linux-kernel - Re: [PATCH v2 3/3] intel_pstate: Declare pid_params/pstate_funcs/hwp_active __read

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Date:	Tue, 28 Jun 2016 10:29:27 +0800
From:	Jisheng Zhang <jszhang@...vell.com>
To:	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
	<lenb@...nel.org>, <rjw@...ysocki.net>, <viresh.kumar@...aro.org>
CC:	<linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 3/3] intel_pstate: Declare
 pid_params/pstate_funcs/hwp_active __read_mostly

Dear Rafael,

On Mon, 27 Jun 2016 10:29:54 -0700
Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com> wrote:

> On Mon, 2016-06-27 at 18:07 +0800, Jisheng Zhang wrote:
> > pid_params is written once by copy_pid_params() during
> > initialization,
> > and thereafter is mostly read by hot path intel_pstate_update_util().
> > The read of pid_params gets more after commit a4675fbc4a7a ("cpufreq:
> > intel_pstate: Replace timers with utilization update callbacks")
> > 
> > pstate_funcs is written once by copy_cpu_funcs() during
> > initialization,
> > and thereafter is mostly read by hot path intel_pstate_update_util()
> > 
> > hwp_active is written to once during initialization and thereafter is
> > mostly read by hot path intel_pstate_update_util().
> > 
> > The fact that they are mostly read and not written to makes them
> > candidates for __read_mostly declarations.
> > 
> > Signed-off-by: Jisheng Zhang <jszhang@...vell.com>  
> Acked-by: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>

oops, I missed Viresh's Ack in this patch, so can you please add the missing

Acked-by: Viresh Kumar <viresh.kumar@...aro.org>

Sorry for inconvenience,
Jisheng

> > ---
> >  drivers/cpufreq/intel_pstate.c | 6 +++---
> >  1 file changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/cpufreq/intel_pstate.c
> > b/drivers/cpufreq/intel_pstate.c
> > index 861bcba..2eda50d 100644
> > --- a/drivers/cpufreq/intel_pstate.c
> > +++ b/drivers/cpufreq/intel_pstate.c
> > @@ -281,9 +281,9 @@ struct cpu_defaults {
> >  static inline int32_t get_target_pstate_use_performance(struct
> > cpudata *cpu);
> >  static inline int32_t get_target_pstate_use_cpu_load(struct cpudata
> > *cpu);
> >  
> > -static struct pstate_adjust_policy pid_params;
> > -static struct pstate_funcs pstate_funcs;
> > -static int hwp_active;
> > +static struct pstate_adjust_policy pid_params __read_mostly;
> > +static struct pstate_funcs pstate_funcs __read_mostly;
> > +static int hwp_active __read_mostly;
> >  
> >  #ifdef CONFIG_ACPI
> >  static bool acpi_ppc;