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libxl: implement NUMA capabilities reporting

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From: Dario Faggioli <dario.faggioli@citrix.com>

Starting from Xen 4.2, libxl has all the bits and pieces in place
for retrieving an adequate amount of information about the host
NUMA topology. It is therefore possible, after a bit of shuffling,
to arrange those information in the way libvirt wants to present
them to the outside world.

Therefore, with this patch, the <topology> section of the host
capabilities is properly populated, when running on Xen, so that
we can figure out whether or not we're running on a NUMA host,
and what its characteristics are.

[raistlin@Zhaman ~]$ sudo virsh --connect xen:/// capabilities
<capabilities>
  <host>
    <cpu>
    ....
    <topology>
      <cells num='2'>
        <cell id='0'>
          <memory unit='KiB'>6291456</memory>
          <cpus num='8'>
            <cpu id='0' socket_id='1' core_id='0' siblings='0-1'/>
            <cpu id='1' socket_id='1' core_id='0' siblings='0-1'/>
            <cpu id='2' socket_id='1' core_id='1' siblings='2-3'/>
            <cpu id='3' socket_id='1' core_id='1' siblings='2-3'/>
            <cpu id='4' socket_id='1' core_id='9' siblings='4-5'/>
            <cpu id='5' socket_id='1' core_id='9' siblings='4-5'/>
            <cpu id='6' socket_id='1' core_id='10' siblings='6-7'/>
            <cpu id='7' socket_id='1' core_id='10' siblings='6-7'/>
          </cpus>
        </cell>
        <cell id='1'>
          <memory unit='KiB'>6881280</memory>
          <cpus num='8'>
            <cpu id='8' socket_id='0' core_id='0' siblings='8-9'/>
            <cpu id='9' socket_id='0' core_id='0' siblings='8-9'/>
            <cpu id='10' socket_id='0' core_id='1' siblings='10-11'/>
            <cpu id='11' socket_id='0' core_id='1' siblings='10-11'/>
            <cpu id='12' socket_id='0' core_id='9' siblings='12-13'/>
            <cpu id='13' socket_id='0' core_id='9' siblings='12-13'/>
            <cpu id='14' socket_id='0' core_id='10' siblings='14-15'/>
            <cpu id='15' socket_id='0' core_id='10' siblings='14-15'/>
          </cpus>
        </cell>
      </cells>
    </topology>
  </host>
  ....
This commit is contained in:
Jim Fehlig 2013-08-16 15:37:46 -06:00
parent e0e61b4cf7
commit 0192fd6711
1 changed files with 112 additions and 0 deletions
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112
src/libxl/libxl_conf.c
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@ -100,6 +100,115 @@ libxlCapsInitHost(libxl_ctx *ctx, virCapsPtr caps)
return 0;
}
static int
libxlCapsInitNuma(libxl_ctx *ctx, virCapsPtr caps)
{
libxl_numainfo *numa_info = NULL;
libxl_cputopology *cpu_topo = NULL;
int nr_nodes = 0, nr_cpus = 0;
virCapsHostNUMACellCPUPtr *cpus = NULL;
int *nr_cpus_node = NULL;
size_t i;
int ret = -1;
/* Let's try to fetch all the topology information */
numa_info = libxl_get_numainfo(ctx, &nr_nodes);
if (numa_info == NULL || nr_nodes == 0) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("libxl_get_numainfo failed"));
goto cleanup;
} else {
cpu_topo = libxl_get_cpu_topology(ctx, &nr_cpus);
if (cpu_topo == NULL || nr_cpus == 0) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("libxl_get_cpu_topology failed"));
goto cleanup;
}
}
if (VIR_ALLOC_N(cpus, nr_nodes) < 0)
goto cleanup;
if (VIR_ALLOC_N(nr_cpus_node, nr_nodes) < 0)
goto cleanup;
/* For each node, prepare a list of CPUs belonging to that node */
for (i = 0; i < nr_cpus; i++) {
int node = cpu_topo[i].node;
if (cpu_topo[i].core == LIBXL_CPUTOPOLOGY_INVALID_ENTRY)
continue;
nr_cpus_node[node]++;
if (nr_cpus_node[node] == 1) {
if (VIR_ALLOC(cpus[node]) < 0)
goto cleanup;
} else {
if (VIR_REALLOC_N(cpus[node], nr_cpus_node[node]) < 0)
goto cleanup;
}
/* Mapping between what libxl tells and what libvirt wants */
cpus[node][nr_cpus_node[node]-1].id = i;
cpus[node][nr_cpus_node[node]-1].socket_id = cpu_topo[i].socket;
cpus[node][nr_cpus_node[node]-1].core_id = cpu_topo[i].core;
/* Allocate the siblings maps. We will be filling them later */
cpus[node][nr_cpus_node[node]-1].siblings = virBitmapNew(nr_cpus);
if (!cpus[node][nr_cpus_node[node]-1].siblings) {
virReportOOMError();
goto cleanup;
}
}
/* Let's now populate the siblings bitmaps */
for (i = 0; i < nr_cpus; i++) {
int node = cpu_topo[i].node;
size_t j;
if (cpu_topo[i].core == LIBXL_CPUTOPOLOGY_INVALID_ENTRY)
continue;
for (j = 0; j < nr_cpus_node[node]; j++) {
if (cpus[node][j].socket_id == cpu_topo[i].socket &&
cpus[node][j].core_id == cpu_topo[i].core)
ignore_value(virBitmapSetBit(cpus[node][j].siblings, i));
}
}
for (i = 0; i < nr_nodes; i++) {
if (numa_info[i].size == LIBXL_NUMAINFO_INVALID_ENTRY)
continue;
if (virCapabilitiesAddHostNUMACell(caps, i, nr_cpus_node[i],
numa_info[i].size / 1024,
cpus[i]) < 0) {
virCapabilitiesClearHostNUMACellCPUTopology(cpus[i],
nr_cpus_node[i]);
goto cleanup;
}
/* This is safe, as the CPU list is now stored in the NUMA cell */
cpus[i] = NULL;
}
ret = 0;
cleanup:
if (ret != 0) {
for (i = 0; i < nr_nodes; i++)
VIR_FREE(cpus[i]);
virCapabilitiesFreeNUMAInfo(caps);
}
VIR_FREE(cpus);
VIR_FREE(nr_cpus_node);
libxl_cputopology_list_free(cpu_topo, nr_cpus);
libxl_numainfo_list_free(numa_info, nr_nodes);
return ret;
}
static int
libxlCapsInitGuests(libxl_ctx *ctx, virCapsPtr caps)
{
@ -880,6 +989,9 @@ libxlMakeCapabilities(libxl_ctx *ctx)
if (libxlCapsInitHost(ctx, caps) < 0)
goto error;
if (libxlCapsInitNuma(ctx, caps) < 0)
goto error;
if (libxlCapsInitGuests(ctx, caps) < 0)
goto error;