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

[Soeren Moch]

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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