From e20780439b26ba95aeb29d3e27cd8cc32bc82a4c Mon Sep 17 00:00:00 2001 From: Ben Widawsky Date: Fri, 6 Dec 2013 14:11:22 -0800 Subject: [PATCH] drm/i915: Defer request freeing With context destruction, we always want to be able to tear down the underlying address space. This is invoked on the last unreference to the context which could happen before we've moved all objects to the inactive list. To enable a clean tear down the address space, make sure to process the request free lastly. Without this change, we cannot guarantee to we don't still have active objects in the VM. As an example of a failing case: CTX-A is created, count=1 CTX-A is used during execbuf does a context switch count = 2 and add_request count = 3 CTX B runs, switches, CTX-A count = 2 CTX-A is destroyed, count = 1 retire requests is called free_request from CTX-A, count = 0 <--- free context with active object As mentioned above, by doing the free request after processing the active list, we can avoid this case. Signed-off-by: Ben Widawsky Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_gem.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 89e2f92e8335..99c05e3cf419 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -2423,6 +2423,8 @@ void i915_gem_reset(struct drm_device *dev) void i915_gem_retire_requests_ring(struct intel_ring_buffer *ring) { + LIST_HEAD(deferred_request_free); + struct drm_i915_gem_request *request; uint32_t seqno; if (list_empty(&ring->request_list)) @@ -2433,8 +2435,6 @@ i915_gem_retire_requests_ring(struct intel_ring_buffer *ring) seqno = ring->get_seqno(ring, true); while (!list_empty(&ring->request_list)) { - struct drm_i915_gem_request *request; - request = list_first_entry(&ring->request_list, struct drm_i915_gem_request, list); @@ -2450,7 +2450,7 @@ i915_gem_retire_requests_ring(struct intel_ring_buffer *ring) */ ring->last_retired_head = request->tail; - i915_gem_free_request(request); + list_move_tail(&request->list, &deferred_request_free); } /* Move any buffers on the active list that are no longer referenced @@ -2475,6 +2475,13 @@ i915_gem_retire_requests_ring(struct intel_ring_buffer *ring) ring->trace_irq_seqno = 0; } + /* Finish processing active list before freeing request */ + while (!list_empty(&deferred_request_free)) { + request = list_first_entry(&deferred_request_free, + struct drm_i915_gem_request, + list); + i915_gem_free_request(request); + } WARN_ON(i915_verify_lists(ring->dev)); } -- 2.20.1