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From: joel@joelfernandes.org (Joel Fernandes)
Subject: [PATCH v9 4/7] tracepoint: Make rcuidle tracepoint callers use SRCU
Date: Wed, 11 Jul 2018 19:32:37 -0700	[thread overview]
Message-ID: <20180712023237.GA122777@joelaf.mtv.corp.google.com> (raw)
Message-ID: <20180712023237.RA4op6GHJ3O_O7CL5lmJDsqP0sGbiIre6P23HrTq3Bw@z> (raw)
In-Reply-To: <20180711125322.GF2476@hirez.programming.kicks-ass.net>

On Wed, Jul 11, 2018@02:53:22PM +0200, Peter Zijlstra wrote:
> On Thu, Jun 28, 2018@11:21:46AM -0700, Joel Fernandes wrote:
> > -		rcu_read_lock_sched_notrace();				\
> > -		it_func_ptr = rcu_dereference_sched((tp)->funcs);	\
> > +									\
> > +		/*							\
> > +		 * For rcuidle callers, use srcu since sched-rcu	\
> > +		 * doesn't work from the idle path.			\
> > +		 */							\
> > +		if (rcuidle) {						\
> > +			if (in_nmi()) {					\
> > +				WARN_ON_ONCE(1);			\
> > +				return; /* no srcu from nmi */		\
> > +			}						\
> > +									\
> > +			idx = srcu_read_lock_notrace(&tracepoint_srcu);	\
> > +			it_func_ptr =					\
> > +				srcu_dereference_notrace((tp)->funcs,	\
> > +						&tracepoint_srcu);	\
> > +			/* To keep it consistent with !rcuidle path */	\
> > +			preempt_disable_notrace();			\
> > +		} else {						\
> > +			rcu_read_lock_sched_notrace();			\
> > +			it_func_ptr =					\
> > +				rcu_dereference_sched((tp)->funcs);	\
> > +		}							\
> > +									\
> >  		if (it_func_ptr) {					\
> >  			do {						\
> >  				it_func = (it_func_ptr)->func;		\
> > @@ -148,9 +177,13 @@ extern void syscall_unregfunc(void);
> >  				((void(*)(proto))(it_func))(args);	\
> >  			} while ((++it_func_ptr)->func);		\
> >  		}							\
> > -		rcu_read_unlock_sched_notrace();			\
> > -		if (rcucheck)						\
> > -			rcu_irq_exit_irqson();				\
> > +									\
> > +		if (rcuidle) {						\
> > +			preempt_enable_notrace();			\
> > +			srcu_read_unlock_notrace(&tracepoint_srcu, idx);\
> > +		} else {						\
> > +			rcu_read_unlock_sched_notrace();		\
> > +		}							\
> >  	} while (0)
> 
> In fact, I would write the thing like:
> 
> 		preempt_disable_notrace();
> 		if (rcuidle)
> 			idx = srcu_read_lock_notrace(&tracepoint_srcu);
> 
> 		it_func_ptr = rcu_dereference_raw((tp)->funcs);
> 
> 		/* ... */
> 
> 		if (rcu_idle)
> 			srcu_read_unlock_notrace(&tracepoint_srcu, idx);
> 		preempt_enable_notrace();
> 
> Much simpler and very much the same.

Cool, thanks! I will do it this way and resend.

- Joel

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  reply	other threads:[~2018-07-12  2:32 UTC|newest]

