From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <akpm@linux-foundation.org>
Received: from smtp1.linux-foundation.org (smtp1.linux-foundation.org
	[65.172.181.25])
	(using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits))
	(Client CN "smtp.osdl.org",
	Issuer "CA Cert Signing Authority" (verified OK))
	by ozlabs.org (Postfix) with ESMTP id 0E87DDDF2D
	for <linuxppc-dev@ozlabs.org>; Tue,  1 May 2007 07:54:55 +1000 (EST)
Date: Mon, 30 Apr 2007 14:54:14 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Mark Fortescue <mark@mtfhpc.demon.co.uk>
Subject: Re: vm changes from linux-2.6.14 to linux-2.6.15
Message-Id: <20070430145414.88fda272.akpm@linux-foundation.org>
In-Reply-To: <Pine.LNX.4.61.0704302159140.3178@mtfhpc.demon.co.uk>
References: <Pine.LNX.4.61.0704291345480.690@mtfhpc.demon.co.uk>
	<1177852457.4390.26.camel@localhost.localdomain>
	<Pine.LNX.4.61.0704302159140.3178@mtfhpc.demon.co.uk>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Cc: sparclinux@vger.kernel.org, linuxppc-dev@ozlabs.org,
	Andrea Arcangeli <andrea@suse.de>, wli@holomorphy.com, linux-mm@kvack.org
List-Id: Linux on PowerPC Developers Mail List <linuxppc-dev.ozlabs.org>
List-Unsubscribe: <https://ozlabs.org/mailman/listinfo/linuxppc-dev>,
	<mailto:linuxppc-dev-request@ozlabs.org?subject=unsubscribe>
List-Archive: <http://ozlabs.org/pipermail/linuxppc-dev>
List-Post: <mailto:linuxppc-dev@ozlabs.org>
List-Help: <mailto:linuxppc-dev-request@ozlabs.org?subject=help>
List-Subscribe: <https://ozlabs.org/mailman/listinfo/linuxppc-dev>,
	<mailto:linuxppc-dev-request@ozlabs.org?subject=subscribe>

On Mon, 30 Apr 2007 22:36:27 +0100 (BST)
Mark Fortescue <mark@mtfhpc.demon.co.uk> wrote:

> Hi all,
> 
> I have tracked down a failure to successfully load/run the init task on my 
> Sparcstation 1 clone (SS1) and Sparcstation 2 (SS2), sparc32 sun4c 
> systems, to a patch:
> 
>    commit 1a44e149084d772a1bcf4cdbdde8a013a8a1cfde.
>    [PATCH] .text page fault SMP scalability optimization
> 
> Removing this patch fixes the issue and allows me to use kernels later 
> than v2.5.14. (tested using linux-2.6.20.9).
> 
> Given the comment provided by the git bisect, backing out this patch will 
> probably have undesirable conseqnences for other platforms (especially 
> powerpc64) so, if an architecture independent solution is not available, 
> some/all of the code in handle_pte_fault() in mm/memory.c will need be to 
> made architecture dependent.
> 
> I am not sufficiently familear with the how the SS1/SS2 mmu works and how 
> the linux memory management system works to understand why this patch 
> prevents my sun4c SS1/SS2 systems from working.
> 
> Advice and help on the approch to take and any code changes regarding this 
> issue would be most welcome.
> 

Interesting - thanks for working that out.  Let's keep linux-mm on cc please.