On Tue, Nov 22, 2016 at 10:59 AM, Serguei Sagalovitch <serguei.sagalovitch@xxxxxxx> wrote: > Dan, > > I personally like "device-DAX" idea but my concerns are: > > - How well it will co-exists with the DRM infrastructure / implementations > in part dealing with CPU pointers? Inside the kernel a device-DAX range is "just memory" in the sense that you can perform pfn_to_page() on it and issue I/O, but the vma is not migratable. To be honest I do not know how well that co-exists with drm infrastructure. > - How well we will be able to handle case when we need to "move"/"evict" > memory/data to the new location so CPU pointer should point to the new > physical location/address > (and may be not in PCI device memory at all)? So, device-DAX deliberately avoids support for in-kernel migration or overcommit. Those cases are left to the core mm or drm. The device-dax interface is for cases where all that is needed is a direct-mapping to a statically-allocated physical-address range be it persistent memory or some other special reserved memory range. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
