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: 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
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 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).