>>> On Wed, Apr 23, 2008 at 7:13 AM, in message <20080423111329.4981.88455.stgit@xxxxxxxxxxxxxxxxxxx>, Gregory Haskins <ghaskins@xxxxxxxxxx> wrote: > Dmitry Adamushko pointed out a logic error in task_wake_up_rt() where we > will always evaluate to "true". You can find the thread here: > > http://lkml.org/lkml/2008/4/22/296 > > In reality, we only want to try to push tasks away when a wake up request is > not going to preempt the current task. So lets fix it. > > Note: We introduce test_tsk_need_resched() instead of open-coding the flag > check so that the merge-conflict with -rt should help remind us that we > may need to support NEEDS_RESCHED_DELAYED in the future, too. > > Signed-off-by: Gregory Haskins <ghaskins@xxxxxxxxxx> > CC: Dmitry Adamushko <dmitry.adamushko@xxxxxxxxx> > CC: Ingo Molnar <mingo@xxxxxxx> > CC: Steven Rostedt <rostedt@xxxxxxxxxxx> Hi Ingo, So based on the discussion and the sign-off on this patch from Dmitry and Steven, I would propose to move patch #1 from "RFC" to "Consider for inclusion" status. Patch #2 should remain RFC pending further discussion. I would recommend #1 to be considered for both 25.y stable as well as going into the 26 merge window (pending positive testing results, and your discretion). Regards, -Greg > --- > > include/linux/sched.h | 7 ++++++- > kernel/sched_rt.c | 7 +++++-- > 2 files changed, 11 insertions(+), 3 deletions(-) > > diff --git a/include/linux/sched.h b/include/linux/sched.h > index 949bd54..55d4bd4 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -1966,6 +1966,11 @@ static inline void clear_tsk_need_resched(struct > task_struct *tsk) > clear_tsk_thread_flag(tsk,TIF_NEED_RESCHED); > } > > +static inline int test_tsk_need_resched(struct task_struct *tsk) > +{ > + return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED)); > +} > + > static inline int signal_pending(struct task_struct *p) > { > return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING)); > @@ -1980,7 +1985,7 @@ static inline int fatal_signal_pending(struct > task_struct *p) > > static inline int need_resched(void) > { > - return unlikely(test_thread_flag(TIF_NEED_RESCHED)); > + return unlikely(test_tsk_need_resched(current)); > } > > /* > diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c > index 79e5ad5..ae6b0e6 100644 > --- a/kernel/sched_rt.c > +++ b/kernel/sched_rt.c > @@ -1058,11 +1058,14 @@ static void post_schedule_rt(struct rq *rq) > } > } > > - > +/* > + * If we are not running and we are not going to reschedule soon, we should > + * try to push tasks away now > + */ > static void task_wake_up_rt(struct rq *rq, struct task_struct *p) > { > if (!task_running(rq, p) && > - (p->prio >= rq->rt.highest_prio) && > + !test_tsk_need_resched(rq->curr) && > rq->rt.overloaded) > push_rt_tasks(rq); > } > > -- > To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
