[RFC 10/17] drm: Add ability to query drm cgroup GPU time

[Tvrtko Ursulin]

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>
---
 drivers/gpu/drm/drm_cgroup.c | 24 ++++++++++++++++++++++++
 include/drm/drm_clients.h    |  1 +
 include/drm/drm_drv.h        |  9 +++++++++
 3 files changed, 34 insertions(+)

diff --git a/drivers/gpu/drm/drm_cgroup.c b/drivers/gpu/drm/drm_cgroup.c
index 59b730ed1334..e0cadb5e5659 100644
--- a/drivers/gpu/drm/drm_cgroup.c
+++ b/drivers/gpu/drm/drm_cgroup.c
@@ -206,3 +206,27 @@ void drm_pid_update_priority(struct pid *pid, int priority)
 	rcu_read_unlock();
 }
 EXPORT_SYMBOL_GPL(drm_pid_update_priority);
+
+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 3a0b1cdb338f..f25e09ed5feb 100644
--- a/include/drm/drm_clients.h
+++ b/include/drm/drm_clients.h
@@ -37,5 +37,6 @@ static inline void drm_clients_migrate(struct drm_file *file_priv)
 
 unsigned int drm_pid_priority_levels(struct pid *pid, bool *non_uniform);
 void drm_pid_update_priority(struct pid *pid, int priority);
+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 2371d73e12cf..0f1802df01fe 100644
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -183,6 +183,15 @@ struct drm_cgroup_ops {
 	 * priorities of already running workloads.
 	 */
 	void (*update_priority) (struct drm_file *, int priority);
+
+	/**
+	 * @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 *);
 };
 
 /**
-- 
2.34.1