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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: linux-mm@kvack.org, benh@kernel.crashing.org, paulus@samba.org,
	linuxppc-dev@lists.ozlabs.org,
	Michal Nazarewicz <mina86@mina86.com>
Subject: Re: [RFC PATCH 1/3] mm/cma: Move dma contiguous changes into a seperate config
Date: Fri, 28 Jun 2013 11:27:38 +0530	[thread overview]
Message-ID: <87li5u93ql.fsf@linux.vnet.ibm.com> (raw)
In-Reply-To: <51CC2530.2060605@samsung.com>

Marek Szyprowski <m.szyprowski@samsung.com> writes:

> Hello,
>
> On 6/24/2013 10:25 AM, Aneesh Kumar K.V wrote:
>> From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
>>
>> We want to use CMA for allocating hash page table and real mode area for
>> PPC64. Hence move DMA contiguous related changes into a seperate config
>> so that ppc64 can enable CMA without requiring DMA contiguous.
>>
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
>
> It's nice to see that CMA is gaining another client in mainline Linux 
> kernel.
> I also like the idea of adding CONFIG_DMA_CMA for DMA-mapping related CMA
> use to let others to use alloc_contig_range() interface.
>
> However I noticed that You have almost copied the whole drivers/base.c for
> separate use with PPC64 KVM. Is this really necessary? I think it should be
> possible to isolate some common code, which plays with contiguous region
> management and use it for both alloc_contig_range() clients (dma-mapping and
> ppc64 kvm).
>

One of the reason for having book3s_hv_cma.c is that few specifics vary
between dma contiguous. We have different alignment needs. Also i will be
switching the allocation to 256K chunks, not page size, in the next
update. It is also not large code duplication. I will post V2 soon and
may be we can see if it is worth consolidating.

-aneesh

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      reply	other threads:[~2013-06-28  5:57 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-06-24  8:25 [RFC PATCH 1/3] mm/cma: Move dma contiguous changes into a seperate config Aneesh Kumar K.V
2013-06-24  8:25 ` [RFC PATCH 2/3] powerpc: Contiguous memory allocator based hash page allocation Aneesh Kumar K.V
2013-06-24  8:25 ` [RFC PATCH 3/3] powerpc: Contiguous memory allocator based RMA allocation Aneesh Kumar K.V
2013-06-25 10:15 ` [RFC PATCH 1/3] mm/cma: Move dma contiguous changes into a seperate config Anshuman Khandual
2013-06-27 11:42 ` Marek Szyprowski
2013-06-28  5:57   ` Aneesh Kumar K.V [this message]

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