Re: [PATCH v2 1/1] cgroup: make per-cgroup pressure stall tracking configurable
From: Peter Zijlstra <peterz@infradead.org>
Date: 2021-05-18 18:53:29
Also in:
cgroups, lkml
On Mon, May 17, 2021 at 07:02:00PM -0700, Suren Baghdasaryan wrote:
quoted hunk ↗ jump to hunk
diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index cc25a3cff41f..4b8e72640ac9 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c@@ -148,6 +148,7 @@ static int psi_bug __read_mostly; DEFINE_STATIC_KEY_FALSE(psi_disabled); +DEFINE_STATIC_KEY_FALSE(psi_cgroups_disabled);
I'm thinking the whole thing will be easier/clearer when you make this: DEFINE_STATIC_KEY_TRUE(psi_cgroups_enabled);
quoted hunk ↗ jump to hunk
#ifdef CONFIG_PSI_DEFAULT_DISABLED static bool psi_enable;@@ -211,6 +212,9 @@ void __init psi_init(void) return; } + if (!cgroup_psi_enabled()) + static_branch_enable(&psi_cgroups_disabled);
if (!cgroup_psi_enabled()) static_branch_disable(&psi_cgroups_enabled);
quoted hunk ↗ jump to hunk
+ psi_period = jiffies_to_nsecs(PSI_FREQ); group_init(&psi_system); }@@ -744,23 +748,23 @@ static void psi_group_change(struct psi_group *group, int cpu, static struct psi_group *iterate_groups(struct task_struct *task, void **iter) { + if (*iter == &psi_system) + return NULL; + #ifdef CONFIG_CGROUPS + if (!static_branch_likely(&psi_cgroups_disabled)) {
if (static_branch_likely(&psi_cgroups_enabled)) {
+ struct cgroup *cgroup = NULL;
+ if (!*iter)
+ cgroup = task->cgroups->dfl_cgrp;
+ else
+ cgroup = cgroup_parent(*iter);
+ if (cgroup && cgroup_parent(cgroup)) {
+ *iter = cgroup;
+ return cgroup_psi(cgroup);
+ }
}
#endif
*iter = &psi_system;
return &psi_system;But yes, very nice.