RE: [PATCH v2 10/10] cacheinfo: Move resctrl's get_cache_id() to the cacheinfo header file

[Babu Moger <babu.moger@amd.com>]

> -----Original Message-----
> From: James Morse <james.morse@arm.com>
> Sent: Thursday, April 30, 2020 12:04 PM
> To: x86@kernel.org; linux-kernel@vger.kernel.org
> Cc: Fenghua Yu <fenghua.yu@intel.com>; Reinette Chatre
> <reinette.chatre@intel.com>; Thomas Gleixner <tglx@linutronix.de>; Ingo
> Molnar <mingo@redhat.com>; Borislav Petkov <bp@alien8.de>; H Peter Anvin
> <hpa@zytor.com>; Moger, Babu <Babu.Moger@amd.com>; James Morse
> <james.morse@arm.com>
> Subject: [PATCH v2 10/10] cacheinfo: Move resctrl's get_cache_id() to the
> cacheinfo header file
> 
> resctrl/core.c defines get_cache_id() for use in its cpu-hotplug
> callbacks. This gets the id attribute of the cache at the corresponding
> level of a cpu.
> 
> Later rework means this private function needs to be shared. Move
> it to the header file.
> 
> The name conflicts with a different definition in intel_cacheinfo.c,
> name it get_cpu_cacheinfo_id() to show its relation with
> get_cpu_cacheinfo().
> 
> Now this is visible on other architectures, check the id attribute
> has actually been set.
> 
> Signed-off-by: James Morse <james.morse@arm.com>

Reviewed-by: Babu Moger <babu.moger@amd.com>

> ---
>  arch/x86/kernel/cpu/resctrl/core.c | 17 ++---------------
>  include/linux/cacheinfo.h          | 21 +++++++++++++++++++++
>  2 files changed, 23 insertions(+), 15 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/resctrl/core.c
> b/arch/x86/kernel/cpu/resctrl/core.c
> index 00c88f42742c..f6458cefcac3 100644
> --- a/arch/x86/kernel/cpu/resctrl/core.c
> +++ b/arch/x86/kernel/cpu/resctrl/core.c
> @@ -350,19 +350,6 @@ static void rdt_get_cdp_l2_config(void)
>  	rdt_get_cdp_config(RDT_RESOURCE_L2, RDT_RESOURCE_L2CODE);
>  }
> 
> -static int get_cache_id(int cpu, int level)
> -{
> -	struct cpu_cacheinfo *ci = get_cpu_cacheinfo(cpu);
> -	int i;
> -
> -	for (i = 0; i < ci->num_leaves; i++) {
> -		if (ci->info_list[i].level == level)
> -			return ci->info_list[i].id;
> -	}
> -
> -	return -1;
> -}
> -
>  static void
>  mba_wrmsr_amd(struct rdt_domain *d, struct msr_param *m, struct
> rdt_resource *r)
>  {
> @@ -560,7 +547,7 @@ static int domain_setup_mon_state(struct rdt_resource
> *r, struct rdt_domain *d)
>   */
>  static void domain_add_cpu(int cpu, struct rdt_resource *r)
>  {
> -	int id = get_cache_id(cpu, r->cache_level);
> +	int id = get_cpu_cacheinfo_id(cpu, r->cache_level);
>  	struct list_head *add_pos = NULL;
>  	struct rdt_domain *d;
> 
> @@ -606,7 +593,7 @@ static void domain_add_cpu(int cpu, struct rdt_resource
> *r)
> 
>  static void domain_remove_cpu(int cpu, struct rdt_resource *r)
>  {
> -	int id = get_cache_id(cpu, r->cache_level);
> +	int id = get_cpu_cacheinfo_id(cpu, r->cache_level);
>  	struct rdt_domain *d;
> 
>  	d = rdt_find_domain(r, id, NULL);
> diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h
> index 46b92cd61d0c..4f72b47973c3 100644
> --- a/include/linux/cacheinfo.h
> +++ b/include/linux/cacheinfo.h
> @@ -3,6 +3,7 @@
>  #define _LINUX_CACHEINFO_H
> 
>  #include <linux/bitops.h>
> +#include <linux/cpu.h>
>  #include <linux/cpumask.h>
>  #include <linux/smp.h>
> 
> @@ -119,4 +120,24 @@ int acpi_find_last_cache_level(unsigned int cpu);
> 
>  const struct attribute_group *cache_get_priv_group(struct cacheinfo
> *this_leaf);
> 
> +/*
> + * Get the id of the cache associated with @cpu at level @level.
> + * cpuhp lock must be held.
> + */
> +static inline int get_cpu_cacheinfo_id(int cpu, int level)
> +{
> +	struct cpu_cacheinfo *ci = get_cpu_cacheinfo(cpu);
> +	int i;
> +
> +	for (i = 0; i < ci->num_leaves; i++) {
> +		if (ci->info_list[i].level == level) {
> +			if (ci->info_list[i].attributes & CACHE_ID)
> +				return ci->info_list[i].id;
> +			return -1;
> +		}
> +	}
> +
> +	return -1;
> +}
> +
>  #endif /* _LINUX_CACHEINFO_H */
> --
> 2.26.1