linux-kernel - Re: [PATCH] x86/mce/therm_throt: Handle case where throttle_active_work() is called on behalf of an offline CPU

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Message-ID: <20200224125525.GA29318@zn.tnic>
Date:   Mon, 24 Feb 2020 13:55:25 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Cc:     tony.luck@...el.com, tglx@...utronix.de, mingo@...hat.com,
        hpa@...or.com, x86@...nel.org, linux-edac@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Chris Wilson <chris@...is-wilson.co.uk>
Subject: Re: [PATCH] x86/mce/therm_throt: Handle case where
 throttle_active_work() is called on behalf of an offline CPU

On Sat, Feb 22, 2020 at 04:25:59PM -0800, Srinivas Pandruvada wrote:
> If the condition is false, will it prevent offline CPU before executing
> next statement and reschedule on another CPU? Although It will not
> cause any error or crash but in rare circumstance may print premature
> warning/normal message based on the current CPU's state.

Why, offline CPU is offline CPU?

Btw, I'm asking whether you can do the simpler thing *instead* of your
patch. You basically don't run the workqueue callback on offlined CPUs:

	get_online_cpus();

	if (cpu_is_offline(smp_processor_id()))
		goto out;

	...


out:
	put_online_cpus();

Hmm?

-- 
Regards/Gruss,
    Boris.

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