Re: [PULL 0/7] Migration.next patches

[Peter Maydell]

On Thu, 9 Sept 2021 at 16:23, Juan Quintela <quintela@redhat.com> wrote:
> From 964e436bdb8aef7dbebc28415e4ac3c5822b552e Mon Sep 17 00:00:00 2001
> From: Juan Quintela <quintela@redhat.com>
> Date: Thu, 9 Sep 2021 17:07:17 +0200
> Subject: [PATCH] rdma: test for ibv_advise_mr API
>
> Signed-off-by: Juan Quintela <quintela@redhat.com>
> ---
>  configure        | 28 ++++++++++++++++++++++++++++
>  migration/rdma.c |  2 ++
>  2 files changed, 30 insertions(+)
>
> diff --git a/configure b/configure
> index 8adf2127c3..70054fd702 100755
> --- a/configure
> +++ b/configure
> @@ -339,6 +339,7 @@ whpx="auto"
>  nvmm="auto"
>  rdma="$default_feature"
>  pvrdma="$default_feature"
> +rdma_ibv_advise_mr="no"
>  gprof="no"
>  debug_tcg="no"
>  debug="no"
> @@ -2918,6 +2919,29 @@ EOF
>      fi
>  fi
>
> +# Let's see if enhanced reg_mr is supported
> +if test "$rdma" = "yes" ; then
> +
> +cat > $TMPC <<EOF &&
> +#include <infiniband/verbs.h>
> +
> +int
> +main(void)
> +{
> +    int advice = wr ? IBV_ADVISE_MR_ADVICE_PREFETCH_WRITE :
> +                 IBV_ADVISE_MR_ADVICE_PREFETCH;
> +    struct ibv_sge sg_list = {.lkey = lkey, .addr = addr, .length = len};
> +
> +    ibv_advise_mr(pd, advice, IBV_ADVISE_MR_FLAG_FLUSH, &sg_list, 1);
> +    return 0;
> +}
> +EOF
> +    if ! compile_prog "" "-libverbs"; then
> +       rdma_ibv_advise_mr="yes"
> +    fi
> +fi

We don't really want new compilation tests in configure:
anything new should be done in meson.build. I think Paolo
has work in progress to migrate the remaining configure tests.
Something like

config_host_data.set('HAVE_IBV_ADVICE_MR',
cc.has_function('ibv_advise_mr', dependencies: rdma))

in the same bit of meson.build as the other has_function tests
is probably sufficient.

thanks
-- PMM