linux-kernel - Re: [Xen-devel] [PATCH] xen: Add comment for missing FROZEN notifier transitions

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Message-ID: <57029AC7.90201@oracle.com>
Date:	Mon, 4 Apr 2016 12:48:07 -0400
From:	Boris Ostrovsky <boris.ostrovsky@...cle.com>
To:	David Vrabel <david.vrabel@...rix.com>,
	Julien Grall <julien.grall@....com>,
	Anna-Maria Gleixner <anna-maria@...utronix.de>,
	linux-kernel@...r.kernel.org
Cc:	xen-devel@...ts.xenproject.org, sstabellini@...nel.org,
	rt@...utronix.de, Juergen Gross <JGross@...e.com>
Subject: Re: [Xen-devel] [PATCH] xen: Add comment for missing FROZEN notifier
 transitions

On 04/04/2016 12:30 PM, David Vrabel wrote:
> On 04/04/16 17:21, Julien Grall wrote:
>> (CC Stefano new e-mail address)
>>
>> Hello Anna-Maria,
>>
>> On 04/04/2016 13:32, Anna-Maria Gleixner wrote:
>>> Xen guests do not offline/online CPUs during suspend/resume and
>>> therefore FROZEN notifier transitions are not required. Add this
>>> explanation as a comment in the code to get not confused why
>>> CPU_TASKS_FROZEN masked transitions are not considered.
> Alternatively, these could be added even if they are not encountered.
> This might be more future-proof but the documentation might be clearer.
>
> Boris, Juergen, any opinion?

Wouldn't the same comment need to be added to xen_hvm_cpu_notify()?


-boris


>
> David>> --- a/drivers/xen/events/events_fifo.c
>>> +++ b/drivers/xen/events/events_fifo.c
>>> @@ -425,6 +425,12 @@ static int evtchn_fifo_cpu_notification(
>>>        int cpu = (long)hcpu;
>>>        int ret = 0;
>>>
>>> +    /*
>>> +     * Xen guests do not offline/online CPUs during
>>> +     * suspend/resume, thus CPU_TASKS_FROZEN masked transitions
>>> +     * are not considered.
>>> +    */
>> NIT: The '*' is not aligned with the others.
> If this doesn't need any other changes, I'll fix this on commit.
>
> David