[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20080321132417.GJ27245@elte.hu>
Date: Fri, 21 Mar 2008 14:24:17 +0100
From: Ingo Molnar <mingo@...e.hu>
To: venkatesh.pallipadi@...el.com
Cc: ak@....de, ebiederm@...ssion.com, rdreier@...co.com,
torvalds@...ux-foundation.org, gregkh@...e.de, airlied@...net.ie,
davej@...hat.com, tglx@...utronix.de, hpa@...or.com,
akpm@...ux-foundation.org, arjan@...radead.org,
jesse.barnes@...el.com, linux-kernel@...r.kernel.org
Subject: Re: [patch 00/13] x86: PAT support updated - v3
* venkatesh.pallipadi@...el.com <venkatesh.pallipadi@...el.com> wrote:
> Follow up on earlier PAT patch series here:
> http://lkml.org/lkml/2008/1/10/312
>
> This patch series adds Page Attribute Table (PAT) support on x86.
> There have been few changes based on comments for earlier patches and
> also issues that was seen while the earlier patchset was in mm. The
> main changes include:
>
> * Unlike earlier patchset, there are no changes to identity mapping of
> reserved regions.
> * Unlike earlier patches, there are no chanegs to early ioremap.
> * We look at MTRR setting and PAT request and track the resultant type
> to avoid aliasing.
> * UC_MINUS in PAT to provide backward compatibility to /dem/mem mmap users.
>
> In general, we have tried to make patches more simpler and cleaner.
> Hope is to cause less disruption along the way. The changes/cleaups
> that went into x86/mm (specifically pageattr.c) has helped us along
> the way.
>
> The patchset is against x86 testing from couple of days back.
thanks Venki, i've queued this up so that we can see how well it goes.
It now looks a lot less dangerous and more compatible than it did before
- but i'm sure there'll be issues nevertheless :-/
> There are two issues that we are leaving out at the moment to make the patch
> simple. We will be addressing them with incremental patches soon:
> * FB/DRM drivers using pgprot_val and changing protection on their own
> without using any proper APIs like ioremap. There are few such usages and
> each one will be addressed separately.
> * To change attributes from WC to WB in a "perfect way", one has to follow
> certain sequence like make page non-present etc.
hm, until this is done correctly i guess we should disallow WC to WB
transitions? A good number of erratas apply i suspect :-/
Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists