.8/8.13.8/NCO v9.0) with ESMTP id m67HSBKi2412780 for ; Mon, 7 Jul 2008 18:28:11 +0100 Received: from d06av01.portsmouth.uk.ibm.com (loopback [127.0.0.1]) by d06av01.portsmouth.uk.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m67HSA7V000822 for ; Mon, 7 Jul 2008 18:28:11 +0100 Subject: Re: [PATCH] Make CONFIG_MIGRATION available for s390 From: Gerald Schaefer In-Reply-To: <4872319B.9040809@linux-foundation.org> References: <1215354957.9842.19.camel@localhost.localdomain> <4872319B.9040809@linux-foundation.org> Content-Type: text/plain Date: Mon, 07 Jul 2008 19:28:09 +0200 Message-Id: <1215451689.8431.80.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, KAMEZAWA Hiroyuki , Yasunori Goto , Dave Hansen , Andy Whitcroft List-ID: On Mon, 2008-07-07 at 10:09 -0500, Christoph Lameter wrote: > This will extend the number of pages that are migratable and lead to strange > semantics in the NUMA case. There suddenly vma_is migratable will forbid hotplug > to migrate certain pages. > > I think we need two functions: > > vma_migratable() General migratability > > vma_policy_migratable() Migratable under NUMA policies. Nothing will change here for the NUMA case, this is all about making it compile w/o NUMA and with MIGRATION. What new strange semantics do you mean? BTW, the latest patch in this thread will not touch vma_migratable() anymore, I haven't read your mail before, sorry. > That wont work since the migrate function takes a nodemask! The point of > the function is to move memory from node to node which is something that you > *cannot* do in a non NUMA configuration. So leave this chunk out. Right, but I noticed that this function definition was needed to make it compile with MIGRATION and w/o NUMA, although it would never be called in non-NUMA config. A better solution would probably be to put migrate_vmas(), the only caller of vm_ops->migrate(), inside '#ifdef CONFIG_NUMA', because it will only be called from NUMA-only mm/mempolicy.c. Does that sound reasonable? > Hmmm... Okay. I tried to make MIGRATION as independent of CONFIG_NUMA as possible so hopefully this will work. Umm, it doesn't compile with MIGRATION and w/o NUMA, which was the reason for this patch, because of the policy_zone reference in vma_migratable() and the missing vm_ops->migrate() function. Thanks, Gerald -- 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