[RFC 06/12] drm/cgroup: Add ability to query drm cgroup GPU time

Tvrtko Ursulin
2023-01-12T16:56:03Z

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

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@intel.com>
---
drivers/gpu/drm/drm_cgroup.c | 24 ++++++++++++++++++++++++
include/drm/drm_clients.h | 2 ++
include/drm/drm_drv.h | 28 ++++++++++++++++++++++++++++
3 files changed, 54 insertions(+)

diff --git a/drivers/gpu/drm/drm_cgroup.c b/drivers/gpu/drm/drm_cgroup.c
index 46b012d2be42..bc1e34f1a552 100644
--- a/drivers/gpu/drm/drm_cgroup.c
+++ b/drivers/gpu/drm/drm_cgroup.c
@@ -138,3 +138,27 @@ drm_clients_migrate(struct drm_file *file_priv,
pid_nr(old), pid_nr(new));
rcu_read_unlock();
}
+
+u64 drm_pid_get_active_time_us(struct pid *pid)
+{
+ struct drm_pid_clients *clients;
+ u64 total = 0;
+
+ rcu_read_lock();
+ clients = xa_load(&drm_pid_clients, (unsigned long)pid);
+ if (clients) {
+ struct drm_file *fpriv;
+
+ list_for_each_entry_rcu(fpriv, &clients->file_list, 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);
+ }
+ }
+ rcu_read_unlock();
+
+ return total;
+}
+EXPORT_SYMBOL_GPL(drm_pid_get_active_time_us);
diff --git a/include/drm/drm_clients.h b/include/drm/drm_clients.h
index 2732fffab3f0..7e0c0cf14f25 100644
--- a/include/drm/drm_clients.h
+++ b/include/drm/drm_clients.h
@@ -41,4 +41,6 @@ drm_clients_migrate(struct drm_file *file_priv,
}
#endif

+u64 drm_pid_get_active_time_us(struct pid *pid);
+
#endif
diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
index d7c521e8860f..f5f0e088e1fe 100644
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -158,6 +158,24 @@ enum drm_driver_feature {
DRIVER_KMS_LEGACY_CONTEXT = BIT(31),
};

+/**
+ * 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
*
@@ -469,6 +487,16 @@ 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: */
--
2.34.1