From: Peter Zijlstra <peterz@infradead.org>
To: Frederic Weisbecker <frederic@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
"Paul E . McKenney" <paulmck@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [RFC PATCH 1/3] lockdep/irq: Be more strict about IRQ-threadable code end
Date: Mon, 23 Mar 2020 17:31:05 +0100 [thread overview]
Message-ID: <20200323163105.GM2452@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20200323153039.GA5755@lenoir>
On Mon, Mar 23, 2020 at 04:30:40PM +0100, Frederic Weisbecker wrote:
> On Mon, Mar 23, 2020 at 02:53:20PM +0100, Peter Zijlstra wrote:
> > On Mon, Mar 23, 2020 at 04:32:05AM +0100, Frederic Weisbecker wrote:
> > > --- a/kernel/irq/handle.c
> > > +++ b/kernel/irq/handle.c
> > > @@ -144,18 +144,24 @@ irqreturn_t __handle_irq_event_percpu(struct irq_desc *desc, unsigned int *flags
> > >
> > > for_each_action_of_desc(desc, action) {
> > > irqreturn_t res;
> > > + bool threadable;
> > >
> > > /*
> > > * If this IRQ would be threaded under force_irqthreads, mark it so.
> > > */
> > > - if (irq_settings_can_thread(desc) &&
> > > - !(action->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT)))
> > > + threadable = (irq_settings_can_thread(desc) &&
> > > + !(action->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT)));
> > > +
> > > + if (threadable)
> > > trace_hardirq_threaded();
> > >
> > > trace_irq_handler_entry(irq, action);
> > > res = action->handler(irq, action->dev_id);
> > > trace_irq_handler_exit(irq, action, res);
> > >
> > > + if (threadable)
> > > + trace_hardirq_unthreaded();
> >
> > AFAICT this doesn't work for nested IRQ handlers.
>
> So current->hardirq_threaded should be a counter perhaps?
Yeah, see how the old code used the hardirq_context counter for exactly
that. Also note how the old code was actually cheaper than this
(minimally, but still).
next prev parent reply other threads:[~2020-03-23 16:31 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-23 3:32 [RFC PATCH 0/3] lockdep/irq: wait-type related cleanups Frederic Weisbecker
2020-03-23 3:32 ` [RFC PATCH 1/3] lockdep/irq: Be more strict about IRQ-threadable code end Frederic Weisbecker
2020-03-23 13:53 ` Peter Zijlstra
2020-03-23 15:30 ` Frederic Weisbecker
2020-03-23 16:31 ` Peter Zijlstra [this message]
2020-03-24 3:20 ` Frederic Weisbecker
2020-03-23 3:32 ` [RFC PATCH 2/3] lockdep: Merge hardirq_threaded and irq_config together Frederic Weisbecker
2020-03-23 14:02 ` Peter Zijlstra
2020-03-23 14:53 ` Sebastian Andrzej Siewior
2020-03-23 16:14 ` Frederic Weisbecker
2020-03-23 3:32 ` [RFC PATCH 3/3] lockdep: Briefly comment current->hardirq_threadable usecases Frederic Weisbecker
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