[RFC PATCH v3 2/3] powerpc: Only set numa node information for present cpus at boottime

[Li Zhong]

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 at linux.vnet.ibm.com>
Cc: Nathan Fontenot <nfont at linux.vnet.ibm.com>
Signed-off-by: Li Zhong <zhong at linux.vnet.ibm.com>
---
 arch/powerpc/kernel/smp.c | 10 ++++++++--
 arch/powerpc/mm/numa.c    |  2 +-
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index a0738af..dc0e774 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -379,8 +379,11 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 		/*
 		 * 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);
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index 9918c02..3a9061e 100644
--- 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);
 	}
 }
-- 
1.9.1