Messages in this thread | | | Date | Tue, 16 Jun 2015 21:25:20 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH 09/10] x86/intel_rdt: Hot cpu support for Cache Allocation |
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On Tue, 16 Jun 2015, Vikas Shivappa wrote: > On Tue, 16 Jun 2015, Thomas Gleixner wrote: > > > On Fri, 12 Jun 2015, Vikas Shivappa wrote: > > > +static inline void intel_rdt_cpu_start(int cpu) > > > +{ > > > + struct intel_pqr_state *state = &per_cpu(pqr_state, cpu); > > > + > > > + state->closid = 0; > > > + mutex_lock(&rdt_group_mutex); > > > > This is called from CPU_STARTING, which runs on the starting cpu with > > interrupts disabled. Clearly never tested with any of the mandatory > > debug configs enabled. > > But this can race with cbm_update_all calling on_each_cpu_mask ? or in other > words the lock helps on_each_cpu_mask not race with hot cpu code updating the > rdt_cpumask since the on_each_cpu_mask is also called with the lock always. > > Its tested on the 0 day build which should include the debug config. Will add > a tested tag.
And that tag gives you special permission to take a mutex in irq disabled context on a cpu which cannot schedule, right?
Thanks,
tglx
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