search for: free_pages_vq_elem

...tIODevice *vdev, VirtQueue *vq) +{ + VirtIOBalloon *s = VIRTIO_BALLOON(vdev); + VirtQueueElement *elem; + size_t offset = 0; + uint64_t bitmap_bytes = 0, free_pages_count = 0; + + elem = virtqueue_pop(vq, sizeof(VirtQueueElement)); + if (!elem) { + return; + } + s->free_pages_vq_elem = elem; + + if (!elem->out_num) { + return; + } + + iov_to_buf(elem->out_sg, elem->out_num, offset, + &free_pages_count, sizeof(uint64_t)); + + offset += sizeof(uint64_t); + iov_to_buf(elem->out_sg, elem->out_num, offset, + &b...

...OBalloon *s = VIRTIO_BALLOON(vdev); > + VirtQueueElement *elem; > + size_t offset = 0; > + uint64_t bitmap_bytes = 0, free_pages_count = 0; > + > + elem = virtqueue_pop(vq, sizeof(VirtQueueElement)); > + if (!elem) { > + return; > + } > + s->free_pages_vq_elem = elem; > + > + if (!elem->out_num) { > + return; > + } > + > + iov_to_buf(elem->out_sg, elem->out_num, offset, > + &free_pages_count, sizeof(uint64_t)); > + > + offset += sizeof(uint64_t); > + iov_to_buf(elem->out_sg...

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

...id *opaque, > + unsigned 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_layo...