Re: [PATCH v2] mm: dmapool: use provided gfp flags for all dma_alloc_coherent() calls

Greg KH
2013-01-15T17:49:27Z

On Tue, Jan 15, 2013 at 11:56:42AM -0500, Jason Cooper wrote:
> Greg,
>
> I've added you to the this thread hoping for a little insight into USB
> drivers and their use of coherent and GFP_ATOMIC. Am I barking up the
> wrong tree by looking a the drivers?

I don't understand, which drivers are you referring to? USB host
controller drivers, or the "normal" drivers? Most USB drivers use
GFP_ATOMIC if they are creating memory during their URB callback path,
as that is interrupt context. But it shouldn't be all that bad, and the
USB core hasn't changed in a while, so something else must be causing
this.

greg k-h