[Intel-gfx] [PATCH 7/9] drm/i915: Update i915_scheduler to operate on i915_sched_engine

Jason Ekstrand jason at jlekstrand.net
Fri Jun 4 19:17:58 UTC 2021


On Thu, Jun 3, 2021 at 4:09 PM Matthew Brost <matthew.brost at intel.com> wrote:
>
> Rather passing around an intel_engine_cs in the scheduling code, pass
> around a i915_sched_engine.

👍

> Signed-off-by: Matthew Brost <matthew.brost at intel.com>
> ---
>  .../drm/i915/gt/intel_execlists_submission.c  | 11 +++--
>  .../gpu/drm/i915/gt/uc/intel_guc_submission.c |  2 +-
>  drivers/gpu/drm/i915/i915_scheduler.c         | 46 +++++++++----------
>  drivers/gpu/drm/i915/i915_scheduler.h         |  2 +-
>  4 files changed, 32 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> index 3fac17103837..7240c153be35 100644
> --- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> +++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> @@ -382,7 +382,8 @@ __unwind_incomplete_requests(struct intel_engine_cs *engine)
>                 GEM_BUG_ON(rq_prio(rq) == I915_PRIORITY_INVALID);
>                 if (rq_prio(rq) != prio) {
>                         prio = rq_prio(rq);
> -                       pl = i915_sched_lookup_priolist(engine, prio);
> +                       pl = i915_sched_lookup_priolist(engine->sched_engine,
> +                                                       prio);
>                 }
>                 GEM_BUG_ON(i915_sched_engine_is_empty(engine->sched_engine));
>
> @@ -1096,7 +1097,8 @@ static void defer_active(struct intel_engine_cs *engine)
>         if (!rq)
>                 return;
>
> -       defer_request(rq, i915_sched_lookup_priolist(engine, rq_prio(rq)));
> +       defer_request(rq, i915_sched_lookup_priolist(engine->sched_engine,
> +                                                    rq_prio(rq)));
>  }
>
>  static bool
> @@ -2083,7 +2085,7 @@ static void __execlists_unhold(struct i915_request *rq)
>
>                 i915_request_clear_hold(rq);
>                 list_move_tail(&rq->sched.link,
> -                              i915_sched_lookup_priolist(rq->engine,
> +                              i915_sched_lookup_priolist(rq->engine->sched_engine,
>                                                           rq_prio(rq)));
>                 set_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
>
> @@ -2452,7 +2454,8 @@ static void queue_request(struct intel_engine_cs *engine,
>  {
>         GEM_BUG_ON(!list_empty(&rq->sched.link));
>         list_add_tail(&rq->sched.link,
> -                     i915_sched_lookup_priolist(engine, rq_prio(rq)));
> +                     i915_sched_lookup_priolist(engine->sched_engine,
> +                                                rq_prio(rq)));
>         set_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
>  }
>
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> index 4c5bbec0775d..7ed21670ef14 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -529,7 +529,7 @@ static inline void queue_request(struct intel_engine_cs *engine,
>  {
>         GEM_BUG_ON(!list_empty(&rq->sched.link));
>         list_add_tail(&rq->sched.link,
> -                     i915_sched_lookup_priolist(engine, prio));
> +                     i915_sched_lookup_priolist(engine->sched_engine, prio));
>         set_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
>  }
>
> diff --git a/drivers/gpu/drm/i915/i915_scheduler.c b/drivers/gpu/drm/i915/i915_scheduler.c
> index 035b88f2e4aa..3d36e4447b5d 100644
> --- a/drivers/gpu/drm/i915/i915_scheduler.c
> +++ b/drivers/gpu/drm/i915/i915_scheduler.c
> @@ -61,14 +61,13 @@ static void assert_priolists(struct i915_sched_engine * const sched_engine)
>  }
>
>  struct list_head *
> -i915_sched_lookup_priolist(struct intel_engine_cs *engine, int prio)
> +i915_sched_lookup_priolist(struct i915_sched_engine *sched_engine, int prio)
>  {
> -       struct i915_sched_engine * const sched_engine = engine->sched_engine;
>         struct i915_priolist *p;
>         struct rb_node **parent, *rb;
>         bool first = true;
>
> -       lockdep_assert_held(&engine->sched_engine->lock);
> +       lockdep_assert_held(&sched_engine->lock);
>         assert_priolists(sched_engine);
>
>         if (unlikely(sched_engine->no_priolist))
> @@ -130,13 +129,13 @@ struct sched_cache {
>         struct list_head *priolist;
>  };
>
> -static struct intel_engine_cs *
> -sched_lock_engine(const struct i915_sched_node *node,
> -                 struct intel_engine_cs *locked,
> +static struct i915_sched_engine *
> +lock_sched_engine(struct i915_sched_node *node,
> +                 struct i915_sched_engine *locked,
>                   struct sched_cache *cache)
>  {
>         const struct i915_request *rq = node_to_request(node);
> -       struct intel_engine_cs *engine;
> +       struct i915_sched_engine *sched_engine;
>
>         GEM_BUG_ON(!locked);
>
> @@ -146,14 +145,14 @@ sched_lock_engine(const struct i915_sched_node *node,
>          * engine lock. The simple ploy we use is to take the lock then
>          * check that the rq still belongs to the newly locked engine.
>          */
> -       while (locked != (engine = READ_ONCE(rq->engine))) {
> -               spin_unlock(&locked->sched_engine->lock);
> +       while (locked != (sched_engine = rq->engine->sched_engine)) {

You lost the READ_ONCE here.  Based on the comment above, that may
matter.  I guess it depends on what all barriers spin_lock() implies.

