Sasha Levin
2011-Jul-02 03:06 UTC
[PATCH] virtio_balloon: Notify guest only after deflating the balloon
Unless the host requires that requested pages won't be used until he us notified (VIRTIO_BALLOON_F_MUST_TELL_HOST), only notify after deflating the balloon. This will avoid having to take an exit before actually using the pages. Cc: Rusty Russell <rusty at rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst at redhat.com> Cc: virtualization at lists.linux-foundation.org Cc: kvm at vger.kernel.org Signed-off-by: Sasha Levin <levinsasha928 at gmail.com> --- drivers/virtio/virtio_balloon.c | 16 ++++++++++------ 1 files changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index e058ace..055f95d 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -148,14 +148,18 @@ static void leak_balloon(struct virtio_balloon *vb, size_t num) vb->num_pages--; } - /* - * Note that if - * virtio_has_feature(vdev, VIRTIO_BALLOON_F_MUST_TELL_HOST); - * is true, we *have* to do it in this order + * If the host doesn't require us to notify him before using + * pages which belong to the balloon, update him only after + * freeing those pages for guest use. */ - tell_host(vb, vb->deflate_vq); - release_pages_by_pfn(vb->pfns, vb->num_pfns); + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_MUST_TELL_HOST)) { + tell_host(vb, vb->deflate_vq); + release_pages_by_pfn(vb->pfns, vb->num_pfns); + } else { + release_pages_by_pfn(vb->pfns, vb->num_pfns); + tell_host(vb, vb->deflate_vq); + } } static inline void update_stat(struct virtio_balloon *vb, int idx, -- 1.7.6
Michael S. Tsirkin
2011-Jul-03 08:27 UTC
[PATCH] virtio_balloon: Notify guest only after deflating the balloon
Doesn't this basically just revert bf50e69f63d21091e525185c3ae761412be0ba72? On Sat, Jul 02, 2011 at 06:06:56AM +0300, Sasha Levin wrote:> Unless the host requires that requested pages won't be used until > he us notified (VIRTIO_BALLOON_F_MUST_TELL_HOST), only notify after > deflating the balloon. > > This will avoid having to take an exit before actually using the pages. > > Cc: Rusty Russell <rusty at rustcorp.com.au> > Cc: "Michael S. Tsirkin" <mst at redhat.com> > Cc: virtualization at lists.linux-foundation.org > Cc: kvm at vger.kernel.org > Signed-off-by: Sasha Levin <levinsasha928 at gmail.com> > --- > drivers/virtio/virtio_balloon.c | 16 ++++++++++------ > 1 files changed, 10 insertions(+), 6 deletions(-) > > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > index e058ace..055f95d 100644 > --- a/drivers/virtio/virtio_balloon.c > +++ b/drivers/virtio/virtio_balloon.c > @@ -148,14 +148,18 @@ static void leak_balloon(struct virtio_balloon *vb, size_t num) > vb->num_pages--; > } > > - > /* > - * Note that if > - * virtio_has_feature(vdev, VIRTIO_BALLOON_F_MUST_TELL_HOST); > - * is true, we *have* to do it in this order > + * If the host doesn't require us to notify him before using > + * pages which belong to the balloon, update him only after > + * freeing those pages for guest use. > */ > - tell_host(vb, vb->deflate_vq); > - release_pages_by_pfn(vb->pfns, vb->num_pfns); > + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_MUST_TELL_HOST)) { > + tell_host(vb, vb->deflate_vq); > + release_pages_by_pfn(vb->pfns, vb->num_pfns); > + } else { > + release_pages_by_pfn(vb->pfns, vb->num_pfns); > + tell_host(vb, vb->deflate_vq); > + } > } > > static inline void update_stat(struct virtio_balloon *vb, int idx, > -- > 1.7.6
Apparently Analagous Threads
- [PATCH] virtio_balloon: Notify guest only after deflating the balloon
- [RFC][PATCH] virtio balloon: kill tell-host-first logic
- [RFC][PATCH] virtio balloon: kill tell-host-first logic
- [PATCH v1 3/3] virtio-balloon: Switch back to OOM handler for VIRTIO_BALLOON_F_DEFLATE_ON_OOM
- [PATCH v1 3/3] virtio-balloon: Switch back to OOM handler for VIRTIO_BALLOON_F_DEFLATE_ON_OOM