From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>,
Arjan van de Ven <arjan@linux.intel.com>,
lenb@kernel.org, rjw@rjwysocki.net,
Eliezer Tamir <eliezer.tamir@linux.intel.com>,
Chris Leech <christopher.leech@intel.com>,
David Miller <davem@davemloft.net>,
rui.zhang@intel.com, Mike Galbraith <bitbucket@online.de>,
Ingo Molnar <mingo@kernel.org>,
hpa@zytor.com, Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Subject: Re: [PATCH 3/7] idle, thermal, acpi: Remove home grown idle implementations
Date: Fri, 22 Nov 2013 09:17:27 -0800 [thread overview]
Message-ID: <20131122171727.GT4138@linux.vnet.ibm.com> (raw)
In-Reply-To: <20131122113300.GM10022@twins.programming.kicks-ass.net>
On Fri, Nov 22, 2013 at 12:33:00PM +0100, Peter Zijlstra wrote:
> On Thu, Nov 21, 2013 at 08:20:36PM -0800, Paul E. McKenney wrote:
> > The 6ms to 25ms range should be just fine as far as normal RCU grace
> > periods are concerned. However, it does mean that expedited grace
> > periods could be delayed: They normally take a few tens of microseconds,
> > but if they were unlucky enough to show up during an idle injection,
> > they would be magnified by two to three orders of magnitude, which is
> > not pretty.
> >
> > Hence my suggestion of hooking into RCU on idle-injection start and end
> > so that RCU considers that time period to be idle. Just like it does
> > for user-mode execution on NO_HZ_FULL kernels, so I still don't see this
> > approach to be a problem. I must confess that I still don't understand
> > what Arjan doesn't like about it.
>
> Using these patches it would indeed use the RCU idle machinery as per
> the normal idle path.
OK, sorry for my confusion!
> If you can I can add more WARN_ON()s in play_idle() to ensure we're not
> called while holding any RCU locks.
An rcu_sleep_check() or something similar, please!
Thanx, Paul
next prev parent reply other threads:[~2013-11-22 17:17 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-20 16:04 [PATCH 0/7] Cure some vaux idle wrackage Peter Zijlstra
2013-11-20 16:04 ` [PATCH 1/7] x86, acpi, idle: Restructure the mwait idle routines Peter Zijlstra
2013-11-20 16:04 ` [PATCH 2/7] sched, preempt: Fixup missed PREEMPT_NEED_RESCHED folding Peter Zijlstra
2013-11-21 8:25 ` Peter Zijlstra
2013-11-20 16:04 ` [PATCH 3/7] idle, thermal, acpi: Remove home grown idle implementations Peter Zijlstra
2013-11-20 16:40 ` Arjan van de Ven
2013-11-20 16:59 ` Peter Zijlstra
2013-11-20 17:23 ` Thomas Gleixner
2013-11-20 17:23 ` Arjan van de Ven
2013-11-20 17:55 ` Thomas Gleixner
2013-11-20 18:21 ` Arjan van de Ven
2013-11-20 19:38 ` Thomas Gleixner
2013-11-20 22:08 ` Jacob Pan
2013-11-21 0:54 ` Jacob Pan
2013-11-21 8:21 ` Peter Zijlstra
2013-11-21 16:07 ` Paul E. McKenney
2013-11-21 16:21 ` Arjan van de Ven
2013-11-21 19:19 ` Paul E. McKenney
2013-11-21 19:45 ` Arjan van de Ven
2013-11-21 20:07 ` Paul E. McKenney
2013-11-22 0:10 ` Jacob Pan
2013-11-22 4:20 ` Paul E. McKenney
2013-11-22 11:33 ` Peter Zijlstra
2013-11-22 17:17 ` Paul E. McKenney [this message]
2013-11-21 16:29 ` Peter Zijlstra
2013-11-21 17:27 ` Paul E. McKenney
2013-11-20 16:04 ` [PATCH 4/7] preempt, locking: Rework local_bh_{dis,en}able() Peter Zijlstra
2013-11-20 16:04 ` [PATCH 5/7] locking: Optimize lock_bh functions Peter Zijlstra
2013-11-20 16:04 ` [PATCH 6/7] sched: Clean up preempt_enable_no_resched() abuse Peter Zijlstra
2013-11-20 18:02 ` Eliezer Tamir
2013-11-20 18:15 ` Peter Zijlstra
2013-11-20 20:14 ` Eliezer Tamir
2013-11-21 10:10 ` Peter Zijlstra
2013-11-21 13:26 ` Eliezer Tamir
2013-11-21 13:39 ` Peter Zijlstra
2013-11-22 6:56 ` Eliezer Tamir
2013-11-22 11:30 ` Peter Zijlstra
2013-11-26 7:15 ` Eliezer Tamir
2013-11-26 10:51 ` Thomas Gleixner
2013-11-20 16:04 ` [PATCH 7/7] preempt: Take away preempt_enable_no_resched() from modules Peter Zijlstra
2013-11-20 18:54 ` Jacob Pan
2013-11-20 19:00 ` Peter Zijlstra
2013-11-20 19:18 ` Peter Zijlstra
2013-11-20 19:29 ` Jacob Pan
2013-11-20 16:34 ` [PATCH 0/7] Cure some vaux idle wrackage Peter Zijlstra
2013-11-20 17:19 ` Jacob Pan
2013-11-20 17:24 ` Peter Zijlstra
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