drm: Add fdinfo memory stats

Add support to dump GEM stats to fdinfo.

v2: Fix typos, change size units to match docs, use div_u64
v3: Do it in core
v4: more kerneldoc
v5: doc fixes
v6: Actually use u64, bit more comment docs

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230524155956.382440-6-robdclark@gmail.com

1 files changed, 32 insertions, 0 deletions

diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
index b8efd836edef..bbc721870c13 100644
--- a/include/drm/drm_gem.h
+++ b/include/drm/drm_gem.h
@@ -43,6 +43,25 @@ struct iosys_map;
 struct drm_gem_object;
 
 /**
+ * enum drm_gem_object_status - bitmask of object state for fdinfo reporting
+ * @DRM_GEM_OBJECT_RESIDENT: object is resident in memory (ie. not unpinned)
+ * @DRM_GEM_OBJECT_PURGEABLE: object marked as purgeable by userspace
+ *
+ * Bitmask of status used for fdinfo memory stats, see &drm_gem_object_funcs.status
+ * and drm_show_fdinfo().  Note that an object can DRM_GEM_OBJECT_PURGEABLE if
+ * it still active or not resident, in which case drm_show_fdinfo() will not
+ * account for it as purgeable.  So drivers do not need to check if the buffer
+ * is idle and resident to return this bit.  (Ie. userspace can mark a buffer
+ * as purgeable even while it is still busy on the GPU.. it does not _actually_
+ * become puregeable until it becomes idle.  The status gem object func does
+ * not need to consider this.)
+ */
+enum drm_gem_object_status {
+	DRM_GEM_OBJECT_RESIDENT  = BIT(0),
+	DRM_GEM_OBJECT_PURGEABLE = BIT(1),
+};
+
+/**
  * struct drm_gem_object_funcs - GEM object functions
  */
 struct drm_gem_object_funcs {
@@ -175,6 +194,19 @@ struct drm_gem_object_funcs {
 	int (*evict)(struct drm_gem_object *obj);
 
 	/**
+	 * @status:
+	 *
+	 * The optional status callback can return additional object state
+	 * which determines which stats the object is counted against.  The
+	 * callback is called under table_lock.  Racing against object status
+	 * change is "harmless", and the callback can expect to not race
+	 * against object destruction.
+	 *
+	 * Called by drm_show_memory_stats().
+	 */
+	enum drm_gem_object_status (*status)(struct drm_gem_object *obj);
+
+	/**
 	 * @vm_ops:
 	 *
 	 * Virtual memory operations used with mmap.