Messages in this thread | | | Date | Mon, 16 Jan 2017 17:43:37 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH tip/core/rcu 3/6] rcu: Abstract dynticks extended quiescent state enter/exit operations |
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On Sat, Jan 14, 2017 at 12:54:42AM -0800, Paul E. McKenney wrote: > /* > + * Record entry into an extended quiescent state. This is only to be > + * called when not already in an extended quiescent state. > + */ > +static void rcu_dynticks_eqs_enter(void) > +{ > + struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks); > + > + /* > + * CPUs seeing atomic_inc() must see prior RCU read-side critical > + * sections, and we also must force ordering with the next idle > + * sojourn. > + */ > + smp_mb__before_atomic(); /* See above. */ > + atomic_inc(&rdtp->dynticks); > + smp_mb__after_atomic(); /* See above. */ > + WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && > + atomic_read(&rdtp->dynticks) & 0x1); > +}
In an earlier patch you replaced things with atomic_add_return(), why not use atomic_inc_return() here?
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