Thread overview: 156+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-07 20:38 [PATCH v9 0/7] Centralize and unify usage of preempt/irq Joel Fernandes
2018-06-07 20:38 ` [PATCH v9 4/7] tracepoint: Make rcuidle tracepoint callers use SRCU Joel Fernandes
2018-06-07 20:38   ` Joel Fernandes
2018-06-07 20:38   ` joelaf
2018-06-21 22:32 [PATCH v9 0/7] Centralize and unify usage of preempt/irq tracepoints Joel Fernandes
2018-06-21 22:32 ` [PATCH v9 4/7] tracepoint: Make rcuidle tracepoint callers use SRCU Joel Fernandes
2018-06-21 22:32   ` Joel Fernandes
2018-06-21 22:32   ` joel
2018-06-28 18:21 [PATCH v9 0/7] Centralize and unify usage of preempt/irq tracepoints Joel Fernandes
2018-06-28 18:21 ` Joel Fernandes
2018-06-28 18:21 ` joel
2018-06-28 18:21 ` [PATCH v9 1/7] srcu: Add notrace variants of srcu_read_{lock,unlock} Joel Fernandes
2018-06-28 18:21   ` Joel Fernandes
2018-06-28 18:21   ` joel
2018-06-28 18:21 ` [PATCH v9 2/7] srcu: Add notrace variant of srcu_dereference Joel Fernandes
2018-06-28 18:21   ` Joel Fernandes
2018-06-28 18:21   ` joel
2018-06-28 18:21 ` [PATCH v9 3/7] trace/irqsoff: Split reset into separate functions Joel Fernandes
2018-06-28 18:21   ` Joel Fernandes
2018-06-28 18:21   ` joel
2018-06-28 18:21 ` [PATCH v9 4/7] tracepoint: Make rcuidle tracepoint callers use SRCU Joel Fernandes
2018-06-28 18:21   ` Joel Fernandes
2018-06-28 18:21   ` joel
2018-07-11 12:49   ` Peter Zijlstra
2018-07-11 12:49     ` Peter Zijlstra
2018-07-11 12:49     ` peterz
2018-07-11 13:00     ` Steven Rostedt
2018-07-11 13:00       ` Steven Rostedt
2018-07-11 13:00       ` rostedt
2018-07-11 14:27       ` Paul E. McKenney
2018-07-11 14:27         ` Paul E. McKenney
2018-07-11 14:27         ` paulmck
2018-07-11 14:46         ` Steven Rostedt
2018-07-11 14:46           ` Steven Rostedt
2018-07-11 14:46           ` rostedt
2018-07-11 15:15           ` Paul E. McKenney
2018-07-11 15:15             ` Paul E. McKenney
2018-07-11 15:15             ` paulmck
2018-07-11 20:56             ` Joel Fernandes
2018-07-11 20:56               ` Joel Fernandes
2018-07-11 20:56               ` joel
2018-07-12  1:22               ` Steven Rostedt
2018-07-12  1:22                 ` Steven Rostedt
2018-07-12  1:22                 ` rostedt
2018-07-12  2:35                 ` Joel Fernandes
2018-07-12  2:35                   ` Joel Fernandes
2018-07-12  2:35                   ` joel
2018-07-11 20:52           ` Joel Fernandes
2018-07-11 20:52             ` Joel Fernandes
2018-07-11 20:52             ` joel
2018-07-12  3:21             ` Steven Rostedt
2018-07-12  3:21               ` Steven Rostedt
2018-07-12  3:21               ` rostedt
2018-07-12  4:28               ` Joel Fernandes
2018-07-12  4:28                 ` Joel Fernandes
2018-07-12  4:28                 ` joel
2018-07-12 13:35                 ` Steven Rostedt
2018-07-12 13:35                   ` Steven Rostedt
2018-07-12 13:35                   ` rostedt
2018-07-12 19:17                   ` Joel Fernandes
2018-07-12 19:17                     ` Joel Fernandes
2018-07-12 19:17                     ` joel
2018-07-12 20:15                     ` Steven Rostedt
2018-07-12 20:15                       ` Steven Rostedt
2018-07-12 20:15                       ` rostedt
2018-07-12 20:29                       ` Joel Fernandes
2018-07-12 20:29                         ` Joel Fernandes
2018-07-12 20:29                         ` joel
2018-07-12 20:31                         ` Steven Rostedt
2018-07-12 20:31                           ` Steven Rostedt
2018-07-12 20:31                           ` rostedt
