Re: [PATCH 08 of 10 v2] libxl: automatic placement deals with node-affinity

[George Dunlap <george.dunlap@eu.citrix.com>]

On 19/12/12 19:07, Dario Faggioli wrote:
> Which basically means the following two things:
>   1) during domain creation, it is the node-affinity of
>      the domain --rather than the vcpu-affinities of its
>      VCPUs-- that is affected by automatic placement;
>   2) during automatic placement, when counting how many
>      VCPUs are already "bound" to a placement candidate
>      (as part of the process of choosing the best
>      candidate), both vcpu-affinity and node-affinity
>      are considered.
>
> Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
> Acked-by: George Dunlap <george.dunlap@eu.citrix.com>
> Acked-by: Juergen Gross <juergen.gross@ts.fujitsu.com>

Re-confirming Ack.
  -George

>
> diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
> --- a/tools/libxl/libxl_dom.c
> +++ b/tools/libxl/libxl_dom.c
> @@ -133,13 +133,13 @@ static int numa_place_domain(libxl__gc *
>   {
>       int found;
>       libxl__numa_candidate candidate;
> -    libxl_bitmap candidate_nodemap;
> +    libxl_bitmap cpupool_nodemap;
>       libxl_cpupoolinfo cpupool_info;
>       int i, cpupool, rc = 0;
>       uint32_t memkb;
>   
>       libxl__numa_candidate_init(&candidate);
> -    libxl_bitmap_init(&candidate_nodemap);
> +    libxl_bitmap_init(&cpupool_nodemap);
>   
>       /*
>        * Extract the cpumap from the cpupool the domain belong to. In fact,
> @@ -156,7 +156,7 @@ static int numa_place_domain(libxl__gc *
>       rc = libxl_domain_need_memory(CTX, info, &memkb);
>       if (rc)
>           goto out;
> -    if (libxl_node_bitmap_alloc(CTX, &candidate_nodemap, 0)) {
> +    if (libxl_node_bitmap_alloc(CTX, &cpupool_nodemap, 0)) {
>           rc = ERROR_FAIL;
>           goto out;
>       }
> @@ -174,17 +174,19 @@ static int numa_place_domain(libxl__gc *
>       if (found == 0)
>           goto out;
>   
> -    /* Map the candidate's node map to the domain's info->cpumap */
> -    libxl__numa_candidate_get_nodemap(gc, &candidate, &candidate_nodemap);
> -    rc = libxl_nodemap_to_cpumap(CTX, &candidate_nodemap, &info->cpumap);
> +    /* Map the candidate's node map to the domain's info->nodemap */
> +    libxl__numa_candidate_get_nodemap(gc, &candidate, &info->nodemap);
> +
> +    /* Avoid trying to set the affinity to nodes that might be in the
> +     * candidate's nodemap but out of our cpupool. */
> +    rc = libxl_cpumap_to_nodemap(CTX, &cpupool_info.cpumap,
> +                                 &cpupool_nodemap);
>       if (rc)
>           goto out;
>   
> -    /* Avoid trying to set the affinity to cpus that might be in the
> -     * nodemap but not in our cpupool. */
> -    libxl_for_each_set_bit(i, info->cpumap) {
> -        if (!libxl_bitmap_test(&cpupool_info.cpumap, i))
> -            libxl_bitmap_reset(&info->cpumap, i);
> +    libxl_for_each_set_bit(i, info->nodemap) {
> +        if (!libxl_bitmap_test(&cpupool_nodemap, i))
> +            libxl_bitmap_reset(&info->nodemap, i);
>       }
>   
>       LOG(DETAIL, "NUMA placement candidate with %d nodes, %d cpus and "
> @@ -193,7 +195,7 @@ static int numa_place_domain(libxl__gc *
>   
>    out:
>       libxl__numa_candidate_dispose(&candidate);
> -    libxl_bitmap_dispose(&candidate_nodemap);
> +    libxl_bitmap_dispose(&cpupool_nodemap);
>       libxl_cpupoolinfo_dispose(&cpupool_info);
>       return rc;
>   }
> @@ -211,10 +213,10 @@ int libxl__build_pre(libxl__gc *gc, uint
>       /*
>        * Check if the domain has any CPU affinity. If not, try to build
>        * up one. In case numa_place_domain() find at least a suitable
> -     * candidate, it will affect info->cpumap accordingly; if it
> +     * candidate, it will affect info->nodemap accordingly; if it
>        * does not, it just leaves it as it is. This means (unless
>        * some weird error manifests) the subsequent call to
> -     * libxl_set_vcpuaffinity_all() will do the actual placement,
> +     * libxl_domain_set_nodeaffinity() will do the actual placement,
>        * whatever that turns out to be.
>        */
>       if (libxl_defbool_val(info->numa_placement)) {
> diff --git a/tools/libxl/libxl_numa.c b/tools/libxl/libxl_numa.c
> --- a/tools/libxl/libxl_numa.c
> +++ b/tools/libxl/libxl_numa.c
> @@ -184,7 +184,7 @@ static int nr_vcpus_on_nodes(libxl__gc *
>                                int vcpus_on_node[])
>   {
>       libxl_dominfo *dinfo = NULL;
> -    libxl_bitmap vcpu_nodemap;
> +    libxl_bitmap dom_nodemap, vcpu_nodemap;
>       int nr_doms, nr_cpus;
>       int i, j, k;
>   
> @@ -197,6 +197,12 @@ static int nr_vcpus_on_nodes(libxl__gc *
>           return ERROR_FAIL;
>       }
>   
> +    if (libxl_node_bitmap_alloc(CTX, &dom_nodemap, 0) < 0) {
> +        libxl_bitmap_dispose(&vcpu_nodemap);
> +        libxl_dominfo_list_free(dinfo, nr_doms);
> +        return ERROR_FAIL;
> +    }
> +
>       for (i = 0; i < nr_doms; i++) {
>           libxl_vcpuinfo *vinfo;
>           int nr_dom_vcpus;
> @@ -205,14 +211,21 @@ static int nr_vcpus_on_nodes(libxl__gc *
>           if (vinfo == NULL)
>               continue;
>   
> +        /* Retrieve the domain's node-affinity map */
> +        libxl_domain_get_nodeaffinity(CTX, dinfo[i].domid, &dom_nodemap);
> +
>           for (j = 0; j < nr_dom_vcpus; j++) {
> -            /* For each vcpu of each domain, increment the elements of
> -             * the array corresponding to the nodes where the vcpu runs */
> +            /*
> +             * For each vcpu of each domain, it must have both vcpu-affinity
> +             * and node-affinity to (a pcpu belonging to) a certain node to
> +             * cause an increment in the corresponding element of the array.
> +             */
>               libxl_bitmap_set_none(&vcpu_nodemap);
>               libxl_for_each_set_bit(k, vinfo[j].cpumap) {
>                   int node = tinfo[k].node;
>   
>                   if (libxl_bitmap_test(suitable_cpumap, k) &&
> +                    libxl_bitmap_test(&dom_nodemap, node) &&
>                       !libxl_bitmap_test(&vcpu_nodemap, node)) {
>                       libxl_bitmap_set(&vcpu_nodemap, node);
>                       vcpus_on_node[node]++;
> @@ -223,6 +236,7 @@ static int nr_vcpus_on_nodes(libxl__gc *
>           libxl_vcpuinfo_list_free(vinfo, nr_dom_vcpus);
>       }
>   
> +    libxl_bitmap_dispose(&dom_nodemap);
>       libxl_bitmap_dispose(&vcpu_nodemap);
>       libxl_dominfo_list_free(dinfo, nr_doms);
>       return 0;