From: Frederic Weisbecker <fweisbec@gmail.com>
To: Jonathan Corbet <corbet@lwn.net>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
LKML <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Ingo Molnar <mingo@elte.hu>, Steven Rostedt <rostedt@goodmis.org>,
Lai Jiangshan <laijs@cn.fujitsu.com>,
Andrew Morton <akpm@linux-foundation.org>,
Anton Blanchard <anton@au1.ibm.com>,
Tim Pepper <lnxninja@linux.vnet.ibm.com>
Subject: Re: [RFC PATCH 06/15] nohz_task: Keep the tick if rcu needs it
Date: Tue, 21 Dec 2010 03:10:59 +0100 [thread overview]
Message-ID: <20101221021046.GQ1715@nowhere> (raw)
In-Reply-To: <20101220171259.1d3cb6ad@bike.lwn.net>
On Mon, Dec 20, 2010 at 05:12:59PM -0700, Jonathan Corbet wrote:
> On Tue, 21 Dec 2010 00:49:38 +0100
> Frederic Weisbecker <fweisbec@gmail.com> wrote:
>
> > Nope, the new config can only be built after [RFC PATCH 11/15] x86: Nohz task support
> >
> > I know I split up the patches in some unusual way but I did that on purpose:
> > I wanted to have a finegrained patchset so that it's more reviewable than a big
> > "core support" - "arch support" dual patch based style.
> >
> > But I ensured the new config can not be enabled before it's entirely buildable
> > and has no known bugs.
>
> Which is a nice thought (it helped me to understand the patches - article
> forthcoming)
Oh great :)
> but there is a downside: if anybody tries to bisect a
> problem, they'll end up at #11. This stuff is sufficiently tricky that it
> would be nice to be able to bisect a little closer to the patch which
> actually introduced a bug.
Yeah indeed. I think I could split that up another way while keeping the fine
grained progression (if any).
I could enable the interface and CONFIG a bit sooner, once we have the support
for tick stop and restart handling basic things like woken up tasks and rcu
pending works checks.
And then handle the rcu extended grace periods in userspace later.
Because it works without, the nohz task would just be regularly interrupted by
rcu IPIs to note the quiescent states.
There are lots of changes to be done anyway, so I'm sure there will be enough
new takes of this for me to train more patchset split-up flavours ;-)
next prev parent reply other threads:[~2010-12-21 2:11 UTC|newest]
Thread overview: 98+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-20 15:24 [RFC PATCH 00/15] Nohz task support Frederic Weisbecker
2010-12-20 15:24 ` [RFC PATCH 01/15] nohz_task: New mask for cpus having nohz task Frederic Weisbecker
2010-12-24 8:00 ` Lai Jiangshan
2010-12-24 8:19 ` Dario Faggioli
2010-12-24 12:29 ` Frederic Weisbecker
2010-12-20 15:24 ` [RFC PATCH 02/15] nohz_task: Avoid nohz task cpu as non-idle timer target Frederic Weisbecker
2010-12-20 15:47 ` Peter Zijlstra
2010-12-20 16:06 ` Steven Rostedt
2010-12-20 16:12 ` Peter Zijlstra
2010-12-21 0:20 ` Frederic Weisbecker
2010-12-21 7:51 ` Peter Zijlstra
2010-12-21 13:58 ` Frederic Weisbecker
2010-12-21 0:13 ` Frederic Weisbecker
2010-12-21 7:50 ` Peter Zijlstra
2010-12-21 13:52 ` Frederic Weisbecker
2010-12-20 15:24 ` [RFC PATCH 03/15] nohz_task: Make tick stop and restart callable outside idle Frederic Weisbecker
2010-12-20 15:48 ` Peter Zijlstra
2010-12-20 16:19 ` Steven Rostedt
2010-12-20 16:25 ` Peter Zijlstra
2010-12-21 1:34 ` Frederic Weisbecker
2010-12-20 15:24 ` [RFC PATCH 04/15] nohz_task: Stop the tick when the nohz task runs alone Frederic Weisbecker
2010-12-20 15:51 ` Peter Zijlstra
2010-12-20 23:37 ` Frederic Weisbecker
2010-12-21 7:35 ` Peter Zijlstra
