From: Frederic Weisbecker <fweisbec@gmail.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
Chris Metcalf <cmetcalf@mellanox.com>,
Luiz Capitulino <lcapitulino@redhat.com>,
Christoph Lameter <cl@linux.com>,
"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
Ingo Molnar <mingo@kernel.org>, Mike Galbraith <efault@gmx.de>,
Rik van Riel <riel@redhat.com>, Wanpeng Li <kernellwp@gmail.com>
Subject: Re: [RFC PATCH 12/12] housekeeping: Reimplement isolcpus on housekeeping
Date: Fri, 1 Sep 2017 01:00:00 +0200 [thread overview]
Message-ID: <20170831225959.GB18249@lerouge> (raw)
In-Reply-To: <alpine.DEB.2.20.1708312050040.2346@nanos>
On Thu, Aug 31, 2017 at 08:53:56PM +0200, Thomas Gleixner wrote:
> On Mon, 28 Aug 2017, Frederic Weisbecker wrote:
> > On Mon, Aug 28, 2017 at 06:24:16PM +0200, Peter Zijlstra wrote:
> > > On Mon, Aug 28, 2017 at 05:27:15PM +0200, Frederic Weisbecker wrote:
> > > > Although for example I guess (IIUC) that if you create an unbound
> > > > timer on a NULL domain, it will be stuck on it for ever as we can't
> > > > walk any hierarchy from the current CPU domain.
> > >
> > > Not sure what you're on about. Timers have their own hierarchy.
> >
> > Check out get_nohz_timer_target() which relies on scheduler hierarchies to
> > look up a CPU to enqueue an unpinned timer on.
>
> Which is one of the most idiotic things we have in that code
> path. Anna-Maria has posted this series which gets rid of that nonsense, by
> queueing the timer on the current cpu into a wheel, which gets pulled in by
> others. That makes a lot of sense because most of these timers get canceled
> before expiry anyway. But we still need to fix the fallout and the few
> corner cases to make that work reliably. We'll do that hopefully sooner
> than later.
Sure, I definetly agree with that change.
prev parent reply other threads:[~2017-08-31 23:00 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-23 1:50 [RFC 00/12] Introduce housekeeping subsystem v2 Frederic Weisbecker
2017-08-23 1:51 ` [RFC PATCH 01/12] housekeeping: Move housekeeping related code to its own file Frederic Weisbecker
2017-08-31 20:16 ` Rik van Riel
2017-08-31 22:58 ` Frederic Weisbecker
2017-08-23 1:51 ` [RFC PATCH 02/12] watchdog: Use housekeeping_cpumask() instead of ad-hoc version Frederic Weisbecker
2017-08-23 1:51 ` [RFC PATCH 03/12] housekeeping: Provide a dynamic off-case to housekeeping_any_cpu() Frederic Weisbecker
2017-08-23 1:51 ` [RFC PATCH 04/12] housekeeping: Make housekeeping cpumask private Frederic Weisbecker
2017-08-23 1:51 ` [RFC PATCH 05/12] housekeeping: Use its own static key Frederic Weisbecker
2017-08-23 1:51 ` [RFC PATCH 06/12] housekeeping: Rename is_housekeeping_cpu to housekeeping_cpu Frederic Weisbecker
2017-08-23 1:51 ` [RFC PATCH 07/12] housekeeping: Move it under own config, independant from NO_HZ Frederic Weisbecker
2017-08-23 1:51 ` [RFC PATCH 08/12] housekeeping: Introduce housekeeping flags Frederic Weisbecker
2017-08-23 1:51 ` [RFC PATCH 09/12] workqueue: Affine unbound workqueues to housekeeping cpumask Frederic Weisbecker
2017-08-23 1:51 ` [RFC PATCH 10/12] housekeeping: Affine unbound kthreads Frederic Weisbecker
2017-08-23 1:51 ` [RFC PATCH 11/12] housekeeping: Handle nohz_full= parameter Frederic Weisbecker
2017-08-23 1:51 ` [RFC PATCH 12/12] housekeeping: Reimplement isolcpus on housekeeping Frederic Weisbecker
2017-08-23 14:55 ` Christopher Lameter
2017-08-24 13:19 ` Frederic Weisbecker
2017-08-28 10:10 ` Peter Zijlstra
2017-08-28 15:38 ` Christopher Lameter
2017-08-28 10:09 ` Peter Zijlstra
2017-08-28 13:23 ` Frederic Weisbecker
2017-08-28 13:31 ` Peter Zijlstra
2017-08-28 15:27 ` Frederic Weisbecker
2017-08-28 16:24 ` Peter Zijlstra
2017-08-28 16:53 ` Christopher Lameter
2017-08-28 17:33 ` Frederic Weisbecker
2017-08-31 18:53 ` Thomas Gleixner
2017-08-31 23:00 ` Frederic Weisbecker [this message]
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