Re: [PATCH 08/16] nouveau/hmm: fault one page at a time

[Jason Gunthorpe]

On Fri, Jun 19, 2020 at 02:56:41PM -0700, Ralph Campbell wrote:
> The SVM page fault handler groups faults into a range of contiguous
> virtual addresses and requests hmm_range_fault() to populate and
> return the page frame number of system memory mapped by the CPU.
> In preparation for supporting large pages to be mapped by the GPU,
> process faults one page at a time. In addition, use the hmm_range
> default_flags to fix a corner case where the input hmm_pfns array
> is not reinitialized after hmm_range_fault() returns -EBUSY and must
> be called again.

Are you sure? hmm_range_fault is pretty expensive per call..

Jason