Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755720AbaDGTnb (ORCPT ); Mon, 7 Apr 2014 15:43:31 -0400 Received: from terminus.zytor.com ([198.137.202.10]:58062 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755510AbaDGTn3 (ORCPT ); Mon, 7 Apr 2014 15:43:29 -0400 Message-ID: <5342FFB0.6010501@zytor.com> Date: Mon, 07 Apr 2014 12:42:40 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: Cyrill Gorcunov CC: Mel Gorman , David Vrabel , Linus Torvalds , Ingo Molnar , Steven Noonan , Rik van Riel , Andrew Morton , Peter Zijlstra , Andrea Arcangeli , Linux-MM , Linux-X86 , LKML , Pavel Emelyanov Subject: Re: [PATCH 2/3] x86: Define _PAGE_NUMA with unused physical address bits PMD and PTE levels References: <1396883443-11696-1-git-send-email-mgorman@suse.de> <1396883443-11696-3-git-send-email-mgorman@suse.de> <5342C517.2020305@citrix.com> <20140407154935.GD7292@suse.de> <20140407161910.GJ1444@moon> <20140407182854.GH7292@suse.de> <5342FC0E.9080701@zytor.com> <20140407193646.GC23983@moon> In-Reply-To: <20140407193646.GC23983@moon> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/07/2014 12:36 PM, Cyrill Gorcunov wrote: > On Mon, Apr 07, 2014 at 12:27:10PM -0700, H. Peter Anvin wrote: >> On 04/07/2014 11:28 AM, Mel Gorman wrote: >>> >>> I had considered the soft-dirty tracking usage of the same bit. I thought I'd >>> be able to swizzle around it or a further worst case of having soft-dirty and >>> automatic NUMA balancing mutually exclusive. Unfortunately upon examination >>> it's not obvious how to have both of them share a bit and I suspect any >>> attempt to will break CRIU. In my current tree, NUMA_BALANCING cannot be >>> set if MEM_SOFT_DIRTY which is not particularly satisfactory. Next on the >>> list is examining if _PAGE_BIT_IOMAP can be used. >> >> Didn't we smoke the last user of _PAGE_BIT_IOMAP? > > Seems so, at least for non-kernel pages (not considering this bit references in > xen code, which i simply don't know but i guess it's used for kernel pages only). > David Vrabel has a patchset which I presumed would be pulled through the Xen tree this merge window: [PATCHv5 0/8] x86/xen: fixes for mapping high MMIO regions (and remove _PAGE_IOMAP) That frees up this bit. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/