From: "Jan Beulich" <JBeulich@suse.com>
To: David Vrabel <david.vrabel@citrix.com>
Cc: xen-devel@lists.xenproject.org, Keir Fraser <keir@xen.org>,
Ian Campbell <ian.campbell@citrix.com>, Tim Deegan <tim@xen.org>
Subject: Re: [PATCHv3 2/6] evtchn: defer freeing struct evtchn's until evtchn_destroy_final()
Date: Fri, 19 Jun 2015 10:29:19 +0100 [thread overview]
Message-ID: <5583FD0F0200007800086EF1@mail.emea.novell.com> (raw)
In-Reply-To: <5582A02A.9050803@citrix.com>
>>> On 18.06.15 at 12:40, <david.vrabel@citrix.com> wrote:
> On 18/06/15 11:36, Jan Beulich wrote:
>>>>> On 17.06.15 at 14:02, <david.vrabel@citrix.com> wrote:
>>> --- a/xen/common/event_channel.c
>>> +++ b/xen/common/event_channel.c
>>> @@ -1175,22 +1175,6 @@ int alloc_unbound_xen_event_channel(
>>>
>>> void free_xen_event_channel(struct domain *d, int port)
>>> {
>>> - struct evtchn *chn;
>>> -
>>> - spin_lock(&d->event_lock);
>>> -
>>> - if ( unlikely(d->is_dying) )
>>> - {
>>> - spin_unlock(&d->event_lock);
>>> - return;
>>> - }
>>> -
>>> - BUG_ON(!port_is_valid(d, port));
>
> I can keep this one.
>
>>> - chn = evtchn_from_port(d, port);
>>> - BUG_ON(!consumer_is_xen(chn));
>>
>> At least in debug builds I think these would better be retained.
>
> But this one has to go because it will always trip when
> free_xen_event_channel() is called after evtchn_destroy() (which will
> have cleared xen_consumer).
Then why not
BUG_ON(!consumer_is_xen(chn) && !d->is_dying);
or keep the d->is_dying check in place? I can see why accelerating
notify_via_xen_event_channel() is useful, but
free_xen_event_channel()?
Jan
next prev parent reply other threads:[~2015-06-19 9:29 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-17 12:02 [PATCHv3 0/6] evtchn: Improve scalebility David Vrabel
2015-06-17 12:02 ` [PATCHv3 1/6] evtchn: clear xen_consumer when clearing state David Vrabel
2015-06-18 10:30 ` Jan Beulich
2015-06-17 12:02 ` [PATCHv3 2/6] evtchn: defer freeing struct evtchn's until evtchn_destroy_final() David Vrabel
2015-06-18 10:36 ` Jan Beulich
2015-06-18 10:40 ` David Vrabel
2015-06-18 11:01 ` Jan Beulich
2015-06-19 9:29 ` Jan Beulich [this message]
2015-06-19 9:52 ` David Vrabel
2015-06-19 10:55 ` Jan Beulich
2015-06-19 12:23 ` David Vrabel
2015-06-19 13:04 ` Jan Beulich
2015-06-19 16:58 ` David Vrabel
2015-06-17 12:03 ` [PATCHv3 3/6] evtchn: simplify port_is_valid() David Vrabel
2015-06-17 12:03 ` [PATCHv3 4/6] evtchn: use a per-event channel lock for sending events David Vrabel
2015-06-18 11:20 ` Jan Beulich
2015-06-18 11:39 ` David Vrabel
2015-06-17 12:03 ` [PATCHv3 5/6] evtchn: remove the locking when unmasking an event channel David Vrabel
2015-06-18 11:30 ` Jan Beulich
2015-06-18 11:36 ` David Vrabel
2015-06-18 12:08 ` Jan Beulich
2015-06-18 12:17 ` David Vrabel
2015-06-17 12:03 ` [PATCHv3 6/6] evtchn: pad struct evtchn to 64 bytes David Vrabel
2015-06-18 11:31 ` Jan Beulich
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