On Mon, Mar 16, 2020 at 03:49:51PM -0700, Ralph Campbell wrote: > On 3/16/20 12:32 PM, Christoph Hellwig wrote: >> Remove the code to fault device private pages back into system memory >> that has never been used by any driver. Also replace the usage of the >> HMM_PFN_DEVICE_PRIVATE flag in the pfns array with a simple >> is_device_private_page check in nouveau. >> >> Signed-off-by: Christoph Hellwig <hch@xxxxxx> > > Getting rid of HMM_PFN_DEVICE_PRIVATE seems reasonable to me since a driver can > look at the struct page but what if a driver needs to fault in a page from > another device's private memory? Should it call handle_mm_fault()? Obviously no driver cared for that so far. Once we have test cases for that and thus testable code we can add code to fault it in from hmm_vma_handle_pte.