From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with ESMTP id A3C666B01F1 for ; Mon, 19 Apr 2010 09:22:48 -0400 (EDT) Subject: Re: [PATCH 1/8] numa: add generic percpu var numa_node_id() implementation From: Lee Schermerhorn In-Reply-To: <20100416133324.fcb1c168.akpm@linux-foundation.org> References: <20100415172950.8801.60358.sendpatchset@localhost.localdomain> <20100415172956.8801.18133.sendpatchset@localhost.localdomain> <20100416133324.fcb1c168.akpm@linux-foundation.org> Content-Type: text/plain Date: Mon, 19 Apr 2010 09:22:31 -0400 Message-Id: <1271683352.10937.34.camel@useless.americas.hpqcorp.net> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Andrew Morton Cc: linux-mm@kvack.org, linux-numa@vger.kernel.org, Tejun Heo , Mel Gorman , andi@firstfloor.org, Christoph Lameter , Nick Piggin , David Rientjes , eric.whitney@hp.com, KAMEZAWA Hiroyuki , linux-arch@vger.kernel.org List-ID: On Fri, 2010-04-16 at 13:33 -0700, Andrew Morton wrote: > On Thu, 15 Apr 2010 13:29:56 -0400 > Lee Schermerhorn wrote: > > > Rework the generic version of the numa_node_id() function to use the > > new generic percpu variable infrastructure. > > > > Guard the new implementation with a new config option: > > > > CONFIG_USE_PERCPU_NUMA_NODE_ID. > > > > Archs which support this new implemention will default this option > > to 'y' when NUMA is configured. This config option could be removed > > if/when all archs switch over to the generic percpu implementation > > of numa_node_id(). Arch support involves: > > > > 1) converting any existing per cpu variable implementations to use > > this implementation. x86_64 is an instance of such an arch. > > 2) archs that don't use a per cpu variable for numa_node_id() will > > need to initialize the new per cpu variable "numa_node" as cpus > > are brought on-line. ia64 is an example. > > 3) Defining USE_PERCPU_NUMA_NODE_ID in arch dependent Kconfig--e.g., > > when NUMA is configured. This is required because I have > > retained the old implementation by default to allow archs to > > be modified incrementally, as desired. > > > > Subsequent patches will convert x86_64 and ia64 to use this > > implemenation. > > So which arches _aren't_ converted? powerpc, sparc and alpha? Right. Plus ARM, mips, ... I could take a cut at other archs, but can't test them. I'm hoping that this patch doesn't break the existing implementation for them. It should be a no-op until the new support is enabled via Kconfig. The fact that both x86_64 and ia64 build with just this patch gives me some hope but not a lot of confidence. I see that you've merged the series with into -mm. We'll see what happens. Of course, no reports of errors could just mean no testing. > > Is there sufficient info here for the maintainers to be able to > perform the conversion with minimal head-scratching? Arch maintainers will need to chime in on that. I'd hoped that the list above and the examples of x86_64 and ia64 in the subsequent patches would suffice. Lee -- 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