Re: [PATCH] nouveau/hmm: fix migrate zero page to GPU

[Jason Gunthorpe]

On Wed, May 20, 2020 at 11:36:52AM -0700, Ralph Campbell wrote:
> When calling OpenCL clEnqueueSVMMigrateMem() on a region of memory that
> is backed by pte_none() or zero pages, migrate_vma_setup() will fill the
> source PFN array with an entry indicating the source page is zero.
> Use this to optimize migration to device private memory by allocating
> GPU memory and zero filling it instead of failing to migrate the page.
> 
> Signed-off-by: Ralph Campbell <rcampbell@xxxxxxxxxx>
> 
> This patch applies cleanly to Jason's Gunthorpe's hmm tree plus two
> patches I posted earlier. The first is queued in Ben Skegg's nouveau
> tree and the second is still pending review/not queued.
> [1] ("nouveau/hmm: map pages after migration")
> https://lore.kernel.org/linux-mm/20200304001339.8248-5-rcampbell@xxxxxxxxxx/
> [2] ("nouveau/hmm: fix nouveau_dmem_chunk allocations")
> https://lore.kernel.org/lkml/20200421231107.30958-1-rcampbell@xxxxxxxxxx/

It would be best if it goes through Ben's tree if it doesn't have
conflicts with the hunks I have in the hmm tree.. Is it the case?

Jason