@@ -29,6 +29,7 @@
#include <linux/seq_file.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
+#include <linux/sched/hotplug.h>
#include <asm/cputhreads.h>
#include <asm/sparsemem.h>
#include <asm/prom.h>
@@ -1424,6 +1425,20 @@ int numa_update_cpu_topology(bool cpus_locked)
changed = 1;
}
+ /*
+ * Scheduler maintains a sched_domain_numa_masks table that needs to
+ * be updated whenever cpu-node mapping changes. Cpu-node mapping
+ * changes only with VPHN and PRRN. 'topology_inited' indicates if
+ * cpu-hotplug infrastructure is initialized and good to use.
+ */
+ if (!(topology_inited && (vphn_enabled || prrn_enabled)))
+ goto out;
+
+ for_each_cpu(cpu, &updated_cpus) {
+ sched_cpu_deactivate(cpu);
+ sched_cpu_activate(cpu);
+ }
+
out:
kfree(updates);
topology_update_needed = 0;
Commit 2ea626306810 ("powerpc/topology: Get topology for shared processors at boot") will update the cpu node topology for shared lpars on PowerVM. However shared lpars on PowerVM also support VPHN and PRRN events. On receiving a VPHN, PRRN events, cpu to node mapping might change. Scheduler maintains sched_domains_numa_masks[], which is currently not updated on cpu to node mapping changes. This can lead to machine hangs or performance hit. Fix numa_update_cpu_topology() to update sched_domains_numa_masks[]. Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> --- Changelog: v1->v2: - Updated changelog. - Updated comments to refer to topology_inited. arch/powerpc/mm/numa.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)