[Intel-gfx] [PATCH] drm/i915/gem: Lazily acquire the device wakeref for freeing objects

[Chris Wilson]

We only need the device wakeref on freeing the objects if we have to
unbind the object from the global GTT, or otherwise update device
information. If the objects are clean, we never need the wakeref, so
avoid taking until required.

For this to be effective in preventing us from waking the device after
it is unbind, we also need to mark the GGTT as closed on device removal.
The GGTT will be rebuilt from scratch the next time we need to open it
(on binding a new device).

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Janusz Krzysztofik <janusz.krzysztofik at linux.intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_mman.c   | 3 +++
 drivers/gpu/drm/i915/gem/i915_gem_object.c | 3 ---
 drivers/gpu/drm/i915/gt/intel_ggtt.c       | 9 +++++++--
 drivers/gpu/drm/i915/gt/intel_gtt.h        | 1 +
 drivers/gpu/drm/i915/i915_drv.c            | 1 +
 drivers/gpu/drm/i915/i915_vma.c            | 3 ++-
 6 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
index b39c24dae64e..c6cead6f2b3e 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
@@ -421,6 +421,9 @@ static void i915_gem_object_release_mmap_gtt(struct drm_i915_gem_object *obj)
 	struct drm_i915_private *i915 = to_i915(obj->base.dev);
 	intel_wakeref_t wakeref;
 
+	if (!atomic_read(&i915->ggtt.vm.open))
+		return;
+
 	/*
 	 * Serialisation between user GTT access and our code depends upon
 	 * revoking the CPU's PTE whilst the mutex is held. The next user
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.c b/drivers/gpu/drm/i915/gem/i915_gem_object.c
index 9d1d0131f7c2..99356c00c19e 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.c
@@ -162,9 +162,7 @@ static void __i915_gem_free_objects(struct drm_i915_private *i915,
 				    struct llist_node *freed)
 {
 	struct drm_i915_gem_object *obj, *on;
-	intel_wakeref_t wakeref;
 
-	wakeref = intel_runtime_pm_get(&i915->runtime_pm);
 	llist_for_each_entry_safe(obj, on, freed, freed) {
 		struct i915_mmap_offset *mmo, *mn;
 
@@ -224,7 +222,6 @@ static void __i915_gem_free_objects(struct drm_i915_private *i915,
 		call_rcu(&obj->rcu, __i915_gem_free_object_rcu);
 		cond_resched();
 	}
-	intel_runtime_pm_put(&i915->runtime_pm, wakeref);
 }
 
 void i915_gem_flush_free_objects(struct drm_i915_private *i915)
diff --git a/drivers/gpu/drm/i915/gt/intel_ggtt.c b/drivers/gpu/drm/i915/gt/intel_ggtt.c
index 66165b10256e..b65545182ef5 100644
--- a/drivers/gpu/drm/i915/gt/intel_ggtt.c
+++ b/drivers/gpu/drm/i915/gt/intel_ggtt.c
@@ -681,8 +681,6 @@ static void ggtt_cleanup_hw(struct i915_ggtt *ggtt)
 {
 	struct i915_vma *vma, *vn;
 
-	atomic_set(&ggtt->vm.open, 0);
-
 	rcu_barrier(); /* flush the RCU'ed__i915_vm_release */
 	flush_workqueue(ggtt->vm.i915->wq);
 
@@ -709,6 +707,13 @@ static void ggtt_cleanup_hw(struct i915_ggtt *ggtt)
 		io_mapping_fini(&ggtt->iomap);
 }
 
+void i915_ggtt_driver_remove(struct drm_i915_private *i915)
+{
+	struct i915_ggtt *ggtt = &i915->ggtt;
+
+	atomic_set(&ggtt->vm.open, 0);
+}
+
 /**
  * i915_ggtt_driver_release - Clean up GGTT hardware initialization
  * @i915: i915 device
diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.h b/drivers/gpu/drm/i915/gt/intel_gtt.h
index d93ebdf3fa0e..f140ce5c171a 100644
--- a/drivers/gpu/drm/i915/gt/intel_gtt.h
+++ b/drivers/gpu/drm/i915/gt/intel_gtt.h
@@ -501,6 +501,7 @@ int i915_ggtt_enable_hw(struct drm_i915_private *i915);
 void i915_ggtt_enable_guc(struct i915_ggtt *ggtt);
 void i915_ggtt_disable_guc(struct i915_ggtt *ggtt);
 int i915_init_ggtt(struct drm_i915_private *i915);
+void i915_ggtt_driver_remove(struct drm_i915_private *i915);
 void i915_ggtt_driver_release(struct drm_i915_private *i915);
 
 static inline bool i915_ggtt_has_aperture(const struct i915_ggtt *ggtt)
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 2d62efd9316f..bdf97a1cb7cc 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -768,6 +768,7 @@ static void i915_driver_hw_remove(struct drm_i915_private *dev_priv)
 
 	i915_perf_fini(dev_priv);
 
+	i915_ggtt_driver_remove(dev_priv);
 	if (pdev->msi_enabled)
 		pci_disable_msi(pdev);
 
diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index fc14ebf9a0b7..6fe56ad2a542 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -1319,7 +1319,8 @@ int i915_vma_unbind(struct i915_vma *vma)
 		return -EAGAIN;
 	}
 
-	if (i915_vma_is_bound(vma, I915_VMA_GLOBAL_BIND))
+	if (i915_vma_is_bound(vma, I915_VMA_GLOBAL_BIND) &&
+	    atomic_read(&vma->vm->open))
 		/* XXX not always required: nop_clear_range */
 		wakeref = intel_runtime_pm_get(&vm->i915->runtime_pm);
 
-- 
2.20.1