From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1751397AbbCTAX3 (ORCPT <rfc822;w@1wt.eu>);
	Thu, 19 Mar 2015 20:23:29 -0400
Received: from ipmail07.adl2.internode.on.net ([150.101.137.131]:34394 "EHLO
	ipmail07.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK)
	by vger.kernel.org with ESMTP id S1751032AbbCTAX1 (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Thu, 19 Mar 2015 20:23:27 -0400
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: A2DECAAUZwtV/wYQLHlcgwaBLLMWBpkGBAICgT9NAQEBAQEBfYQQAQUnExwjEAgDGAklDwUlAyETiC7ODwEBAQcCIBiFcoUNhHEHhC0BBI4+i3qUKSKEAioxgkMBAQE
Date: Fri, 20 Mar 2015 11:23:11 +1100
From: Dave Chinner <david@fromorbit.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>, Ingo Molnar <mingo@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux-MM <linux-mm@kvack.org>, xfs@oss.sgi.com,
        ppc-dev <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH 4/4] mm: numa: Slow PTE scan rate if migration failures
 occur
Message-ID: <20150320002311.GG28621@dastard>
References: <20150317070655.GB10105@dastard>
 <CA+55aFzdLnFdku-gnm3mGbeS=QauYBNkFQKYXJAGkrMd2jKXhw@mail.gmail.com>
 <20150317205104.GA28621@dastard>
 <CA+55aFzSPcNgxw4GC7aAV1r0P5LniyVVC66COz=3cgMcx73Nag@mail.gmail.com>
 <20150317220840.GC28621@dastard>
 <CA+55aFwne-fe_Gg-_GTUo+iOAbbNpLBa264JqSFkH79EULyAqw@mail.gmail.com>
 <CA+55aFy-Mw74rAdLMMMUgnsG3ZttMWVNGz7CXZJY7q9fqyRYfg@mail.gmail.com>
 <CA+55aFyxA9u2cVzV+S7TSY9ZvRXCX=z22YAbi9mdPVBKmqgR5g@mail.gmail.com>
 <20150319224143.GI10105@dastard>
 <CA+55aFy5UeNnFUTi619cs3b9Up2NQ1wbuyvcCS614+o3=z=wBQ@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CA+55aFy5UeNnFUTi619cs3b9Up2NQ1wbuyvcCS614+o3=z=wBQ@mail.gmail.com>
User-Agent: Mutt/1.5.21 (2010-09-15)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Thu, Mar 19, 2015 at 04:05:46PM -0700, Linus Torvalds wrote:
> Can you try Mel's change to make it use
> 
>         if (!(vma->vm_flags & VM_WRITE))
> 
> instead of the pte details? Again, on otherwise plain 3.19, just so
> that we have a baseline. I'd be *so* much happer with checking the vma
> details over per-pte details, especially ones that change over the
> lifetime of the pte entry, and the NUMA code explicitly mucks with.

$ sudo perf_3.18 stat -a -r 6 -e migrate:mm_migrate_pages sleep 10

 Performance counter stats for 'system wide' (6 runs):

    266,750      migrate:mm_migrate_pages ( +-  7.43% )

	  10.002032292 seconds time elapsed ( +-  0.00% )

Bit more variance there than the pte checking, but runtime
difference is in the noise - 5m4s vs 4m54s - and profiles are
identical to the pte checking version.

Cheers,

Dave.

-- 
Dave Chinner
david@fromorbit.com