[PATCH v2] drm/i915: Allow shrinking of userptr objects once again

[Tvrtko Ursulin <tursulin@ursulin.net>]

From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Commit 1bec9b0bda3d ("drm/i915/shrinker: Only shmemfs objects
are backed by swap") stopped considering the userptr objects
in shrinker callbacks.

Restore that so idle userptr objects can be discarded in order
to free up memory.

One change further to what was introduced in 1bec9b0bda3d is
to start considering userptr objects in oom but that should
also be a correct thing to do.

v2: Introduce I915_GEM_OBJECT_IS_SHRINKABLE. (Chris Wilson)

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Fixes: 1bec9b0bda3d ("drm/i915/shrinker: Only shmemfs objects are backed by swap")
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: <stable@vger.kernel.org>
---
 drivers/gpu/drm/i915/i915_drv.h          | 7 +++++++
 drivers/gpu/drm/i915/i915_gem.c          | 3 ++-
 drivers/gpu/drm/i915/i915_gem_internal.c | 3 ++-
 drivers/gpu/drm/i915/i915_gem_shrinker.c | 4 ++--
 drivers/gpu/drm/i915/i915_gem_userptr.c  | 3 ++-
 5 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 086396e16de7..0525e5b448b0 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2181,6 +2181,7 @@ enum hdmi_force_audio {
 struct drm_i915_gem_object_ops {
 	unsigned int flags;
 #define I915_GEM_OBJECT_HAS_STRUCT_PAGE 0x1
+#define I915_GEM_OBJECT_IS_SHRINKABLE   0x2
 
 	/* Interface between the GEM object and its backing storage.
 	 * get_pages() is called once prior to the use of the associated set
@@ -2430,6 +2431,12 @@ i915_gem_object_has_struct_page(const struct drm_i915_gem_object *obj)
 }
 
 static inline bool
+i915_gem_object_is_shrinkable(const struct drm_i915_gem_object *obj)
+{
+	return obj->ops->flags & I915_GEM_OBJECT_IS_SHRINKABLE;
+}
+
+static inline bool
 i915_gem_object_is_active(const struct drm_i915_gem_object *obj)
 {
 	return obj->active_count;
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index cbbfaa7761b9..e1bf456c62c3 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4146,7 +4146,8 @@ void i915_gem_object_init(struct drm_i915_gem_object *obj,
 }
 
 static const struct drm_i915_gem_object_ops i915_gem_object_ops = {
-	.flags = I915_GEM_OBJECT_HAS_STRUCT_PAGE,
+	.flags = I915_GEM_OBJECT_HAS_STRUCT_PAGE |
+		 I915_GEM_OBJECT_IS_SHRINKABLE,
 	.get_pages = i915_gem_object_get_pages_gtt,
 	.put_pages = i915_gem_object_put_pages_gtt,
 };
diff --git a/drivers/gpu/drm/i915/i915_gem_internal.c b/drivers/gpu/drm/i915/i915_gem_internal.c
index 1b0607a44a9a..4b3ff3e5b911 100644
--- a/drivers/gpu/drm/i915/i915_gem_internal.c
+++ b/drivers/gpu/drm/i915/i915_gem_internal.c
@@ -132,7 +132,8 @@ static void i915_gem_object_put_pages_internal(struct drm_i915_gem_object *obj,
 }
 
 static const struct drm_i915_gem_object_ops i915_gem_object_internal_ops = {
-	.flags = I915_GEM_OBJECT_HAS_STRUCT_PAGE,
+	.flags = I915_GEM_OBJECT_HAS_STRUCT_PAGE |
+		 I915_GEM_OBJECT_IS_SHRINKABLE,
 	.get_pages = i915_gem_object_get_pages_internal,
 	.put_pages = i915_gem_object_put_pages_internal,
 };
diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c
index f988652f1e26..87dd27d5146c 100644
--- a/drivers/gpu/drm/i915/i915_gem_shrinker.c
+++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c
@@ -83,8 +83,8 @@ static bool can_release_pages(struct drm_i915_gem_object *obj)
 	if (!obj->mm.pages)
 		return false;
 
-	/* Only shmemfs objects are backed by swap */
-	if (!obj->base.filp)
+	/* Consider only shrinkable ojects. */
+	if (!i915_gem_object_is_shrinkable(obj))
 		return false;
 
 	/* Only report true if by unbinding the object and putting its pages
diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c
index 9bf44b5bca10..64261639f547 100644
--- a/drivers/gpu/drm/i915/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/i915_gem_userptr.c
@@ -707,7 +707,8 @@ i915_gem_userptr_dmabuf_export(struct drm_i915_gem_object *obj)
 }
 
 static const struct drm_i915_gem_object_ops i915_gem_userptr_ops = {
-	.flags = I915_GEM_OBJECT_HAS_STRUCT_PAGE,
+	.flags = I915_GEM_OBJECT_HAS_STRUCT_PAGE |
+		 I915_GEM_OBJECT_IS_SHRINKABLE,
 	.get_pages = i915_gem_userptr_get_pages,
 	.put_pages = i915_gem_userptr_put_pages,
 	.dmabuf_export = i915_gem_userptr_dmabuf_export,
-- 
2.7.4