2018-07-11 12:53   ` Peter Zijlstra
2018-07-11 12:53     ` Peter Zijlstra
2018-07-11 12:53     ` peterz
2018-07-12  2:32     ` Joel Fernandes [this message]
2018-07-12  2:32       ` Joel Fernandes
2018-07-12  2:32       ` joel
2018-07-11 12:56   ` Peter Zijlstra
2018-07-11 12:56     ` Peter Zijlstra
2018-07-11 12:56     ` peterz
2018-07-11 13:06     ` Steven Rostedt
2018-07-11 13:06       ` Steven Rostedt
2018-07-11 13:06       ` rostedt
2018-07-11 15:17       ` Peter Zijlstra
2018-07-11 15:17         ` Peter Zijlstra
2018-07-11 15:17         ` peterz
2018-07-11 15:26         ` Steven Rostedt
2018-07-11 15:26           ` Steven Rostedt
2018-07-11 15:26           ` rostedt
2018-07-11 16:46           ` Mathieu Desnoyers
2018-07-11 16:46             ` Mathieu Desnoyers
2018-07-11 16:46             ` mathieu.desnoyers
2018-07-11 16:40         ` Mathieu Desnoyers
2018-07-11 16:40           ` Mathieu Desnoyers
2018-07-11 16:40           ` mathieu.desnoyers
2018-07-12  0:31       ` Joel Fernandes
2018-07-12  0:31         ` Joel Fernandes
2018-07-12  0:31         ` joel
2018-07-12  1:26         ` Steven Rostedt
2018-07-12  1:26           ` Steven Rostedt
2018-07-12  1:26           ` rostedt
2018-06-28 18:21 ` [PATCH v9 5/7] tracing: Centralize preemptirq tracepoints and unify their usage Joel Fernandes
2018-06-28 18:21   ` Joel Fernandes
2018-06-28 18:21   ` joel
2018-07-06 22:06   ` Steven Rostedt
2018-07-06 22:06     ` Steven Rostedt
2018-07-06 22:06     ` rostedt
2018-07-07  4:20     ` Joel Fernandes
2018-07-07  4:20       ` Joel Fernandes
2018-07-07  4:20       ` joel
2018-07-10 14:20   ` Steven Rostedt
2018-07-10 14:20     ` Steven Rostedt
2018-07-10 14:20     ` rostedt
2018-07-10 17:33     ` Joel Fernandes
2018-07-10 17:33       ` Joel Fernandes
2018-07-10 17:33       ` joel
2018-07-11 13:12   ` Peter Zijlstra
2018-07-11 13:12     ` Peter Zijlstra
2018-07-11 13:12     ` peterz
2018-07-11 13:19     ` Steven Rostedt
2018-07-11 13:19       ` Steven Rostedt
2018-07-11 13:19       ` rostedt
2018-07-11 13:22       ` Steven Rostedt
2018-07-11 13:22         ` Steven Rostedt
2018-07-11 13:22         ` rostedt
2018-07-12  8:38       ` Joel Fernandes
2018-07-12  8:38         ` Joel Fernandes
2018-07-12  8:38         ` joel
2018-07-12 13:37         ` Steven Rostedt
2018-07-12 13:37           ` Steven Rostedt
2018-07-12 13:37           ` rostedt
2018-07-12  0:44     ` Joel Fernandes
2018-07-12  0:44       ` Joel Fernandes
2018-07-12  0:44       ` joel
2018-06-28 18:21 ` [PATCH v9 6/7] lib: Add module to simulate atomic sections for testing preemptoff tracers Joel Fernandes
2018-06-28 18:21   ` Joel Fernandes
2018-06-28 18:21   ` joel
2018-07-11  0:47   ` Steven Rostedt
2018-07-11  0:47     ` Steven Rostedt
2018-07-11  0:47     ` rostedt
2018-07-11  5:26     ` Joel Fernandes
2018-07-11  5:26       ` Joel Fernandes
2018-07-11  5:26       ` joel
2018-06-28 18:21 ` [PATCH v9 7/7] kselftests: Add tests for the preemptoff and irqsoff tracers Joel Fernandes
2018-06-28 18:21   ` Joel Fernandes
2018-06-28 18:21   ` joel
2018-07-11  0:49   ` Steven Rostedt
2018-07-11  0:49     ` Steven Rostedt
2018-07-11  0:49     ` rostedt
2018-07-11  5:27     ` Joel Fernandes
2018-07-11  5:27       ` Joel Fernandes
2018-07-11  5:27       ` joel
2018-07-03 14:15 ` [PATCH v9 0/7] Centralize and unify usage of preempt/irq tracepoints Joel Fernandes
2018-07-03 14:15   ` Joel Fernandes
2018-07-03 14:15   ` joel
2018-07-03 14:23   ` Steven Rostedt
2018-07-03 14:23     ` Steven Rostedt
2018-07-03 14:23     ` rostedt

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