drm/i915: Allow fence allocations to fail

If a fence allocation fails in a blocking context, we will sleep on the
fence as a last resort. We can therefore allow ourselves to fail and
sleep on the fence instead of triggering a system-wide oom. This allows
us to throttle malicious clients that are consuming lots of system
resources by capping the amount of memory used by fences.

Testcase: igt/gem_shrink/execbufX
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171212180652.22061-2-chris@chris-wilson.co.uk

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
index c28a4ceb016d..4d5e2b714382 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -782,7 +782,7 @@ i915_gem_request_await_request(struct drm_i915_gem_request *to,
 	if (to->engine == from->engine) {
 		ret = i915_sw_fence_await_sw_fence_gfp(&to->submit,
 						       &from->submit,
-						       GFP_KERNEL);
+						       I915_FENCE_GFP);
 		return ret < 0 ? ret : 0;
 	}
 
@@ -810,7 +810,7 @@ i915_gem_request_await_request(struct drm_i915_gem_request *to,
 await_dma_fence:
 	ret = i915_sw_fence_await_dma_fence(&to->submit,
 					    &from->fence, 0,
-					    GFP_KERNEL);
+					    I915_FENCE_GFP);
 	return ret < 0 ? ret : 0;
 }
 
@@ -861,7 +861,7 @@ i915_gem_request_await_dma_fence(struct drm_i915_gem_request *req,
 		else
 			ret = i915_sw_fence_await_dma_fence(&req->submit, fence,
 							    I915_FENCE_TIMEOUT,
-							    GFP_KERNEL);
+							    I915_FENCE_GFP);
 		if (ret < 0)
 			return ret;