[PATCH 3.17 114/146] powerpc: Only set numa node information for present cpus at boottime

From: Greg Kroah-Hartman
Date: Mon Oct 27 2014 - 23:40:37 EST


3.17-stable review patch. If anyone has any objections, please let me know.

------------------

From: Li Zhong <zhong@xxxxxxxxxxxxxxxxxx>

commit bc3c4327c92b9ceb9a6356ec64d1b2ab2dc851f9 upstream.

As Nish suggested, it makes more sense to init the numa node informatiion
for present cpus at boottime, which could also avoid WARN_ON(1) in
numa_setup_cpu().

With this change, we also need to change the smp_prepare_cpus() to set up
numa information only on present cpus.

For those possible, but not present cpus, their numa information
will be set up after they are started, as the original code did before commit
2fabf084b6ad.

Cc: Nishanth Aravamudan <nacc@xxxxxxxxxxxxxxxxxx>
Cc: Nathan Fontenot <nfont@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Li Zhong <zhong@xxxxxxxxxxxxxxxxxx>
Acked-by: Nishanth Aravamudan <nacc@xxxxxxxxxxxxxxxxxx>
Tested-by: Cyril Bur <cyril.bur@xxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/powerpc/kernel/smp.c | 10 ++++++++--
arch/powerpc/mm/numa.c | 2 +-
2 files changed, 9 insertions(+), 3 deletions(-)

--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -379,8 +379,11 @@ void __init smp_prepare_cpus(unsigned in
/*
* numa_node_id() works after this.
*/
- set_cpu_numa_node(cpu, numa_cpu_lookup_table[cpu]);
- set_cpu_numa_mem(cpu, local_memory_node(numa_cpu_lookup_table[cpu]));
+ if (cpu_present(cpu)) {
+ set_cpu_numa_node(cpu, numa_cpu_lookup_table[cpu]);
+ set_cpu_numa_mem(cpu,
+ local_memory_node(numa_cpu_lookup_table[cpu]));
+ }
}

cpumask_set_cpu(boot_cpuid, cpu_sibling_mask(boot_cpuid));
@@ -728,6 +731,9 @@ void start_secondary(void *unused)
}
traverse_core_siblings(cpu, true);

+ set_numa_node(numa_cpu_lookup_table[cpu]);
+ set_numa_mem(local_memory_node(numa_cpu_lookup_table[cpu]));
+
smp_wmb();
notify_cpu_starting(cpu);
set_cpu_online(cpu, true);
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -1127,7 +1127,7 @@ void __init do_init_bootmem(void)
* even before we online them, so that we can use cpu_to_{node,mem}
* early in boot, cf. smp_prepare_cpus().
*/
- for_each_possible_cpu(cpu) {
+ for_each_present_cpu(cpu) {
numa_setup_cpu((unsigned long)cpu);
}
}


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