drm/i915: Move obj->active:5 to obj->flags

We are motivated to avoid using a bitfield for obj->active for a couple
of reasons. Firstly, we wish to document our lockless read of obj->active
using READ_ONCE inside i915_gem_busy_ioctl() and that requires an
integral type (i.e. not a bitfield). Secondly, gcc produces abysmal code
when presented with a bitfield and that shows up high on the profiles of
request tracking (mainly due to excess memory traffic as it converts
the bitfield to a register and back and generates frequent AGI in the
process).

v2: BIT, break up a long line in compute the other engines, new paint
for i915_gem_object_is_active (now i915_gem_object_get_active).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1470324762-2545-23-git-send-email-chris@chris-wilson.co.uk

1 files changed, 36 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 3de75e82ca76..db5dc5bd78d8 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2155,12 +2155,16 @@ struct drm_i915_gem_object {
 
 	struct list_head batch_pool_link;
 
+	unsigned long flags;
 	/**
 	 * This is set if the object is on the active lists (has pending
 	 * rendering and so a non-zero seqno), and is not set if it i s on
 	 * inactive (ready to be unbound) list.
 	 */
-	unsigned int active:I915_NUM_ENGINES;
+#define I915_BO_ACTIVE_SHIFT 0
+#define I915_BO_ACTIVE_MASK ((1 << I915_NUM_ENGINES) - 1)
+#define __I915_BO_ACTIVE(bo) \
+	((READ_ONCE((bo)->flags) >> I915_BO_ACTIVE_SHIFT) & I915_BO_ACTIVE_MASK)
 
 	/**
 	 * This is set if the object has been written to since last bound
@@ -2325,6 +2329,37 @@ i915_gem_object_has_struct_page(const struct drm_i915_gem_object *obj)
 	return obj->ops->flags & I915_GEM_OBJECT_HAS_STRUCT_PAGE;
 }
 
+static inline unsigned long
+i915_gem_object_get_active(const struct drm_i915_gem_object *obj)
+{
+	return (obj->flags >> I915_BO_ACTIVE_SHIFT) & I915_BO_ACTIVE_MASK;
+}
+
+static inline bool
+i915_gem_object_is_active(const struct drm_i915_gem_object *obj)
+{
+	return i915_gem_object_get_active(obj);
+}
+
+static inline void
+i915_gem_object_set_active(struct drm_i915_gem_object *obj, int engine)
+{
+	obj->flags |= BIT(engine + I915_BO_ACTIVE_SHIFT);
+}
+
+static inline void
+i915_gem_object_clear_active(struct drm_i915_gem_object *obj, int engine)
+{
+	obj->flags &= ~BIT(engine + I915_BO_ACTIVE_SHIFT);
+}
+
+static inline bool
+i915_gem_object_has_active_engine(const struct drm_i915_gem_object *obj,
+				  int engine)
+{
+	return obj->flags & BIT(engine + I915_BO_ACTIVE_SHIFT);
+}
+
 /*
  * Optimised SGL iterator for GEM objects
  */