Re: [PATCH v3 2/2] migration/rdma: advise prefetch write for ODP region

[Juan Quintela]

Li Zhijian <lizhijian@cn.fujitsu.com> wrote:
> The responder mr registering with ODP will sent RNR NAK back to
> the requester in the face of the page fault.
> ---------
> ibv_poll_cq wc.status=13 RNR retry counter exceeded!
> ibv_poll_cq wrid=WRITE RDMA!
> ---------
> ibv_advise_mr(3) helps to make pages present before the actual IO is
> conducted so that the responder does page fault as little as possible.
>
> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
> Reviewed-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
>
> ---
> V3: Fix FreeBSD compiling errors
> V2: use IBV_ADVISE_MR_FLAG_FLUSH instead of IB_UVERBS_ADVISE_MR_FLAG_FLUSH
>     and add Reviewed-by tag. # Marcel
> ---
>  meson.build            |  6 ++++++
>  migration/rdma.c       | 42 ++++++++++++++++++++++++++++++++++++++++++
>  migration/trace-events |  1 +
>  3 files changed, 49 insertions(+)

Reviewed-by: Juan Quintela <quintela@redhat.com>