Messages in this thread | | | Date | Tue, 15 Jan 2013 21:40:14 -0500 | From | Jason Cooper <> | Subject | Re: [PATCH v2] mm: dmapool: use provided gfp flags for all dma_alloc_coherent() calls |
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Soeren,
On Wed, Jan 16, 2013 at 01:17:59AM +0100, Soeren Moch wrote: > On 15.01.2013 22:56, Jason Cooper wrote: > >On Tue, Jan 15, 2013 at 03:16:17PM -0500, Jason Cooper wrote: > >>If my understanding is correct, one of the drivers (most likely one) > >>either asks for too small of a dma buffer, or is not properly > >>deallocating blocks from the per-device pool. Either case leads to > >>exhaustion, and falling back to the atomic pool. Which subsequently > >>gets wiped out as well. > > > >If my hunch is right, could you please try each of the three dvb drivers > >in turn and see which one (or more than one) causes the error? > > In fact I use only 2 types of DVB sticks: em28xx usb bridge plus drxk > demodulator, and dib0700 usb bridge plus dib7000p demod. > > I would bet for em28xx causing the error, but this is not thoroughly > tested. Unfortunately testing with removed sticks is not easy, because > this is a production system and disabling some services for the long > time we need to trigger this error will certainly result in unhappy > users.
Just out of curiosity, what board is it?
> I will see what I can do here. Is there an easy way to track the buffer > usage without having to wait for complete exhaustion?
DMA_API_DEBUG
> In linux-3.5.x there is no such problem. Can we use all available memory > for dma buffers here on armv5 architectures, in contrast to newer > kernels?
Were the loads exactly the same when you tested 3.5.x? I looked at the changes from v3.5 to v3.7.1 for all four drivers you mentioned as well as sata_mv.
The biggest thing I see is that all of the media drivers got shuffled around into their own subdirectories after v3.5. 'git show -M 0c0d06c' shows it was a clean copy of all the files.
What would be most helpful is if you could do a git bisect between v3.5.x (working) and the oldest version where you know it started failing (v3.7.1 or earlier if you know it).
thx,
Jason.
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