linux-kernel - Re: [PATCH v7 20/24] x86/resctrl: Add CPU online callback for resctrl work

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Message-ID: <a8725d37-e3f5-4fd4-a426-b03b143a3b26@amd.com>
Date:   Thu, 9 Nov 2023 14:51:46 -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 20/24] x86/resctrl: Add CPU online callback for resctrl
 work



On 10/25/23 13:03, James Morse wrote:
> The resctrl architecture specific code may need to create a domain when
> a CPU comes online, it also needs to reset the CPUs PQR_ASSOC register.
> The resctrl filesystem code needs to update the rdtgroup_default CPU
> mask when CPUs are brought online.
> 
> Currently this is all done in one function, resctrl_online_cpu().
> This will need to be split into architecture and filesystem parts
> before resctrl can be moved to /fs/.
> 
> Pull the rdtgroup_default update work out as a filesystem specific
> cpu_online helper. resctrl_online_cpu() is the obvious name for this,
> which means the version in core.c needs renaming.
> 
> resctrl_online_cpu() is called by the arch code once it has done the
> work to add the new CPU to any domains.
> 
> In future patches, resctrl_online_cpu() will take the rdtgroup_mutex
> itself.
> 
> 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>

> ---
> Changes since v3:
>  * Renamed err to ret
> 
> Changes since v4:
>  * Changes in capitalisation.
> 
> Changes since v5:
>  * More changes in capitalisation.
>  * Made resctrl_online_cpu() return void.
> 
> No changes since v6
> ---
>  arch/x86/kernel/cpu/resctrl/core.c     | 8 ++++----
>  arch/x86/kernel/cpu/resctrl/rdtgroup.c | 8 ++++++++
>  include/linux/resctrl.h                | 1 +
>  3 files changed, 13 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
> index fc70a2650729..1a74e9c47416 100644
> --- a/arch/x86/kernel/cpu/resctrl/core.c
> +++ b/arch/x86/kernel/cpu/resctrl/core.c
> @@ -608,16 +608,16 @@ static void clear_closid_rmid(int cpu)
>  	      RESCTRL_RESERVED_CLOSID);
>  }
>  
> -static int resctrl_online_cpu(unsigned int cpu)
> +static int resctrl_arch_online_cpu(unsigned int cpu)
>  {
>  	struct rdt_resource *r;
>  
>  	mutex_lock(&rdtgroup_mutex);
>  	for_each_capable_rdt_resource(r)
>  		domain_add_cpu(cpu, r);
> -	/* The cpu is set in default rdtgroup after online. */
> -	cpumask_set_cpu(cpu, &rdtgroup_default.cpu_mask);
>  	clear_closid_rmid(cpu);
> +
> +	resctrl_online_cpu(cpu);
>  	mutex_unlock(&rdtgroup_mutex);
>  
>  	return 0;
> @@ -969,7 +969,7 @@ static int __init resctrl_late_init(void)
>  
>  	state = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
>  				  "x86/resctrl/cat:online:",
> -				  resctrl_online_cpu, resctrl_offline_cpu);
> +				  resctrl_arch_online_cpu, resctrl_offline_cpu);
>  	if (state < 0)
>  		return state;
>  
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index bd4d1c8a9b4f..ab9db7ce706f 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -4012,6 +4012,14 @@ int resctrl_online_domain(struct rdt_resource *r, struct rdt_domain *d)
>  	return 0;
>  }
>  
> +void resctrl_online_cpu(unsigned int cpu)
> +{
> +	lockdep_assert_held(&rdtgroup_mutex);
> +
> +	/* The CPU is set in default rdtgroup after online. */
> +	cpumask_set_cpu(cpu, &rdtgroup_default.cpu_mask);
> +}
> +
>  /*
>   * rdtgroup_init - rdtgroup initialization
>   *
> diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
> index bf460c912bf5..4c4bad3c34e4 100644
> --- a/include/linux/resctrl.h
> +++ b/include/linux/resctrl.h
> @@ -223,6 +223,7 @@ u32 resctrl_arch_get_config(struct rdt_resource *r, struct rdt_domain *d,
>  			    u32 closid, enum resctrl_conf_type type);
>  int resctrl_online_domain(struct rdt_resource *r, struct rdt_domain *d);
>  void resctrl_offline_domain(struct rdt_resource *r, struct rdt_domain *d);
> +void resctrl_online_cpu(unsigned int cpu);
>  
>  /**
>   * resctrl_arch_rmid_read() - Read the eventid counter corresponding to rmid

-- 
Thanks
Babu Moger