From: Christoph Lameter <cl@linux-foundation.org>
To: Robin Holt <holt@sgi.com>
Cc: Andi Kleen <andi@firstfloor.org>,
Yasunori Goto <y-goto@jp.fujitsu.com>,
"Luck, Tony" <tony.luck@intel.com>,
FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>,
linux-ia64@vger.kernel.org,
Linux Kernel ML <linux-kernel@vger.kernel.org>,
Joerg Roedel <joerg.roedel@amd.com>
Subject: Re: [Q] Why does dma_alloc_coherent() of ia64 GFP_DMA?
Date: Mon, 10 Nov 2008 21:57:40 +0000 [thread overview]
Message-ID: <Pine.LNX.4.64.0811101555380.32105@quilx.com> (raw)
In-Reply-To: <20081110190711.GG8483@sgi.com>
On Mon, 10 Nov 2008, Robin Holt wrote:
> I am not sure what is be referred to here, but all of an Altix's memory is
> DMA capable with the exception of the stuff covered by the MSPEC driver
> (that is uncached memory). There are certainly all sort of special
> requirements for doing transfers on Altix to eliminate memory ordering
> problems, but nothing specific that I recall related to address ranges
> and DMA.
But then ZONE_DMA has nothing to do with memory being dmaable or not.
ZONE_DMA is for legacy devices that cannot do DMA to all of memory.
I vaguely remember having stuffed all the memory into ZONE_NORMAL at some
point. ZONE_DMA vanishes for Altix configurations.
next prev parent reply other threads:[~2008-11-10 21:57 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-10 4:47 [Q] Why does dma_alloc_coherent() of ia64 GFP_DMA? Yasunori Goto
2008-11-10 12:59 ` Andi Kleen
2008-11-10 19:07 ` Robin Holt
2008-11-10 21:57 ` Christoph Lameter [this message]
2008-11-11 5:14 ` Yasunori Goto
2008-11-11 5:48 ` FUJITA Tomonori
2008-11-10 22:06 ` Christoph Lameter
2008-11-11 5:39 ` Yasunori Goto
2008-11-11 20:34 ` Christoph Lameter
2008-11-11 5:53 ` FUJITA Tomonori
2008-11-11 20:32 ` Christoph Lameter
2008-11-12 1:40 ` FUJITA Tomonori
2008-11-11 5:41 ` FUJITA Tomonori
2008-11-11 6:21 ` Yasunori Goto
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