introduced by cs 4b9eec50fe2c23343 ("libxl: implement per NUMA node free memory reporting"). What was wrong was that libxl_get_numainfo() put in nr_nodes the actual number of host NUMA nodes, not the highest node ID (like libnuma's numa_max_node() does instead). While at it, turn the failure of libxl_get_numainfo() from a simple warning to a proper error, as requested during the review of another patch of the original series. Signed-off-by: Dario Faggioli <dario.faggioli(a)citrix.com&gt; Cc: Daniel P. Berrange <berrange(a)redhat.com&gt; --- src/libxl/libxl_driver.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c index 9e9bc89..04058d3 100644 --- a/src/libxl/libxl_driver.c +++ b/src/libxl/libxl_driver.c @@ -4107,23 +4107,23 @@ libxlNodeGetCellsFreeMemory(virConnectPtr conn, if (virNodeGetCellsFreeMemoryEnsureACL(conn) < 0) return -1; - /* Early failure is probably worth just a warning */ numa_info = libxl_get_numainfo(driver->ctx, &nr_nodes); if (numa_info == NULL || nr_nodes == 0) { - VIR_WARN("libxl_get_numainfo failed to retrieve NUMA data"); - return 0; + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("libxl_get_numainfo failed")); + goto cleanup; } /* Check/sanitize the cell range */ - if (startCell > nr_nodes) { + if (startCell >= nr_nodes) { virReportError(VIR_ERR_INTERNAL_ERROR, _("start cell %d out of range (0-%d)"), - startCell, nr_nodes); + startCell, nr_nodes - 1); goto cleanup; } lastCell = startCell + maxCells - 1; - if (lastCell > nr_nodes) - lastCell = nr_nodes; + if (lastCell >= nr_nodes) + lastCell = nr_nodes - 1; for (numCells = 0, n = startCell; n <= lastCell; n++) { if (numa_info[n].size == LIBXL_NUMAINFO_INVALID_ENTRY)

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> .... Signed-off-by: Dario Faggioli <dario.faggioli(a)citrix.com&gt; Cc: Daniel P. Berrange <berrange(a)redhat.com&gt; --- Changes from v3: * updated VIR_*ALLOC* call sites not to invoke virReportOOMError(); * failing at getting NUMA and CPU topology info from libxl are now considered proper errors, as requested during review; * s/out/cleanup/ as requested during review. Changes from v2: * iterators turned from int to size_t; * fixed wrong sibling maps if on same node but different socket; * code motion and error handling, as requested during review. Changes from v1: * fixed a typo in the commit message, as requested during review; * fixed coding style (one function parameters per line and no spaces between variable definitions), as requested during review; * avoid zero-filling memory after VIR_ALLOC_N(), since it does that already, as requested during review; * improved out of memory error reporting, as requested during review; * libxlMakeNumaCapabilities() created, accommodating all the NUMA related additions, instead of having them within libxlMakeCapabilitiesInternal(), as suggested during review. --- src/libxl/libxl_conf.c | 140 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 139 insertions(+), 1 deletion(-) diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c index 827dfdd..2c84191 100644 --- a/src/libxl/libxl_conf.c +++ b/src/libxl/libxl_conf.c @@ -161,6 +161,107 @@ libxlBuildCapabilities(virArch hostarch, } static virCapsPtr +libxlMakeNumaCapabilities(libxl_numainfo *numa_info, + int nr_nodes, + libxl_cputopology *cpu_topo, + int nr_cpus, + virCapsPtr caps) +{ + virCapsHostNUMACellCPUPtr *cpus = NULL; + int *nr_cpus_node = NULL; + bool numa_failed = true; + size_t i; + + 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; + } + + numa_failed = false; + + cleanup: + if (numa_failed) { + /* Something went wrong: deallocate everything and unref caps */ + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("libxenlight failed to build the NUMA topology")); + + for (i = 0; i < nr_nodes; i++) { + VIR_FREE(cpus[i]); + } + virCapabilitiesFreeNUMAInfo(caps); + + if (!virObjectUnref(caps)) + caps = NULL; + } + + VIR_FREE(cpus); + VIR_FREE(nr_cpus_node); + + return caps; +} + +static virCapsPtr libxlMakeCapabilitiesInternal(virArch hostarch, libxl_physinfo *phy_info, char *capabilities) @@ -876,7 +977,11 @@ libxlMakeCapabilities(libxl_ctx *ctx) { int err; libxl_physinfo phy_info; + libxl_numainfo *numa_info = NULL; + libxl_cputopology *cpu_topo = NULL; const libxl_version_info *ver_info; + int nr_nodes = 0, nr_cpus = 0; + virCapsPtr caps; err = regcomp(&xen_cap_rec, xen_cap_re, REG_EXTENDED); if (err != 0) { @@ -900,9 +1005,42 @@ libxlMakeCapabilities(libxl_ctx *ctx) return NULL; } - return libxlMakeCapabilitiesInternal(virArchFromHost(), + caps = libxlMakeCapabilitiesInternal(virArchFromHost(), &phy_info, ver_info->capabilities); + + /* Check if caps is valid. If it is, it must remain so till the end! */ + if (caps == NULL) + goto cleanup; + + /* 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; + } + else { + /* And add topology information to caps */ + caps = libxlMakeNumaCapabilities(numa_info, + nr_nodes, + cpu_topo, + nr_cpus, + caps); + } + } + +cleanup: + libxl_cputopology_list_free(cpu_topo, nr_cpus); + libxl_numainfo_list_free(numa_info, nr_nodes); + + return caps; } int

On lun, 2013-08-12 at 14:25 -0600, Jim Fehlig wrote: To be fully honest, I knew you were going to say that! :-P It's just, with the code looking like it does _before_ your patch reworking the host and guest capabilities, I still liked my approach more, and that's why I decided to give it a try! With your patch (the one in [2]) in place, I probably also think that making this a "proper function" returning an int. I think I like it, and I can certainly rework this patch one more time on top of yours. Apparently, this patch seems to suffer from some particular bad luck, since I'm going on vacation for ~2 weeks, so such rework and repost will be delayed some more time. :-P Anyway, thanks for having a look at it. I'll respin the patch as soon as coming back to work. Regards, Dario -- <<This happens because I choose it to happen!>> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://about.me/dario.faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)