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From: subashrp@gmail.com (Subash Patel)
To: linux-arm-kernel@lists.infradead.org
Subject: [Linaro-mm-sig] [PATCH 08/10] mm: cma: Contiguous Memory Allocator added
Date: Wed, 15 Jun 2011 11:59:01 +0530	[thread overview]
Message-ID: <4DF8512D.4020902@gmail.com> (raw)
In-Reply-To: <201106142242.25157.arnd@arndb.de>

Hi Arnd,

On 06/15/2011 02:12 AM, Arnd Bergmann wrote:
> On Tuesday 14 June 2011 20:58:25 Zach Pfeffer wrote:
>> I've seen this split bank allocation in Qualcomm and TI SoCs, with
>> Samsung, that makes 3 major SoC vendors (I would be surprised if
>> Nvidia didn't also need to do this) - so I think some configurable
>> method to control allocations is necessarily. The chips can't do
>> decode without it (and by can't do I mean 1080P and higher decode is
>> not functionally useful). Far from special, this would appear to be
>> the default.
>
> Thanks for the insight, that's a much better argument than 'something
> may need it'. Are those all chips without an IOMMU or do we also
> need to solve the IOMMU case with split bank allocation?

In exynos4, the IP's can work with/without IOMMU. So contiguous 
allocator like CMA needs to have provision for this as well (now or 
sometime in future). I hope someone will throw light on the other SoC's 
as well (and I hope they aren't different either)

>
> I think I'd still prefer to see the support for multiple regions split
> out into one of the later patches, especially since that would defer
> the question of how to do the initialization for this case and make
> sure we first get a generic way.
>
> You've convinced me that we need to solve the problem of allocating
> memory from a specific bank eventually, but separating it from the
> one at hand (contiguous allocation) should help getting the important
> groundwork in at first.
>
> The possible conflict that I still see with per-bank CMA regions are:
>
> * It completely destroys memory power management in cases where that
>    is based on powering down entire memory banks.

I agree. But what if we release the per-bank buffers after we use it? 
Shouldn't the memory power management switch-off the un-used banks then?

>
> * We still need to solve the same problem in case of IOMMU mappings
>    at some point, even if today's hardware doesn't have this combination.
>    It would be good to use the same solution for both.
>
> 	Arnd
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Regards,
Subash
SISO-SLG

  parent reply	other threads:[~2011-06-15  6:29 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-10  9:54 [PATCHv10 0/10] Contiguous Memory Allocator Marek Szyprowski
2011-06-10  9:54 ` [PATCH 01/10] lib: bitmap: Added alignment offset for bitmap_find_next_zero_area() Marek Szyprowski
2011-06-10  9:54 ` [PATCH 02/10] lib: genalloc: Generic allocator improvements Marek Szyprowski
2011-06-10 11:24   ` Alan Cox
2011-06-10 12:22     ` Marek Szyprowski
2011-06-10 12:52       ` Alan Cox
2011-06-10 17:16         ` Michal Nazarewicz
2011-06-14 15:49         ` [Linaro-mm-sig] " Jordan Crouse
2011-06-10  9:54 ` [PATCH 03/10] mm: move some functions from memory_hotplug.c to page_isolation.c Marek Szyprowski
2011-06-10  9:54 ` [PATCH 04/10] mm: alloc_contig_freed_pages() added Marek Szyprowski
2011-06-10  9:54 ` [PATCH 05/10] mm: alloc_contig_range() added Marek Szyprowski
2011-06-10  9:54 ` [PATCH 06/10] mm: MIGRATE_CMA migration type added Marek Szyprowski
2011-06-10  9:54 ` [PATCH 07/10] mm: MIGRATE_CMA isolation functions added Marek Szyprowski
2011-06-10  9:54 ` [PATCH 08/10] mm: cma: Contiguous Memory Allocator added Marek Szyprowski
2011-06-10 16:21   ` Arnd Bergmann
2011-06-13  9:05     ` Marek Szyprowski
2011-06-14 13:49       ` Arnd Bergmann
2011-06-14 13:55         ` Michal Nazarewicz
2011-06-14 16:03           ` Arnd Bergmann
2011-06-14 16:58             ` Michal Nazarewicz
2011-06-14 18:30               ` Arnd Bergmann
2011-06-14 18:40                 ` Michal Nazarewicz
2011-06-15  7:11                 ` Marek Szyprowski
2011-06-15  7:37                   ` Arnd Bergmann
2011-06-15  8:14                     ` Marek Szyprowski
2011-06-16  0:48                     ` [Linaro-mm-sig] " Philip Balister
2011-06-16  7:03                       ` Arnd Bergmann
2011-06-22  7:03                     ` Hans Verkuil
2011-06-22  7:32                       ` Michal Nazarewicz
2011-06-22 12:42                       ` Arnd Bergmann
2011-06-22 13:15                         ` Marek Szyprowski
2011-06-22 13:39                           ` Arnd Bergmann
2011-06-22 16:04                             ` Michal Nazarewicz
2011-06-22 15:54                           ` Michal Nazarewicz
2011-06-15 11:53                 ` Daniel Vetter
2011-06-15 13:12                   ` Thomas Hellstrom
2011-06-17 16:08                   ` Arnd Bergmann
2011-06-14 17:01             ` Daniel Stone
2011-06-14 18:58               ` Zach Pfeffer
2011-06-14 20:42                 ` Arnd Bergmann
2011-06-14 21:01                   ` Jordan Crouse
2011-06-15 11:27                     ` Arnd Bergmann
2011-06-15  6:29                   ` Subash Patel [this message]
2011-06-15  8:36                   ` Marek Szyprowski
2011-06-15 21:39                     ` Larry Bassel
2011-06-15 22:06                       ` Arnd Bergmann
2011-06-16 17:01                         ` Larry Bassel
2011-06-17 12:45                           ` Arnd Bergmann
2011-07-04  5:25                         ` Ankita Garg
2011-07-04 14:45                           ` Arnd Bergmann
2011-06-16  3:20                       ` Zach Pfeffer
2011-06-15  9:26                   ` Michal Nazarewicz
2011-06-15 11:20                     ` Arnd Bergmann
2011-06-15 11:30                       ` Michal Nazarewicz
2011-06-15  6:01             ` Subash Patel
2011-06-15  8:02         ` Marek Szyprowski
2011-06-15 11:14           ` Arnd Bergmann
2011-06-10  9:54 ` [PATCH 09/10] ARM: integrate CMA with dma-mapping subsystem Marek Szyprowski
2011-06-10  9:54 ` [PATCH 10/10] ARM: S5PV210: add CMA support for FIMC devices on Aquila board Marek Szyprowski

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