Re: [PATCH] sched/deadline: dome some cleanup for push_dl_task()
On Fri, Jul 24, 2020 at 09:14:26AM +0200, 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 > > --- > > 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(). > Thanks for your time. > 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". > > Thanks, > > Juri >
Re: [PATCH] sched/deadline: dome some cleanup for push_dl_task()
On 24/07/2020 17:31, Daniel Bristot de Oliveira wrote: > 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 >>> --- >>> 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 Yes, makes sense to me! Reviewed-by: Dietmar Eggemann
Re: [PATCH] sched/deadline: dome some cleanup for push_dl_task()
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 >> --- >> 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 Thanks -- Daniel
Re: [PATCH] sched/deadline: dome some cleanup for push_dl_task()
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 > --- > 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". Thanks, Juri
[PATCH] sched/deadline: dome some cleanup for push_dl_task()
'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 --- 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; resched_curr(later_rq); -- 2.20.1