obj->pin_global was original used as a means to keep the shrinker off
the active scanout, but we use the vma->pin_count itself for that and
the obj->frontbuffer to delay shrinking active framebuffers. The other
role that obj->pin_global gained was for spotting display objects inside
GEM and working harder to keep those coherent; for which we can again
simply inspect obj->frontbuffer directly.
Coming up next, we will want to manipulate the pin_global counter
outside of the principle locks, so would need to make pin_global atomic.
However, since obj->frontbuffer is already managed atomically, it makes
sense to use that the primary key for display objects instead of having
pin_global.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx>
---
.../gpu/drm/i915/display/intel_frontbuffer.c | 13 +++++--
drivers/gpu/drm/i915/gem/i915_gem_domain.c | 34 ++++++-------------
drivers/gpu/drm/i915/gem/i915_gem_object.h | 3 +-
.../gpu/drm/i915/gem/i915_gem_object_types.h | 2 --
drivers/gpu/drm/i915/gem/i915_gem_shrinker.c | 15 +++-----
drivers/gpu/drm/i915/i915_debugfs.c | 12 ++-----
6 files changed, 29 insertions(+), 50 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_frontbuffer.c b/drivers/gpu/drm/i915/display/intel_frontbuffer.c
index 719379774fa5..fc40dc1fdbcc 100644
--- a/drivers/gpu/drm/i915/display/intel_frontbuffer.c
+++ b/drivers/gpu/drm/i915/display/intel_frontbuffer.c
@@ -220,11 +220,18 @@ static void frontbuffer_release(struct kref *ref)
{
struct intel_frontbuffer *front =
container_of(ref, typeof(*front), ref);
+ struct drm_i915_gem_object *obj = front->obj;
+ struct i915_vma *vma;
- front->obj->frontbuffer = NULL;
- spin_unlock(&to_i915(front->obj->base.dev)->fb_tracking.lock);
+ spin_lock(&obj->vma.lock);
+ for_each_ggtt_vma(vma, obj)
+ vma->display_alignment = I915_GTT_MIN_ALIGNMENT;
+ spin_unlock(&obj->vma.lock);
- i915_gem_object_put(front->obj);
+ obj->frontbuffer = NULL;
+ spin_unlock(&to_i915(obj->base.dev)->fb_tracking.lock);
+
+ i915_gem_object_put(obj);
kfree(front);
}
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_domain.c b/drivers/gpu/drm/i915/gem/i915_gem_domain.c
index 9c58e8fac1d9..0341b3da930a 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_domain.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_domain.c
@@ -27,7 +27,7 @@ static void __i915_gem_object_flush_for_display(struct drm_i915_gem_object *obj)
void i915_gem_object_flush_if_display(struct drm_i915_gem_object *obj)
{
- if (!READ_ONCE(obj->pin_global))
+ if (!READ_ONCE(obj->frontbuffer))
return;
i915_gem_object_lock(obj);
@@ -422,12 +422,8 @@ i915_gem_object_pin_to_display_plane(struct drm_i915_gem_object *obj,
assert_object_held(obj);
- /* Mark the global pin early so that we account for the
- * display coherency whilst setting up the cache domains.
- */
- obj->pin_global++;
-
- /* The display engine is not coherent with the LLC cache on gen6. As
+ /*
+ * The display engine is not coherent with the LLC cache on gen6. As
* a result, we make sure that the pinning that is about to occur is
* done with uncached PTEs. This is lowest common denominator for all
* chipsets.
@@ -439,12 +435,11 @@ i915_gem_object_pin_to_display_plane(struct drm_i915_gem_object *obj,
ret = i915_gem_object_set_cache_level(obj,
HAS_WT(to_i915(obj->base.dev)) ?
I915_CACHE_WT : I915_CACHE_NONE);
- if (ret) {
- vma = ERR_PTR(ret);
- goto err_unpin_global;
- }
+ if (ret)
+ return ERR_PTR(ret);
- /* As the user may map the buffer once pinned in the display plane
+ /*
+ * As the user may map the buffer once pinned in the display plane
* (e.g. libkms for the bootup splash), we have to ensure that we
* always use map_and_fenceable for all scanout buffers. However,
* it may simply be too big to fit into mappable, in which case
@@ -461,22 +456,19 @@ i915_gem_object_pin_to_display_plane(struct drm_i915_gem_object *obj,
if (IS_ERR(vma))
vma = i915_gem_object_ggtt_pin(obj, view, 0, alignment, flags);
if (IS_ERR(vma))
- goto err_unpin_global;
+ return vma;
vma->display_alignment = max_t(u64, vma->display_alignment, alignment);
__i915_gem_object_flush_for_display(obj);
- /* It should now be out of any other write domains, and we can update
+ /*
+ * It should now be out of any other write domains, and we can update
* the domain values for our changes.
