Messages in this thread Patch in this message | | | Date | Wed, 12 Feb 2020 01:05:20 -0800 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH v2] tracing/perf: Move rcu_irq_enter/exit_irqson() to perf trace point hook |
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On Wed, Feb 12, 2020 at 09:05:22AM +0100, Peter Zijlstra wrote: > On Tue, Feb 11, 2020 at 10:54:57AM -0800, Paul E. McKenney wrote: > > On Tue, Feb 11, 2020 at 06:32:13PM +0100, Peter Zijlstra wrote: > > > On Tue, Feb 11, 2020 at 06:29:52PM +0100, Peter Zijlstra wrote: > > > > +#define trace_rcu_enter() \ > > > > +({ \ > > > > + unsigned long state = 0; \ > > > > + if (!rcu_is_watching()) { \ > > > > > > Also, afaict rcu_is_watching() itself needs more love, the functio has > > > notrace, but calls other stuff that does not have notrace or inline. > > > > Good catch! Like this? > > > > Thanx, Paul > > > > ------------------------------------------------------------------------ > > > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > > index 1f5fdf7..51616e72 100644 > > --- a/kernel/rcu/tree.c > > +++ b/kernel/rcu/tree.c > > @@ -295,7 +295,7 @@ static void rcu_dynticks_eqs_online(void) > > * > > * No ordering, as we are sampling CPU-local information. > > */ > > -static bool rcu_dynticks_curr_cpu_in_eqs(void) > > +static bool notrace rcu_dynticks_curr_cpu_in_eqs(void) > > Right, except that, given the size of the thing, I'd opt for 'inline' > over 'notrace'.
Like this, then?
Thanx, Paul
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commit 164a7e5204cf32d22d0e444efd97ac7f2243b8d2 Author: Paul E. McKenney <paulmck@kernel.org> Date: Tue Feb 11 11:10:00 2020 -0800
rcu: Make rcu_dynticks_curr_cpu_in_eqs() be inline The rcu_is_watching() function is and must be notrace in order to allow it to be used by the tracing infrastructure. However, it also invokes rcu_dynticks_curr_cpu_in_eqs(), which therefore needs to be either notrace or inline. But isn't. This commit therefore adds "inline" to the rcu_dynticks_curr_cpu_in_eqs() definition. Reported-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 1f5fdf7..16fd113 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -295,7 +295,7 @@ static void rcu_dynticks_eqs_online(void) * * No ordering, as we are sampling CPU-local information. */ -static bool rcu_dynticks_curr_cpu_in_eqs(void) +static bool inline rcu_dynticks_curr_cpu_in_eqs(void) { struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
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