Re: [PATCH v2] drm/sched: Further optimise drm_sched_entity_push_job

[Christian König <christian.koenig@xxxxxxx>]

Am 26.09.24 um 10:18 schrieb Philipp Stanner:
> On Tue, 2024-09-24 at 14:02 +0200, Christian König wrote:
> > Am 24.09.24 um 11:58 schrieb Tvrtko Ursulin:
> > > On 24/09/2024 10:45, Tvrtko Ursulin wrote:
> > > > On 24/09/2024 09:20, Christian König wrote:
> > > > > Am 16.09.24 um 19:30 schrieb Tvrtko Ursulin:
> > > > > > From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxx>
> > > > > >
> > > > > > Having removed one re-lock cycle on the entity->lock in a
> > > > > > patch titled
> > > > > > "drm/sched: Optimise drm_sched_entity_push_job", with only a
> > > > > > tiny bit
> > > > > > larger refactoring we can do the same optimisation on the rq-
> > > > > > > lock.
> > > > > > (Currently both drm_sched_rq_add_entity() and
> > > > > > drm_sched_rq_update_fifo_locked() take and release the same
> > > > > > lock.)
> > > > > >
> > > > > > To achieve this we make drm_sched_rq_update_fifo_locked() and
> > > > > > drm_sched_rq_add_entity() expect the rq->lock to be held.
> > > > > >
> > > > > > We also align drm_sched_rq_update_fifo_locked(),
> > > > > > drm_sched_rq_add_entity() and
> > > > > > drm_sched_rq_remove_fifo_locked() function signatures, by
> > > > > > adding rq
> > > > > > as a
> > > > > > parameter to the latter.
> > > > > >
> > > > > > v2:
> > > > > >    * Fix after rebase of the series.
> > > > > >    * Avoid naming incosistency between
> > > > > > drm_sched_rq_add/remove.
> > > > > > (Christian)
> > > > > >
> > > > > > Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxx>
> > > > > > Cc: Christian König <christian.koenig@xxxxxxx>
> > > > > > Cc: Alex Deucher <alexander.deucher@xxxxxxx>
> > > > > > Cc: Luben Tuikov <ltuikov89@xxxxxxxxx>
> > > > > > Cc: Matthew Brost <matthew.brost@xxxxxxxxx>
> > > > > > Cc: Philipp Stanner <pstanner@xxxxxxxxxx>
> > > > > Reviewed-by: Christian König <christian.koenig@xxxxxxx>
> > > > Thanks!
> > > >
> > > > Are you okay to pull into drm-misc-next or we should do some more
> > > > testing on this?
> > > >
> > > > And/or should I resend the series once more in it's entirety so
> > > > this
> > > > v2 is not a reply-to to the original?
> > > I have to respin for the drm_sched_wakeup fix that landed.
> > When I should push the series to drm-misc-next then please send it to
> > me
> > once more.
> >
> > On the other hand we should now have to maintainers for that.
> Yup, will pick up this responsibilities soonish. Danilo and I have been
> on conference recently and I'm out of office soon for a bit, but you
> can expect me / us to take over that work soonish in early autumn.

But please don't push this set. I have messed up the push because I 
didn't realized that the first three patches were supposed to land in 
-fixes instead of -next.

Should be cleaned up my me by the end of the day.

Sorry for the noise,
Christian.

