[Intel-gfx] [PATCH v2 3/6] drm/i915: Only track live rings for retiring
Tvrtko Ursulin
tvrtko.ursulin at linux.intel.com
Tue Apr 24 09:37:03 UTC 2018
On 23/04/2018 19:08, Chris Wilson wrote:
> We don't need to track every ring for its lifetime as they are managed
> by the contexts/engines. What we do want to track are the live rings so
> that we can sporadically clean up requests if userspace falls behind. We
> can simply restrict the gt->rings list to being only gt->live_rings.
>
> v2: s/live/active/ for consistency with gt.active_requests
>
> Suggested-by: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
> ---
> drivers/gpu/drm/i915/i915_drv.h | 3 ++-
> drivers/gpu/drm/i915/i915_gem.c | 6 ++++--
> drivers/gpu/drm/i915/i915_request.c | 10 ++++++++--
> drivers/gpu/drm/i915/intel_ringbuffer.c | 4 ----
> drivers/gpu/drm/i915/intel_ringbuffer.h | 2 +-
> drivers/gpu/drm/i915/selftests/mock_engine.c | 4 ----
> drivers/gpu/drm/i915/selftests/mock_gem_device.c | 5 +++--
> 7 files changed, 18 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 1837c01d44d0..54351cace362 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2060,7 +2060,8 @@ struct drm_i915_private {
>
> struct i915_gem_timeline global_timeline;
> struct list_head timelines;
> - struct list_head rings;
> +
> + struct list_head active_rings;
> u32 active_requests;
> u32 request_serial;
>
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 906e2395c245..56c79df5ebce 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -141,6 +141,7 @@ static u32 __i915_gem_park(struct drm_i915_private *i915)
> {
> lockdep_assert_held(&i915->drm.struct_mutex);
> GEM_BUG_ON(i915->gt.active_requests);
> + GEM_BUG_ON(!list_empty(&i915->gt.active_rings));
>
> if (!i915->gt.awake)
> return I915_EPOCH_INVALID;
> @@ -5599,9 +5600,10 @@ int i915_gem_init_early(struct drm_i915_private *dev_priv)
> if (!dev_priv->priorities)
> goto err_dependencies;
>
> - mutex_lock(&dev_priv->drm.struct_mutex);
> - INIT_LIST_HEAD(&dev_priv->gt.rings);
> INIT_LIST_HEAD(&dev_priv->gt.timelines);
> + INIT_LIST_HEAD(&dev_priv->gt.active_rings);
> +
> + mutex_lock(&dev_priv->drm.struct_mutex);
> err = i915_gem_timeline_init__global(dev_priv);
> mutex_unlock(&dev_priv->drm.struct_mutex);
> if (err)
> diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
> index 0a117bf9e455..f13b7a1a0aa9 100644
> --- a/drivers/gpu/drm/i915/i915_request.c
> +++ b/drivers/gpu/drm/i915/i915_request.c
> @@ -321,6 +321,7 @@ static void advance_ring(struct i915_request *request)
> * noops - they are safe to be replayed on a reset.
> */
> tail = READ_ONCE(request->tail);
> + list_del(&ring->active_link);
> } else {
> tail = request->postfix;
> }
> @@ -1081,6 +1082,8 @@ void __i915_request_add(struct i915_request *request, bool flush_caches)
> i915_gem_active_set(&timeline->last_request, request);
>
> list_add_tail(&request->ring_link, &ring->request_list);
> + if (list_is_first(&request->ring_link, &ring->request_list))
> + list_add(&ring->active_link, &request->i915->gt.active_rings);
So sneaky.. lets see if it is justified in its new home. :)
> request->emitted_jiffies = jiffies;
>
> /*
> @@ -1403,14 +1406,17 @@ static void ring_retire_requests(struct intel_ring *ring)
>
> void i915_retire_requests(struct drm_i915_private *i915)
> {
> - struct intel_ring *ring, *next;
> + struct intel_ring *ring, *tmp;
>
> lockdep_assert_held(&i915->drm.struct_mutex);
>
> if (!i915->gt.active_requests)
> return;
>
> - list_for_each_entry_safe(ring, next, &i915->gt.rings, link)
> + /* An outstanding request must be on a still active ring somewhere */
> + GEM_BUG_ON(list_empty(&i915->gt.active_rings));
Okay, but I still think my assert would be stronger. As long as we allow
calling this function with no active requests, why not check both
internal states are consistent every time?
> +
> + list_for_each_entry_safe(ring, tmp, &i915->gt.active_rings, active_link)
> ring_retire_requests(ring);
> }
>
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> index 75dca28782ee..3d02b2c779e7 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> @@ -1149,8 +1149,6 @@ intel_engine_create_ring(struct intel_engine_cs *engine, int size)
> }
> ring->vma = vma;
>
> - list_add(&ring->link, &engine->i915->gt.rings);
> -
> return ring;
> }
>
> @@ -1162,8 +1160,6 @@ intel_ring_free(struct intel_ring *ring)
> i915_vma_close(ring->vma);
> __i915_gem_object_release_unless_active(obj);
>
> - list_del(&ring->link);
> -
> kfree(ring);
> }
>
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
> index d816f8dea245..e8d17bcd9bee 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.h
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
> @@ -129,7 +129,7 @@ struct intel_ring {
> void *vaddr;
>
> struct list_head request_list;
> - struct list_head link;
> + struct list_head active_link;
>
> u32 head;
> u32 tail;
> diff --git a/drivers/gpu/drm/i915/selftests/mock_engine.c b/drivers/gpu/drm/i915/selftests/mock_engine.c
> index a0bc324edadd..74a88913623f 100644
> --- a/drivers/gpu/drm/i915/selftests/mock_engine.c
> +++ b/drivers/gpu/drm/i915/selftests/mock_engine.c
> @@ -140,15 +140,11 @@ static struct intel_ring *mock_ring(struct intel_engine_cs *engine)
> INIT_LIST_HEAD(&ring->request_list);
> intel_ring_update_space(ring);
>
> - list_add(&ring->link, &engine->i915->gt.rings);
> -
> return ring;
> }
>
> static void mock_ring_free(struct intel_ring *ring)
> {
> - list_del(&ring->link);
> -
> kfree(ring);
> }
>
> diff --git a/drivers/gpu/drm/i915/selftests/mock_gem_device.c b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
> index ac4bacf8b5b9..f22a2b35a283 100644
> --- a/drivers/gpu/drm/i915/selftests/mock_gem_device.c
> +++ b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
> @@ -224,9 +224,10 @@ struct drm_i915_private *mock_gem_device(void)
> if (!i915->priorities)
> goto err_dependencies;
>
> - mutex_lock(&i915->drm.struct_mutex);
> - INIT_LIST_HEAD(&i915->gt.rings);
> INIT_LIST_HEAD(&i915->gt.timelines);
> + INIT_LIST_HEAD(&i915->gt.active_rings);
> +
> + mutex_lock(&i915->drm.struct_mutex);
> err = i915_gem_timeline_init__global(i915);
> if (err) {
> mutex_unlock(&i915->drm.struct_mutex);
>
Regards,
Tvrtko
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