Re: [PATCH 0/2] arm64, cma, gicv3-its: Use CMA for allocation of large device tables

From: Marc Zyngier
Date: Mon Feb 29 2016 - 05:46:58 EST


Hi Robert,

On 25/02/16 11:02, Robert Richter wrote:
> From: Robert Richter <rrichter@xxxxxxxxxx>
>
> This series implements the use of CMA for allocation of large device
> tables for the arm64 gicv3 interrupt controller.
>
> There are 2 patches, the first is for early activation of cma, which
> needs to be done before interrupt initialization to make it available
> to the gicv3. The second implements the use of CMA to allocate
> gicv3-its device tables.
>
> This solves the problem where mem allocation is limited to 4MB. A
> previous patch sent to the list to address this that instead increases
> FORCE_MAX_ZONEORDER becomes obsolete.

I think you're looking at the problem the wrong way. Instead of going
through CMA directly, I'd rather go through the normal DMA API
(dma_alloc_coherent), which can itself try CMA (should it be enabled).

That will give you all the benefit of the CMA allocation, and also make
the driver more robust. I meant to do this for a while, and never found
the time. Any chance you could have a look?

Thanks,

M.
--
Jazz is not dead. It just smells funny...