As per PAPR that defines the OS to hypervisor interface on POWER,
there is no way to calculate the node_distance between 2 nodes, when
either of the nodes are offline. However scheduler needs the distance
map to be populated at boot time. On POWER, this information is
provided within the distance_ref_points_depth array, which needs to be
parsed to extract the potential node distances.
To handle this scenario, lets overload arch_populate_distance_map(),
to provide all the distances that are possible in the current
platform.
Cc: LKML <linux-ker...@vger.kernel.org>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Nathan Lynch <nath...@linux.ibm.com>
Cc: Michael Ellerman <m...@ellerman.id.au>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Valentin Schneider <valentin.schnei...@arm.com>
Cc: Scott Cheloha <chel...@linux.ibm.com>
Cc: Gautham R Shenoy <e...@linux.vnet.ibm.com>
Cc: Dietmar Eggemann <dietmar.eggem...@arm.com>
Cc: Mel Gorman <mgor...@techsingularity.net>
Cc: Vincent Guittot <vincent.guit...@linaro.org>
Cc: Rik van Riel <r...@surriel.com>
Cc: Geetika Moolchandani <geetika.moolchanda...@ibm.com>
Reported-by: Geetika Moolchandani <geetika.moolchanda...@ibm.com>
Signed-off-by: Srikar Dronamraju <sri...@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/topology.h | 3 +++
arch/powerpc/mm/numa.c | 19 +++++++++++++++++++
2 files changed, 22 insertions(+)
diff --git a/arch/powerpc/include/asm/topology.h
b/arch/powerpc/include/asm/topology.h
index e4db64c0e184..d7605d833b8d 100644
--- a/arch/powerpc/include/asm/topology.h
+++ b/arch/powerpc/include/asm/topology.h
@@ -22,6 +22,9 @@ struct drmem_lmb;
cpu_all_mask : \
node_to_cpumask_map[node])
+#define arch_populate_distance_map arch_populate_distance_map
+extern int arch_populate_distance_map(unsigned long *distance_map);
+
struct pci_bus;
#ifdef CONFIG_PCI
extern int pcibus_to_node(struct pci_bus *bus);
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index f2bf98bdcea2..9a225b29814a 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -221,6 +221,25 @@ static void initialize_distance_lookup_table(int nid,
}
}
+int arch_populate_distance_map(unsigned long *distance_map)
+{
+ int i;
+ int distance = LOCAL_DISTANCE;
+
+ bitmap_set(distance_map, distance, 1);
+
+ if (!form1_affinity) {
+ bitmap_set(distance_map, REMOTE_DISTANCE, 1);
+ return 0;
+ }
+
+ for (i = 0; i < distance_ref_points_depth; i++) {
+ distance *= 2;
+ bitmap_set(distance_map, distance, 1);
+ }
+ return 0;
+}
+
/*
* Returns nid in the range [0..nr_node_ids], or -1 if no useful NUMA
* info is found.
--
2.27.0