> Regards,
> P.
>
> > Regards,
> > Christian.
> >
> > > Regards,
> > >
> > > Tvrtko
> > >
> > > > Regards,
> > > >
> > > > Tvrtko
> > > >
> > > > > > ---
> > > > > >    drivers/gpu/drm/scheduler/sched_entity.c | 12 ++++++++--
> > > > > >    drivers/gpu/drm/scheduler/sched_main.c   | 29
> > > > > > ++++++++++++------------
> > > > > >    include/drm/gpu_scheduler.h              |  3 ++-
> > > > > >    3 files changed, 26 insertions(+), 18 deletions(-)
> > > > > >
> > > > > > diff --git a/drivers/gpu/drm/scheduler/sched_entity.c
> > > > > > b/drivers/gpu/drm/scheduler/sched_entity.c
> > > > > > index d982cebc6bee..8ace1f1ea66b 100644
> > > > > > --- a/drivers/gpu/drm/scheduler/sched_entity.c
> > > > > > +++ b/drivers/gpu/drm/scheduler/sched_entity.c
> > > > > > @@ -515,9 +515,14 @@ struct drm_sched_job
> > > > > > *drm_sched_entity_pop_job(struct drm_sched_entity *entity)
> > > > > >            next =
> > > > > > to_drm_sched_job(spsc_queue_peek(&entity->job_queue));
> > > > > >            if (next) {
> > > > > > +            struct drm_sched_rq *rq;
> > > > > > +
> > > > > >                spin_lock(&entity->lock);
> > > > > > -            drm_sched_rq_update_fifo_locked(entity,
> > > > > > +            rq = entity->rq;
> > > > > > +            spin_lock(&rq->lock);
> > > > > > +            drm_sched_rq_update_fifo_locked(entity, rq,
> > > > > >                                next->submit_ts);
> > > > > > +            spin_unlock(&rq->lock);
> > > > > >                spin_unlock(&entity->lock);
> > > > > >            }
> > > > > >        }
> > > > > > @@ -618,11 +623,14 @@ void drm_sched_entity_push_job(struct
> > > > > > drm_sched_job *sched_job)
> > > > > >            sched = rq->sched;
> > > > > >            atomic_inc(sched->score);
> > > > > > +
> > > > > > +        spin_lock(&rq->lock);
> > > > > >            drm_sched_rq_add_entity(rq, entity);
> > > > > >            if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
> > > > > > -            drm_sched_rq_update_fifo_locked(entity,
> > > > > > submit_ts);
> > > > > > +            drm_sched_rq_update_fifo_locked(entity, rq,
> > > > > > submit_ts);
> > > > > > +        spin_unlock(&rq->lock);
> > > > > >            spin_unlock(&entity->lock);
> > > > > >            drm_sched_wakeup(sched, entity);
> > > > > > diff --git a/drivers/gpu/drm/scheduler/sched_main.c
> > > > > > b/drivers/gpu/drm/scheduler/sched_main.c
> > > > > > index 18a952f73ecb..5c83fb92bb89 100644
> > > > > > --- a/drivers/gpu/drm/scheduler/sched_main.c
> > > > > > +++ b/drivers/gpu/drm/scheduler/sched_main.c
> > > > > > @@ -153,17 +153,18 @@ static __always_inline bool
> > > > > > drm_sched_entity_compare_before(struct rb_node *a,
> > > > > >        return ktime_before(ent_a->oldest_job_waiting,
> > > > > > ent_b->oldest_job_waiting);
> > > > > >    }
> > > > > > -static inline void drm_sched_rq_remove_fifo_locked(struct
> > > > > > drm_sched_entity *entity)
> > > > > > +static void drm_sched_rq_remove_fifo_locked(struct
> > > > > > drm_sched_entity *entity,
> > > > > > +                        struct drm_sched_rq *rq)
> > > > > >    {
> > > > > > -    struct drm_sched_rq *rq = entity->rq;
> > > > > > -
> > > > > >        if (!RB_EMPTY_NODE(&entity->rb_tree_node)) {
> > > > > >            rb_erase_cached(&entity->rb_tree_node, &rq-
> > > > > > > rb_tree_root);
> > > > > >            RB_CLEAR_NODE(&entity->rb_tree_node);
> > > > > >        }
> > > > > >    }
> > > > > > -void drm_sched_rq_update_fifo_locked(struct drm_sched_entity
> > > > > > *entity, ktime_t ts)
> > > > > > +void drm_sched_rq_update_fifo_locked(struct drm_sched_entity
