[RFC 08/13] drm/cgroup: Add over budget signalling callback

[Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>]

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

Add a new callback via which the drm cgroup controller is notifying the
drm core that a certain process is above its allotted GPU time.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 drivers/gpu/drm/drm_cgroup.c | 21 +++++++++++++++++++++
 include/drm/drm_clients.h    |  1 +
 include/drm/drm_drv.h        |  8 ++++++++
 3 files changed, 30 insertions(+)

diff --git a/drivers/gpu/drm/drm_cgroup.c b/drivers/gpu/drm/drm_cgroup.c
index 06810b4c3ff1..e3854741c584 100644
--- a/drivers/gpu/drm/drm_cgroup.c
+++ b/drivers/gpu/drm/drm_cgroup.c
@@ -152,3 +152,24 @@ u64 drm_pid_get_active_time_us(struct pid *pid)
 	return total;
 }
 EXPORT_SYMBOL_GPL(drm_pid_get_active_time_us);
+
+void drm_pid_signal_budget(struct pid *pid, u64 usage, u64 budget)
+{
+	struct drm_pid_clients *clients;
+
+	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->signal_budget)
+				cg_ops->signal_budget(fpriv, usage, budget);
+		}
+	}
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(drm_pid_signal_budget);
diff --git a/include/drm/drm_clients.h b/include/drm/drm_clients.h
index b9b8009c28a6..356ee92792a6 100644
--- a/include/drm/drm_clients.h
+++ b/include/drm/drm_clients.h
@@ -42,5 +42,6 @@ drm_clients_migrate(struct drm_file *file_priv,
 #endif
 
 u64 drm_pid_get_active_time_us(struct pid *pid);
+void drm_pid_signal_budget(struct pid *pid, u64 usage, u64 budget);
 
 #endif
diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
index c09fe9bd517f..c30afe97f922 100644
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -164,6 +164,14 @@ struct drm_cgroup_ops {
 	 * Used by the DRM core when queried by the DRM cgroup controller.
 	 */
 	u64 (*active_time_us) (struct drm_file *);
+
+	/**
+	 * @signal_budget:
+	 *
+	 * Optional callback used by the DRM core to forward over/under GPU time
+	 * messages sent by the DRM cgroup controller.
+	 */
+	int (*signal_budget) (struct drm_file *, u64 used, u64 budget);
 };
 
 /**
-- 
2.34.1