Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> writes:
> Sometimes we want to emit a terminator request, a request that flushes
> the pipeline and allows no request to come after it. This can be used
> for a "preempt-to-idle" to ensure that upon processing the
> context-switch to that request, all other active contexts have been
> flushed.
>
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/gt/intel_lrc.c | 6 ++++++
> drivers/gpu/drm/i915/i915_request.h | 10 ++++++++--
> 2 files changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
> index 4e45cd972267..59a7e4eb7e2a 100644
> --- a/drivers/gpu/drm/i915/gt/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
> @@ -759,6 +759,9 @@ static bool can_merge_rq(const struct i915_request *prev,
> GEM_BUG_ON(prev == next);
> GEM_BUG_ON(!assert_priority_queue(prev, next));
>
> + if (i915_request_has_sentinel(prev))
> + return false;
> +
> if (!can_merge_ctx(prev->hw_context, next->hw_context))
> return false;
>
> @@ -1250,6 +1253,9 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
> if (last->hw_context == rq->hw_context)
> goto done;
>
> + if (i915_request_has_sentinel(last))
> + goto done;
> +
> /*
> * If GVT overrides us we only ever submit
> * port[0], leaving port[1] empty. Note that we
> diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
> index 313df3c37158..c41ecbe0bd0c 100644
> --- a/drivers/gpu/drm/i915/i915_request.h
> +++ b/drivers/gpu/drm/i915/i915_request.h
> @@ -217,8 +217,9 @@ struct i915_request {
> unsigned long emitted_jiffies;
>
> unsigned long flags;
> -#define I915_REQUEST_WAITBOOST BIT(0)
> -#define I915_REQUEST_NOPREEMPT BIT(1)
> +#define I915_REQUEST_WAITBOOST BIT(0)
> +#define I915_REQUEST_NOPREEMPT BIT(1)
> +#define I915_REQUEST_SENTINEL BIT(2)
Would it be possible to use 'empty' ie non payloadable
requests as a sentinel? (using the request->postfix).
Or is the advantage here that by attaching it as
a property, you avoid submitting an extra (empty)?
-Mika
>
> /** timeline->request entry for this request */
> struct list_head link;
> @@ -443,6 +444,11 @@ static inline bool i915_request_has_nopreempt(const struct i915_request *rq)
> return unlikely(rq->flags & I915_REQUEST_NOPREEMPT);
> }
>
> +static inline bool i915_request_has_sentinel(const struct i915_request *rq)
> +{
> + return unlikely(rq->flags & I915_REQUEST_SENTINEL);
> +}
> +
> bool i915_retire_requests(struct drm_i915_private *i915);
>
> #endif /* I915_REQUEST_H */
> --
> 2.23.0.rc1
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
_______________________________________________
Intel-gfx mailing list
Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
