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.
References: 11abf0c5a021 ("drm/i915: Limit the backpressure for i915_request allocation")
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_request.c | 35 +++++++++++++++++++++--------
1 file changed, 26 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 1e158eb8cb97..e183009f47f4 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -477,6 +477,31 @@ submit_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify state)
return NOTIFY_DONE;
}
+static noinline struct i915_request *
+i915_request_alloc_slow(struct intel_context *ce)
+{
+ struct intel_ring *ring = ce->ring;
+ struct i915_request *rq, *next;
+
+ 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 */
+ list_for_each_entry_safe(rq, next, &ring->request_list, ring_link) {
+ if (!i915_request_completed(rq))
+ break;
+
+ i915_request_retire(rq);
+ }
+
+out:
+ return kmem_cache_alloc(ce->gem_context->i915->requests, GFP_KERNEL);
+}
+
/**
* i915_request_alloc - allocate a request structure
*
@@ -559,15 +584,7 @@ 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;
--
2.20.1
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