From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yk0-f171.google.com (mail-yk0-f171.google.com [209.85.160.171]) by kanga.kvack.org (Postfix) with ESMTP id 46E756B0095 for ; Tue, 8 Apr 2014 05:31:40 -0400 (EDT) Received: by mail-yk0-f171.google.com with SMTP id q9so552636ykb.30 for ; Tue, 08 Apr 2014 02:31:38 -0700 (PDT) Received: from SMTP02.CITRIX.COM (smtp02.citrix.com. [66.165.176.63]) by mx.google.com with ESMTPS id m27si1719479yha.60.2014.04.08.02.31.38 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 08 Apr 2014 02:31:38 -0700 (PDT) Message-ID: <5343C1F6.4090600@citrix.com> Date: Tue, 8 Apr 2014 10:31:34 +0100 From: David Vrabel MIME-Version: 1.0 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> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Cyrill Gorcunov Cc: "H. Peter Anvin" , Mel Gorman , Linus Torvalds , Ingo Molnar , Steven Noonan , Rik van Riel , Andrew Morton , Peter Zijlstra , Andrea Arcangeli , Linux-MM , Linux-X86 , LKML , Pavel Emelyanov On 07/04/14 20:36, 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? Not yet. A last minute regression with mapping of I/O regions from userspace was found so I had to drop the series from 3.15. It should be back for 3.16. > 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). Xen uses it for all I/O mappings, both kernel and for userspace. David -- 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