[Patch V3 7/9] x86, numa: Kill useless code to improve code readability

From: Jiang Liu
Date: Sun Aug 16 2015 - 23:16:40 EST


According to x86 boot sequence, early_cpu_to_node() always returns
NUMA_NO_NODE when called from numa_init(). So kill useless code
to improve code readability.

Related code sequence as below:
x86_cpu_to_node_map is set until step 2, so it is still the default
value (NUMA_NO_NODE) when accessed at step 1.

start_kernel()
setup_arch()
initmem_init()
x86_numa_init()
numa_init()
early_cpu_to_node()
1) return early_per_cpu_ptr(x86_cpu_to_node_map)[cpu];
acpi_boot_init();
sfi_init()
x86_dtb_init()
generic_processor_info()
early_per_cpu(x86_cpu_to_apicid, cpu) = apicid;
init_cpu_to_node()
numa_set_node(cpu, node);
2) per_cpu(x86_cpu_to_node_map, cpu) = node;

rest_init()
kernel_init()
smp_init()
native_cpu_up()
start_secondary()
numa_set_node()
per_cpu(x86_cpu_to_node_map, cpu) = node;

Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
---
arch/x86/mm/numa.c | 10 ----------
1 file changed, 10 deletions(-)

diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index 4053bb58bf92..08860bdf5744 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -591,8 +591,6 @@ static void __init numa_init_array(void)

rr = first_node(node_online_map);
for (i = 0; i < nr_cpu_ids; i++) {
- if (early_cpu_to_node(i) != NUMA_NO_NODE)
- continue;
numa_set_node(i, rr);
rr = next_node(rr, node_online_map);
if (rr == MAX_NUMNODES)
@@ -644,14 +642,6 @@ static int __init numa_init(int (*init_func)(void))
if (ret < 0)
return ret;

- for (i = 0; i < nr_cpu_ids; i++) {
- int nid = early_cpu_to_node(i);
-
- if (nid == NUMA_NO_NODE)
- continue;
- if (!node_online(nid))
- numa_clear_node(i);
- }
numa_init_array();

return 0;
--
1.7.10.4

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