On Wed, Aug 03, 2011 at 12:43:50PM -0500, James Bottomley wrote:
> I assume from the above that ARM has a hardware page walker?
Correct, and speculative prefetch (which isn't prevented by not having
TLB entries), so you can't keep entries out of the TLB. If it's in
the page tables it can end up i
Hello,
I'm sorry for the late reply. I must have missed this mail...
On Wednesday, August 03, 2011 7:44 PM James Bottomley wrote:
> [cc to ks-discuss added, since this may be a relevant topic]
>
> On Tue, 2011-07-05 at 14:27 +0200, Arnd Bergmann wrote:
> > On Tuesday 05 July 2011, Russell King
The Contiguous Memory Allocator is a set of helper functions for DMA
mapping framework that improves allocations of contiguous memory chunks.
CMA grabs memory on system boot, marks it with CMA_MIGRATE_TYPE and
gives back to the system. Kernel is allowed to allocate movable pages
within CMA's manag
[cc to ks-discuss added, since this may be a relevant topic]
On Tue, 2011-07-05 at 14:27 +0200, Arnd Bergmann wrote:
> On Tuesday 05 July 2011, Russell King - ARM Linux wrote:
> > On Tue, Jul 05, 2011 at 09:41:48AM +0200, Marek Szyprowski wrote:
> > > The Contiguous Memory Allocator is a set of he
The Contiguous Memory Allocator is a set of helper functions for DMA
mapping framework that improves allocations of contiguous memory chunks.
CMA grabs memory on system boot, marks it with CMA_MIGRATE_TYPE and
gives back to the system. Kernel is allowed to allocate movable pages
within CMA's manag
Hello,
I've just found two nasty bugs in this version of CMA. Sadly, both are the
results of posting the patches in a big hurry. I'm really sorry.
Alignment argument was not passed correctly to the
bitmap_find_next_zero_area() function and there was an ugly bug in the
dma_release_from_contiguou
On Friday 08 July 2011, Russell King - ARM Linux wrote:
> On Tue, Jul 05, 2011 at 03:58:39PM +0200, Arnd Bergmann wrote:
>
> > If I'm reading your "ARM: DMA: steal memory for DMA coherent mappings"
> > correctly, the idea is to have a per-platform compile-time amount
> > of memory that is reserved
Hello,
On Monday, July 11, 2011 9:01 PM Janusz Krzysztofik wrote:
> Dnia poniedziałek, 11 lipca 2011 o 15:47:32 Marek Szyprowski napisał(a):
> > Hello,
> >
> > On Saturday, July 09, 2011 4:57 PM Janusz Krzysztofik wrote:
> > > On Wed, 6 Jul 2011 at 16:59:45 Arnd Bergmann wrote:
> > > > On W
Dnia poniedziałek, 11 lipca 2011 o 15:47:32 Marek Szyprowski napisał(a):
> Hello,
>
> On Saturday, July 09, 2011 4:57 PM Janusz Krzysztofik wrote:
> > On Wed, 6 Jul 2011 at 16:59:45 Arnd Bergmann wrote:
> > > On Wednesday 06 July 2011, Nicolas Pitre wrote:
> > > > On Wed, 6 Jul 2011, Russell King
Hello,
On Saturday, July 09, 2011 4:57 PM Janusz Krzysztofik wrote:
> On Wed, 6 Jul 2011 at 16:59:45 Arnd Bergmann wrote:
> > On Wednesday 06 July 2011, Nicolas Pitre wrote:
> > > On Wed, 6 Jul 2011, Russell King - ARM Linux wrote:
> > > > Another issue is that when a platform has restricted DM
On Wed, 6 Jul 2011 at 16:59:45 Arnd Bergmann wrote:
> On Wednesday 06 July 2011, Nicolas Pitre wrote:
> > On Wed, 6 Jul 2011, Russell King - ARM Linux wrote:
> > > Another issue is that when a platform has restricted DMA regions,
> > > they typically don't fall into the highmem zone. As the
> > >
On Tue, Jul 05, 2011 at 03:58:39PM +0200, Arnd Bergmann wrote:
> Ah, sorry I missed that patch on the mailing list, found it now in
> your for-next branch.
I've been searching for this email to reply to for the last day or
so...
