[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v3 07/11] x86/intel_pstate: changes in cpufreq_del_cpu for CPU offline
On 11/06/2015 22:06, Julien Grall wrote: > On 11/06/2015 04:28, Wei Wang wrote: > > cpufreq_cpu_policy is used in intel_pstate_set_pstate(), so we change > > to NULL it after the call of cpufreq_driver->exit. Otherwise, a > > calltrace will show up on your screen due to the reference of a NULL > > pointer when you power down the system. > > > > Signed-off-by: Wei Wang <wei.w.wang@xxxxxxxxx> > > --- > > xen/drivers/cpufreq/cpufreq.c | 6 +++--- > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > diff --git a/xen/drivers/cpufreq/cpufreq.c > > b/xen/drivers/cpufreq/cpufreq.c index 6003a8c..a8772e8 100644 > > --- a/xen/drivers/cpufreq/cpufreq.c > > +++ b/xen/drivers/cpufreq/cpufreq.c > > @@ -335,12 +335,11 @@ int cpufreq_del_cpu(unsigned int cpu) > > > > /* for HW_ALL, stop gov for each core of the _PSD domain */ > > /* for SW_ALL & SW_ANY, stop gov for the 1st core of the _PSD domain > */ > > - if (hw_all || (cpumask_weight(cpufreq_dom->map) == > > - perf->domain_info.num_processors)) > > + if (!policy->policy && (hw_all || (cpumask_weight(cpufreq_dom->map) > == > > + perf->domain_info.num_processors))) > > Based on your patch #6, the field policy contains value which is defined per- > cpufreq driver (because you defined internal value). How can you be sure > that a driver will never use 0 as a valid value? Hi Julien, what do you mean by "per-cpufreq driver"? We currently have two P-state drivers. This filed is currently only used by the intel_pstate driver, and the four usable values are: #define CPUFREQ_POLICY_POWERSAVE (1) #define CPUFREQ_POLICY_PERFORMANCE (2) #define CPUFREQ_POLICY_USERSPACE (3) #define CPUFREQ_POLICY_ONDEMAND (4) The intel_pstate won't use 0 as a valid value, and the default value is CPUFREQ_POLICY_ONDEMAND. If it's 0, it basically means the old acpi-cpufreq driver is being used. Best, Wei _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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