From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752889AbbCHSqQ (ORCPT ); Sun, 8 Mar 2015 14:46:16 -0400 Received: from mail-ie0-f177.google.com ([209.85.223.177]:40016 "EHLO mail-ie0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751831AbbCHSqM (ORCPT ); Sun, 8 Mar 2015 14:46:12 -0400 MIME-Version: 1.0 In-Reply-To: References: <1425741651-29152-1-git-send-email-mgorman@suse.de> <1425741651-29152-5-git-send-email-mgorman@suse.de> <20150307163657.GA9702@gmail.com> <20150308100223.GC15487@gmail.com> Date: Sun, 8 Mar 2015 11:46:10 -0700 X-Google-Sender-Auth: 5N2_5hU8Z1ym6EG9a25JOnqkoEI Message-ID: Subject: Re: [PATCH 4/4] mm: numa: Slow PTE scan rate if migration failures occur From: Linus Torvalds To: Ingo Molnar Cc: Mel Gorman , Dave Chinner , Andrew Morton , Aneesh Kumar , Linux Kernel Mailing List , Linux-MM , xfs@oss.sgi.com, ppc-dev Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Mar 8, 2015 at 11:35 AM, Linus Torvalds wrote: >> As a second hack (not to be applied), could we change: >> >> #define _PAGE_BIT_PROTNONE _PAGE_BIT_GLOBAL >> >> to: >> >> #define _PAGE_BIT_PROTNONE (_PAGE_BIT_GLOBAL+1) >> >> to double check that the position of the bit does not matter? > > Agreed. We should definitely try that. There's a second reason to do that, actually: the __supported_pte_mask thing, _and_ the pageattr stuff in __split_large_page() etc play games with _PAGE_GLOBAL. As does drivers/lguest for some reason. So looking at this all, there's a lot of room for confusion with _PAGE_GLOBAL. That kind of confusion would certainly explain the whole "the changes _look_ like they do the same thing, but don't" - because of silly semantic conflicts with PROTNONE vs GLOBAL. Linus From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay3.corp.sgi.com [198.149.34.15]) by oss.sgi.com (Postfix) with ESMTP id EE7D67F69 for ; Sun, 8 Mar 2015 13:46:17 -0500 (CDT) Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by relay3.corp.sgi.com (Postfix) with ESMTP id 7E288AC002 for ; Sun, 8 Mar 2015 11:46:17 -0700 (PDT) Received: from mail-ie0-f180.google.com (mail-ie0-f180.google.com [209.85.223.180]) by cuda.sgi.com with ESMTP id Xmca3i4SOos6Syys (version=TLSv1 cipher=RC4-SHA bits=128 verify=NO) for ; Sun, 08 Mar 2015 11:46:11 -0700 (PDT) Received: by iecrd18 with SMTP id rd18so6862766iec.13 for ; Sun, 08 Mar 2015 11:46:10 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <1425741651-29152-1-git-send-email-mgorman@suse.de> <1425741651-29152-5-git-send-email-mgorman@suse.de> <20150307163657.GA9702@gmail.com> <20150308100223.GC15487@gmail.com> Date: Sun, 8 Mar 2015 11:46:10 -0700 Message-ID: Subject: Re: [PATCH 4/4] mm: numa: Slow PTE scan rate if migration failures occur From: Linus Torvalds List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Ingo Molnar Cc: Linux Kernel Mailing List , xfs@oss.sgi.com, Linux-MM , Mel Gorman , Andrew Morton , ppc-dev , Aneesh Kumar On Sun, Mar 8, 2015 at 11:35 AM, Linus Torvalds wrote: >> As a second hack (not to be applied), could we change: >> >> #define _PAGE_BIT_PROTNONE _PAGE_BIT_GLOBAL >> >> to: >> >> #define _PAGE_BIT_PROTNONE (_PAGE_BIT_GLOBAL+1) >> >> to double check that the position of the bit does not matter? > > Agreed. We should definitely try that. There's a second reason to do that, actually: the __supported_pte_mask thing, _and_ the pageattr stuff in __split_large_page() etc play games with _PAGE_GLOBAL. As does drivers/lguest for some reason. So looking at this all, there's a lot of room for confusion with _PAGE_GLOBAL. That kind of confusion would certainly explain the whole "the changes _look_ like they do the same thing, but don't" - because of silly semantic conflicts with PROTNONE vs GLOBAL. Linus _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ie0-f181.google.com (mail-ie0-f181.google.com [209.85.223.181]) by kanga.kvack.org (Postfix) with ESMTP id AF7E56B0038 for ; Sun, 8 Mar 2015 14:46:10 -0400 (EDT) Received: by iecat20 with SMTP id at20so44229167iec.6 for ; Sun, 08 Mar 2015 11:46:10 -0700 (PDT) Received: from mail-ig0-x231.google.com (mail-ig0-x231.google.com. [2607:f8b0:4001:c05::231]) by mx.google.com with ESMTPS id ad4si7264686igd.18.2015.03.08.11.46.10 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 08 Mar 2015 11:46:10 -0700 (PDT) Received: by igdh15 with SMTP id h15so15665115igd.3 for ; Sun, 08 Mar 2015 11:46:10 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <1425741651-29152-1-git-send-email-mgorman@suse.de> <1425741651-29152-5-git-send-email-mgorman@suse.de> <20150307163657.GA9702@gmail.com> <20150308100223.GC15487@gmail.com> Date: Sun, 8 Mar 2015 11:46:10 -0700 Message-ID: Subject: Re: [PATCH 4/4] mm: numa: Slow PTE scan rate if migration failures occur From: Linus Torvalds Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Ingo Molnar Cc: Mel Gorman , Dave Chinner , Andrew Morton , Aneesh Kumar , Linux Kernel Mailing List , Linux-MM , xfs@oss.sgi.com, ppc-dev On Sun, Mar 8, 2015 at 11:35 AM, Linus Torvalds wrote: >> As a second hack (not to be applied), could we change: >> >> #define _PAGE_BIT_PROTNONE _PAGE_BIT_GLOBAL >> >> to: >> >> #define _PAGE_BIT_PROTNONE (_PAGE_BIT_GLOBAL+1) >> >> to double check that the position of the bit does not matter? > > Agreed. We should definitely try that. There's a second reason to do that, actually: the __supported_pte_mask thing, _and_ the pageattr stuff in __split_large_page() etc play games with _PAGE_GLOBAL. As does drivers/lguest for some reason. So looking at this all, there's a lot of room for confusion with _PAGE_GLOBAL. That kind of confusion would certainly explain the whole "the changes _look_ like they do the same thing, but don't" - because of silly semantic conflicts with PROTNONE vs GLOBAL. Linus -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ie0-x22d.google.com (mail-ie0-x22d.google.com [IPv6:2607:f8b0:4001:c03::22d]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 45EEA1A04C0 for ; Mon, 9 Mar 2015 05:46:12 +1100 (AEDT) Received: by iecrl12 with SMTP id rl12so14920818iec.8 for ; Sun, 08 Mar 2015 11:46:10 -0700 (PDT) MIME-Version: 1.0 Sender: linus971@gmail.com In-Reply-To: References: <1425741651-29152-1-git-send-email-mgorman@suse.de> <1425741651-29152-5-git-send-email-mgorman@suse.de> <20150307163657.GA9702@gmail.com> <20150308100223.GC15487@gmail.com> Date: Sun, 8 Mar 2015 11:46:10 -0700 Message-ID: Subject: Re: [PATCH 4/4] mm: numa: Slow PTE scan rate if migration failures occur From: Linus Torvalds To: Ingo Molnar Content-Type: text/plain; charset=UTF-8 Cc: Dave Chinner , Linux Kernel Mailing List , xfs@oss.sgi.com, Linux-MM , Mel Gorman , Andrew Morton , ppc-dev , Aneesh Kumar List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sun, Mar 8, 2015 at 11:35 AM, Linus Torvalds wrote: >> As a second hack (not to be applied), could we change: >> >> #define _PAGE_BIT_PROTNONE _PAGE_BIT_GLOBAL >> >> to: >> >> #define _PAGE_BIT_PROTNONE (_PAGE_BIT_GLOBAL+1) >> >> to double check that the position of the bit does not matter? > > Agreed. We should definitely try that. There's a second reason to do that, actually: the __supported_pte_mask thing, _and_ the pageattr stuff in __split_large_page() etc play games with _PAGE_GLOBAL. As does drivers/lguest for some reason. So looking at this all, there's a lot of room for confusion with _PAGE_GLOBAL. That kind of confusion would certainly explain the whole "the changes _look_ like they do the same thing, but don't" - because of silly semantic conflicts with PROTNONE vs GLOBAL. Linus