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Message-ID: <50a87b32-282e-e4d5-8fb4-a4a99d1b0ed5@intel.com>
Date:   Wed, 5 Apr 2023 16:48:37 -0700
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Subject: Re: [PATCH v3 18/19] x86/resctrl: Add cpu offline callback for
 resctrl work
Content-Language: en-US
To:     James Morse <james.morse@arm.com>, <x86@kernel.org>,
        <linux-kernel@vger.kernel.org>
CC:     Fenghua Yu <fenghua.yu@intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        H Peter Anvin <hpa@zytor.com>,
        Babu Moger <Babu.Moger@amd.com>,
        <shameerali.kolothum.thodi@huawei.com>,
        D Scott Phillips OS <scott@os.amperecomputing.com>,
        <carl@os.amperecomputing.com>, <lcherian@marvell.com>,
        <bobo.shaobowang@huawei.com>, <tan.shaopeng@fujitsu.com>,
        <xingxin.hx@openanolis.org>, <baolin.wang@linux.alibaba.com>,
        Jamie Iles <quic_jiles@quicinc.com>,
        Xin Hao <xhao@linux.alibaba.com>, <peternewman@google.com>
References: <20230320172620.18254-1-james.morse@arm.com>
 <20230320172620.18254-19-james.morse@arm.com>
From:   Reinette Chatre <reinette.chatre@intel.com>
In-Reply-To: <20230320172620.18254-19-james.morse@arm.com>
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Hi James,

On 3/20/2023 10:26 AM, James Morse wrote:

> -static int resctrl_offline_cpu(unsigned int cpu)
> -{
> -	struct rdtgroup *rdtgrp;
>  	struct rdt_resource *r;
>  
>  	mutex_lock(&rdtgroup_mutex);
> +	resctrl_offline_cpu(cpu);
> +
>  	for_each_capable_rdt_resource(r)
>  		domain_remove_cpu(cpu, r);
> -	list_for_each_entry(rdtgrp, &rdt_all_groups, rdtgroup_list) {
> -		if (cpumask_test_and_clear_cpu(cpu, &rdtgrp->cpu_mask)) {
> -			clear_childcpus(rdtgrp, cpu);
> -			break;
> -		}
> -	}
>  	clear_closid_rmid(cpu);
>  	mutex_unlock(&rdtgroup_mutex);
>  

I find this and the previous patch to be very complicated. It is not clear
to me why resctrl_offline_cpu(cpu) is required to be before offline of domain.
Previous patch would not be needed if the existing order of operations
is maintained.

Reinette