linux-kernel - Re: [PATCH v7 17/24] x86/resctrl: Move alloc/mon static keys into helpers

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Message-ID: <4153b90c-5b1d-42f3-8647-5711809781a2@amd.com>
Date:   Thu, 9 Nov 2023 14:48:07 -0600
From:   "Moger, Babu" <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,
        D Scott Phillips OS <scott@...amperecomputing.com>,
        carl@...amperecomputing.com, lcherian@...vell.com,
        bobo.shaobowang@...wei.com, tan.shaopeng@...itsu.com,
        baolin.wang@...ux.alibaba.com, Jamie Iles <quic_jiles@...cinc.com>,
        Xin Hao <xhao@...ux.alibaba.com>, peternewman@...gle.com,
        dfustini@...libre.com, amitsinght@...vell.com
Subject: Re: [PATCH v7 17/24] x86/resctrl: Move alloc/mon static keys into
 helpers



On 10/25/23 13:03, James Morse wrote:
> resctrl enables three static keys depending on the features it has enabled.
> Another architecture's context switch code may look different, any
> static keys that control it should be buried behind helpers.
> 
> Move the alloc/mon logic into arch-specific helpers as a preparatory step
> for making the rdt_enable_key's status something the arch code decides.
> 
> This means other architectures don't have to mirror the static keys.
> 
> Tested-by: Shaopeng Tan <tan.shaopeng@...itsu.com>
> Tested-by: Peter Newman <peternewman@...gle.com>
> Reviewed-by: Shaopeng Tan <tan.shaopeng@...itsu.com>
> Reviewed-by: Reinette Chatre <reinette.chatre@...el.com>
> Signed-off-by: James Morse <james.morse@....com>

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

> ---
> No changes since v6
> 
>  arch/x86/include/asm/resctrl.h         | 20 ++++++++++++++++++++
>  arch/x86/kernel/cpu/resctrl/internal.h |  5 -----
>  arch/x86/kernel/cpu/resctrl/rdtgroup.c |  8 ++++----
>  3 files changed, 24 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/x86/include/asm/resctrl.h b/arch/x86/include/asm/resctrl.h
> index 29c4cc343787..3c9137b6ad4f 100644
> --- a/arch/x86/include/asm/resctrl.h
> +++ b/arch/x86/include/asm/resctrl.h
> @@ -42,6 +42,26 @@ DECLARE_STATIC_KEY_FALSE(rdt_enable_key);
>  DECLARE_STATIC_KEY_FALSE(rdt_alloc_enable_key);
>  DECLARE_STATIC_KEY_FALSE(rdt_mon_enable_key);
>  
> +static inline void resctrl_arch_enable_alloc(void)
> +{
> +	static_branch_enable_cpuslocked(&rdt_alloc_enable_key);
> +}
> +
> +static inline void resctrl_arch_disable_alloc(void)
> +{
> +	static_branch_disable_cpuslocked(&rdt_alloc_enable_key);
> +}
> +
> +static inline void resctrl_arch_enable_mon(void)
> +{
> +	static_branch_enable_cpuslocked(&rdt_mon_enable_key);
> +}
> +
> +static inline void resctrl_arch_disable_mon(void)
> +{
> +	static_branch_disable_cpuslocked(&rdt_mon_enable_key);
> +}
> +
>  /*
>   * __resctrl_sched_in() - Writes the task's CLOSid/RMID to IA32_PQR_MSR
>   *
> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
> index 5ce49503fcd8..68b9beed8e42 100644
> --- a/arch/x86/kernel/cpu/resctrl/internal.h
> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
> @@ -95,9 +95,6 @@ static inline struct rdt_fs_context *rdt_fc2context(struct fs_context *fc)
>  	return container_of(kfc, struct rdt_fs_context, kfc);
>  }
>  
> -DECLARE_STATIC_KEY_FALSE(rdt_enable_key);
> -DECLARE_STATIC_KEY_FALSE(rdt_mon_enable_key);
> -
>  /**
>   * struct mon_evt - Entry in the event list of a resource
>   * @evtid:		event id
> @@ -454,8 +451,6 @@ extern struct mutex rdtgroup_mutex;
>  
>  extern struct rdt_hw_resource rdt_resources_all[];
>  extern struct rdtgroup rdtgroup_default;
> -DECLARE_STATIC_KEY_FALSE(rdt_alloc_enable_key);
> -
>  extern struct dentry *debugfs_resctrl;
>  
>  enum resctrl_res_level {
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index 9ce1f981c8e1..48418857b685 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -2673,9 +2673,9 @@ static int rdt_get_tree(struct fs_context *fc)
>  		goto out_psl;
>  
>  	if (rdt_alloc_capable)
> -		static_branch_enable_cpuslocked(&rdt_alloc_enable_key);
> +		resctrl_arch_enable_alloc();
>  	if (rdt_mon_capable)
> -		static_branch_enable_cpuslocked(&rdt_mon_enable_key);
> +		resctrl_arch_enable_mon();
>  
>  	if (rdt_alloc_capable || rdt_mon_capable) {
>  		static_branch_enable_cpuslocked(&rdt_enable_key);
> @@ -2951,8 +2951,8 @@ static void rdt_kill_sb(struct super_block *sb)
>  	rdtgroup_default.mode = RDT_MODE_SHAREABLE;
>  	schemata_list_destroy();
>  	rdtgroup_destroy_root();
> -	static_branch_disable_cpuslocked(&rdt_alloc_enable_key);
> -	static_branch_disable_cpuslocked(&rdt_mon_enable_key);
> +	resctrl_arch_disable_alloc();
> +	resctrl_arch_disable_mon();
>  	static_branch_disable_cpuslocked(&rdt_enable_key);
>  	resctrl_mounted = false;
>  	kernfs_kill_sb(sb);

-- 
Thanks
Babu Moger