On 12/09/2025 14:19, Adrián Larumbe wrote:
> From: Boris Brezillon <boris.brezil...@collabora.com>
>
> For DebugFS builds, create a filesystem knob that, for every single open
> file of the Panfrost DRM device, shows its command name information and
> PID (when applicable), and all of its existing JM contexts.
>
> For every context, show the DRM scheduler priority value of all of its
> scheduling entities.
>
> Signed-off-by: Boris Brezillon <boris.brezil...@collabora.com>
> Signed-off-by: Adrián Larumbe <adrian.laru...@collabora.com>
Reviewed-by: Steven Price <steven.pr...@arm.com>
> ---
> drivers/gpu/drm/panfrost/panfrost_drv.c | 96 +++++++++++++++++++++++++
> 1 file changed, 96 insertions(+)
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c
> b/drivers/gpu/drm/panfrost/panfrost_drv.c
> index 69e72a800cd1..3af4b4753ca4 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_drv.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
> @@ -716,6 +716,47 @@ static int panthor_gems_show(struct seq_file *m, void
> *data)
> return 0;
> }
>
> +static void show_panfrost_jm_ctx(struct panfrost_jm_ctx *jm_ctx, u32 handle,
> + struct seq_file *m)
> +{
> + struct drm_device *ddev = ((struct drm_info_node
> *)m->private)->minor->dev;
> + const char *prio = "UNKNOWN";
> +
> + static const char * const prios[] = {
> + [DRM_SCHED_PRIORITY_HIGH] = "HIGH",
> + [DRM_SCHED_PRIORITY_NORMAL] = "NORMAL",
> + [DRM_SCHED_PRIORITY_LOW] = "LOW",
> + };
> +
> + if (jm_ctx->slot_entity[0].priority !=
> + jm_ctx->slot_entity[1].priority)
> + drm_warn(ddev, "Slot priorities should be the same in a single
> context");
> +
> + if (jm_ctx->slot_entity[0].priority < ARRAY_SIZE(prios))
> + prio = prios[jm_ctx->slot_entity[0].priority];
> +
> + seq_printf(m, " JM context %u: priority %s\n", handle, prio);
> +}
> +
> +static int show_file_jm_ctxs(struct panfrost_file_priv *pfile,
> + struct seq_file *m)
> +{
> + struct panfrost_jm_ctx *jm_ctx;
> + unsigned long i;
> +
> + xa_lock(&pfile->jm_ctxs);
> + xa_for_each(&pfile->jm_ctxs, i, jm_ctx) {
> + jm_ctx = panfrost_jm_ctx_get(jm_ctx);
> + xa_unlock(&pfile->jm_ctxs);
> + show_panfrost_jm_ctx(jm_ctx, i, m);
> + panfrost_jm_ctx_put(jm_ctx);
> + xa_lock(&pfile->jm_ctxs);
> + }
> + xa_unlock(&pfile->jm_ctxs);
> +
> + return 0;
> +}
> +
> static struct drm_info_list panthor_debugfs_list[] = {
> {"gems", panthor_gems_show, 0, NULL},
> };
> @@ -729,9 +770,64 @@ static int panthor_gems_debugfs_init(struct drm_minor
> *minor)
> return 0;
> }
>
> +static int show_each_file(struct seq_file *m, void *arg)
> +{
> + struct drm_info_node *node = (struct drm_info_node *)m->private;
> + struct drm_device *ddev = node->minor->dev;
> + int (*show)(struct panfrost_file_priv *, struct seq_file *) =
> + node->info_ent->data;
> + struct drm_file *file;
> + int ret;
> +
> + ret = mutex_lock_interruptible(&ddev->filelist_mutex);
> + if (ret)
> + return ret;
> +
> + list_for_each_entry(file, &ddev->filelist, lhead) {
> + struct task_struct *task;
> + struct panfrost_file_priv *pfile = file->driver_priv;
> + struct pid *pid;
> +
> + /*
> + * Although we have a valid reference on file->pid, that does
> + * not guarantee that the task_struct who called get_pid() is
> + * still alive (e.g. get_pid(current) => fork() => exit()).
> + * Therefore, we need to protect this ->comm access using RCU.
> + */
> + rcu_read_lock();
> + pid = rcu_dereference(file->pid);
> + task = pid_task(pid, PIDTYPE_TGID);
> + seq_printf(m, "client_id %8llu pid %8d command %s:\n",
> + file->client_id, pid_nr(pid),
> + task ? task->comm : "<unknown>");
> + rcu_read_unlock();
> +
> + ret = show(pfile, m);
> + if (ret < 0)
> + break;
> +
> + seq_puts(m, "\n");
> + }
> +
> + mutex_unlock(&ddev->filelist_mutex);
> + return ret;
> +}
> +
> +static struct drm_info_list panfrost_sched_debugfs_list[] = {
> + { "sched_ctxs", show_each_file, 0, show_file_jm_ctxs },
> +};
> +
> +static void panfrost_sched_debugfs_init(struct drm_minor *minor)
> +{
> + drm_debugfs_create_files(panfrost_sched_debugfs_list,
> + ARRAY_SIZE(panfrost_sched_debugfs_list),
> + minor->debugfs_root, minor);
> +}
> +
> static void panfrost_debugfs_init(struct drm_minor *minor)
> {
> panthor_gems_debugfs_init(minor);
> + panfrost_sched_debugfs_init(minor);
> }
> #endif
>
