Messages in this thread | | | Date | Wed, 25 Sep 2013 16:40:07 +0000 | From | Christoph Lameter <> | Subject | Re: [pchecks v2 2/2] percpu: Add preemption checks to __this_cpu ops |
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On Tue, 24 Sep 2013, Ingo Molnar wrote:
> Ok, this variant looks pretty good, modulo testing. I'd do: > > s/check_preemption/check_preemption_disabled > > but that's a minor detail.
Sure.
> > +config DEBUG_THIS_CPU_OPERATIONS > > + bool "Debug __this_cpu operations" > > + depends on DEBUG_PREEMPT > > + default n > > + help > > + Enables preemption checks for __this_cpu macros. These > > + are macros to generate single instruction operations on > > + per cpu data. The option only affects the __this_cpu variant > > + which is used when fallback to multiple instructions without > > + other synchronization is possible. A verification is then > > + done to make sure that the thread cannot be preempted. > > I don't think there's a need to make this a separate preemption debug > option: smp_processor_id() is really just a subset of the checks.
I think this is necessary since it seems that the discussions on how to do the raw_cpu conversions may take some time. If we enable it by default then there will be numerous new log messages. That way a developer can enable it for working on this.
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