From: Juergen Gross <jgross@suse.com>
To: Boris Ostrovsky <boris.ostrovsky@oracle.com>,
David Vrabel <david.vrabel@citrix.com>,
Julien Grall <julien.grall@arm.com>,
Anna-Maria Gleixner <anna-maria@linutronix.de>,
linux-kernel@vger.kernel.org
Cc: xen-devel@lists.xenproject.org, sstabellini@kernel.org, rt@linutronix.de
Subject: Re: [PATCH] xen: Add comment for missing FROZEN notifier transitions
Date: Tue, 5 Apr 2016 06:22:16 +0200 [thread overview]
Message-ID: <57033D78.8010306__1561.26646693355$1459830223$gmane$org@suse.com> (raw)
In-Reply-To: <57029AC7.90201@oracle.com>
On 04/04/16 18:48, Boris Ostrovsky wrote:
> 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?
I'd rather do more than a comment:
Either mask CPU_TASKS_FROZEN from action if it really doesn't matter
whether the flag is set or not (which IMHO is the case here), or
BUG_ON(action & CPU_TASKS_FROZEN) if this really should never happen.
> Wouldn't the same comment need to be added to xen_hvm_cpu_notify()?
The patch of Anna-Maria does that.
Juergen
>
>
> -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
>
>
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
next prev parent reply other threads:[~2016-04-05 4:22 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1459773140-43707-1-git-send-email-anna-maria@linutronix.de>
2016-04-04 16:21 ` [PATCH] xen: Add comment for missing FROZEN notifier transitions Julien Grall
[not found] ` <57029499.7070007@arm.com>
2016-04-04 16:30 ` David Vrabel
[not found] ` <570296C3.70805@citrix.com>
2016-04-04 16:48 ` Boris Ostrovsky
[not found] ` <57029AC7.90201@oracle.com>
2016-04-05 4:22 ` Juergen Gross [this message]
[not found] ` <57033D78.8010306@suse.com>
2016-04-06 23:52 ` Stefano Stabellini
2016-04-06 13:09 ` David Vrabel
[not found] ` <57050A98.80901@cantab.net>
2016-04-06 14:08 ` [PREEMPT-RT] " Anna-Maria Gleixner
2016-04-06 23:53 ` Stefano Stabellini
2016-04-04 12:32 Anna-Maria Gleixner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='57033D78.8010306__1561.26646693355$1459830223$gmane$org@suse.com' \
--to=jgross@suse.com \
--cc=anna-maria@linutronix.de \
--cc=boris.ostrovsky@oracle.com \
--cc=david.vrabel@citrix.com \
--cc=julien.grall@arm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=rt@linutronix.de \
--cc=sstabellini@kernel.org \
--cc=xen-devel@lists.xenproject.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).