On 22/02/2017 13:40, Chris Wilson wrote:
On Wed, Feb 22, 2017 at 01:33:22PM +0000, Tvrtko Ursulin wrote:
On 22/02/2017 11:46, Chris Wilson wrote:
+void __i915_gem_request_unsubmit(struct drm_i915_gem_request *request)
+{
+ struct intel_engine_cs *engine = request->engine;
+ struct intel_timeline *timeline;
+
+ assert_spin_locked(&engine->timeline->lock);
+
+ /* Only unwind in reverse order, required so that the per-context list
+ * is kept in seqno/ring order.
+ */
+ GEM_BUG_ON(request->global_seqno != engine->timeline->seqno);
+ engine->timeline->seqno--;
+
+ /* We may be recursing from the signal callback of another i915 fence */
Copy-paste of the comment of there will really be preemption
triggered from the signal callback?
I believe it may be. Say an RCS request was waiting on a BCS request,
and we decide to preempt, and can do so immediately. I think being
prepared for the same recursion here is predundant.
Yeah OK, just wasn't sure at which level will we handle preemption.
static int __i915_sw_fence_call
submit_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify state)
{
@@ -1034,9 +1083,11 @@ long i915_wait_request(struct drm_i915_gem_request *req,
if (flags & I915_WAIT_LOCKED)
add_wait_queue(errq, &reset);
- intel_wait_init(&wait, i915_gem_request_global_seqno(req));
+ wait.tsk = current;
+restart:
reset_wait_queue(&req->execute, &exec);
+ wait.seqno = i915_gem_request_global_seqno(req);
Not sure if it is worth dropping intel_wait_init, I presume to avoid
assigning the task twice? It will still be the same task so just
moving the intel_wait_init here would be clearer.
I was thinking the opposite, since we are looking at wait.seqno directly
elsewhere, so wanted that to be clear. And current is in a special
register, so why pay the cost to reload it onto stack :)
I can see that but intel_wait_init was so nice as a marker when reading
the code.
Maybe leave it and add intel_wait_update_seqno?
Regards,
Tvrtko
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