linux-kernel - Re: [PATCH v2 04/23] x86/resctrl: Merge mon_capable and mon

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Date:   Tue, 19 Oct 2021 18:18:08 -0500
From:   Babu Moger <babu.moger@....com>
To:     James Morse <james.morse@....com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Cc:     Fenghua Yu <fenghua.yu@...el.com>,
        Reinette Chatre <reinette.chatre@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        H Peter Anvin <hpa@...or.com>,
        shameerali.kolothum.thodi@...wei.com,
        Jamie Iles <jamie@...iainc.com>,
        D Scott Phillips OS <scott@...amperecomputing.com>,
        lcherian@...vell.com, bobo.shaobowang@...wei.com,
        tan.shaopeng@...itsu.com
Subject: Re: [PATCH v2 04/23] x86/resctrl: Merge mon_capable and mon_enabled

Hi James,

On 10/1/21 11:02 AM, James Morse wrote:
> mon_enabled and mon_capable are always set as a pair by
> rdt_get_mon_l3_config().
> 
> There is no point having two values.
> 
> Merge them together.
> 
> Signed-off-by: James Morse <james.morse@....com>
> ---
> Changes since v1:
>  * Removed stray cdp_capable changes.
> ---
>  arch/x86/kernel/cpu/resctrl/internal.h | 4 ----
>  arch/x86/kernel/cpu/resctrl/monitor.c  | 1 -
>  arch/x86/kernel/cpu/resctrl/rdtgroup.c | 8 ++++----
>  include/linux/resctrl.h                | 2 --
>  4 files changed, 4 insertions(+), 11 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
> index 53f3d275a98f..8828b5c1b6d2 100644
> --- a/arch/x86/kernel/cpu/resctrl/internal.h
> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
> @@ -459,10 +459,6 @@ int resctrl_arch_set_cdp_enabled(enum resctrl_res_level l, bool enable);
>  	for_each_rdt_resource(r)					      \
>  		if (r->mon_capable)
>  
> -#define for_each_mon_enabled_rdt_resource(r)				      \
> -	for_each_rdt_resource(r)					      \
> -		if (r->mon_enabled)
> -
>  /* CPUID.(EAX=10H, ECX=ResID=1).EAX */
>  union cpuid_0x10_1_eax {
>  	struct {
> diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
> index c9f0f3d63f75..37af1790337f 100644
> --- a/arch/x86/kernel/cpu/resctrl/monitor.c
> +++ b/arch/x86/kernel/cpu/resctrl/monitor.c
> @@ -717,7 +717,6 @@ int rdt_get_mon_l3_config(struct rdt_resource *r)
>  	l3_mon_evt_init(r);
>  
>  	r->mon_capable = true;
> -	r->mon_enabled = true;
>  
>  	return 0;
>  }
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index e327f8d1c8a3..e243c7d15b81 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -1765,7 +1765,7 @@ static int rdtgroup_create_info_dir(struct kernfs_node *parent_kn)
>  			goto out_destroy;
>  	}
>  
> -	for_each_mon_enabled_rdt_resource(r) {
> +	for_each_mon_capable_rdt_resource(r) {
>  		fflags =  r->fflags | RF_MON_INFO;
>  		sprintf(name, "%s_MON", r->name);
>  		ret = rdtgroup_mkdir_info_resdir(r, name, fflags);
> @@ -2504,7 +2504,7 @@ void rmdir_mondata_subdir_allrdtgrp(struct rdt_resource *r, unsigned int dom_id)
>  	struct rdtgroup *prgrp, *crgrp;
>  	char name[32];
>  
> -	if (!r->mon_enabled)
> +	if (!r->mon_capable)
>  		return;
>  
>  	list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) {
> @@ -2572,7 +2572,7 @@ void mkdir_mondata_subdir_allrdtgrp(struct rdt_resource *r,
>  	struct rdtgroup *prgrp, *crgrp;
>  	struct list_head *head;
>  
> -	if (!r->mon_enabled)
> +	if (!r->mon_capable)
>  		return;
>  
>  	list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) {
> @@ -2642,7 +2642,7 @@ static int mkdir_mondata_all(struct kernfs_node *parent_kn,
>  	 * Create the subdirectories for each domain. Note that all events
>  	 * in a domain like L3 are grouped into a resource whose domain is L3
>  	 */
> -	for_each_mon_enabled_rdt_resource(r) {
> +	for_each_mon_capable_rdt_resource(r) {
>  		ret = mkdir_mondata_subdir_alldom(kn, r, prgrp);
>  		if (ret)
>  			goto out_destroy;
> diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
> index 386ab3a41500..8180c539800d 100644
> --- a/include/linux/resctrl.h
> +++ b/include/linux/resctrl.h
> @@ -130,7 +130,6 @@ struct resctrl_schema;
>  /**
>   * struct rdt_resource - attributes of a resctrl resource
>   * @rid:		The index of the resource
> - * @mon_enabled:	Is monitoring enabled for this feature
>   * @alloc_capable:	Is allocation available on this machine
>   * @mon_capable:	Is monitor feature available on this machine
>   * @num_rmid:		Number of RMIDs available
> @@ -149,7 +148,6 @@ struct resctrl_schema;
>   */
>  struct rdt_resource {
>  	int			rid;
> -	bool			mon_enabled;
>  	bool			alloc_capable;
>  	bool			mon_capable;

Also we should probably rename alloc_capable and mon_capable to
alloc_supported and mon_supported respectively. We dont have an option to
enable and disable these feature. If it is supported, it is always supported.

Thanks
Babu