Messages in this thread | | | Date | Sat, 2 Dec 2017 09:56:26 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH tip/core/rcu 10/10] rcu: Account for rcu_all_qs() in cond_resched() |
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On Fri, Dec 01, 2017 at 11:21:44AM -0800, Paul E. McKenney wrote: > If cond_resched() returns false, then it has already invoked > rcu_all_qs(). This is also invoked (now redundantly) by > rcu_note_voluntary_context_switch(). This commit therefore changes > cond_resched_rcu_qs() to invoke rcu_note_voluntary_context_switch_lite() > instead of rcu_note_voluntary_context_switch() to avoid the redundant > invocation of rcu_all_qs(). > > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > --- > include/linux/rcupdate.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h > index a6ddc42f87a5..7bd8b5a6db10 100644 > --- a/include/linux/rcupdate.h > +++ b/include/linux/rcupdate.h > @@ -197,7 +197,7 @@ static inline void exit_tasks_rcu_finish(void) { } > #define cond_resched_rcu_qs() \ > do { \ > if (!cond_resched()) \ > - rcu_note_voluntary_context_switch(current); \ > + rcu_note_voluntary_context_switch_lite(current); \ > } while (0) >
Maybe I'm confused, but why are we keeping cond_resched_rcu_qs() around at all?
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