From: "Jan Beulich" <JBeulich@suse.com>
To: David Vrabel <david.vrabel@citrix.com>
Cc: xen-devel <xen-devel@lists.xenproject.org>,
Keir Fraser <keir@xen.org>,
Ian Jackson <Ian.Jackson@eu.citrix.com>, TimDeegan <tim@xen.org>
Subject: Re: [PATCH] spinlock: improve spin_is_locked() for recursive locks
Date: Thu, 24 Mar 2016 10:19:48 -0600 [thread overview]
Message-ID: <56F421B402000078000E046C@prv-mh.provo.novell.com> (raw)
In-Reply-To: <56F40DDD.9020303@citrix.com>
>>> On 24.03.16 at 16:55, <david.vrabel@citrix.com> wrote:
> On 24/03/16 11:30, Jan Beulich wrote:
>> Recursive locks know their current owner, and since we use the function
>> solely to determine whether a particular lock is being held by the
>> current CPU (which so far has been an imprecise check), make actually
>> check the owner for recusrively acquired locks.
>
> What's the expected behaviour of _spin_is_locked() if the lock is held
> by another CPU?
>
> Before it may return true if it is held by another CPU, now it will
> always return false in this case.
Correct - hence the reference to this only being used for a limited
set of cases (read: ASSERT()s and alike).
Jan
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next prev parent reply other threads:[~2016-03-24 16:19 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-24 11:30 [PATCH] spinlock: improve spin_is_locked() for recursive locks Jan Beulich
2016-03-24 14:19 ` Dario Faggioli
2016-03-24 14:38 ` Andrew Cooper
2016-03-24 15:55 ` David Vrabel
2016-03-24 16:19 ` Jan Beulich [this message]
2016-03-29 10:36 ` George Dunlap
2016-03-29 10:45 ` Jan Beulich
2016-03-25 10:19 ` Xu, Quan
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