> > > > > > *entity,
> > > > > > +                     struct drm_sched_rq *rq,
> > > > > > +                     ktime_t ts)
> > > > > >    {
> > > > > >        /*
> > > > > >         * Both locks need to be grabbed, one to protect from
> > > > > > entity->rq change
> > > > > > @@ -171,17 +172,14 @@ void
> > > > > > drm_sched_rq_update_fifo_locked(struct
> > > > > > drm_sched_entity *entity, ktime_t ts
> > > > > >         * other to update the rb tree structure.
> > > > > >         */
> > > > > >        lockdep_assert_held(&entity->lock);
> > > > > > +    lockdep_assert_held(&rq->lock);
> > > > > > -    spin_lock(&entity->rq->lock);
> > > > > > -
> > > > > > -    drm_sched_rq_remove_fifo_locked(entity);
> > > > > > +    drm_sched_rq_remove_fifo_locked(entity, rq);
> > > > > >        entity->oldest_job_waiting = ts;
> > > > > > -    rb_add_cached(&entity->rb_tree_node, &entity->rq-
> > > > > > > rb_tree_root,
> > > > > > +    rb_add_cached(&entity->rb_tree_node, &rq->rb_tree_root,
> > > > > >                  drm_sched_entity_compare_before);
> > > > > > -
> > > > > > -    spin_unlock(&entity->rq->lock);
> > > > > >    }
> > > > > >    /**
> > > > > > @@ -213,15 +211,14 @@ static void drm_sched_rq_init(struct
> > > > > > drm_gpu_scheduler *sched,
> > > > > >    void drm_sched_rq_add_entity(struct drm_sched_rq *rq,
> > > > > >                     struct drm_sched_entity *entity)
> > > > > >    {
> > > > > > +    lockdep_assert_held(&entity->lock);
> > > > > > +    lockdep_assert_held(&rq->lock);
> > > > > > +
> > > > > >        if (!list_empty(&entity->list))
> > > > > >            return;
> > > > > > -    spin_lock(&rq->lock);
> > > > > > -
> > > > > >        atomic_inc(rq->sched->score);
> > > > > >        list_add_tail(&entity->list, &rq->entities);
> > > > > > -
> > > > > > -    spin_unlock(&rq->lock);
> > > > > >    }
> > > > > >    /**
> > > > > > @@ -235,6 +232,8 @@ void drm_sched_rq_add_entity(struct
> > > > > > drm_sched_rq *rq,
> > > > > >    void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
> > > > > >                    struct drm_sched_entity *entity)
> > > > > >    {
> > > > > > +    lockdep_assert_held(&entity->lock);
> > > > > > +
> > > > > >        if (list_empty(&entity->list))
> > > > > >            return;
> > > > > > @@ -247,7 +246,7 @@ void drm_sched_rq_remove_entity(struct
> > > > > > drm_sched_rq *rq,
> > > > > >            rq->current_entity = NULL;
> > > > > >        if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
> > > > > > -        drm_sched_rq_remove_fifo_locked(entity);
> > > > > > +        drm_sched_rq_remove_fifo_locked(entity, rq);
> > > > > >        spin_unlock(&rq->lock);
> > > > > >    }
> > > > > > diff --git a/include/drm/gpu_scheduler.h
> > > > > > b/include/drm/gpu_scheduler.h
> > > > > > index 80198e6cf537..b21806d5a8eb 100644
> > > > > > --- a/include/drm/gpu_scheduler.h
> > > > > > +++ b/include/drm/gpu_scheduler.h
> > > > > > @@ -596,7 +596,8 @@ void drm_sched_rq_add_entity(struct
> > > > > > drm_sched_rq *rq,
> > > > > >    void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
> > > > > >                    struct drm_sched_entity *entity);
> > > > > > -void drm_sched_rq_update_fifo_locked(struct drm_sched_entity
> > > > > > *entity, ktime_t ts);
> > > > > > +void drm_sched_rq_update_fifo_locked(struct drm_sched_entity
> > > > > > *entity,
> > > > > > +                     struct drm_sched_rq *rq, ktime_t ts);
> > > > > >    int drm_sched_entity_init(struct drm_sched_entity *entity,
> > > > > >                  enum drm_sched_priority priority,