From: Thomas Gleixner <tglx@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
Frederic Weisbecker <frederic@kernel.org>,
Paul McKenney <paulmck@kernel.org>
Subject: Re: [patch V2 9/9] tasklets: Prevent kill/unlock_wait deadlock on RT
Date: Mon, 07 Dec 2020 18:55:51 +0100 [thread overview]
Message-ID: <87o8j54i1k.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20201207142727.GU3021@hirez.programming.kicks-ass.net>
On Mon, Dec 07 2020 at 15:27, Peter Zijlstra wrote:
> On Mon, Dec 07, 2020 at 03:00:40PM +0100, Sebastian Andrzej Siewior wrote:
>> On 2020-12-07 12:47:43 [+0100], Peter Zijlstra wrote:
>> > On Fri, Dec 04, 2020 at 06:02:00PM +0100, Thomas Gleixner wrote:
>> > > @@ -825,7 +848,20 @@ void tasklet_kill(struct tasklet_struct
>> > >
>> > > while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) {
>> > > do {
>> > > - yield();
>> > > } while (test_bit(TASKLET_STATE_SCHED, &t->state));
>> > > }
>> > > tasklet_unlock_wait(t);
>> >
>> >
>> > Egads... should we not start by doing something like this?
>>
>> So we keep the RT part as-is and replace the non-RT bits with this?
>
> For RT you probably want to wrap the wait_var_event() in that
> local_bh_disable()/enable() pear.
Is that a new species local to the Netherlands? Never heard about
bh-pears before. Are they tasty?
> I just figured those unbounded spin/yield loops suck and we should get
> rid of em.
Ack.
next prev parent reply other threads:[~2020-12-07 17:57 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-04 17:01 [patch V2 0/9] softirq: Make it RT aware Thomas Gleixner
2020-12-04 17:01 ` [patch V2 1/9] softirq: Add RT specific softirq accounting Thomas Gleixner
2020-12-07 13:06 ` Frederic Weisbecker
2020-12-04 17:01 ` [patch V2 2/9] irqtime: Make accounting correct on RT Thomas Gleixner
2020-12-07 0:23 ` Frederic Weisbecker
2020-12-07 0:57 ` Thomas Gleixner
2020-12-07 1:14 ` Frederic Weisbecker
2020-12-07 13:27 ` Frederic Weisbecker
2020-12-07 14:44 ` Thomas Gleixner
2020-12-04 17:01 ` [patch V2 3/9] softirq: Move various protections into inline helpers Thomas Gleixner
2020-12-07 13:37 ` Frederic Weisbecker
2020-12-04 17:01 ` [patch V2 4/9] softirq: Make softirq control and processing RT aware Thomas Gleixner
2020-12-07 14:16 ` Frederic Weisbecker
2020-12-07 15:08 ` Thomas Gleixner
2020-12-08 0:08 ` Frederic Weisbecker
2020-12-09 10:11 ` Peter Zijlstra
2020-12-09 12:36 ` Thomas Gleixner
2020-12-09 12:42 ` Peter Zijlstra
2020-12-09 13:30 ` Thomas Gleixner
2020-12-09 10:34 ` Peter Zijlstra
2020-12-04 17:01 ` [patch V2 5/9] tick/sched: Prevent false positive softirq pending warnings on RT Thomas Gleixner
2020-12-08 12:23 ` Frederic Weisbecker
2020-12-04 17:01 ` [patch V2 6/9] rcu: Prevent false positive softirq warning " Thomas Gleixner
2020-12-04 17:59 ` Paul E. McKenney
2020-12-04 17:01 ` [patch V2 7/9] softirq: Replace barrier() with cpu_relax() in tasklet_unlock_wait() Thomas Gleixner
2020-12-07 11:39 ` Peter Zijlstra
2020-12-07 15:21 ` Thomas Gleixner
2020-12-04 17:01 ` [patch V2 8/9] tasklets: Use static inlines for stub implementations Thomas Gleixner
2020-12-04 17:02 ` [patch V2 9/9] tasklets: Prevent kill/unlock_wait deadlock on RT Thomas Gleixner
2020-12-07 11:47 ` Peter Zijlstra
2020-12-07 14:00 ` Sebastian Andrzej Siewior
2020-12-07 14:27 ` Peter Zijlstra
2020-12-07 17:55 ` Thomas Gleixner [this message]
2020-12-07 15:22 ` Thomas Gleixner
2020-12-07 15:39 ` Sebastian Andrzej Siewior
2020-12-07 17:49 ` Thomas Gleixner
2020-12-07 17:50 ` Thomas Gleixner
2020-12-06 10:05 ` [patch V2 0/9] softirq: Make it RT aware Sebastian Andrzej Siewior
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