linux-kernel - Re: [PATCH v7 21/24] x86/resctrl: Allow overflow/limbo handlers to be scheduled on any-but cpu

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Date:   Thu, 14 Dec 2023 11:38:28 +0000
From:   James Morse <james.morse@....com>
To:     babu.moger@....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 21/24] x86/resctrl: Allow overflow/limbo handlers to be
 scheduled on any-but cpu

Hi Babu,

On 09/11/2023 20:51, Moger, Babu wrote:
> On 10/25/23 13:03, James Morse wrote:
>> When a CPU is taken offline resctrl may need to move the overflow or
>> limbo handlers to run on a different CPU.
>>
>> Once the offline callbacks have been split, cqm_setup_limbo_handler()
>> will be called while the CPU that is going offline is still present
>> in the cpu_mask.
>>
>> Pass the CPU to exclude to cqm_setup_limbo_handler() and
>> mbm_setup_overflow_handler(). These functions can use a variant of
>> cpumask_any_but() when selecting the CPU. -1 is used to indicate no CPUs
>> need excluding.
>>
>> A subsequent patch moves these calls to be before CPUs have been removed,
>> so this exclude_cpus behaviour is temporary.

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

Thanks!


James