Subject: Re: vm changes from linux-2.6.14 to linux-2.6.15

From: Andrew Morton <[email-masked]>
Date: Mon, 30 Apr 2007 14:54:14 -0700

On Mon, 30 Apr 2007 22:36:27 +0100 (BST)
Mark Fortescue <[email-masked]> 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.