From: Thomas Gleixner <tglx@linutronix.de>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Avi Kivity <avi@redhat.com>, KVM <kvm@vger.kernel.org>,
Gleb Natapov <gleb@redhat.com>,
RT <linux-rt-users@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [patch] x86: kvm: Convert i8254/i8259 locks to raw_spinlocks
Date: Tue, 23 Feb 2010 23:23:37 +0100 (CET) [thread overview]
Message-ID: <alpine.LFD.2.00.1002232321320.3232@localhost.localdomain> (raw)
In-Reply-To: <4B842A1F.50601@siemens.com>
On Tue, 23 Feb 2010, Jan Kiszka wrote:
> Thomas Gleixner wrote:
> > The i8254/i8259 locks need to be real spinlocks on preempt-rt. Convert
> > them to raw_spinlock. No change for !RT kernels.
>
> Doesn't fly for -rt anymore: pic_irq_update runs under this raw lock and
> calls kvm_vcpu_kick which tries to wake_up some thread -> scheduling
> while atomic.
Hmm, a wakeup itself is fine. Is that code waking a wake queue ?
> This used to work up to 956f97cf. -rt for 2.6.31 is not yet affected,
> but 2.6.33 should be broken (haven't checked, using kvm-kmod over 2.6.31
> ATM). I can provide a patch that restores the deferred kicking if it's
> acceptable for upstream.
Well, at least is would be nice to have one for -rt.
Thanks,
tglx
next prev parent reply other threads:[~2010-02-23 22:23 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20100217135901.331576359@linutronix.de>
2010-02-23 19:18 ` [patch] x86: kvm: Convert i8254/i8259 locks to raw_spinlocks Jan Kiszka
2010-02-23 22:23 ` Thomas Gleixner [this message]
2010-02-24 9:41 ` [PATCH] KVM: x86: Kick VCPU outside PIC lock again Jan Kiszka
2010-02-24 9:48 ` Avi Kivity
2010-02-24 9:54 ` Jan Kiszka
2010-02-24 10:04 ` Avi Kivity
2010-02-24 10:13 ` Jan Kiszka
2010-02-24 10:17 ` Avi Kivity
2010-02-24 10:22 ` Jan Kiszka
2010-02-24 10:27 ` Avi Kivity
2010-02-24 10:31 ` Jan Kiszka
2010-02-24 10:28 ` Jan Kiszka
2010-02-24 10:41 ` Avi Kivity
2010-02-24 11:42 ` Jan Kiszka
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