Messages in this thread | | | Date | Thu, 11 Aug 2016 14:48:39 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH] x86/smp: Fix __max_logical_packages value setup |
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On Wed, Aug 10, 2016 at 06:14:18PM +0200, Jiri Olsa wrote: > > Maybe one nit, the variable is no longer used for a max, so maybe rename > > it too?
> diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h > index cf75871d2f81..c28010088651 100644 > --- a/arch/x86/include/asm/topology.h > +++ b/arch/x86/include/asm/topology.h > @@ -118,8 +118,8 @@ extern const struct cpumask *cpu_coregroup_mask(int cpu); > #define topology_core_cpumask(cpu) (per_cpu(cpu_core_map, cpu)) > #define topology_sibling_cpumask(cpu) (per_cpu(cpu_sibling_map, cpu)) > > -extern unsigned int __max_logical_packages; > -#define topology_max_packages() (__max_logical_packages) > +extern unsigned int logical_packages; > +#define topology_max_packages() (logical_packages) > > extern int __max_smt_threads; >
Aaahh, I missed this bit yesterday..
Imagine a machine with physical hotplug, where we boot with half the sockets populated (say 2), then topology_max_packages() will return 2 when we run the uncore driver init.
That driver will allocate resources based on 2.
Then we physically hotplug the remaining sockets (another 2), which will result in topology_max_packages() to now return 4.
When we run the cpuhotplug hook, it will try and access resources based on 4, which were not allocated.
blergh..
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