search for: virtio_balloon_f_free_page_hint

Negotiation of the VIRTIO_BALLOON_F_FREE_PAGE_HINT feature indicates the support of reporting hints of guest free pages to host via virtio-balloon. Host requests the guest to report free page hints by sending a command to the guest via setting the VIRTIO_BALLOON_HOST_CMD_FREE_PAGE_HINT bit of the host_cmd config register. As the first step here,...

Negotiation of the VIRTIO_BALLOON_F_FREE_PAGE_HINT feature indicates the support of reporting hints of guest free pages to host via virtio-balloon. Host requests the guest to report free pages by sending a new cmd id to the guest via the free_page_report_cmd_id configuration register. When the guest starts to report, the first element added to th...

...s not a mandate for host to > corrupt memory. It's just some info about page use guest > gives host. If host corrupts memory it's broken ... I don't think that's true, and that's not what we currently implement in the hypervisor for speeding up migration. I still consider VIRTIO_BALLOON_F_FREE_PAGE_HINT as an alternative technique of temporarily inflating/deflating. E.g., we don't migrate any of these pages in the hypervisor, so the content will be zeroed out on the migration target. If migration fails, the ld content will remain. You can call that "corrupting memory" - it's exac...

...we get a STOP signal. That is not really possible because it might >> take an infinite amount of time. >> >> Michael, any clue on which event we have to wait with >> VIRTIO_BALLOON_F_MUST_TELL_HOST? IMHO, I don't think >> VIRTIO_BALLOON_F_MUST_TELL_HOST applies to VIRTIO_BALLOON_F_FREE_PAGE_HINT and >> we'd better document that. It introduces complexity with no clear benefit. > > I meant that we must wait for host to see the hint. Signalled via using > the buffer. But maybe that's too far in the meaning from > VIRTIO_BALLOON_F_MUST_TELL_HOST and we need a separa...

...we get a STOP signal. That is not really possible because it might >> take an infinite amount of time. >> >> Michael, any clue on which event we have to wait with >> VIRTIO_BALLOON_F_MUST_TELL_HOST? IMHO, I don't think >> VIRTIO_BALLOON_F_MUST_TELL_HOST applies to VIRTIO_BALLOON_F_FREE_PAGE_HINT and >> we'd better document that. It introduces complexity with no clear benefit. > > I meant that we must wait for host to see the hint. Signalled via using > the buffer. But maybe that's too far in the meaning from > VIRTIO_BALLOON_F_MUST_TELL_HOST and we need a separa...

Negotiation of the VIRTIO_BALLOON_F_FREE_PAGE_HINT feature indicates the support of reporting hints of guest free pages to host via virtio-balloon. Host requests the guest to report free pages by sending a new cmd id to the guest via the free_page_report_cmd_id configuration register. When the guest starts to report, the first element added to th...

Negotiation of the VIRTIO_BALLOON_F_FREE_PAGE_HINT feature indicates the support of reporting hints of guest free pages to host via virtio-balloon. Host requests the guest to report free page hints by sending a new cmd id to the guest via the free_page_report_cmd_id configuration register. When the guest starts to report, the first element added...

Negotiation of the VIRTIO_BALLOON_F_FREE_PAGE_HINT feature indicates the support of reporting hints of guest free pages to host via virtio-balloon. Host requests the guest to report free page hints by sending a new cmd id to the guest via the free_page_report_cmd_id configuration register. When the guest starts to report, the first element added...

Two fixes for issues I stumbled over while working on patch #3. Switch back to the good ol' OOM handler for VIRTIO_BALLOON_F_DEFLATE_ON_OOM as the switch to the shrinker introduce some undesired side effects. Keep the shrinker in place to handle VIRTIO_BALLOON_F_FREE_PAGE_HINT. Lengthy discussion under [1]. I tested with QEMU and "deflate-on-oom=on". Works as expected. Did not test the shrinker for VIRTIO_BALLOON_F_FREE_PAGE_HINT, as it is hard to trigger (only when migrating a VM, and even then, it might not trigger). [1] https://www.spinics.net/lists/linux-...

On Wed, Feb 07, 2018 at 11:01:06AM +0800, Wei Wang wrote: > Negotiation of the VIRTIO_BALLOON_F_FREE_PAGE_HINT feature indicates the > support of reporting hints of guest free pages to host via virtio-balloon. > > Host requests the guest to report free page hints by sending a new cmd > id to the guest via the free_page_report_cmd_id configuration register. > > When the guest starts to re...

