From: Thomas Gleixner <tglx@linutronix.de>
To: Frederic Weisbecker <fweisbec@gmail.com>
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: Thu, 31 Aug 2017 20:53:56 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.20.1708312050040.2346@nanos> (raw)
In-Reply-To: <20170828173315.GA3631@lerouge>
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.
Thanks,
tglx
next prev parent reply other threads:[~2017-08-31 18:54 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 [this message]
2017-08-31 23:00 ` Frederic Weisbecker
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