[Intel-gfx] [PATCH 03/10] drm/i915/gt: Replace intel_engine_transfer_stale_breadcrumbs
Tvrtko Ursulin
tvrtko.ursulin at linux.intel.com
Mon Jul 20 09:32:31 UTC 2020
On 20/07/2020 10:23, Chris Wilson wrote:
> After staring at the breadcrumb enabling/cancellation and coming to the
> conclusion that the cause of the mysterious stale breadcrumbs must the
> act of submitting a completed requests, we can then redirect those
> completed requests onto a dedicated signaled_list at the time of
> construction and so eliminate intel_engine_transfer_stale_breadcrumbs().
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Regards,
Tvrtko
> ---
> drivers/gpu/drm/i915/gt/intel_breadcrumbs.c | 50 ++++++++-------------
> drivers/gpu/drm/i915/gt/intel_engine.h | 3 --
> drivers/gpu/drm/i915/gt/intel_lrc.c | 15 -------
> drivers/gpu/drm/i915/i915_request.c | 5 +--
> 4 files changed, 21 insertions(+), 52 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
> index 3d211a0c2b5a..fbdc465a5870 100644
> --- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
> +++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
> @@ -142,16 +142,16 @@ static void add_retire(struct intel_breadcrumbs *b, struct intel_timeline *tl)
> intel_engine_add_retire(engine, tl);
> }
>
> -static void __signal_request(struct i915_request *rq, struct list_head *signals)
> +static bool __signal_request(struct i915_request *rq, struct list_head *signals)
> {
> - GEM_BUG_ON(!test_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags));
> clear_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags);
>
> if (!__dma_fence_signal(&rq->fence))
> - return;
> + return false;
>
> i915_request_get(rq);
> list_add_tail(&rq->signal_link, signals);
> + return true;
> }
>
> static void signal_irq_work(struct irq_work *work)
> @@ -278,32 +278,6 @@ void intel_engine_reset_breadcrumbs(struct intel_engine_cs *engine)
> spin_unlock_irqrestore(&b->irq_lock, flags);
> }
>
> -void intel_engine_transfer_stale_breadcrumbs(struct intel_engine_cs *engine,
> - struct intel_context *ce)
> -{
> - struct intel_breadcrumbs *b = &engine->breadcrumbs;
> - unsigned long flags;
> -
> - spin_lock_irqsave(&b->irq_lock, flags);
> - if (!list_empty(&ce->signals)) {
> - struct i915_request *rq, *next;
> -
> - /* Queue for executing the signal callbacks in the irq_work */
> - list_for_each_entry_safe(rq, next, &ce->signals, signal_link) {
> - GEM_BUG_ON(rq->engine != engine);
> - GEM_BUG_ON(!__request_completed(rq));
> -
> - __signal_request(rq, &b->signaled_requests);
> - }
> -
> - INIT_LIST_HEAD(&ce->signals);
> - list_del_init(&ce->signal_link);
> -
> - irq_work_queue(&b->irq_work);
> - }
> - spin_unlock_irqrestore(&b->irq_lock, flags);
> -}
> -
> void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine)
> {
> }
> @@ -317,6 +291,17 @@ static void insert_breadcrumb(struct i915_request *rq,
> if (test_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags))
> return;
>
> + /*
> + * If the request is already completed, we can transfer it
> + * straight onto a signaled list, and queue the irq worker for
> + * its signal completion.
> + */
> + if (__request_completed(rq)) {
> + if (__signal_request(rq, &b->signaled_requests))
> + irq_work_queue(&b->irq_work);
> + return;
> + }
> +
> __intel_breadcrumbs_arm_irq(b);
>
> /*
> @@ -344,8 +329,11 @@ static void insert_breadcrumb(struct i915_request *rq,
> if (pos == &ce->signals) /* catch transitions from empty list */
> list_move_tail(&ce->signal_link, &b->signalers);
> GEM_BUG_ON(!check_signal_order(ce, rq));
> -
> set_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags);
> +
> + /* Check after attaching to irq, interrupt may have already fired. */
> + if (__request_completed(rq))
> + irq_work_queue(&b->irq_work);
> }
>
> bool i915_request_enable_breadcrumb(struct i915_request *rq)
> @@ -401,7 +389,7 @@ bool i915_request_enable_breadcrumb(struct i915_request *rq)
>
> spin_unlock(&b->irq_lock);
>
> - return !__request_completed(rq);
> + return true;
> }
>
> void i915_request_cancel_breadcrumb(struct i915_request *rq)
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine.h b/drivers/gpu/drm/i915/gt/intel_engine.h
> index a9249a23903a..faf00a353e25 100644
> --- a/drivers/gpu/drm/i915/gt/intel_engine.h
> +++ b/drivers/gpu/drm/i915/gt/intel_engine.h
> @@ -237,9 +237,6 @@ intel_engine_signal_breadcrumbs(struct intel_engine_cs *engine)
> void intel_engine_reset_breadcrumbs(struct intel_engine_cs *engine);
> void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine);
>
> -void intel_engine_transfer_stale_breadcrumbs(struct intel_engine_cs *engine,
> - struct intel_context *ce);
> -
> void intel_engine_print_breadcrumbs(struct intel_engine_cs *engine,
> struct drm_printer *p);
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
> index 21c16e31c4fe..88a5c155154d 100644
> --- a/drivers/gpu/drm/i915/gt/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
> @@ -1805,18 +1805,6 @@ static bool virtual_matches(const struct virtual_engine *ve,
> return true;
> }
>
> -static void virtual_xfer_breadcrumbs(struct virtual_engine *ve)
> -{
> - /*
> - * All the outstanding signals on ve->siblings[0] must have
> - * been completed, just pending the interrupt handler. As those
> - * signals still refer to the old sibling (via rq->engine), we must
> - * transfer those to the old irq_worker to keep our locking
> - * consistent.
> - */
> - intel_engine_transfer_stale_breadcrumbs(ve->siblings[0], &ve->context);
> -}
> -
> #define for_each_waiter(p__, rq__) \
> list_for_each_entry_lockless(p__, \
> &(rq__)->sched.waiters_list, \
> @@ -2275,9 +2263,6 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
> virtual_update_register_offsets(regs,
> engine);
>
> - if (!list_empty(&ve->context.signals))
> - virtual_xfer_breadcrumbs(ve);
> -
> /*
> * Move the bound engine to the top of the list
> * for future execution. We then kick this
> diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
> index 58e37f96ae21..ada630677cf3 100644
> --- a/drivers/gpu/drm/i915/i915_request.c
> +++ b/drivers/gpu/drm/i915/i915_request.c
> @@ -592,9 +592,8 @@ bool __i915_request_submit(struct i915_request *request)
> */
> __notify_execute_cb_irq(request);
>
> - if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &request->fence.flags) &&
> - !i915_request_enable_breadcrumb(request))
> - intel_engine_signal_breadcrumbs(engine);
> + if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &request->fence.flags))
> + i915_request_enable_breadcrumb(request);
>
> return result;
> }
>
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