From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Uladzislau Rezki <urezki@gmail.com>
Cc: rcu@vger.kernel.org, "Paul E. McKenney" <paulmck@kernel.org>,
Josh Triplett <josh@joshtriplett.org>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Mike Galbraith <efault@gmx.de>
Subject: Re: [PATCH 1/3] rcu: Use static initializer for krc.lock
Date: Thu, 16 Apr 2020 18:33:02 +0200 [thread overview]
Message-ID: <20200416163302.3fsroillwk2om5dh@linutronix.de> (raw)
In-Reply-To: <20200416161819.GA8551@pc636>
On 2020-04-16 18:18:19 [+0200], Uladzislau Rezki wrote:
> On Thu, Apr 16, 2020 at 06:11:49PM +0200, Sebastian Andrzej Siewior wrote:
> > On 2020-04-16 18:01:29 [+0200], Uladzislau Rezki wrote:
> > > > As written in my previous email to Joel (who somehow fell of the Cc
> > > > list in this part of the thread):
> > > > |local_irq_save() + spin_lock() is the problem, see
> > > > | https://www.kernel.org/doc/html/latest/locking/locktypes.html#spinlock-t-and-rwlock-t
> > > >
> > > You mean that in CONFIG_PREEMPT_RT:
> > >
> > > <snip>
> > > local_irq_save(flags);
> > > krcp = this_cpu_ptr(&krc);
> > > spin_lock(&krcp->lock);
> > > <snip>
> > >
> > > it will not be preempted, what does not follow PREEMPT_RT policy. Is that correct?
> >
> > No. local_irq_save() disables interrupts and spin_lock() acquires a
> > sleeping lock which may schedule() if contended. The documentation has
> > this piece:
> >
> Ah. Got it. Then it is a problem, agree. Do you have something
> that would guarantee of being staying on the same CPU?
> migration_disable()?
migrate_disable() would work.
> Thanks!
Sebastian
next prev parent reply other threads:[~2020-04-16 16:33 UTC|newest]
Thread overview: 85+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-15 16:00 [PATCH 0/3] rcu: Static initializer + misc Sebastian Andrzej Siewior
2020-04-15 16:00 ` [PATCH 1/3] rcu: Use static initializer for krc.lock Sebastian Andrzej Siewior
2020-04-16 14:42 ` Joel Fernandes
2020-04-16 15:01 ` Uladzislau Rezki
2020-04-16 15:20 ` Sebastian Andrzej Siewior
2020-04-16 15:38 ` Uladzislau Rezki
2020-04-16 15:46 ` Sebastian Andrzej Siewior
2020-04-16 16:01 ` Uladzislau Rezki
2020-04-16 16:11 ` Sebastian Andrzej Siewior
2020-04-16 16:18 ` Uladzislau Rezki
2020-04-16 16:33 ` Sebastian Andrzej Siewior [this message]
2020-04-16 17:29 ` Paul E. McKenney
2020-04-16 18:23 ` Sebastian Andrzej Siewior
2020-04-16 18:29 ` Paul E. McKenney
2020-04-16 18:43 ` Joel Fernandes
2020-04-16 20:56 ` Sebastian Andrzej Siewior
2020-04-16 21:04 ` Joel Fernandes
2020-04-16 21:07 ` Sebastian Andrzej Siewior
2020-04-16 18:40 ` Steven Rostedt
2020-04-16 18:53 ` Joel Fernandes
2020-04-16 19:24 ` Steven Rostedt
2020-04-16 20:41 ` Joel Fernandes
2020-04-16 21:05 ` Sebastian Andrzej Siewior
2020-04-16 17:28 ` Paul E. McKenney
2020-04-16 15:18 ` Sebastian Andrzej Siewior
2020-04-16 18:41 ` Joel Fernandes
2020-04-16 18:59 ` Joel Fernandes
2020-04-16 19:26 ` Steven Rostedt
2020-04-16 19:53 ` Paul E. McKenney
2020-04-16 20:05 ` Uladzislau Rezki
2020-04-16 20:25 ` Paul E. McKenney
2020-04-16 21:02 ` Joel Fernandes
2020-04-16 21:18 ` Uladzislau Rezki
2020-04-16 21:26 ` Uladzislau Rezki
2020-04-16 21:28 ` Sebastian Andrzej Siewior
2020-04-16 20:36 ` Joel Fernandes
2020-04-16 21:00 ` Paul E. McKenney
2020-04-16 21:34 ` Sebastian Andrzej Siewior
2020-04-17 3:05 ` Joel Fernandes
2020-04-17 8:47 ` Uladzislau Rezki
2020-04-17 15:04 ` Sebastian Andrzej Siewior
2020-04-17 18:26 ` Joel Fernandes
2020-04-17 18:54 ` Paul E. McKenney
2020-04-18 12:37 ` Uladzislau Rezki
2020-04-19 14:58 ` Paul E. McKenney
2020-04-20 0:27 ` Joel Fernandes
2020-04-20 1:17 ` Joel Fernandes
2020-04-20 1:44 ` Paul E. McKenney
2020-04-20 12:13 ` Uladzislau Rezki
2020-04-20 12:36 ` joel
2020-04-20 13:00 ` Uladzislau Rezki
2020-04-20 13:26 ` Paul E. McKenney
2020-04-20 16:08 ` Uladzislau Rezki
2020-04-20 16:25 ` Paul E. McKenney
2020-04-20 16:29 ` Uladzislau Rezki
2020-04-20 16:46 ` Paul E. McKenney
2020-04-20 16:59 ` Uladzislau Rezki
2020-04-20 17:21 ` Paul E. McKenney
2020-04-20 17:40 ` Uladzislau Rezki
2020-04-20 17:57 ` Joel Fernandes
2020-04-20 18:13 ` Paul E. McKenney
2020-04-20 17:59 ` Paul E. McKenney
2020-04-20 19:06 ` Uladzislau Rezki
2020-04-20 20:17 ` Uladzislau Rezki
2020-04-20 22:16 ` Paul E. McKenney
2020-04-21 1:22 ` Steven Rostedt
2020-04-21 5:18 ` Uladzislau Rezki
2020-04-21 13:30 ` Steven Rostedt
2020-04-21 13:45 ` Uladzislau Rezki
2020-04-21 13:39 ` Sebastian Andrzej Siewior
2020-04-21 15:41 ` Paul E. McKenney
2020-04-21 17:05 ` Sebastian Andrzej Siewior
2020-04-21 18:09 ` Paul E. McKenney
2020-04-22 11:13 ` Sebastian Andrzej Siewior
2020-04-22 13:33 ` Paul E. McKenney
2020-04-22 15:46 ` Sebastian Andrzej Siewior
2020-04-22 16:19 ` Paul E. McKenney
2020-04-22 16:35 ` Paul E. McKenney
2020-04-20 3:02 ` Mike Galbraith
2020-04-20 12:30 ` joel
2020-04-17 16:11 ` Uladzislau Rezki
2020-04-19 12:15 ` Uladzislau Rezki
2020-04-15 16:00 ` [PATCH 2/3] rcu: Use consistent locking around kfree_rcu_drain_unlock() Sebastian Andrzej Siewior
2020-04-15 16:00 ` [PATCH 3/3] rcu: Avoid using xchg() in kfree_call_rcu_add_ptr_to_bulk() Sebastian Andrzej Siewior
2020-04-20 15:23 ` Joel Fernandes
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