> If I'm reading your "ARM: DMA: steal memory for DMA coherent mappi
On Wed, 6 Jul 2011, Arnd Bergmann wrote:
> On Wednesday 06 July 2011 21:10:07 Nicolas Pitre wrote:
> > If you get a highmem page, because the cache is VIPT, that page might
> > still be cached even if it wasn't mapped. With a VIVT cache we must
> > flush the cache whenever a highmem page is unm
On Wednesday 06 July 2011 21:10:07 Nicolas Pitre wrote:
> If you get a highmem page, because the cache is VIPT, that page might
> still be cached even if it wasn't mapped. With a VIVT cache we must
> flush the cache whenever a highmem page is unmapped. There is no such
> restriction with VIPT
On Wed, 6 Jul 2011, Arnd Bergmann wrote:
> On Wednesday 06 July 2011, Russell King - ARM Linux wrote:
> > On Wed, Jul 06, 2011 at 04:51:49PM +0200, Arnd Bergmann wrote:
> > > On Wednesday 06 July 2011, Russell King - ARM Linux wrote:
> > >
> > > I don't see how. The pages get allocated from an un
On Wed, 6 Jul 2011, Russell King - ARM Linux wrote:
> So, ARM is no different from x86, with the exception that the 16MB DMA
> zone due to ISA ends up being different sizes on ARM depending on our
> restrictions.
Sounds good. Thank you.
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On Wed, Jul 06, 2011 at 11:19:00AM -0500, Christoph Lameter wrote:
> What I described is the basic memory architecture of Linux. I am not that
> familiar with ARM and the issue discussed here. Only got involved because
> ZONE_DMA was mentioned. The nature of ZONE_DMA is often misunderstood.
>
> Th
On Wed, Jul 06, 2011 at 11:05:00AM -0500, Christoph Lameter wrote:
> On Wed, 6 Jul 2011, Russell King - ARM Linux wrote:
>
> > > > they typically don't fall into the highmem zone. As the dmabounce
> > > > code allocates from the DMA coherent allocator to provide it with
> > > > guaranteed DMA-abl
On Wednesday 06 July 2011, Russell King - ARM Linux wrote:
> On Wed, Jul 06, 2011 at 04:51:49PM +0200, Arnd Bergmann wrote:
> > On Wednesday 06 July 2011, Russell King - ARM Linux wrote:
> >
> > I don't see how. The pages get allocated from an unmapped area
> > or memory, mapped into the kernel ad
On Wed, 6 Jul 2011, Michal Nazarewicz wrote:
> On Wed, 06 Jul 2011 18:05:00 +0200, Christoph Lameter wrote:
> > ZONE_DMA is a zone for memory of legacy (crippled) devices that cannot DMA
> > into all of memory (and so is ZONE_DMA32). Memory from ZONE_NORMAL
> > can be used for DMA as well and a
On Wed, 6 Jul 2011, Russell King - ARM Linux wrote:
> > > they typically don't fall into the highmem zone. As the dmabounce
> > > code allocates from the DMA coherent allocator to provide it with
> > > guaranteed DMA-able memory, that would be rather inconvenient.
> >
> > True. The dmabounce code
On Wed, 06 Jul 2011 18:05:00 +0200, Christoph Lameter wrote:
ZONE_DMA is a zone for memory of legacy (crippled) devices that cannot
DMA into all of memory (and so is ZONE_DMA32). Memory from ZONE_NORMAL
can be used for DMA as well and a fully capable device would be expected
to handle any mem
On Wed, Jul 06, 2011 at 04:51:49PM +0200, Arnd Bergmann wrote:
> On Wednesday 06 July 2011, Russell King - ARM Linux wrote:
> > On Wed, Jul 06, 2011 at 04:09:29PM +0200, Arnd Bergmann wrote:
> > > Maybe you can simply adapt the default location of the contiguous memory
> > > are like this:
> > > -
Hello,
On Wednesday, July 06, 2011 5:37 PM Russell King - ARM Linux wrote:
> On Wed, Jul 06, 2011 at 04:56:23PM +0200, Marek Szyprowski wrote:
> > This will not solve our problems. We need CMA also to create at least one
> > device private area that for sure will be in low memory (video codec).
>
On Wed, Jul 06, 2011 at 04:56:23PM +0200, Marek Szyprowski wrote:
> This will not solve our problems. We need CMA also to create at least one
> device private area that for sure will be in low memory (video codec).
