From: Tvrtko Ursulin <[email protected]> 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 <[email protected]> --- 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
