[Intel-gfx] [PATCH v3 3/3] drm/i915/selftests: Exercise adding requests to a full GGTT

[Chris Wilson]

Quoting Chris Wilson (2017-10-12 13:57:26)
> +               count = 0;
> +               mutex_lock(&i915->drm.struct_mutex);
> +               onstack_fence_init(&fence);
> +               do {
> +                       struct drm_i915_gem_request *rq;
> +                       struct i915_gem_context *ctx;
> +
> +                       ctx = live_context(i915, file);
> +                       if (!ctx)
> +                               break;
> +
> +                       igt_evict_ctl.fail_if_busy = true;
> +                       rq = i915_gem_request_alloc(engine, ctx);
> +                       igt_evict_ctl.fail_if_busy = false;
> +
> +                       if (IS_ERR(rq)) {
> +                               /* When full, fail_if_busy will trigger -EBUSY */
> +                               if (PTR_ERR(rq) != -EBUSY) {
> +                                       pr_err("Unexpected error from request alloc (ctx hw id %u, on %s): %d\n",
> +                                              ctx->hw_id, engine->name,
> +                                              (int)PTR_ERR(rq));
> +                                       err = PTR_ERR(rq);
> +                               }
> +                               break;
> +                       }
> +
> +                       /* Keep every request busy until we are full */
> +                       err = i915_sw_fence_await_sw_fence_gfp(&rq->submit,
> +                                                              &fence,
> +                                                              GFP_KERNEL);
> +                       if (err < 0)
> +                               break;
> +
> +                       i915_add_request(rq);
> +                       count++;
> +                       err = 0;
> +               } while(!i915_sw_fence_done(&fence));

This should now just be 
	} while (1);
The only escape is when we hit EBUSY upon filling the GGTT.
-Chris