Am Montag, 21. Mai 2007 23:36 schrieb David Brownell:
> On Monday 21 May 2007, Oliver Neukum wrote:
> > Am Mittwoch, 16. Mai 2007 16:41 schrieb David Brownell:
> > > > in that when you have
> > > > pre-allocated all buffers and all USB host controller descriptors, you
> > > > will
> > > > never get in the situation of not being able to allocate transfer
> > > > descriptors
> > > > on the fly, like done on Linux.
> > >
> > > That's not a failure mode that's been often observed on Linux. (Never,
> > > in my own experience... which I admit has not focussed on that particular
> > > type of stress load.) So it's hard to argue that it should motivate a
> > > redesign of core APIs.
> >
> > We are seeing report of the networking stack exhausting the atomic
> > pool. They are rare these days, but do exist.
>
> But transfer descriptors don't come from there.
Never, ever, even if the pool is exhausted?
static struct uhci_td *uhci_alloc_td(struct uhci_hcd *uhci)
{
dma_addr_t dma_handle;
struct uhci_td *td;
td = dma_pool_alloc(uhci->td_pool, GFP_ATOMIC, &dma_handle);
if (!td)
return NULL;
Admittedly unlikely, but impossible?
Regards
Oliver
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