powerpc is the only platform that do not rely on
cpu_up()->try_online_node() to bring up a numa node,
and special cases it, instead, deep in its own machinery:
dlpar_online_cpu
find_and_online_cpu_nid
try_online_node
This should not be needed, but the thing is that the try_online_node()
from cpu_up() will not apply on the right node, because cpu_to_node()
will return the old mapping numa<->cpu that gets set on boot stage
for all possible cpus.
That can be seen easily if we try to print out the numa node passed
to try_online_node() in cpu_up().
The thing is that the numa<->cpu mapping does not get updated till a much
later stage in start_secondary:
start_secondary:
set_numa_node(numa_cpu_lookup_table[cpu])
But we do not really care, as we already now the
CPU <-> NUMA associativity back in find_and_online_cpu_nid(),
so let us make use of that and set the proper numa<->cpu mapping,
so cpu_to_node() in cpu_up() returns the right node and
try_online_node() can do its work.
Signed-off-by: Oscar Salvador <osalvador@xxxxxxx>
Reviewed-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
Tested-by: Geetika Moolchandani <Geetika.Moolchandani1@xxxxxxx>
---
arch/powerpc/include/asm/topology.h | 8 ++-----
arch/powerpc/mm/numa.c | 31 +++++++---------------------
arch/powerpc/platforms/pseries/hotplug-cpu.c | 2 +-
3 files changed, 11 insertions(+), 30 deletions(-)
diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
index 36fcafb1fd6d..6ae1b2dce83e 100644
--- a/arch/powerpc/include/asm/topology.h
+++ b/arch/powerpc/include/asm/topology.h
@@ -111,14 +111,10 @@ static inline void unmap_cpu_from_node(unsigned long cpu) {}
#endif /* CONFIG_NUMA */
#if defined(CONFIG_NUMA) && defined(CONFIG_PPC_SPLPAR)
-extern int find_and_online_cpu_nid(int cpu);
+extern void find_and_update_cpu_nid(int cpu);
extern int cpu_to_coregroup_id(int cpu);
#else
-static inline int find_and_online_cpu_nid(int cpu)
-{
- return 0;
-}
-
+static inline void find_and_update_cpu_nid(int cpu) {}
static inline int cpu_to_coregroup_id(int cpu)
{
#ifdef CONFIG_SMP
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index b9b7fefbb64b..b5bc8b1a833d 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -1423,43 +1423,28 @@ static long vphn_get_associativity(unsigned long cpu,
return rc;
}
-int find_and_online_cpu_nid(int cpu)
+void find_and_update_cpu_nid(int cpu)
{
__be32 associativity[VPHN_ASSOC_BUFSIZE] = {0};
int new_nid;
/* Use associativity from first thread for all siblings */
if (vphn_get_associativity(cpu, associativity))
- return cpu_to_node(cpu);
+ return;
+ /* Do not have previous associativity, so find it now. */
new_nid = associativity_to_nid(associativity);
+
if (new_nid < 0 || !node_possible(new_nid))
new_nid = first_online_node;
-
- if (NODE_DATA(new_nid) == NULL) {
-#ifdef CONFIG_MEMORY_HOTPLUG
- /*
- * Need to ensure that NODE_DATA is initialized for a node from
- * available memory (see memblock_alloc_try_nid). If unable to
- * init the node, then default to nearest node that has memory
- * installed. Skip onlining a node if the subsystems are not
- * yet initialized.
- */
- if (!topology_inited || try_online_node(new_nid))
- new_nid = first_online_node;
-#else
- /*
- * Default to using the nearest node that has memory installed.
- * Otherwise, it would be necessary to patch the kernel MM code
- * to deal with more memoryless-node error conditions.
+ else
+ /* Associate node <-> cpu, so cpu_up() calls
+ * try_online_node() on the right node.
*/
- new_nid = first_online_node;
-#endif
- }
+ set_cpu_numa_node(cpu, new_nid);
pr_debug("%s:%d cpu %d nid %d\n", __FUNCTION__, __LINE__,
cpu, new_nid);
- return new_nid;
}
int cpu_to_coregroup_id(int cpu)
diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index b81fc846d99c..0f8cd8b06432 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -398,7 +398,7 @@ static int dlpar_online_cpu(struct device_node *dn)
if (get_hard_smp_processor_id(cpu) != thread)
continue;
cpu_maps_update_done();
- find_and_online_cpu_nid(cpu);
+ find_and_update_cpu_nid(cpu);
rc = device_online(get_cpu_device(cpu));
if (rc) {
dlpar_offline_cpu(dn);
--
2.16.4
