Subject: Re: uncached page allocator
From: Peter Zijlstra <peterz@infradead.org>
To: Dave Airlie <airlied@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
       dri-devel <dri-devel@lists.sourceforge.net>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Linux Memory Management <linux-mm@kvack.org>
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Date: Tue, 21 Aug 2007 16:56:05 +0200
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On Tue, 2007-08-21 at 16:05 +1000, Dave Airlie wrote:

> So you can see why some sort of uncached+writecombined page cache
> would be useful, I could just allocate a bunch of pages at startup as
> uncached+writecombined, and allocate pixmaps from them and when I
> bind/free the pixmap I don't need the flush at all, now I'd really
> like this to be part of the VM so that under memory pressure it can
> just take the pages I've got in my cache back and after flushing turn
> them back into cached pages, the other option is for the DRM to do
> this on its own and penalise the whole system.

Can't you make these pages part of the regular VM by sticking them all
into an address_space.

And for this reclaim behaviour you'd only need to set PG_private and
have a_ops->releasepage() dtrt.


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