From: Peter Zijlstra <peterz@infradead.org>
To: Paul Mackerras <paulus@ozlabs.org>
Cc: Daniel Wagner <daniel.wagner@bmw-carit.de>,
linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org,
Marcelo Tosatti <mtosatti@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v3 2/4] KVM: use simple waitqueue for vcpu->wq
Date: Wed, 21 Oct 2015 13:13:05 +0200 [thread overview]
Message-ID: <20151021111305.GL17308@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20151021092411.GD15591@fergus.ozlabs.ibm.com>
On Wed, Oct 21, 2015 at 08:24:11PM +1100, Paul Mackerras wrote:
> On Tue, Oct 20, 2015 at 04:00:31PM +0200, Peter Zijlstra wrote:
> >
> > Should we not take this opportunity to get rid of these open-coded wait
> > loops?
> >
> >
> > Does this work?
>
> No, on Book3S HV (POWER8) the VM hangs immediately after the kernel
> brings up all the secondary vCPUs, and is then unkillable. I'm not
> sure what's wrong, although I wonder why you have TASK_IDLE rather
> than TASK_INTERRUPTIBLE in the ___wait_event call.
This was under the assumption that INTERRUPTIBLE was because you wanted
to avoid increasing load. Which was based on the lack of
signal_pending() tests near there (although there might have been in the
outermost loop which I overlooked).
If it does rely on signals, then this was obviously false and TASK_IDLE
is indeed wrong.
next prev parent reply other threads:[~2015-10-21 11:13 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-20 7:28 [PATCH v3 0/4] Simple wait queue support Daniel Wagner
2015-10-20 7:28 ` [PATCH v3 1/4] wait.[ch]: Introduce the simple waitqueue (swait) implementation Daniel Wagner
2015-10-26 12:04 ` Boqun Feng
2015-10-26 12:28 ` Peter Zijlstra
2015-10-26 12:59 ` Daniel Wagner
2015-10-26 13:26 ` Peter Zijlstra
2015-10-26 14:19 ` Boqun Feng
2015-11-04 10:33 ` Thomas Gleixner
2015-11-04 12:12 ` Daniel Wagner
2015-11-18 10:33 ` Peter Zijlstra
2015-11-18 15:07 ` Thomas Gleixner
2015-10-20 7:28 ` [PATCH v3 2/4] KVM: use simple waitqueue for vcpu->wq Daniel Wagner
2015-10-20 13:11 ` Paolo Bonzini
2015-10-20 14:00 ` Peter Zijlstra
2015-10-20 15:40 ` Paolo Bonzini
2015-10-20 16:06 ` Peter Zijlstra
2015-10-21 8:55 ` Paul Mackerras
2015-10-21 9:05 ` Peter Zijlstra
2015-10-21 9:10 ` Paul Mackerras
2015-10-21 9:24 ` Paul Mackerras
2015-10-21 11:13 ` Peter Zijlstra [this message]
2015-10-23 11:51 ` Daniel Wagner
2015-10-20 7:28 ` [PATCH v3 3/4] rcu: Do not call rcu_nocb_gp_cleanup() while holding rnp->lock Daniel Wagner
2015-10-20 7:28 ` [PATCH v3 4/4] rcu: use simple wait queues where possible in rcutree Daniel Wagner
2015-10-25 20:10 ` [PATCH v3 0/4] Simple wait queue support Paul E. McKenney
2015-10-26 6:34 ` Daniel Wagner
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