You make these statements but you don't say why. Can you please
explain why the vi
On Wednesday 06 July 2011, Nicolas Pitre wrote:
> On Wed, 6 Jul 2011, Russell King - ARM Linux wrote:
>
> > Another issue is that when a platform has restricted DMA regions,
> > they typically don't fall into the highmem zone. As the dmabounce
> > code allocates from the DMA coherent allocator to
Hello,
On Wednesday, July 06, 2011 4:09 PM Arnd Bergmann wrote:
> On Wednesday 06 July 2011, Marek Szyprowski wrote:
> > The only problem that might need to be resolved is GFP_ATOMIC allocation
> > (updating page properties probably requires some locking), but it can be
> > served from a special
On Wednesday 06 July 2011, Russell King - ARM Linux wrote:
> On Wed, Jul 06, 2011 at 04:09:29PM +0200, Arnd Bergmann wrote:
> > Maybe you can simply adapt the default location of the contiguous memory
> > are like this:
> > - make CONFIG_CMA depend on CONFIG_HIGHMEM on ARM, at compile time
> > - if
On Wed, 6 Jul 2011, Russell King - ARM Linux wrote:
> Another issue is that when a platform has restricted DMA regions,
> they typically don't fall into the highmem zone. As the dmabounce
> code allocates from the DMA coherent allocator to provide it with
> guaranteed DMA-able memory, that would
On Wed, Jul 06, 2011 at 04:09:29PM +0200, Arnd Bergmann wrote:
> Maybe you can simply adapt the default location of the contiguous memory
> are like this:
> - make CONFIG_CMA depend on CONFIG_HIGHMEM on ARM, at compile time
> - if ZONE_HIGHMEM exist during boot, put the CMA area in there
> - otherw
On Wednesday 06 July 2011, Marek Szyprowski wrote:
> The only problem that might need to be resolved is GFP_ATOMIC allocation
> (updating page properties probably requires some locking), but it can be
> served from a special area which is created on boot without low-memory
> mapping at all. None sa
Hello,
On Tuesday, July 05, 2011 1:34 PM Russell King - ARM Linux wrote:
> On Tue, Jul 05, 2011 at 09:41:48AM +0200, Marek Szyprowski wrote:
> > The Contiguous Memory Allocator is a set of helper functions for DMA
> > mapping framework that improves allocations of contiguous memory chunks.
> >
>
On Tuesday 05 July 2011, Russell King - ARM Linux wrote:
> On Tue, Jul 05, 2011 at 02:27:44PM +0200, Arnd Bergmann wrote:
> > It's also a preexisting problem as far as I can tell, and it needs
> > to be solved in __dma_alloc for both cases, dma_alloc_from_contiguous
> > and __alloc_system_pages as
On Tue, Jul 05, 2011 at 02:27:44PM +0200, Arnd Bergmann wrote:
> It's also a preexisting problem as far as I can tell, and it needs
> to be solved in __dma_alloc for both cases, dma_alloc_from_contiguous
> and __alloc_system_pages as introduced in patch 7.
Which is now resolved in linux-next, and
On Tuesday 05 July 2011, Russell King - ARM Linux wrote:
> On Tue, Jul 05, 2011 at 09:41:48AM +0200, Marek Szyprowski wrote:
> > The Contiguous Memory Allocator is a set of helper functions for DMA
> > mapping framework that improves allocations of contiguous memory chunks.
> >
> > CMA grabs memor
On Tue, Jul 05, 2011 at 09:41:48AM +0200, Marek Szyprowski wrote:
> The Contiguous Memory Allocator is a set of helper functions for DMA
> mapping framework that improves allocations of contiguous memory chunks.
>
> CMA grabs memory on system boot, marks it with CMA_MIGRATE_TYPE and
> gives back t
Hello,
On Tuesday, July 05, 2011 9:42 AM Marek Szyprowski wrote:
> The Contiguous Memory Allocator is a set of helper functions for DMA
> mapping framework that improves allocations of contiguous memory chunks.
>
> CMA grabs memory on system boot, marks it with CMA_MIGRATE_TYPE and
> gives back
The Contiguous Memory Allocator is a set of helper functions for DMA
mapping framework that improves allocations of contiguous memory chunks.
CMA grabs memory on system boot, marks it with CMA_MIGRATE_TYPE and
gives back to the system. Kernel is allowed to allocate movable pages
within CMA's manag
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