| Date | Wed, 29 Jul 2015 18:35:02 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 9/9] x86/intel_rdt: Intel haswell Cache Allocation enumeration |
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On Wed, Jul 01, 2015 at 03:21:10PM -0700, Vikas Shivappa wrote: > + boot_cpu_data.x86_cache_max_closid = 4; > + boot_cpu_data.x86_cache_max_cbm_len = 20;
That's just vile. And I'm surprised it even works, I would've expected boot_cpu_data to be const.
So the CQM code has paranoid things like:
max_rmid = MAX_INT; for_each_possible_cpu(cpu) max_rmid = min(max_rmid, cpu_data(cpu)->x86_cache_max_rmid);
And then uses max_rmid. This has the advantage that if you mix parts in a multi-socket environment and hotplug socket 0 to a later part which a bigger {rm,clos}id your allocation isn't suddenly too small.
Please do similar things and only ever look at cpu_data once, at init time.
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