From: Avi Kivity <avi@redhat.com>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Thomas Gleixner <tglx@linutronix.de>, 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] KVM: x86: Kick VCPU outside PIC lock again
Date: Wed, 24 Feb 2010 11:48:04 +0200 [thread overview]
Message-ID: <4B84F5D4.5020202@redhat.com> (raw)
In-Reply-To: <4B84F466.2080009@siemens.com>
On 02/24/2010 11:41 AM, Jan Kiszka wrote:
> Thomas Gleixner wrote:
>
>> 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 ?
>>
> Yes, it's a wake queue.
>
So what's the core issue? Is the lock_t in the wait_queue a sleeping mutex?
> This restores the deferred VCPU kicking before 956f97cf. We need this
> over -rt as wake_up* requires non-atomic context in this configuration.
>
>
Seems sane, will apply once I understand why the current code fails.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2010-02-24 9:48 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-17 14:00 [patch] x86: kvm: Convert i8254/i8259 locks to raw_spinlocks Thomas Gleixner
2010-02-18 9:12 ` Jan Kiszka
2010-02-18 9:20 ` Avi Kivity
2010-02-18 9:40 ` Jan Kiszka
2010-02-18 9:45 ` Avi Kivity
2010-02-18 9:49 ` Jan Kiszka
2010-02-18 9:53 ` Avi Kivity
2010-02-18 9:50 ` Avi Kivity
2010-02-18 10:05 ` Jan Kiszka
2010-02-18 10:18 ` Avi Kivity
2010-02-19 1:14 ` Marcelo Tosatti
2010-02-18 9:19 ` Avi Kivity
2010-02-23 19:18 ` Jan Kiszka
2010-02-23 22:23 ` Thomas Gleixner
2010-02-24 9:41 ` [PATCH] KVM: x86: Kick VCPU outside PIC lock again Jan Kiszka
2010-02-24 9:48 ` Avi Kivity [this message]
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
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=4B84F5D4.5020202@redhat.com \
--to=avi@redhat.com \
--cc=gleb@redhat.com \
--cc=jan.kiszka@siemens.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rt-users@vger.kernel.org \
--cc=tglx@linutronix.de \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.