On 21/04/17 11:42, Luca Abeni wrote: > On Fri, 21 Apr 2017 10:39:26 +0100 > Juri Lelli <juri.le...@arm.com> wrote: > > > Hi Luca, > > > > On 20/04/17 21:30, Luca Abeni wrote: > > > From: Luca Abeni <luca.ab...@santannapisa.it> > > > > > > When switching to -deadline, if the scheduling deadline of a task is > > > in the past then switched_to_dl() calls setup_new_entity() to > > > properly initialize the scheduling deadline and runtime. > > > > > > The problem is that the task is enqueued _before_ having its > > > parameters initialized by setup_new_entity(), and this can cause > > > problems. For example, a task with its out-of-date deadline in the > > > past will potentially be enqueued as the highest priority one; > > > however, its adjusted deadline may not be the earliest one. > > > > > > This patch fixes the problem by initializing the task's parameters > > > before enqueuing it. > > > > > > Signed-off-by: Luca Abeni <luca.ab...@santannapisa.it> > > > Reviewed-by: Daniel Bristot de Oliveira <bris...@redhat.com> > > > --- > > > kernel/sched/deadline.c | 12 ++++-------- > > > 1 file changed, 4 insertions(+), 8 deletions(-) > > > > > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > > > index a2ce590..ec53d24 100644 > > > --- a/kernel/sched/deadline.c > > > +++ b/kernel/sched/deadline.c > > > @@ -950,6 +950,10 @@ enqueue_dl_entity(struct sched_dl_entity > > > *dl_se, update_dl_entity(dl_se, pi_se); > > > else if (flags & ENQUEUE_REPLENISH) > > > replenish_dl_entity(dl_se, pi_se); > > > + else if ((flags & ENQUEUE_RESTORE) && > > > > Not sure I understand how this works. AFAICT we are doing > > __sched_setscheduler() when we want to catch the case of a new > > dl_entity (SCHED_{OTHER,FIFO} -> SCHED_DEADLINE}, but queue_flags > > (which are passed to enqueue_task()) don't seem to have > > ENQUEUE_RESTORE set? > > I was under the impression sched_setscheduler() sets ENQUEUE_RESTORE... >
Oh, I think it works "by coincidence", as ENQUEUE_RESTORE == DEQUEUE_SAVE == 0x02 ? :)