Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755812AbaDGPLH (ORCPT ); Mon, 7 Apr 2014 11:11:07 -0400 Received: from cantor2.suse.de ([195.135.220.15]:50826 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755758AbaDGPKu (ORCPT ); Mon, 7 Apr 2014 11:10:50 -0400 From: Mel Gorman To: Linus Torvalds Cc: Cyrill Gorcunov , Mel Gorman , Peter Anvin , Ingo Molnar , Steven Noonan , Rik van Riel , David Vrabel , Andrew Morton , Peter Zijlstra , Andrea Arcangeli , Linux-MM , Linux-X86 , LKML Subject: [RFC PATCH 0/3] Use an alternative to _PAGE_PROTNONE for _PAGE_NUMA Date: Mon, 7 Apr 2014 16:10:40 +0100 Message-Id: <1396883443-11696-1-git-send-email-mgorman@suse.de> X-Mailer: git-send-email 1.8.4.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Aliasing _PAGE_NUMA and _PAGE_PROTNONE had some convenient properties but it ultimately gave Xen a headache and pisses almost everybody off that looks closely at it. Two discussions on "why this makes sense" is one discussion too many so rather than having a third there is this series. Conceptually it's simple -- use an unused physical address bit for _PAGE_NUMA and make it a 64-bit only feature on x86. This had been avoided before because if the physical address space expands we are back to square one but lets worry about that when it happens unless the x86 maintainers or hardware people warn us that we're about to run headlong into a wall. Testing was minimal -- short lived JVM and autonumabench tests that trigger the relevant paths for NUMA balancing. Functionally it did not die miserably. Performance looks as expected with no major changes. arch/x86/Kconfig | 2 +- arch/x86/include/asm/pgtable.h | 8 +++---- arch/x86/include/asm/pgtable_types.h | 44 ++++++++++++++++++++---------------- mm/memory.c | 12 ---------- 4 files changed, 29 insertions(+), 37 deletions(-) -- 1.8.4.5 -- 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/