On Tue, Jul 22, 2014 at 2:33 PM, Laurent Pinchart
<laurent.pinchart+renesas@xxxxxxxxxxxxxxxx> wrote:
> Unlike DMA transfers descriptors that are preallocated and cached,
> memory used to store hardware descriptors is allocated and freed with
> the DMA coherent allocation API for every transfer. Beside degrading
Besides
> performances, this creates a CMA stress test that seem to cause issues.
seems
> Running dmatest with the noverify option produces
>
> [ 50.066539] alloc_contig_range test_pages_isolated(6b845, 6b846) failed
> [ 50.235180] alloc_contig_range test_pages_isolated(6b848, 6b84e) failed
> [ 52.964584] alloc_contig_range test_pages_isolated(6b847, 6b848) failed
> [ 54.127113] alloc_contig_range test_pages_isolated(6b843, 6b844) failed
> [ 56.270253] alloc_contig_range test_pages_isolated(6b84c, 6b850) failed
>
> The root cause need to be fixed, but in the meantime, as a workaround
needs
> and a performance improvement, cache hardware descriptors.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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