On 25.11.21 03:20, Jason Wang wrote:
> We only process the first in sg which may lead to the bitmap of the
> pages belongs to following sgs were not cleared. This may result more
> pages to be migrated. Fixing this by process all in sgs for
> free_page_vq.
>
> Signed-off-by: Jason Wang <jasow...@redhat.com>
> ---
> hw/virtio/virtio-balloon.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
> index c6962fcbfe..17de2558cb 100644
> --- a/hw/virtio/virtio-balloon.c
> +++ b/hw/virtio/virtio-balloon.c
> @@ -510,6 +510,7 @@ static bool get_free_page_hints(VirtIOBalloon *dev)
> VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> VirtQueue *vq = dev->free_page_vq;
> bool ret = true;
> + int i;
>
> while (dev->block_iothread) {
> qemu_cond_wait(&dev->free_page_cond, &dev->free_page_lock);
> @@ -544,8 +545,10 @@ static bool get_free_page_hints(VirtIOBalloon *dev)
> }
>
> if (elem->in_num && dev->free_page_hint_status ==
> FREE_PAGE_HINT_S_START) {
> - qemu_guest_free_page_hint(elem->in_sg[0].iov_base,
> - elem->in_sg[0].iov_len);
> + for (i = 0; i < elem->in_num; i++) {
> + qemu_guest_free_page_hint(elem->in_sg[i].iov_base,
> + elem->in_sg[i].iov_len);
> + }
> }
>
> out:
>
Yes, but:
1. Linux never used more than one
2. QEMU never consumed more than one
The spec states:
"(b) The driver maps a series of pages and adds them to the free_page_vq
as individual scatter-gather input buffer entries."
However, the spec was written by someone else (Alex) as the code was
(Wei). The code was there first.
I don't particularly care what to adjust (code or spec). However, to me
it feels more like the spec is slightly wrong and it was intended like
the code is by the original code author.
But then again, I don't particularly care :)
--
Thanks,
David / dhildenb
