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From: Peter Zijlstra <peterz@infradead.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
	mingo@kernel.org, joel@joelfernandes.org,
	gregkh@linuxfoundation.org, gustavo@embeddedor.com,
	tglx@linutronix.de, paulmck@kernel.org, josh@joshtriplett.org,
	mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com
Subject: Re: [PATCH 8/8] tracing: Remove regular RCU context for _rcuidle tracepoints (again)
Date: Wed, 12 Feb 2020 16:12:53 +0100	[thread overview]
Message-ID: <20200212151253.GU14897@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200212092952.7bec74e9@gandalf.local.home>

On Wed, Feb 12, 2020 at 09:29:52AM -0500, Steven Rostedt wrote:
> On Wed, 12 Feb 2020 10:32:18 +0100
> Peter Zijlstra <peterz@infradead.org> wrote:
> 
> > Effectively revert commit 865e63b04e9b2 ("tracing: Add back in
> > rcu_irq_enter/exit_irqson() for rcuidle tracepoints") now that we've
> > taught perf how to deal with not having an RCU context provided.
> > 
> > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> > ---
> >  include/linux/tracepoint.h |    8 ++------
> >  1 file changed, 2 insertions(+), 6 deletions(-)
> > 
> > --- a/include/linux/tracepoint.h
> > +++ b/include/linux/tracepoint.h
> > @@ -179,10 +179,8 @@ static inline struct tracepoint *tracepo
> >  		 * For rcuidle callers, use srcu since sched-rcu	\
> >  		 * doesn't work from the idle path.			\
> >  		 */							\
> > -		if (rcuidle) {						\
> > +		if (rcuidle)						\
> >  			__idx = srcu_read_lock_notrace(&tracepoint_srcu);\
> > -			rcu_irq_enter_irqsave();			\
> > -		}							\
> >  									\
> >  		it_func_ptr = rcu_dereference_raw((tp)->funcs);		\
> >  									\
> > @@ -194,10 +192,8 @@ static inline struct tracepoint *tracepo
> >  			} while ((++it_func_ptr)->func);		\
> >  		}							\
> >  									\
> > -		if (rcuidle) {						\
> > -			rcu_irq_exit_irqsave();				\
> > +		if (rcuidle)						\
> >  			srcu_read_unlock_notrace(&tracepoint_srcu, __idx);\
> > -		}							\
> >  									\
> >  		preempt_enable_notrace();				\
> >  	} while (0)
> > 
> 
> Which looks basically the same as this patch...
> 
>   https://lore.kernel.org/r/20200211095047.58ddf750@gandalf.local.home

It is a straight revert of 865e63b04e9b2, how different do you want it
to look?

Also it very much isn't that patch, as this one only does the revert and
doesn't mix it in with other stuff.

  reply	other threads:[~2020-02-12 15:13 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-12  9:32 [PATCH 0/8] tracing vs rcu vs nmi Peter Zijlstra
2020-02-12  9:32 ` [PATCH 1/8] rcu: Rename rcu_irq_{enter,exit}_irqson() Peter Zijlstra
2020-02-12  9:32 ` [PATCH 2/8] rcu: Mark rcu_dynticks_curr_cpu_in_eqs() inline Peter Zijlstra
2020-02-12  9:32 ` [PATCH 3/8] rcu,tracing: Create trace_rcu_{enter,exit}() Peter Zijlstra
2020-02-12  9:32 ` [PATCH 4/8] sched,rcu,tracing: Mark preempt_count_{add,sub}() notrace Peter Zijlstra
2020-02-12 14:24   ` Steven Rostedt
2020-02-12 15:02     ` Peter Zijlstra
2020-02-12 15:14       ` Steven Rostedt
2020-02-12 15:38         ` Peter Zijlstra
2020-02-12  9:32 ` [PATCH 5/8] x86,tracing: Mark debug_stack_{set_zero,reset)() notrace Peter Zijlstra
2020-02-12 14:25   ` Steven Rostedt
2020-02-12 15:04     ` Peter Zijlstra
2020-02-12 15:18       ` Steven Rostedt
2020-02-12 15:39         ` Peter Zijlstra
2020-02-12  9:32 ` [PATCH 6/8] perf,tracing: Prepare the perf-trace interface for RCU changes Peter Zijlstra
2020-02-12 14:26   ` Steven Rostedt
2020-02-12 15:07     ` Mathieu Desnoyers
2020-02-12  9:32 ` [PATCH 7/8] tracing: Employ trace_rcu_{enter,exit}() Peter Zijlstra
2020-02-12  9:32 ` [PATCH 8/8] tracing: Remove regular RCU context for _rcuidle tracepoints (again) Peter Zijlstra
2020-02-12 14:29   ` Steven Rostedt
2020-02-12 15:12     ` Peter Zijlstra [this message]
2020-02-12 10:01 ` [PATCH 0/8] tracing vs rcu vs nmi Peter Zijlstra
2020-02-12 10:56   ` Will Deacon
2020-02-12 11:58     ` Peter Zijlstra
2020-02-12 14:32     ` Steven Rostedt
2020-02-12 15:21       ` Peter Zijlstra
2020-02-12 10:03 ` Peter Zijlstra
2020-02-12 10:07 ` Peter Zijlstra
2020-02-12 10:09 ` Peter Zijlstra

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