From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Show overall status of a task group - whether all DRM clients in a group
support over budget signaling, or some do not, or if there are no DRM
clients in the group to start with.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
---
Documentation/admin-guide/cgroup-v2.rst | 7 ++++
drivers/gpu/drm/drm_cgroup.c | 33 ++++++++++++++++
include/drm/drm_clients.h | 7 ++++
include/drm/drm_drv.h | 11 +++++-
kernel/cgroup/drm.c | 52 +++++++++++++++++++++++++
5 files changed, 109 insertions(+), 1 deletion(-)
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 318f463a1316..6ee94ee109f0 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -2491,6 +2491,13 @@ DRM scheduling soft limits interface files
signal.
Value of zero (defaul) disables the soft limit checking.
+ drm.budget_supported
+ One of:
+ 1) 'yes' - when all DRM clients in the group support the functionality.
+ 2) 'no' - when at least one of the DRM clients does not support the
+ functionality.
+ 3) 'n/a' - when there are no DRM clients in the group.
+
Misc
----
diff --git a/drivers/gpu/drm/drm_cgroup.c b/drivers/gpu/drm/drm_cgroup.c
index ff99d1f4f1d4..d2d8b2cb4ab3 100644
--- a/drivers/gpu/drm/drm_cgroup.c
+++ b/drivers/gpu/drm/drm_cgroup.c
@@ -259,3 +259,36 @@ void drm_pid_signal_budget(struct pid *pid, u64 usage, u64 budget)
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(drm_pid_signal_budget);
+
+enum drm_cg_supported drm_pid_signal_budget_supported(struct pid *pid)
+{
+ enum drm_cg_supported supported = DRM_CG_NOT_APPLICABLE;
+ 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->active_time_us ||
+ !cg_ops->signal_budget ||
+ cg_ops->signal_budget(fpriv, 0, 0) < 0) {
+ supported = DRM_CG_NOT_SUPPORTED;
+ break;
+ }
+
+ if (supported == DRM_CG_NOT_APPLICABLE)
+ supported = DRM_CG_SUPPORTED;
+
+ }
+ }
+ rcu_read_unlock();
+
+ return supported;
+}
+EXPORT_SYMBOL_GPL(drm_pid_signal_budget_supported);
diff --git a/include/drm/drm_clients.h b/include/drm/drm_clients.h
index 7ad09fd0a404..5d14ae26ece6 100644
--- a/include/drm/drm_clients.h
+++ b/include/drm/drm_clients.h
@@ -14,6 +14,12 @@ struct drm_pid_clients {
struct rcu_head rcu;
};
+enum drm_cg_supported {
+ DRM_CG_NOT_APPLICABLE = -1,
+ DRM_CG_NOT_SUPPORTED = 0,
+ DRM_CG_SUPPORTED
+};
+
#if IS_ENABLED(CONFIG_CGROUP_DRM)
void drm_clients_close(struct drm_file *file_priv);
int drm_clients_open(struct drm_file *file_priv);
@@ -39,5 +45,6 @@ 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);
void drm_pid_signal_budget(struct pid *pid, u64 usage, u64 budget);
+enum drm_cg_supported drm_pid_signal_budget_supported(struct pid *pid);
#endif
diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
index 07dec956ebfb..7a1a20d1b8de 100644
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -198,8 +198,17 @@ struct drm_cgroup_ops {
*
* Optional callback used by the DRM core to forward over/under GPU time
* messages sent by the DRM cgroup controller.
+ *
+ * Zero used with zero budget is a special budgeting support status
+ * query which needs to return either zero or -EINVAL if client does not
+ * support budget control.
+ *
+ * Returns:
+ * * 1 when client has been throttled.
+ * * 0 when no action has been taken.
+ * * -EINVAL when not supported by the client.
*/
- void (*signal_budget) (struct drm_file *, u64 used, u64 budget);
+ int (*signal_budget) (struct drm_file *, u64 used, u64 budget);
};
/**
diff --git a/kernel/cgroup/drm.c b/kernel/cgroup/drm.c
index af50ead1564a..dd7db70c2831 100644
--- a/kernel/cgroup/drm.c
+++ b/kernel/cgroup/drm.c
@@ -239,6 +239,53 @@ drmcs_write_weight(struct cgroup_subsys_state *css, struct cftype *cftype,
return 0;
}
+static int drmcs_show_budget_supported(struct seq_file *sf, void *v)
+{
+ struct drm_cgroup_state *drmcs = css_to_drmcs(seq_css(sf));
+ enum drm_cg_supported overall = DRM_CG_NOT_APPLICABLE;
+ struct cgroup *cgrp = drmcs->css.cgroup;
+ struct task_struct *task;
+ struct css_task_iter it;
+
+ css_task_iter_start(&cgrp->self,
+ CSS_TASK_ITER_PROCS | CSS_TASK_ITER_THREADED,
+ &it);
+ while ((task = css_task_iter_next(&it))) {
+ enum drm_cg_supported supported;
+
+ /* Ignore kernel threads here. */
+ if (task->flags & PF_KTHREAD)
+ continue;
+
+ supported = drm_pid_signal_budget_supported(task_pid(task));
+ if (supported == DRM_CG_SUPPORTED &&
+ overall == DRM_CG_NOT_APPLICABLE) {
+ overall = DRM_CG_SUPPORTED;
+ } else if (supported == DRM_CG_NOT_SUPPORTED) {
+ overall = DRM_CG_NOT_SUPPORTED;
+ break;
+ }
+ }
+ css_task_iter_end(&it);
+
+ switch (overall) {
+ case DRM_CG_NOT_APPLICABLE:
+ seq_puts(sf, "n/a\n");
+ break;
+ case DRM_CG_NOT_SUPPORTED:
+ seq_puts(sf, "no\n");
+ break;
+ case DRM_CG_SUPPORTED:
+ seq_puts(sf, "yes\n");
+ break;
+ default:
+ seq_printf(sf, "%u\n", overall);
+ break;
+ }
+
+ return 0;
+}
+
static int drmcs_online(struct cgroup_subsys_state *css)
{
struct drm_cgroup_state *drmcs = css_to_drmcs(css);
@@ -690,6 +737,11 @@ struct cftype files[] = {
.read_u64 = drmcs_read_weight,
.write_u64 = drmcs_write_weight,
},
+ {
+ .name = "budget_supported",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .seq_show = drmcs_show_budget_supported,
+ },
{
.name = "period_us",
.flags = CFTYPE_NOT_ON_ROOT,
--
2.34.1
