On Wednesday, February 5, 2020 3:05 PM, Michael S. Tsirkin wrote: > > Well if we did the hint would be reliable, allowing host to immediately drop > any pages it gets in the hint. "drop", you mean host to unmap the page from guest? I think that's not allowed for hints. > Originally I wanted to speed up hinting by never > waiting for host, but that does not seem to be what was > implemented: the only place we don't wait is the shrinker Didn't get this one. For FREE_PAGE_HINT, the hints are always sent to host without an ack from host about whether it has read the hint or not. (please see get_free_page_and_send) > and it seems a > waste that we introduced complexity to host without getting any real > benefit out of it. > > VIRTIO_BALLOON_F_MUST_TELL_HOST doesn't really apply to hinting right > now, There is no need I think, as host isn't allowed to use or unmap the hint page. Best, Wei
