On 23/04/2018 11:36, Chris Wilson wrote:
Quoting Tvrtko Ursulin (2018-04-23 11:25:54)
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@xxxxxxxxxxxxxxx>
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx>
---
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.
list_is_first tallies nicely with the list_is_last used before the
corresponding list_del.
Yes but to me that's minor, basically immaterial as argument whether or
not to add our own list helper.
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?
I was thinking list when I wrote it. It's small enough we can argue both
and both be right.
Hm obviosuly it is not an error to call i915_retire_requests with
nothing active (early return). So I even briefly wanted to suggest to
make it 100% explicit and have the assert at the top of the function as:
GEM_BUG_ON(!!i915->gt.active_requests ^ !!list_empty(..));
Unless I messed it up, the idea is to check those two are always in the
same state.
+ 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?
Copy'n'paste from list_is_last().
+{
+ 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?
live or active.
active_rings ties in with active_requests, so active_link here.
Fine by me.
Regards,
Tvrtko
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