From: "H. Peter Anvin" <hpa@zytor.com>
To: Akinobu Mita <akinobu.mita@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
x86@kernel.org
Subject: Re: [PATCH] x86: enable DMA CMA with swiotlb
Date: Thu, 21 Nov 2013 10:11:06 -0800 [thread overview]
Message-ID: <528E4CBA.8000808@zytor.com> (raw)
In-Reply-To: <CAC5umyh0Hfx3NgHX11eqskuifhrdYGB8L1nx1u0YUdBGchRTxw@mail.gmail.com>
On 11/21/2013 07:02 AM, Akinobu Mita wrote:
>
> I want to use DMA CMA for the feature that requires a single huge chunk
> (about 64MB) of host memory.
That is tautological. "I want to use the Contiguous Memory Allocator to
allocate contiguous memory."
> Please refer 3 of 24 in:
> http://www.jedec.org/sites/default/files/T_Fujisawa_MF_2013.pdf
But yes, it makes sense that a device using host memory would not be
able to leverage swiotlb, because the software simply has no clue what
the DMA transactions are. In that sense it is fundamentally different
from a real IOTLB.
-hpa
next prev parent reply other threads:[~2013-11-21 18:11 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-19 23:32 [PATCH] x86: enable DMA CMA with swiotlb Akinobu Mita
2013-11-20 14:00 ` Konrad Rzeszutek Wilk
2013-11-20 23:35 ` Akinobu Mita
2013-11-20 23:47 ` H. Peter Anvin
2013-11-21 15:02 ` Akinobu Mita
2013-11-21 18:11 ` H. Peter Anvin [this message]
2013-11-22 12:27 ` Akinobu Mita
2013-11-22 15:02 ` H. Peter Anvin
2013-11-22 21:19 ` Andi Kleen
2013-11-23 13:59 ` Akinobu Mita
2013-11-22 9:15 ` Marek Szyprowski
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