On 12/11/20 1:46 PM, Jason Gunthorpe wrote:
On Fri, Dec 11, 2020 at 08:50:53AM +0100, Thomas Hellström (Intel) wrote:
My understanding of this particular case is that hardware would continue to
DMA to orphaned pages that are pinned until the driver is done with
DMA,
mmu notifier replaces pinning as the locking mechanism. Drivers using
mmu notifier should not be taking pins.
Keep in mind this was all built for HW with real shadow page tables
that can do fine grained manipulation.
OK yes, that makes sense and in that context the fence wait is easier to
understand. Looks like for example the radeon driver is using the
notifier + get_user_pages() but there it looks like it's used to avoid
having get_user_pages() clash with invalidation.
/Thomas
The GPU version of this to instead manipulate a command queue is a big
aberration from what was intended.
Jason
_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/dri-devel