*/
obj->read_domains |= I915_GEM_DOMAIN_GTT;
return vma;
-
-err_unpin_global:
- obj->pin_global--;
- return vma;
}
static void i915_gem_object_bump_inactive_ggtt(struct drm_i915_gem_object *obj)
@@ -514,12 +506,6 @@ i915_gem_object_unpin_from_display_plane(struct i915_vma *vma)
assert_object_held(obj);
- if (WARN_ON(obj->pin_global == 0))
- return;
-
- if (--obj->pin_global == 0)
- vma->display_alignment = I915_GTT_MIN_ALIGNMENT;
-
/* Bump the LRU to try and avoid premature eviction whilst flipping */
i915_gem_object_bump_inactive_ggtt(obj);
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
index 5efb9936e05b..d6005cad9d5c 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
@@ -406,7 +406,8 @@ static inline bool cpu_write_needs_clflush(struct drm_i915_gem_object *obj)
if (!(obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_WRITE))
return true;
- return obj->pin_global; /* currently in use by HW, keep flushed */
+ /* Currently in use by HW (display engine)? Keep flushed. */
+ return READ_ONCE(obj->frontbuffer);
}
static inline void __start_cpu_write(struct drm_i915_gem_object *obj)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
index ede0eb4218a8..13b9dc0e1a89 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
@@ -152,8 +152,6 @@ struct drm_i915_gem_object {
/** Count of VMA actually bound by this object */
atomic_t bind_count;
- /** Count of how many global VMA are currently pinned for use by HW */
- unsigned int pin_global;
struct {
struct mutex lock; /* protects the pages and their use */
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
index edd21d14e64f..4e55cfc2b0dc 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
@@ -61,7 +61,8 @@ static bool can_release_pages(struct drm_i915_gem_object *obj)
if (!i915_gem_object_is_shrinkable(obj))
return false;
- /* Only report true if by unbinding the object and putting its pages
+ /*
+ * Only report true if by unbinding the object and putting its pages
* we can actually make forward progress towards freeing physical
* pages.
*
@@ -72,16 +73,8 @@ static bool can_release_pages(struct drm_i915_gem_object *obj)
if (atomic_read(&obj->mm.pages_pin_count) > atomic_read(&obj->bind_count))
return false;
- /* If any vma are "permanently" pinned, it will prevent us from
- * reclaiming the obj->mm.pages. We only allow scanout objects to claim
- * a permanent pin, along with a few others like the context objects.
- * To simplify the scan, and to avoid walking the list of vma under the
- * object, we just check the count of its permanently pinned.
- */
- if (READ_ONCE(obj->pin_global))
- return false;
-
- /* We can only return physical pages to the system if we can either
+ /*
+ * We can only return physical pages to the system if we can either
* discard the contents (because the user has marked them as being
* purgeable) or if we can move their contents out to swap.
*/
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index e103fcba6435..b90371844689 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -77,11 +77,6 @@ static int i915_capabilities(struct seq_file *m, void *data)
return 0;
}
-static char get_pin_flag(struct drm_i915_gem_object *obj)
-{
- return obj->pin_global ? 'p' : ' ';
-}
-
static char get_tiling_flag(struct drm_i915_gem_object *obj)
{
switch (i915_gem_object_get_tiling(obj)) {
@@ -140,9 +135,8 @@ describe_obj(struct seq_file *m, struct drm_i915_gem_object *obj)
struct i915_vma *vma;
int pin_count = 0;
- seq_printf(m, "%pK: %c%c%c%c %8zdKiB %02x %02x %s%s%s",
+ seq_printf(m, "%pK: %c%c%c %8zdKiB %02x %02x %s%s%s",
&obj->base,
- get_pin_flag(obj),
get_tiling_flag(obj),
get_global_flag(obj),
get_pin_mapped_flag(obj),
@@ -221,8 +215,8 @@ describe_obj(struct seq_file *m, struct drm_i915_gem_object *obj)
seq_printf(m, " (pinned x %d)", pin_count);
if (obj->stolen)
seq_printf(m, " (stolen: %08llx)", obj->stolen->start);
- if (obj->pin_global)
- seq_printf(m, " (global)");
+ if (READ_ONCE(obj->frontbuffer))
+ seq_printf(m, " (front)");
engine = i915_gem_object_last_write_engine(obj);
if (engine)
--
2.23.0
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