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powerpc/numa: Set numa_node for all possible cpus 

A Powerpc system with multiple possible nodes and with CONFIG_NUMA
enabled always used to have a node 0, even if node 0 does not any cpus
or memory attached to it. As per PAPR, node affinity of a cpu is only
available once its present / online. For all cpus that are possible but
not present, cpu_to_node() would point to node 0.

To ensure a cpuless, memoryless dummy node is not online, powerpc need
to make sure all possible but not present cpu_to_node are set to a
proper node.

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200818081104.57888-2-srikar@linux.vnet.ibm.com
This commit is contained in:
Srikar Dronamraju 2020-08-18 13:41:02 +05:30 committed by Michael Ellerman
parent 67df77845c
commit a874f1005e
1 changed files with 15 additions and 1 deletions
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16
arch/powerpc/mm/numa.c
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@ -507,6 +507,11 @@ static int numa_setup_cpu(unsigned long lcpu)
int fcpu = cpu_first_thread_sibling(lcpu);
int nid = NUMA_NO_NODE;
if (!cpu_present(lcpu)) {
set_cpu_numa_node(lcpu, first_online_node);
return first_online_node;
}
/*
* If a valid cpu-to-node mapping is already available, use it
* directly instead of querying the firmware, since it represents
@ -944,8 +949,17 @@ void __init mem_topology_setup(void)
reset_numa_cpu_lookup_table();
for_each_present_cpu(cpu)
for_each_possible_cpu(cpu) {
/*
* Powerpc with CONFIG_NUMA always used to have a node 0,
* even if it was memoryless or cpuless. For all cpus that
* are possible but not present, cpu_to_node() would point
* to node 0. To remove a cpuless, memoryless dummy node,
* powerpc need to make sure all possible but not present
* cpu_to_node are set to a proper node.
*/
numa_setup_cpu(cpu);
}
}
void __init initmem_init(void)