Re: [PATCH 1/1] cgroup: make per-cgroup pressure stall tracking configurable
From: Peter Zijlstra <hidden>
Date: 2021-05-14 11:42:26
Also in:
linux-doc, lkml
On Thu, May 13, 2021 at 10:53:49AM -0700, Suren Baghdasaryan wrote:
+bool cgroup_psi_enabled(void)
+{
+ return (cgroup_feature_disable_mask & (1 << OPT_FEATURE_PRESSURE)) == 0;
+}quoted hunk ↗ jump to hunk
diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index cc25a3cff41f..c73efd7d4fba 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c@@ -747,9 +747,12 @@ static struct psi_group *iterate_groups(struct task_struct *task, void **iter) #ifdef CONFIG_CGROUPS struct cgroup *cgroup = NULL; - if (!*iter) + if (!*iter) { + /* Skip to psi_system if per-cgroup accounting is disabled */ + if (!cgroup_psi_enabled()) + goto update_sys; cgroup = task->cgroups->dfl_cgrp; - else if (*iter == &psi_system) + } else if (*iter == &psi_system) return NULL; else cgroup = cgroup_parent(*iter);@@ -758,6 +761,7 @@ static struct psi_group *iterate_groups(struct task_struct *task, void **iter) *iter = cgroup; return cgroup_psi(cgroup); } +update_sys: #else if (*iter) return NULL;
I'm confused; shouldn't that do the same as that #else branch? Also, can you pretty please make cgroup_psi_enabled() a static_key ?