On Mon, Dec 01, 2014 at 03:28:54PM -0500, Konrad Rzeszutek Wilk wrote:
> On Fri, Nov 28, 2014 at 12:29:08PM +0100, Joerg Roedel wrote:
> > diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c
> > index 77dd0ad..79b2291 100644
> > --- a/arch/x86/kernel/pci-swiotlb.c
> > +++ b/arch/x86/kernel/pci-swiotlb.c
> > @@ -20,6 +20,14 @@ void *x86_swiotlb_alloc_coherent(struct device *hwdev,
> > size_t size,
> > {
> > void *vaddr;
> >
> > + /*
> > + * When booting a kdump kernel in high memory these allocations are very
> > + * likely to fail, as there are by default only 8MB of low memory to
> > + * allocate from. So disable the warnings from the allocator when this
> > + * happens. SWIOTLB also implements fall-backs for failed allocations.
> > + */
> > + flags |= __GFP_NOWARN;
>
> Should this perhaps then have 'if (kdump_kernel)' around it since
> the use-case seems to be kdump related?
Hmm, I don't think this is entirely kdump specific. It can also be
triggered on a non-kdump kernel, it is just much more unlikely. But
maybe I should change the comment to something like:
/*
* Don't print a warning when the first allocation attempt
* fails. The swiotlb_alloc_coherent() function will print a
* warning when the allocation of DMA memory ultimatly failed.
*/
This takes the kdump-specifics out of this change (in the end
kdump-kernel loaded high is just a case where this failure is much more
likely).
Joerg
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