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authorNathan Fontenot <nfont@linux.vnet.ibm.com>2018-01-26 13:41:59 -0600
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-02-22 15:42:16 +0100
commit4386f223b41868197080bd74882c2d31aca92a1a (patch)
tree267fcb933fc5a3564724a31c0950fadc987be8fa
parent5b98d31481f9e216e6df6b31e5a959db259c055e (diff)
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powerpc/numa: Invalidate numa_cpu_lookup_table on cpu remove
commit 1d9a090783bef19fe8cdec878620d22f05191316 upstream. When DLPAR removing a CPU, the unmapping of the cpu from a node in unmap_cpu_from_node() should also invalidate the CPUs entry in the numa_cpu_lookup_table. There is not a guarantee that on a subsequent DLPAR add of the CPU the associativity will be the same and thus could be in a different node. Invalidating the entry in the numa_cpu_lookup_table causes the associativity to be read from the device tree at the time of the add. The current behavior of not invalidating the CPUs entry in the numa_cpu_lookup_table can result in scenarios where the the topology layout of CPUs in the partition does not match the device tree or the topology reported by the HMC. This bug looks like it was introduced in 2004 in the commit titled "ppc64: cpu hotplug notifier for numa", which is 6b15e4e87e32 in the linux-fullhist tree. Hence tag it for all stable releases. Cc: stable@vger.kernel.org Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com> Reviewed-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/powerpc/include/asm/topology.h5
-rw-r--r--arch/powerpc/mm/numa.c5
-rw-r--r--arch/powerpc/platforms/pseries/hotplug-cpu.c2
3 files changed, 7 insertions, 5 deletions
diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
index 023ff9f17501..d5f2ee882f74 100644
--- a/arch/powerpc/include/asm/topology.h
+++ b/arch/powerpc/include/asm/topology.h
@@ -44,6 +44,11 @@ extern int sysfs_add_device_to_node(struct device *dev, int nid);
extern void sysfs_remove_device_from_node(struct device *dev, int nid);
extern int numa_update_cpu_topology(bool cpus_locked);
+static inline void update_numa_cpu_lookup_table(unsigned int cpu, int node)
+{
+ numa_cpu_lookup_table[cpu] = node;
+}
+
static inline int early_cpu_to_node(int cpu)
{
int nid;
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index a51df9ef529d..a81279249bfb 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -142,11 +142,6 @@ static void reset_numa_cpu_lookup_table(void)
numa_cpu_lookup_table[cpu] = -1;
}
-static void update_numa_cpu_lookup_table(unsigned int cpu, int node)
-{
- numa_cpu_lookup_table[cpu] = node;
-}
-
static void map_cpu_to_node(int cpu, int node)
{
update_numa_cpu_lookup_table(cpu, node);
diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index fadb95efbb9e..b1ac8ac38434 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -36,6 +36,7 @@
#include <asm/xics.h>
#include <asm/xive.h>
#include <asm/plpar_wrappers.h>
+#include <asm/topology.h>
#include "pseries.h"
#include "offline_states.h"
@@ -331,6 +332,7 @@ static void pseries_remove_processor(struct device_node *np)
BUG_ON(cpu_online(cpu));
set_cpu_present(cpu, false);
set_hard_smp_processor_id(cpu, -1);
+ update_numa_cpu_lookup_table(cpu, -1);
break;
}
if (cpu >= nr_cpu_ids)