Commit d22ba0cb authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Reduce i915_request_alloc retirement to local context 



In the continual quest to reduce the amount of global work required when
submitting requests, replace i915_retire_requests() after allocation
failure to retiring just our ring.

v2: Don't forget the list iteration included an early break, so we would
never throttle on the last request in the ring/timeline.
v3: Use the common ring_retire_requests()

References: 11abf0c5 ("drm/i915: Limit the backpressure for i915_request allocation")
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190109215932.26454-1-chris@chris-wilson.co.uk
parent 4e8052af

drivers/gpu/drm/i915/i915_request.c

+33 −22
Original line number Diff line number Diff line
@@ -477,6 +477,38 @@ submit_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify state) 
	return NOTIFY_DONE;

}



static void ring_retire_requests(struct intel_ring *ring)

{

	struct i915_request *rq, *rn;



	list_for_each_entry_safe(rq, rn, &ring->request_list, ring_link) {

		if (!i915_request_completed(rq))

			break;



		i915_request_retire(rq);

	}

}



static noinline struct i915_request *

i915_request_alloc_slow(struct intel_context *ce)

{

	struct intel_ring *ring = ce->ring;

	struct i915_request *rq;



	if (list_empty(&ring->request_list))

		goto out;



	/* Ratelimit ourselves to prevent oom from malicious clients */

	rq = list_last_entry(&ring->request_list, typeof(*rq), ring_link);

	cond_synchronize_rcu(rq->rcustate);



	/* Retire our old requests in the hope that we free some */

	ring_retire_requests(ring);



out:

	return kmem_cache_alloc(ce->gem_context->i915->requests, GFP_KERNEL);

}



/**

 * i915_request_alloc - allocate a request structure

 *
@@ -559,15 +591,7 @@ i915_request_alloc(struct intel_engine_cs *engine, struct i915_gem_context *ctx) 
	rq = kmem_cache_alloc(i915->requests,

			      GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN);

	if (unlikely(!rq)) {

		i915_retire_requests(i915);



		/* Ratelimit ourselves to prevent oom from malicious clients */

		rq = i915_gem_active_raw(&ce->ring->timeline->last_request,

					 &i915->drm.struct_mutex);

		if (rq)

			cond_synchronize_rcu(rq->rcustate);



		rq = kmem_cache_alloc(i915->requests, GFP_KERNEL);

		rq = i915_request_alloc_slow(ce);

		if (!rq) {

			ret = -ENOMEM;

			goto err_unreserve;
@@ -1218,19 +1242,6 @@ complete: 
	return timeout;

}



static void ring_retire_requests(struct intel_ring *ring)

{

	struct i915_request *request, *next;



	list_for_each_entry_safe(request, next,

				 &ring->request_list, ring_link) {

		if (!i915_request_completed(request))

			break;



		i915_request_retire(request);

	}

}



void i915_retire_requests(struct drm_i915_private *i915)

{

	struct intel_ring *ring, *tmp;

CRA Git | Maintained and supported by SUSTech CRA and CCSE