2010-12-21 13:22 ` Frederic Weisbecker
2010-12-21 14:34 ` Steven Rostedt
2010-12-21 15:14 ` Frederic Weisbecker
2010-12-20 15:24 ` [RFC PATCH 05/15] nohz_task: Restart the tick when another task compete on the cpu Frederic Weisbecker
2010-12-20 15:53 ` Peter Zijlstra
2010-12-20 23:39 ` Frederic Weisbecker
2010-12-20 15:24 ` [RFC PATCH 06/15] nohz_task: Keep the tick if rcu needs it Frederic Weisbecker
2010-12-20 15:58 ` Peter Zijlstra
2010-12-20 23:49 ` Frederic Weisbecker
2010-12-21 0:12 ` Jonathan Corbet
2010-12-21 2:10 ` Frederic Weisbecker [this message]
2010-12-21 8:10 ` Paul E. McKenney
2010-12-20 15:24 ` [RFC PATCH 07/15] nohz_task: Restart tick when RCU forces nohz task cpu quiescent state Frederic Weisbecker
2010-12-20 16:02 ` Peter Zijlstra
2010-12-20 23:52 ` Frederic Weisbecker
2010-12-21 7:41 ` Peter Zijlstra
2010-12-21 13:28 ` Frederic Weisbecker
2010-12-21 15:35 ` Paul E. McKenney
2010-12-20 15:24 ` [RFC PATCH 08/15] smp: Don't warn if irq are disabled but we don't wait for the ipi Frederic Weisbecker
2010-12-20 16:03 ` Peter Zijlstra
2010-12-21 0:02 ` Frederic Weisbecker
2010-12-20 15:24 ` [RFC PATCH 09/15] rcu: Make rcu_enter,exit_nohz() callable from irq Frederic Weisbecker
2010-12-21 19:26 ` Paul E. McKenney
2010-12-21 19:27 ` Frederic Weisbecker
2010-12-20 15:24 ` [RFC PATCH 10/15] nohz_task: Enter in extended quiescent state when in userspace Frederic Weisbecker
2010-12-20 16:18 ` Peter Zijlstra
2010-12-21 1:27 ` Frederic Weisbecker
2010-12-21 8:04 ` Peter Zijlstra
2010-12-21 14:06 ` Frederic Weisbecker
2010-12-21 19:28 ` Paul E. McKenney
2010-12-21 21:49 ` Frederic Weisbecker
2010-12-22 2:20 ` Paul E. McKenney
2010-12-20 15:24 ` [RFC PATCH 11/15] x86: Nohz task support Frederic Weisbecker
2010-12-20 16:23 ` Peter Zijlstra
2010-12-21 1:30 ` Frederic Weisbecker
2010-12-21 8:05 ` Peter Zijlstra
2010-12-21 14:19 ` Frederic Weisbecker
2010-12-21 15:12 ` Frederic Weisbecker
2010-12-20 15:24 ` [RFC PATCH 12/15] clocksource: Ignore nohz task cpu in clocksource watchdog Frederic Weisbecker
2010-12-20 16:27 ` Peter Zijlstra
2010-12-21 1:40 ` Frederic Weisbecker
2010-12-20 15:24 ` [RFC PATCH 13/15] sched: Protect nohz task cpu affinity Frederic Weisbecker
2010-12-20 16:28 ` Peter Zijlstra
2010-12-20 17:05 ` Steven Rostedt
2010-12-21 1:55 ` Frederic Weisbecker
2010-12-20 15:24 ` [RFC PATCH 14/15] nohz_task: Clear nohz task attribute on exit() Frederic Weisbecker
2010-12-20 16:30 ` Peter Zijlstra
2010-12-21 1:48 ` Frederic Weisbecker
2010-12-21 8:07 ` Peter Zijlstra
2010-12-21 14:22 ` Frederic Weisbecker
2010-12-20 15:24 ` [RFC PATCH 15/15] nohz_task: Procfs interface Frederic Weisbecker
2010-12-20 15:42 ` Peter Zijlstra
2010-12-20 15:57 ` Frederic Weisbecker
2010-12-20 16:16 ` Peter Zijlstra
2010-12-21 1:24 ` Frederic Weisbecker
2010-12-21 8:14 ` Peter Zijlstra
2010-12-21 14:00 ` Avi Kivity
2010-12-21 17:05 ` Frederic Weisbecker
2010-12-21 18:17 ` Avi Kivity
2010-12-21 21:08 ` Frederic Weisbecker
2010-12-22 9:22 ` Avi Kivity
2010-12-22 9:51 ` Peter Zijlstra
2010-12-22 20:41 ` Frederic Weisbecker
2010-12-21 14:26 ` Frederic Weisbecker
2010-12-20 15:44 ` [RFC PATCH 00/15] Nohz task support Steven Rostedt
2010-12-20 23:33 ` Frederic Weisbecker
2010-12-21 1:36 ` Steven Rostedt
2010-12-21 2:15 ` Frederic Weisbecker
2010-12-21 7:34 ` Peter Zijlstra
2010-12-21 13:13 ` Frederic Weisbecker
2010-12-21 13:56 ` Avi Kivity
2010-12-21 17:01 ` Frederic Weisbecker
2010-12-20 16:35 ` Peter Zijlstra
2010-12-21 1:53 ` Frederic Weisbecker
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