Re: [PATCH] mm: dmapool: use provided gfp flags for all dma_alloc_coherent() calls

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On 12.11.2012 11:38, Andrew Lunn wrote:
On Mon, Nov 12, 2012 at 10:48:02AM +0100, Soeren Moch wrote:
On 11.11.2012 18:22, Andrew Lunn wrote:
On Thu, Nov 08, 2012 at 07:38:57AM +0100, Marek Szyprowski wrote:
dmapool always calls dma_alloc_coherent() with GFP_ATOMIC flag,
regardless
the flags provided by the caller. This causes excessive pruning of
emergency memory pools without any good reason. This patch
changes the code
to correctly use gfp flags provided by the dmapool caller. This should
solve the dmapool usage on ARM architecture, where GFP_ATOMIC DMA
allocations can be served only from the special, very limited
memory pool.
Reported-by: Soren Moch <smoch@xxxxxx>
Please use
Reported-by: Soeren Moch <smoch@xxxxxx>

Reported-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Tested-by: Andrew Lunn <andrew@xxxxxxx>

I tested this on a Kirkwood QNAP after removing the call to
init_dma_coherent_pool_size().

     Andrew
Tested-by: Soeren Moch <smoch@xxxxxx>

Now I had a chance to test this patch on my Kirkwood guruplug
system with linux-3.6.6 . It is running much better now, but with the
original 256K coherent pool size I still see errors after several hours
of runtime:

Nov 12 09:42:32 guru kernel: ERROR: 256 KiB atomic DMA coherent pool
is too small!
Nov 12 09:42:32 guru kernel: Please increase it with coherent_pool=
kernel parameter!
Hi Soeren

Could you tell us what DVB devices you are using.

Thanks
	Andrew

from lsusb:
Bus 001 Device 005: ID 0ccd:00b2 TerraTec Electronic GmbH
Bus 001 Device 006: ID 2040:5200 Hauppauge
Bus 001 Device 009: ID 2304:0242 Pinnacle Systems, Inc.

If you want to check the drivers, I recommend to start with "em28xx".

Regards,
Soeren

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