Negotiation of the VIRTIO_BALLOON_F_FREE_PAGE_HINT feature indicates the support of reporting hints of guest free pages to host via virtio-balloon. Host requests the guest to report free page hints by sending a new cmd id to the guest via the free_page_report_cmd_id configuration register. When the guest starts to report, the first element added...

Negotiation of the VIRTIO_BALLOON_F_FREE_PAGE_HINT feature indicates the support of reporting hints of guest free pages to host via virtio-balloon. Host requests the guest to report free page hints by sending a new cmd id to the guest via the free_page_report_cmd_id configuration register. When the guest starts to report, the first element added...

Negotiation of the VIRTIO_BALLOON_F_FREE_PAGE_HINT feature indicates the support of reporting hints of guest free pages to host via virtio-balloon. Host requests the guest to report free page hints by sending a new cmd id to the guest via the free_page_report_cmd_id configuration register. As the first step here, virtio-balloon only reports free...

On Wed, Jan 24, 2018 at 06:42:42PM +0800, Wei Wang wrote: > Negotiation of the VIRTIO_BALLOON_F_FREE_PAGE_HINT feature indicates the > support of reporting hints of guest free pages to host via virtio-balloon. > > Host requests the guest to report free pages by sending a new cmd > id to the guest via the free_page_report_cmd_id configuration register. > > When the guest starts to report,...

On Wed, Jan 24, 2018 at 06:42:42PM +0800, Wei Wang wrote: > Negotiation of the VIRTIO_BALLOON_F_FREE_PAGE_HINT feature indicates the > support of reporting hints of guest free pages to host via virtio-balloon. > > Host requests the guest to report free pages by sending a new cmd > id to the guest via the free_page_report_cmd_id configuration register. > > When the guest starts to report,...

...are >>> actually about to start hitting oom. >> >> I think the shrinker makes sense for free page hinting feature >> (everything on free_page_list). >> >> So instead of only reverting, I think we should split it up and always >> register the shrinker for VIRTIO_BALLOON_F_FREE_PAGE_HINT and the OOM >> notifier (as before) for VIRTIO_BALLOON_F_MUST_TELL_HOST. s/VIRTIO_BALLOON_F_MUST_TELL_HOST/VIRTIO_BALLOON_F_DEFLATE_ON_OOM/ :) >> >> (Of course, adapting what is being done in the shrinker and in the OOM >> notifier) > > David, > > Please kee...

...are >>> actually about to start hitting oom. >> >> I think the shrinker makes sense for free page hinting feature >> (everything on free_page_list). >> >> So instead of only reverting, I think we should split it up and always >> register the shrinker for VIRTIO_BALLOON_F_FREE_PAGE_HINT and the OOM >> notifier (as before) for VIRTIO_BALLOON_F_MUST_TELL_HOST. s/VIRTIO_BALLOON_F_MUST_TELL_HOST/VIRTIO_BALLOON_F_DEFLATE_ON_OOM/ :) >> >> (Of course, adapting what is being done in the shrinker and in the OOM >> notifier) > > David, > > Please kee...

On Fri, Apr 06, 2018 at 08:17:23PM +0800, Wei Wang wrote: > Negotiation of the VIRTIO_BALLOON_F_FREE_PAGE_HINT feature indicates the > support of reporting hints of guest free pages to host via virtio-balloon. > > Host requests the guest to report free page hints by sending a new cmd > id to the guest via the free_page_report_cmd_id configuration register. > > When the guest starts to re...

...gt;> The problem is we cannot communicate the full situation to the >> hypervisor without the page poison feature being present. As such I >> would worry about that backfiring on us due to the hypervisor acting >> on incomplete data. > > > I'll try to think about VIRTIO_BALLOON_F_FREE_PAGE_HINT situation > over the weekend. But for the new page reporting, why not I shared my thoughts about VIRTIO_BALLOON_F_FREE_PAGE_HINT in the other thread and think we should simply not care at all for now. > assume host implementation will be sane? I don't think we should enforce having poi...

...mes[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; > + > + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { > + names[VIRTIO_BALLOON_VQ_STATS] = "stats"; > + callbacks[VIRTIO_BALLOON_VQ_STATS] = stats_request; > + } > + > + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { > + names[VIRTIO_BALLOON_VQ_FREE_PAGE] = "free_page_vq"; > + callbacks[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; > + } > + > + err = vb->vdev->config->find_vqs(vb->vdev, VIRTIO_BALLOON_VQ_MAX, [...]