[Intel-gfx] [PATCH 3/6] drm/i915: Only track live rings for retiring
Tvrtko Ursulin
tvrtko.ursulin at linux.intel.com
Mon Apr 23 10:25:54 UTC 2018
On 23/04/2018 11:13, 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.
>
> 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 | 2 +-
> drivers/gpu/drm/i915/i915_gem.c | 3 ++-
> drivers/gpu/drm/i915/i915_request.c | 6 +++++-
> drivers/gpu/drm/i915/i915_utils.h | 6 ++++++
> 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 | 2 +-
> 8 files changed, 16 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 73936be90aed..a7787c2cb53c 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2060,7 +2060,7 @@ struct drm_i915_private {
>
> struct i915_gem_timeline global_timeline;
> struct list_head timelines;
> - struct list_head rings;
> + struct list_head live_rings;
> u32 active_requests;
>
> /**
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 906e2395c245..0097a77fae8d 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.live_rings));
>
> if (!i915->gt.awake)
> return I915_EPOCH_INVALID;
> @@ -5600,7 +5601,7 @@ int i915_gem_init_early(struct drm_i915_private *dev_priv)
> goto err_dependencies;
>
> mutex_lock(&dev_priv->drm.struct_mutex);
> - INIT_LIST_HEAD(&dev_priv->gt.rings);
> + INIT_LIST_HEAD(&dev_priv->gt.live_rings);
> INIT_LIST_HEAD(&dev_priv->gt.timelines);
> err = i915_gem_timeline_init__global(dev_priv);
> mutex_unlock(&dev_priv->drm.struct_mutex);
> diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
> index 0bf949ec9f1a..534b8d684cef 100644
> --- a/drivers/gpu/drm/i915/i915_request.c
> +++ b/drivers/gpu/drm/i915/i915_request.c
> @@ -316,6 +316,7 @@ 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->live);
> } else {
> tail = request->postfix;
> }
> @@ -1046,6 +1047,8 @@ 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->live, &request->i915->gt.live_rings);
If you re-order the two list adds you could use list_empty and wouldn't
have to add list_is_first.
> request->emitted_jiffies = jiffies;
>
> /*
> @@ -1375,7 +1378,8 @@ void i915_retire_requests(struct drm_i915_private *i915)
> if (!i915->gt.active_requests)
> return;
>
> - list_for_each_entry_safe(ring, next, &i915->gt.rings, link)
> + GEM_BUG_ON(list_empty(&i915->gt.live_rings));
Maybe blank line here since the assert is not logically associated with
the list but with the !i915.active_requests?
> + list_for_each_entry_safe(ring, next, &i915->gt.live_rings, live)
> ring_retire_requests(ring);
> }
>
> diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h
> index 0695717522ea..00165ad55fb3 100644
> --- a/drivers/gpu/drm/i915/i915_utils.h
> +++ b/drivers/gpu/drm/i915/i915_utils.h
> @@ -120,6 +120,12 @@ static inline u64 ptr_to_u64(const void *ptr)
>
> #include <linux/list.h>
>
> +static inline int list_is_first(const struct list_head *list,
> + const struct list_head *head)
Return bool if you decide you prefer to keep list_is_first?
> +{
> + return head->next == list;
> +}
> +
> static inline void __list_del_many(struct list_head *head,
> struct list_head *first)
> {
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> index 792a2ca95872..3453e7426f6b 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> @@ -1150,8 +1150,6 @@ intel_engine_create_ring(struct intel_engine_cs *engine, int size)
> }
> ring->vma = vma;
>
> - list_add(&ring->link, &engine->i915->gt.rings);
> -
> return ring;
> }
>
> @@ -1163,8 +1161,6 @@ 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..fd5a6363ab1d 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 live;
live_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..9335b09d8b04 100644
> --- a/drivers/gpu/drm/i915/selftests/mock_gem_device.c
> +++ b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
> @@ -225,7 +225,7 @@ struct drm_i915_private *mock_gem_device(void)
> goto err_dependencies;
>
> mutex_lock(&i915->drm.struct_mutex);
> - INIT_LIST_HEAD(&i915->gt.rings);
> + INIT_LIST_HEAD(&i915->gt.live_rings);
> INIT_LIST_HEAD(&i915->gt.timelines);
> err = i915_gem_timeline_init__global(i915);
> if (err) {
>
Regards,
Tvrtko
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