On 7/24/20 9:14 AM, Juri Lelli wrote: > Hi, > > On 07/07/20 00:04, Peng Liu wrote: >> 'commit 840d719604b0 ("sched/deadline: Update rq_clock of later_rq when >> pushing a task")' >> introduced the update_rq_clock() to fix the "used-before-update" bug. >> >> 'commit f4904815f97a ("sched/deadline: Fix double accounting of rq/running >> bw in push & pull")' >> took away the bug source(add_running_bw()). >> >> We no longer need to update rq_clock in advance, let activate_task() >> worry about that. >> >> Signed-off-by: Peng Liu <iwtba...@gmail.com> >> --- >> kernel/sched/deadline.c | 8 +------- >> 1 file changed, 1 insertion(+), 7 deletions(-) >> >> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c >> index 504d2f51b0d6..c3fa11f84d93 100644 >> --- a/kernel/sched/deadline.c >> +++ b/kernel/sched/deadline.c >> @@ -2104,13 +2104,7 @@ static int push_dl_task(struct rq *rq) >> >> deactivate_task(rq, next_task, 0); >> set_task_cpu(next_task, later_rq->cpu); >> - >> - /* >> - * Update the later_rq clock here, because the clock is used >> - * by the cpufreq_update_util() inside __add_running_bw(). >> - */ >> - update_rq_clock(later_rq); >> - activate_task(later_rq, next_task, ENQUEUE_NOCLOCK); >> + activate_task(later_rq, next_task, 0); >> ret = 1; > The change looks good to me, since now add_running_bw() is called later > by enqueue_task_dl(), but rq_clock has already been updated by core's > enqueue_task(). > > Daniel, Dietmar, a second pair of eyes (since you authored the commits > above)? > > I'd chage subject to something like "sched/deadline: Stop updating > rq_clock before pushing a task".
Looks good to me! Acked-by: Daniel Bristot de Oliveira <bris...@redhat.com> Thanks -- Daniel