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powerpc: Check cpu_thread_in_subcore() in __cpu_up() 

To support split core we need to change the check in __cpu_up() that
determines if a cpu is allowed to come online.

Currently we refuse to online cpus which are not the primary thread
within their core.

On POWER8 with split core support this check needs to instead refuse to
online cpus which are not the primary thread within their *sub* core.

On POWER7 and other systems that do not support split core,
threads_per_subcore == threads_per_core and so the check is equivalent.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Michael Ellerman 2014-05-23 18:15:28 +10:00 committed by Benjamin Herrenschmidt
parent 5853aef1ac
commit 6f5e40a300
1 changed files with 1 additions and 1 deletions
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2
arch/powerpc/kernel/smp.c
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@ -490,7 +490,7 @@ int __cpu_up(unsigned int cpu, struct task_struct *tidle)
* Don't allow secondary threads to come online if inhibited
*/
if (threads_per_core > 1 && secondaries_inhibited() &&
cpu % threads_per_core != 0)
cpu_thread_in_subcore(cpu))
return -EBUSY;
if (smp_ops == NULL ||