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From: Andi Kleen <ak@suse.de>
To: "Dave Airlie" <airlied@gmail.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
	"Linus Torvalds" <torvalds@osdl.org>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>
Subject: Re: GFP_DMA32 and PAE x86 machines
Date: Thu, 31 May 2007 14:11:39 +0200	[thread overview]
Message-ID: <200705311411.39764.ak@suse.de> (raw)
In-Reply-To: <21d7e9970705301609w88a9f80t20f83806003f699e@mail.gmail.com>


> Funnily enough I have just today with an app I have which uses 1.2GB
> of textures :-)

Realistic app which is something users really run?
Also do the other constraints above apply?

If you use pci_alloc_coherent() then it will already take care of the rules
above btw (e.g. DTRT when the machine has <3GB etc.) 

> we are currently using GFP_DMA32 in the TTM allocator code, however
> what I really want on x86 non-PAE is GFP_HIGHMEM (as DMA32 does
> nothing) however on x86-PAE I don't want that I want a real GFP_DMA32,
> and on x86-64 I want the current GFP_DMA32,

You should be probably using pci_alloc_coherent() at least on x86.
It might get more expensive on some obscure platforms (which DRM
likely doesn't support anyways), but if it does perhaps a pci_alloc_noncoherent()
or so would be useful (on x86 it would be the same) 

-Andi

      parent reply	other threads:[~2007-05-31 12:11 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-05-30 21:10 GFP_DMA32 and PAE x86 machines Dave Airlie
2007-05-30 21:29 ` H. Peter Anvin
2007-05-30 22:07   ` Dave Airlie
2007-05-30 22:13     ` H. Peter Anvin
2007-05-30 22:24     ` Andi Kleen
2007-05-30 22:31       ` H. Peter Anvin
2007-05-30 23:09       ` Dave Airlie
2007-05-30 23:21         ` William Lee Irwin III
2007-05-31 12:11         ` Andi Kleen [this message]

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