提交 e67e02a5 编写于 作者: M Michael Bringmann 提交者: Michael Ellerman

powerpc/pseries: Fix cpu hotplug crash with memoryless nodes

On powerpc systems with shared configurations of CPUs and memory and
memoryless nodes at boot, an event ordering problem was observed on a
SLES12 build platforms with the hot-add of CPUs to the memoryless
nodes.

* The most common error occurred when the memory SLAB driver attempted
  to reference the memoryless node to which a CPU was being added
  before the kernel had finished initializing all of the data
  structures for the CPU and exited 'device_online' under
  DLPAR/hot-add.

  Normally the memoryless node would be initialized through the call
  path device_online ... arch_update_cpu_topology ... find_cpu_nid ...
  try_online_node. This patch ensures that the powerpc node will be
  initialized as early as possible, even if it was memoryless and
  CPU-less at the point when we are trying to hot-add a new CPU to it.
Signed-off-by: NMichael Bringmann <mwb@linux.vnet.ibm.com>
Reviewed-by: NNathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
上级 ea05ba7c
......@@ -1198,7 +1198,7 @@ static long vphn_get_associativity(unsigned long cpu,
return rc;
}
static inline int find_and_online_cpu_nid(int cpu)
int find_and_online_cpu_nid(int cpu)
{
__be32 associativity[VPHN_ASSOC_BUFSIZE] = {0};
int new_nid;
......@@ -1229,6 +1229,8 @@ static inline int find_and_online_cpu_nid(int cpu)
#endif
}
pr_debug("%s:%d cpu %d nid %d\n", __FUNCTION__, __LINE__,
cpu, new_nid);
return new_nid;
}
......
......@@ -340,6 +340,8 @@ static void pseries_remove_processor(struct device_node *np)
cpu_maps_update_done();
}
extern int find_and_online_cpu_nid(int cpu);
static int dlpar_online_cpu(struct device_node *dn)
{
int rc = 0;
......@@ -364,6 +366,7 @@ static int dlpar_online_cpu(struct device_node *dn)
!= CPU_STATE_OFFLINE);
cpu_maps_update_done();
timed_topology_update(1);
find_and_online_cpu_nid(cpu);
rc = device_online(get_cpu_device(cpu));
if (rc)
goto out;
......
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