On Sun, 2010-04-18 at 11:56 +0900, Tejun Heo wrote:
> On 04/17/2010 01:46 AM, Christoph Lameter wrote:
> > Maybe provide a generic function to set the node for cpu X?
>
> Yeap, seconded. Also, why not use numa_node_id() in
> common.c::cpu_init()?
Tejun: do you mean:
#ifdef CONFIG_NUMA
if (cpu != 0 && percpu_read(numa_node) == 0 &&
........................^ here?
early_cpu_to_node(cpu) != NUMA_NO_NODE)
set_numa_node(early_cpu_to_node(cpu));
#endif
Looks like 'numa_node_id()' would work there.
But, I wonder what the "cpu != 0 && percpu_read(numa_node) == 0" is
trying to do?
E.g., is "cpu != 0" testing "cpu != boot_cpu_id"? Is there an implicit
assumption that the boot cpu is zero? Or just a non-zero cpuid is
obviously initialized?
And the "percpu_read(numa_node) == 0" is testing that this cpu's
'numa_node' MAY not be initialized? 0 is a valid node id for !0 cpu
ids. But it's OK to reinitialize numa_node in that case.
Just trying to grok the intent. Maybe someone will chime in.
Anyway, if the intent is to test the percpu 'numa_node' for
initialization, using numa_node_id() might obscure this even more.
Lee
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