Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

powerpc/pseries: Fix cpu hotplug crash with memoryless nodes

Browse source 
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: Michael Bringmann <mwb@linux.vnet.ibm.com>
Reviewed-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Michael Bringmann 2017-11-28 16:58:43 -06:00 committed by Michael Ellerman
parent ea05ba7c55
commit e67e02a544
2 changed files with 6 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
arch/powerpc/mm/numa.c
View file

@ -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;
}

3
arch/powerpc/platforms/pseries/hotplug-cpu.c
View file

@ -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;