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authorNathan Fontenot <nfont@linux.vnet.ibm.com>2018-01-26 13:41:59 -0600
committerMichael Ellerman <mpe@ellerman.id.au>2018-02-08 23:56:10 +1100
commit1d9a090783bef19fe8cdec878620d22f05191316 (patch)
treeafb105639d72a44289bfc1111d37a6dbe915c0be /arch/powerpc/platforms/pseries/hotplug-cpu.c
parent581e400ff935d34d95811258586128bf11baef15 (diff)
downloadlinux-1d9a090783bef19fe8cdec878620d22f05191316.tar.bz2
powerpc/numa: Invalidate numa_cpu_lookup_table on cpu remove
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>
Diffstat (limited to 'arch/powerpc/platforms/pseries/hotplug-cpu.c')
-rw-r--r--arch/powerpc/platforms/pseries/hotplug-cpu.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index dceb51454d8d..f78fd2068d56 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)