RE: [PATCH v9 12/13] x86/resctrl: Replace smp_call_function_many() with on_each_cpu_mask()

[Moger, Babu]

[AMD Official Use Only - General]

Hi Reinette,

> -----Original Message-----
> From: Reinette Chatre <reinette.chatre@xxxxxxxxx>
> Sent: Thursday, December 15, 2022 12:27 PM
> To: Moger, Babu <Babu.Moger@xxxxxxx>; corbet@xxxxxxx;
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> Subject: Re: [PATCH v9 12/13] x86/resctrl: Replace smp_call_function_many()
> with on_each_cpu_mask()
> 
> Hi Babu,
> 
> On 12/1/2022 7:37 AM, Babu Moger wrote:
> > The call on_each_cpu_mask() runs the function on each CPU specified by
> > cpumask, which may include the local processor. So, replace the call
> > smp_call_function_many() with on_each_cpu_mask() to simplify the code.
> 
> Please move the solution to a new paragraph and drop the "So,". The two
> instances of "the call" can be dropped also.

Sure.
> 
> >
> > Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
> > ---
> 
> Could you please move this patch to the beginning of this series?
> Fixes and cleanups should go before new features.

Sure.

> 
> >  arch/x86/kernel/cpu/resctrl/rdtgroup.c |   29 ++++++++---------------------
> >  1 file changed, 8 insertions(+), 21 deletions(-)
> >
> > diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> > b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> > index 6897c480ae55..68e14831a638 100644
> > --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> > +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> > @@ -325,12 +325,7 @@ static void update_cpu_closid_rmid(void *info)
> > static void  update_closid_rmid(const struct cpumask *cpu_mask, struct
> > rdtgroup *r)  {
> > -	int cpu = get_cpu();
> > -
> > -	if (cpumask_test_cpu(cpu, cpu_mask))
> > -		update_cpu_closid_rmid(r);
> > -	smp_call_function_many(cpu_mask, update_cpu_closid_rmid, r, 1);
> > -	put_cpu();
> > +	on_each_cpu_mask(cpu_mask, update_cpu_closid_rmid, r, 1);
> >  }
> >
> >  static int cpus_mon_write(struct rdtgroup *rdtgrp, cpumask_var_t
> > newmask, @@ -2135,13 +2130,9 @@ static int set_cache_qos_cfg(int level,
> bool enable)
> >  			/* Pick one CPU from each domain instance to update
> MSR */
> >  			cpumask_set_cpu(cpumask_any(&d->cpu_mask),
> cpu_mask);
> >  	}
> > -	cpu = get_cpu();
> > -	/* Update QOS_CFG MSR on this cpu if it's in cpu_mask. */
> > -	if (cpumask_test_cpu(cpu, cpu_mask))
> > -		update(&enable);
> > -	/* Update QOS_CFG MSR on all other cpus in cpu_mask. */
> > -	smp_call_function_many(cpu_mask, update, &enable, 1);
> > -	put_cpu();
> > +
> > +	/* Update QOS_CFG MSR on all the CPUs in cpu_mask */
> > +	on_each_cpu_mask(cpu_mask, update, &enable, 1);
> >
> >  	free_cpumask_var(cpu_mask);
> >
> > @@ -2618,7 +2609,7 @@ static int reset_all_ctrls(struct rdt_resource *r)
> >  	struct msr_param msr_param;
> >  	cpumask_var_t cpu_mask;
> >  	struct rdt_domain *d;
> > -	int i, cpu;
> > +	int i;
> >
> >  	if (!zalloc_cpumask_var(&cpu_mask, GFP_KERNEL))
> >  		return -ENOMEM;
> > @@ -2639,13 +2630,9 @@ static int reset_all_ctrls(struct rdt_resource *r)
> >  		for (i = 0; i < hw_res->num_closid; i++)
> >  			hw_dom->ctrl_val[i] = r->default_ctrl;
> >  	}
> > -	cpu = get_cpu();
> > -	/* Update CBM on this cpu if it's in cpu_mask. */
> > -	if (cpumask_test_cpu(cpu, cpu_mask))
> > -		rdt_ctrl_update(&msr_param);
> > -	/* Update CBM on all other cpus in cpu_mask. */
> > -	smp_call_function_many(cpu_mask, rdt_ctrl_update, &msr_param, 1);
> > -	put_cpu();
> > +
> > +	/* Update CBM on all the CPUs in cpu_mask */
> > +	on_each_cpu_mask(cpu_mask, rdt_ctrl_update, &msr_param, 1);
> >
> >  	free_cpumask_var(cpu_mask);
> >
> >
> >
> 
> Should the snippet in resctrl_arch_update_domains() also be updated?

Yes. It should be changed also.  Will fix it.
Thanks
Babu
> 
> Reinette