Messages in this thread | | | Date | Tue, 15 Nov 2011 13:13:02 -0800 | From | Josh Triplett <> | Subject | Re: [PATCH tip/core/rcu 4/9] sched: add is_idle_task() to handle invalidated uses of idle_cpu() |
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On Tue, Nov 15, 2011 at 12:28:00PM -0800, Paul E. McKenney wrote: > From: Paul E. McKenney <paul.mckenney@linaro.org> > > Commit 908a3283 (Fix idle_cpu()) invalidated some uses of idle_cpu(), > which used to say whether or not the CPU was running the idle task, > but now instead says whether or not the CPU is running the idle task > in the absence of pending wakeups. Although this new implementation > gives a better answer to the question "is this CPU idle?", it also > invalidates other uses that were made of idle_cpu(). > > This commit therefore introduces a new is_idle_task() API member > that determines whether or not the specified task is one of the > idle tasks, allowing open-coded "->pid == 0" sequences to be replaced > by something more meaningful. > > Suggested-by: Josh Triplett <josh@joshtriplett.org> > Suggested-by: Peter Zijlstra <peterz@infradead.org> > Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > --- > include/linux/sched.h | 1 + > kernel/sched.c | 9 +++++++++ > 2 files changed, 10 insertions(+), 0 deletions(-) > > diff --git a/include/linux/sched.h b/include/linux/sched.h > index 68daf4f..4b1077b 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -2071,6 +2071,7 @@ extern int sched_setscheduler(struct task_struct *, int, > extern int sched_setscheduler_nocheck(struct task_struct *, int, > const struct sched_param *); > extern struct task_struct *idle_task(int cpu); > +extern int is_idle_task(struct task_struct *p);
The kernel has a bool type; please use it here rather than int, to make the return value more obvious.
Also, any particular reason not to make this a static inline?
- Josh Triplett
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