From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-vc0-f181.google.com (mail-vc0-f181.google.com [209.85.220.181]) by kanga.kvack.org (Postfix) with ESMTP id 8DFB56B0035 for ; Fri, 30 May 2014 09:48:45 -0400 (EDT) Received: by mail-vc0-f181.google.com with SMTP id hq11so108919vcb.40 for ; Fri, 30 May 2014 06:48:45 -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 t3si2937435vcx.5.2014.05.30.06.48.44 for ; Fri, 30 May 2014 06:48:44 -0700 (PDT) Date: Fri, 30 May 2014 08:48:41 -0500 (CDT) From: Christoph Lameter Subject: Re: [PATCH] page_alloc: skip cpuset enforcement for lower zone allocations (v4) In-Reply-To: <20140529161253.73ff978f723972f503123fe8@linux-foundation.org> Message-ID: References: <20140523193706.GA22854@amt.cnet> <20140526185344.GA19976@amt.cnet> <53858A06.8080507@huawei.com> <20140528224324.GA1132@amt.cnet> <20140529184303.GA20571@amt.cnet> <20140529161253.73ff978f723972f503123fe8@linux-foundation.org> Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: David Rientjes , Marcelo Tosatti , Li Zefan , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Lai Jiangshan , Mel Gorman , Tejun Heo , Andi Kleen On Thu, 29 May 2014, Andrew Morton wrote: > > > > if (!nodemask && gfp_zone(gfp_mask) < policy_zone) > > nodemask = &node_states[N_ONLINE]; > > OK, thanks, I made the patch go away for now. > And another issue is that the policy_zone may be highmem on 32 bit platforms which will result in ZONE_NORMAL to be exempted. policy zone can actually even be ZONE_DMA for some platforms. The check would not be useful at all on those. Ignoring the containing cpuset only makes sense for GFP_DMA32 on 64 bit platforms and for GFP_DMA on platforms where there is an actual difference in the address spaces supported by GFP_DMA (such as x86). Generally I think this is only useful for platforms that attempt to support legacy devices only able to DMA to a portion of the memory address space and that at the same time support NUMA for large address spaces. This is a contradiction on the one hand this is a high end system and on the other hand it attempts to support crippled DMA devices? -- 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