On Fri, Aug 16, 2019 at 12:30:41PM +0000, Jason Gunthorpe wrote: > > For instance, a system may have multiple DEVICE_PRIVATE map's owned by > the same driver - but multiple physical devices using that driver. > > Each physical device's driver should only ever get DEVICE_PRIVATE > pages for it's own on-device memory. Never a DEVICE_PRIVATE for > another device's memory. > > The dev_pagemap_ops would not be unique enough, right? True. > > Probably also clusters of same-driver struct device can share a > DEVICE_PRIVATE, at least high end GPU's now have private memory > coherency busses between their devices. > > Since we want to trigger migration to CPU on incompatible > DEVICE_PRIVATE pages, it seems best to sort this out in the > hmm_range_fault? > > Maybe some sort of unique ID inside the page->pgmap and passed as > input? Yes, we'll probably need an owner field. And it's not just hmm_range_fault, the migrate_vma_* routines as affected in the same way.
