Re: [PATCH 1/1] cgroup: make per-cgroup pressure stall tracking configurable
From: Peter Zijlstra <peterz@infradead.org>
Date: 2021-05-14 17:55:33
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cgroups, lkml
On Fri, May 14, 2021 at 08:54:47AM -0700, Suren Baghdasaryan wrote:
Correct, for this function CONFIG_CGROUPS=n and cgroup_disable=pressure are treated the same. True, from the code it's not very obvious. Do you have some refactoring in mind that would make it more explicit?
Does this make sense?
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c@@ -744,24 +744,26 @@ static void psi_group_change(struct psi_ static struct psi_group *iterate_groups(struct task_struct *task, void **iter) { + if (cgroup_psi_enabled()) { #ifdef CONFIG_CGROUPS - struct cgroup *cgroup = NULL; + struct cgroup *cgroup = NULL; - if (!*iter) - cgroup = task->cgroups->dfl_cgrp; - else if (*iter == &psi_system) - return NULL; - else - cgroup = cgroup_parent(*iter); + if (!*iter) + cgroup = task->cgroups->dfl_cgrp; + else if (*iter == &psi_system) + return NULL; + else + cgroup = cgroup_parent(*iter); - if (cgroup && cgroup_parent(cgroup)) { - *iter = cgroup; - return cgroup_psi(cgroup); - } -#else - if (*iter) - return NULL; + if (cgroup && cgroup_parent(cgroup)) { + *iter = cgroup; + return cgroup_psi(cgroup); + } #endif + } else { + if (*iter) + return NULL; + } *iter = &psi_system; return &psi_system; }