Assuming that's all good,

Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>

> +               spin_unlock(&locked->lock);
>                 memset(cache, 0, sizeof(*cache));
> -               spin_lock(&engine->sched_engine->lock);
> -               locked = engine;
> +               spin_lock(&sched_engine->lock);
> +               locked = sched_engine;
>         }
>
> -       GEM_BUG_ON(locked != engine);
> +       GEM_BUG_ON(locked != sched_engine);
>         return locked;
>  }
>
> @@ -161,7 +160,7 @@ static void __i915_schedule(struct i915_sched_node *node,
>                             const struct i915_sched_attr *attr)
>  {
>         const int prio = max(attr->priority, node->attr.priority);
> -       struct intel_engine_cs *engine;
> +       struct i915_sched_engine *sched_engine;
>         struct i915_dependency *dep, *p;
>         struct i915_dependency stack;
>         struct sched_cache cache;
> @@ -236,23 +235,24 @@ static void __i915_schedule(struct i915_sched_node *node,
>         }
>
>         memset(&cache, 0, sizeof(cache));
> -       engine = node_to_request(node)->engine;
> -       spin_lock(&engine->sched_engine->lock);
> +       sched_engine = node_to_request(node)->engine->sched_engine;
> +       spin_lock(&sched_engine->lock);
>
>         /* Fifo and depth-first replacement ensure our deps execute before us */
> -       engine = sched_lock_engine(node, engine, &cache);
> +       sched_engine = lock_sched_engine(node, sched_engine, &cache);
>         list_for_each_entry_safe_reverse(dep, p, &dfs, dfs_link) {
>                 INIT_LIST_HEAD(&dep->dfs_link);
>
>                 node = dep->signaler;
> -               engine = sched_lock_engine(node, engine, &cache);
> -               lockdep_assert_held(&engine->sched_engine->lock);
> +               sched_engine = lock_sched_engine(node, sched_engine, &cache);
> +               lockdep_assert_held(&sched_engine->lock);
>
>                 /* Recheck after acquiring the engine->timeline.lock */
>                 if (prio <= node->attr.priority || node_signaled(node))
>                         continue;
>
> -               GEM_BUG_ON(node_to_request(node)->engine != engine);
> +               GEM_BUG_ON(node_to_request(node)->engine->sched_engine !=
> +                          sched_engine);
>
>                 WRITE_ONCE(node->attr.priority, prio);
>
> @@ -270,17 +270,17 @@ static void __i915_schedule(struct i915_sched_node *node,
>                 if (i915_request_in_priority_queue(node_to_request(node))) {
>                         if (!cache.priolist)
>                                 cache.priolist =
> -                                       i915_sched_lookup_priolist(engine,
> +                                       i915_sched_lookup_priolist(sched_engine,
>                                                                    prio);
>                         list_move_tail(&node->link, cache.priolist);
>                 }
>
>                 /* Defer (tasklet) submission until after all of our updates. */
> -               if (engine->sched_engine->kick_backend)
> -                       engine->sched_engine->kick_backend(node_to_request(node), prio);
> +               if (sched_engine->kick_backend)
> +                       sched_engine->kick_backend(node_to_request(node), prio);
>         }
>
> -       spin_unlock(&engine->sched_engine->lock);
> +       spin_unlock(&sched_engine->lock);
>  }
>
>  void i915_schedule(struct i915_request *rq, const struct i915_sched_attr *attr)
> diff --git a/drivers/gpu/drm/i915/i915_scheduler.h b/drivers/gpu/drm/i915/i915_scheduler.h
> index 713c38c99de9..0014745bda30 100644
> --- a/drivers/gpu/drm/i915/i915_scheduler.h
> +++ b/drivers/gpu/drm/i915/i915_scheduler.h
> @@ -39,7 +39,7 @@ void i915_schedule(struct i915_request *request,
>                    const struct i915_sched_attr *attr);
>
>  struct list_head *
> -i915_sched_lookup_priolist(struct intel_engine_cs *engine, int prio);
> +i915_sched_lookup_priolist(struct i915_sched_engine *sched_engine, int prio);
>
>  void __i915_priolist_free(struct i915_priolist *p);
>  static inline void i915_priolist_free(struct i915_priolist *p)
> --
> 2.28.0
>
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