search for: balloon_free_pages_supported

Get the free pages information through virtio and filter out the free pages in the ram bulk stage. This can significantly reduce the total live migration time as well as network traffic. Signed-off-by: Liang Li <liang.z.li at intel.com> --- migration/ram.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 46 insertions(+), 6 deletions(-) diff --git

...lloon.c b/hw/virtio/virtio-balloon.c index e9c30e9..a5b9d08 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -76,6 +76,12 @@ static bool balloon_stats_supported(const VirtIOBalloon *s) return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_STATS_VQ); } +static bool balloon_free_pages_supported(const VirtIOBalloon *s) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(s); + return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_GET_FREE_PAGES); +} + static bool balloon_stats_enabled(const VirtIOBalloon *s) { return s->stats_poll_interval > 0; @@ -293,6 +299,37 @@ out: } } +...

...; index e9c30e9..a5b9d08 100644 > --- a/hw/virtio/virtio-balloon.c > +++ b/hw/virtio/virtio-balloon.c > @@ -76,6 +76,12 @@ static bool balloon_stats_supported(const VirtIOBalloon *s) > return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_STATS_VQ); > } > > +static bool balloon_free_pages_supported(const VirtIOBalloon *s) > +{ > + VirtIODevice *vdev = VIRTIO_DEVICE(s); > + return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_GET_FREE_PAGES); > +} > + > static bool balloon_stats_enabled(const VirtIOBalloon *s) > { > return s->stats_poll_interval > 0;...

The current QEMU live migration implementation mark the all the guest's RAM pages as dirtied in the ram bulk stage, all these pages will be processed and that takes quit a lot of CPU cycles. >From guest's point of view, it doesn't care about the content in free pages. We can make use of this fact and skip processing the free pages in the ram bulk stage, it can save a lot CPU cycles

The current QEMU live migration implementation mark the all the guest's RAM pages as dirtied in the ram bulk stage, all these pages will be processed and that takes quit a lot of CPU cycles. >From guest's point of view, it doesn't care about the content in free pages. We can make use of this fact and skip processing the free pages in the ram bulk stage, it can save a lot CPU cycles

On Thu, 3 Mar 2016 18:44:28 +0800 Liang Li <liang.z.li at intel.com> wrote: > Get the free pages information through virtio and filter out the free > pages in the ram bulk stage. This can significantly reduce the total > live migration time as well as network traffic. > > Signed-off-by: Liang Li <liang.z.li at intel.com> > --- > migration/ram.c | 52

...ed long *free_pages_bitmap, > + unsigned long *free_pages_count) > +{ > + VirtIOBalloon *s = opaque; > + VirtIODevice *vdev = VIRTIO_DEVICE(s); > + VirtQueueElement *elem = s->free_pages_vq_elem; > + int len; > + > + if (!balloon_free_pages_supported(s)) { > + return -1; > + } > + > + if (s->req_status == NOT_STARTED) { > + s->free_pages_bitmap = free_pages_bitmap; > + s->req_status = STARTED; > + s->mem_layout.low_mem = pc_get_lowmem(PC_MACHINE(current_machine)); Please don...

On Thu, Mar 03, 2016 at 06:44:28PM +0800, Liang Li wrote: > Get the free pages information through virtio and filter out the free > pages in the ram bulk stage. This can significantly reduce the total > live migration time as well as network traffic. > > Signed-off-by: Liang Li <liang.z.li at intel.com> > --- > migration/ram.c | 52