Re: [RFC,1/2] powerpc/numa: fix cpu_to_node() usage during boot

On Wed, 2015-07-08 at 16:16 -0700, Nishanth Aravamudan wrote:

On 08.07.2015 [14:00:56 +1000], Michael Ellerman wrote:

quoted

On Thu, 2015-02-07 at 23:02:02 UTC, Nishanth Aravamudan wrote:

quoted

we currently emit at boot:

[    0.000000] pcpu-alloc: [0] 0 1 2 3 [0] 4 5 6 7 

After this commit, we correctly emit:

[    0.000000] pcpu-alloc: [0] 0 1 2 3 [1] 4 5 6 7 

So it looks fairly sane, and I guess it's a bug fix.

But I'm a bit reluctant to put it in straight away without some time in next.

I'm fine with that -- it could use some more extensive testing,
admittedly (I only have been able to verify the pcpu areas are being
correctly allocated on the right node so far).

I still need to test with hotplug and things like that. Hence the RFC.

quoted

It looks like the symptom is that the per-cpu areas are all allocated on node
0, is that all that goes wrong?

Yes, that's the symptom. I cc'd a few folks to see if they could help
indicate the performance implications of such a setup -- sorry, I should
have been more explicit about that.

OK cool. I'm happy to put it in next if you send a non-RFC version.

cheers