[Intel-gfx] [PATCH 1/6] drm/i915: Individual request cancellation

[Matthew Auld]

On Thu, 18 Mar 2021 at 17:04, Tvrtko Ursulin
<tvrtko.ursulin at linux.intel.com> wrote:
>
> From: Chris Wilson <chris at chris-wilson.co.uk>
>
> Currently, we cancel outstanding requests within a context when the
> context is closed. We may also want to cancel individual requests using
> the same graceful preemption mechanism.
>
> v2 (Tvrtko):
>  * Cancel waiters carefully considering no timeline lock and RCU.
>  * Fixed selftests.
>
> v3 (Tvrtko):
>  * Remove error propagation to waiters for now.
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> ---
>  .../gpu/drm/i915/gt/intel_engine_heartbeat.c  |   1 +
>  .../drm/i915/gt/intel_execlists_submission.c  |   9 +-
>  drivers/gpu/drm/i915/i915_request.c           |  52 ++++-
>  drivers/gpu/drm/i915/i915_request.h           |   4 +-
>  drivers/gpu/drm/i915/selftests/i915_request.c | 201 ++++++++++++++++++
>  5 files changed, 261 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c
> index 0b062fad1837..e2fb3ae2aaf3 100644
> --- a/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c
> +++ b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c
> @@ -314,6 +314,7 @@ int intel_engine_pulse(struct intel_engine_cs *engine)
>                 mutex_unlock(&ce->timeline->mutex);
>         }
>
> +       intel_engine_flush_scheduler(engine);
>         intel_engine_pm_put(engine);
>         return err;
>  }
> diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> index 85ff5fe861b4..4c2acb5a6c0a 100644
> --- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> +++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> @@ -421,6 +421,11 @@ static void reset_active(struct i915_request *rq,
>         ce->lrc.lrca = lrc_update_regs(ce, engine, head);
>  }
>
> +static bool bad_request(const struct i915_request *rq)
> +{
> +       return rq->fence.error && i915_request_started(rq);
> +}
> +
>  static struct intel_engine_cs *
>  __execlists_schedule_in(struct i915_request *rq)
>  {
> @@ -433,7 +438,7 @@ __execlists_schedule_in(struct i915_request *rq)
>                      !intel_engine_has_heartbeat(engine)))
>                 intel_context_set_banned(ce);
>
> -       if (unlikely(intel_context_is_banned(ce)))
> +       if (unlikely(intel_context_is_banned(ce) || bad_request(rq)))
>                 reset_active(rq, engine);
>
>         if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
> @@ -1112,7 +1117,7 @@ static unsigned long active_preempt_timeout(struct intel_engine_cs *engine,
>                 return 0;
>
>         /* Force a fast reset for terminated contexts (ignoring sysfs!) */
> -       if (unlikely(intel_context_is_banned(rq->context)))
> +       if (unlikely(intel_context_is_banned(rq->context) || bad_request(rq)))
>                 return 1;
>
>         return READ_ONCE(engine->props.preempt_timeout_ms);
> diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
> index e7b4c4bc41a6..b4511ac05e9a 100644
> --- a/drivers/gpu/drm/i915/i915_request.c
> +++ b/drivers/gpu/drm/i915/i915_request.c
> @@ -33,7 +33,10 @@
>  #include "gem/i915_gem_context.h"
>  #include "gt/intel_breadcrumbs.h"
>  #include "gt/intel_context.h"
> +#include "gt/intel_engine.h"
> +#include "gt/intel_engine_heartbeat.h"
>  #include "gt/intel_gpu_commands.h"
> +#include "gt/intel_reset.h"
>  #include "gt/intel_ring.h"
>  #include "gt/intel_rps.h"
>
> @@ -429,20 +432,22 @@ void __i915_request_skip(struct i915_request *rq)
>         rq->infix = rq->postfix;
>  }
>
> -void i915_request_set_error_once(struct i915_request *rq, int error)
> +bool i915_request_set_error_once(struct i915_request *rq, int error)
>  {
>         int old;
>
>         GEM_BUG_ON(!IS_ERR_VALUE((long)error));
>
>         if (i915_request_signaled(rq))
> -               return;
> +               return false;
>
>         old = READ_ONCE(rq->fence.error);
>         do {
>                 if (fatal_error(old))
> -                       return;
> +                       return false;
>         } while (!try_cmpxchg(&rq->fence.error, &old, error));
> +
> +       return true;
>  }
>
>  struct i915_request *i915_request_mark_eio(struct i915_request *rq)
> @@ -609,6 +614,47 @@ void i915_request_unsubmit(struct i915_request *request)
>         spin_unlock_irqrestore(&se->lock, flags);
>  }
>
> +static struct intel_engine_cs *active_engine(struct i915_request *rq)
> +{
> +       struct intel_engine_cs *engine, *locked;
> +
> +       locked = READ_ONCE(rq->engine);
> +       spin_lock_irq(&locked->sched.lock);
> +       while (unlikely(locked != (engine = READ_ONCE(rq->engine)))) {
> +               spin_unlock(&locked->sched.lock);
> +               locked = engine;
> +               spin_lock(&locked->sched.lock);
> +       }
> +
> +       engine = NULL;
> +       if (i915_request_is_active(rq) && !__i915_request_is_complete(rq))
> +               engine = locked;
> +
> +       spin_unlock_irq(&locked->sched.lock);
> +
> +       return engine;

Bad idea to reuse __active_engine() somehow?

Reviewed-by: Matthew Auld <matthew.auld at intel.com>