Commit cecb2af4 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/gt: Taint the reset mutex with the shrinker 



Declare that, under extreme circumstances, the shrinker may need to wait
upon a request, in which case reset must not itself deadlock in order to
ensure forward progress of the driver. That is since the shrinker may
depend upon a reset, any reset cannot touch the shrinker.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: default avatarMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201229141626.4773-1-chris@chris-wilson.co.uk
parent cc1557ca

drivers/gpu/drm/i915/gt/intel_reset.c

+11 −0
Original line number Diff line number Diff line
@@ -1394,6 +1394,17 @@ void intel_gt_init_reset(struct intel_gt *gt) 
	mutex_init(&gt->reset.mutex);

	init_srcu_struct(&gt->reset.backoff_srcu);



	/*

	 * While undesirable to wait inside the shrinker, complain anyway.

	 *

	 * If we have to wait during shrinking, we guarantee forward progress

	 * by forcing the reset. Therefore during the reset we must not

	 * re-enter the shrinker. By declaring that we take the reset mutex

	 * within the shrinker, we forbid ourselves from performing any

	 * fs-reclaim or taking related locks during reset.

	 */

	i915_gem_shrinker_taints_mutex(gt->i915, &gt->reset.mutex);



	/* no GPU until we are ready! */

	__set_bit(I915_WEDGED, &gt->reset.flags);

}