| Date | Mon, 16 Jan 2017 00:08:43 -0800 | From | Josh Triplett <> | Subject | Re: [PATCH tip/core/rcu 11/20] sched,rcu: Make cond_resched() provide RCU quiescent state |
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On Sat, Jan 14, 2017 at 01:13:12AM -0800, Paul E. McKenney wrote: > There is some confusion as to which of cond_resched() or > cond_resched_rcu_qs() should be added to long in-kernel loops. > This commit therefore eliminates the decision by adding RCU > quiescent states to cond_resched(). > > Warning: This is a prototype. For example, it does not correctly > handle Tasks RCU. Which is OK for the moment, given that no one > actually uses Tasks RCU yet. > > Reported-by: Michal Hocko <mhocko@kernel.org> > Not-yet-signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > Cc: Peter Zijlstra <peterz@infradead.org>
Do you intend to merge this patch, or have you just posted it for review?
You may want to remove it from this 20-patch series and post it as a separate RFC PATCH, to ensure that it doesn't get merged while still a prototype.
> include/linux/sched.h | 3 ++- > kernel/sched/core.c | 1 + > 2 files changed, 3 insertions(+), 1 deletion(-) > > diff --git a/include/linux/sched.h b/include/linux/sched.h > index 4d1905245c7a..1531c48f56e2 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -3352,10 +3352,11 @@ static inline int signal_pending_state(long state, struct task_struct *p) > * cond_resched_lock() will drop the spinlock before scheduling, > * cond_resched_softirq() will enable bhs before scheduling. > */ > +void rcu_all_qs(void); > #ifndef CONFIG_PREEMPT > extern int _cond_resched(void); > #else > -static inline int _cond_resched(void) { return 0; } > +static inline int _cond_resched(void) { rcu_all_qs(); return 0; } > #endif > > #define cond_resched() ({ \ > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index c56fb57f2991..b442f8918eb9 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -4907,6 +4907,7 @@ int __sched _cond_resched(void) > preempt_schedule_common(); > return 1; > } > + rcu_all_qs(); > return 0; > } > EXPORT_SYMBOL(_cond_resched); > -- > 2.5.2 >
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