[PATCH 09/17] drm/cgroup: Add ability to query drm cgroup GPU time

From: Tvrtko Ursulin
Date: Wed Jul 12 2023 - 07:50:40 EST


From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>

Add a driver callback and core helper which allow querying the time spent
on GPUs for processes belonging to a group.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
---
include/drm/drm_drv.h | 28 ++++++++++++++++++++++++++++
kernel/cgroup/drm.c | 20 ++++++++++++++++++++
2 files changed, 48 insertions(+)

diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
index b77f2c7275b7..3116fa4dbc48 100644
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -151,6 +151,24 @@ enum drm_driver_feature {
DRIVER_HAVE_IRQ = BIT(30),
};

+/**
+ * struct drm_cgroup_ops
+ *
+ * This structure contains a number of callbacks that drivers can provide if
+ * they are able to support one or more of the functionalities implemented by
+ * the DRM cgroup controller.
+ */
+struct drm_cgroup_ops {
+ /**
+ * @active_time_us:
+ *
+ * Optional callback for reporting the GPU time consumed by this client.
+ *
+ * Used by the DRM core when queried by the DRM cgroup controller.
+ */
+ u64 (*active_time_us) (struct drm_file *);
+};
+
/**
* struct drm_driver - DRM driver structure
*
@@ -428,6 +446,16 @@ struct drm_driver {
*/
const struct file_operations *fops;

+#ifdef CONFIG_CGROUP_DRM
+ /**
+ * @cg_ops:
+ *
+ * Optional pointer to driver callbacks facilitating integration with
+ * the DRM cgroup controller.
+ */
+ const struct drm_cgroup_ops *cg_ops;
+#endif
+
#ifdef CONFIG_DRM_LEGACY
/* Everything below here is for legacy driver, never use! */
/* private: */
diff --git a/kernel/cgroup/drm.c b/kernel/cgroup/drm.c
index d702be1b441f..acdb76635b60 100644
--- a/kernel/cgroup/drm.c
+++ b/kernel/cgroup/drm.c
@@ -9,6 +9,8 @@
#include <linux/mutex.h>
#include <linux/slab.h>

+#include <drm/drm_drv.h>
+
struct drm_cgroup_state {
struct cgroup_subsys_state css;

@@ -31,6 +33,24 @@ css_to_drmcs(struct cgroup_subsys_state *css)
return container_of(css, struct drm_cgroup_state, css);
}

+static u64 drmcs_get_active_time_us(struct drm_cgroup_state *drmcs)
+{
+ struct drm_file *fpriv;
+ u64 total = 0;
+
+ lockdep_assert_held(&drmcg_mutex);
+
+ list_for_each_entry(fpriv, &drmcs->clients, clink) {
+ const struct drm_cgroup_ops *cg_ops =
+ fpriv->minor->dev->driver->cg_ops;
+
+ if (cg_ops && cg_ops->active_time_us)
+ total += cg_ops->active_time_us(fpriv);
+ }
+
+ return total;
+}
+
static void drmcs_free(struct cgroup_subsys_state *css)
{
struct drm_cgroup_state *drmcs = css_to_drmcs(css);
--
2.39.2