From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qc0-f182.google.com (mail-qc0-f182.google.com [209.85.216.182]) by kanga.kvack.org (Postfix) with ESMTP id D29F76B0035 for ; Fri, 11 Jul 2014 12:19:20 -0400 (EDT) Received: by mail-qc0-f182.google.com with SMTP id r5so372221qcx.13 for ; Fri, 11 Jul 2014 09:19:20 -0700 (PDT) Received: from qmta14.emeryville.ca.mail.comcast.net (qmta14.emeryville.ca.mail.comcast.net. [2001:558:fe2d:44:76:96:27:212]) by mx.google.com with ESMTP id x9si3892898qax.121.2014.07.11.09.19.18 for ; Fri, 11 Jul 2014 09:19:19 -0700 (PDT) Date: Fri, 11 Jul 2014 11:19:14 -0500 (CDT) From: Christoph Lameter Subject: Re: [RFC Patch V1 07/30] mm: Use cpu_to_mem()/numa_mem_id() to support memoryless node In-Reply-To: <20140711160152.GC30865@htj.dyndns.org> Message-ID: References: <1405064267-11678-1-git-send-email-jiang.liu@linux.intel.com> <1405064267-11678-8-git-send-email-jiang.liu@linux.intel.com> <20140711144205.GA27706@htj.dyndns.org> <20140711152156.GB29137@htj.dyndns.org> <20140711160152.GC30865@htj.dyndns.org> Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Tejun Heo Cc: Jiang Liu , Andrew Morton , Mel Gorman , David Rientjes , Mike Galbraith , Peter Zijlstra , "Rafael J . Wysocki" , Vladimir Davydov , Johannes Weiner , "Kirill A. Shutemov" , Rik van Riel , Wanpeng Li , Zhang Yanfei , Catalin Marinas , Jianyu Zhan , malc , Joonsoo Kim , Fabian Frederick , Tony Luck , linux-mm@kvack.org, linux-hotplug@vger.kernel.org, linux-kernel@vger.kernel.org On Fri, 11 Jul 2014, Tejun Heo wrote: > On Fri, Jul 11, 2014 at 10:58:52AM -0500, Christoph Lameter wrote: > > > But, GFP_THISNODE + numa_mem_id() is identical to numa_node_id() + > > > nearest node with memory fallback. Is there any case where the user > > > would actually want to always fail if it's on the memless node? > > > > GFP_THISNODE allocatios must fail if there is no memory available on > > the node. No fallback allowed. > > I don't know. The intention is that the caller wants something on > this node or the caller will fail or fallback ourselves, right? For > most use cases just considering the nearest memory node as "local" for > memless nodes should work and serve the intentions of the users close > enough. Whether that'd be better or we'd be better off with something > else depends on the details for sure. Yes that works. But if we want a consistent node to allocate from (and avoid the fallbacks) then we need this patch. I think this is up to those needing memoryless nodes to figure out what semantics they need. -- 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