linux-kernel - Re: [PATCH] Hyper-V: fix for unwanted manipulation of sched

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Message-ID: <20210713173256.f4guohutujyvfste@liuwe-devbox-debian-v2>
Date:   Tue, 13 Jul 2021 17:32:56 +0000
From:   Wei Liu <wei.liu@...nel.org>
To:     Michael Kelley <mikelley@...rosoft.com>
Cc:     Ani Sinha <ani@...sinha.ca>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "anirban.sinha@...ia.com" <anirban.sinha@...ia.com>,
        KY Srinivasan <kys@...rosoft.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        Stephen Hemminger <sthemmin@...rosoft.com>,
        Wei Liu <wei.liu@...nel.org>, Dexuan Cui <decui@...rosoft.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "x86@...nel.org" <x86@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        "linux-hyperv@...r.kernel.org" <linux-hyperv@...r.kernel.org>
Subject: Re: [PATCH] Hyper-V: fix for unwanted manipulation of sched_clock
 when TSC marked unstable

On Tue, Jul 13, 2021 at 05:25:59PM +0000, Michael Kelley wrote:
> From: Ani Sinha <ani@...sinha.ca> Sent: Monday, July 12, 2021 8:05 PM
[...]
> >  	/*
> > @@ -432,6 +430,12 @@ static void __init ms_hyperv_init_platform(void)
> >  	/* Register Hyper-V specific clocksource */
> >  	hv_init_clocksource();
> >  #endif
> > +	/* TSC should be marked as unstable only after Hyper-V
> > +	 * clocksource has been initialized. This ensures that the
> > +	 * stability of the sched_clock is not altered.
> > +	 */
> 
> For multi-line comments like the above, the first comment line
> should just be "/*".  So:
> 
> 	/* 
> 	 * TSC should be marked as unstable only after Hyper-V
> 	 * clocksource has been initialized. This ensures that the
> 	 * stability of the sched_clock is not altered.
> 	 */
> 
> 
> > +	if (!(ms_hyperv.features & HV_ACCESS_TSC_INVARIANT))
> > +		mark_tsc_unstable("running on Hyper-V");
> >  }
> > 
> >  static bool __init ms_hyperv_x2apic_available(void)
> > --
> > 2.25.1
> 
> Modulo the comment format,
> 

I can fix this while committing. No need to resend.

> Reviewed-by: Michael Kelley <mikelley@...rosoft.com>
> Tested-by: Michael Kelley <mikelley@...rosoft.com> 

Thanks Michael.

Wei.