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-rw-r--r--Documentation/admin-guide/kernel-parameters.txt4
-rw-r--r--include/linux/psi.h3
-rw-r--r--init/Kconfig9
-rw-r--r--kernel/sched/psi.c30
-rw-r--r--kernel/sched/stats.h8
5 files changed, 40 insertions, 14 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 675170c36078..5d6ba930d4f4 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3505,6 +3505,10 @@
before loading.
See Documentation/blockdev/ramdisk.txt.
+ psi= [KNL] Enable or disable pressure stall information
+ tracking.
+ Format: <bool>
+
psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
probe for; one of (bare|imps|exps|lifebook|any).
psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
diff --git a/include/linux/psi.h b/include/linux/psi.h
index 8e0725aac0aa..7006008d5b72 100644
--- a/include/linux/psi.h
+++ b/include/linux/psi.h
@@ -1,6 +1,7 @@
#ifndef _LINUX_PSI_H
#define _LINUX_PSI_H
+#include <linux/jump_label.h>
#include <linux/psi_types.h>
#include <linux/sched.h>
@@ -9,7 +10,7 @@ struct css_set;
#ifdef CONFIG_PSI
-extern bool psi_disabled;
+extern struct static_key_false psi_disabled;
void psi_init(void);
diff --git a/init/Kconfig b/init/Kconfig
index a4112e95724a..cf5b5a0dcbc2 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -509,6 +509,15 @@ config PSI
Say N if unsure.
+config PSI_DEFAULT_DISABLED
+ bool "Require boot parameter to enable pressure stall information tracking"
+ default n
+ depends on PSI
+ help
+ If set, pressure stall information tracking will be disabled
+ per default but can be enabled through passing psi_enable=1
+ on the kernel commandline during boot.
+
endmenu # "CPU/Task time and stats accounting"
config CPU_ISOLATION
diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index 3d7355d7c3e3..fe24de3fbc93 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -136,8 +136,18 @@
static int psi_bug __read_mostly;
-bool psi_disabled __read_mostly;
-core_param(psi_disabled, psi_disabled, bool, 0644);
+DEFINE_STATIC_KEY_FALSE(psi_disabled);
+
+#ifdef CONFIG_PSI_DEFAULT_DISABLED
+bool psi_enable;
+#else
+bool psi_enable = true;
+#endif
+static int __init setup_psi(char *str)
+{
+ return kstrtobool(str, &psi_enable) == 0;
+}
+__setup("psi=", setup_psi);
/* Running averages - we need to be higher-res than loadavg */
#define PSI_FREQ (2*HZ+1) /* 2 sec intervals */
@@ -169,8 +179,10 @@ static void group_init(struct psi_group *group)
void __init psi_init(void)
{
- if (psi_disabled)
+ if (!psi_enable) {
+ static_branch_enable(&psi_disabled);
return;
+ }
psi_period = jiffies_to_nsecs(PSI_FREQ);
group_init(&psi_system);
@@ -549,7 +561,7 @@ void psi_memstall_enter(unsigned long *flags)
struct rq_flags rf;
struct rq *rq;
- if (psi_disabled)
+ if (static_branch_likely(&psi_disabled))
return;
*flags = current->flags & PF_MEMSTALL;
@@ -579,7 +591,7 @@ void psi_memstall_leave(unsigned long *flags)
struct rq_flags rf;
struct rq *rq;
- if (psi_disabled)
+ if (static_branch_likely(&psi_disabled))
return;
if (*flags)
@@ -600,7 +612,7 @@ void psi_memstall_leave(unsigned long *flags)
#ifdef CONFIG_CGROUPS
int psi_cgroup_alloc(struct cgroup *cgroup)
{
- if (psi_disabled)
+ if (static_branch_likely(&psi_disabled))
return 0;
cgroup->psi.pcpu = alloc_percpu(struct psi_group_cpu);
@@ -612,7 +624,7 @@ int psi_cgroup_alloc(struct cgroup *cgroup)
void psi_cgroup_free(struct cgroup *cgroup)
{
- if (psi_disabled)
+ if (static_branch_likely(&psi_disabled))
return;
cancel_delayed_work_sync(&cgroup->psi.clock_work);
@@ -637,7 +649,7 @@ void cgroup_move_task(struct task_struct *task, struct css_set *to)
struct rq_flags rf;
struct rq *rq;
- if (psi_disabled) {
+ if (static_branch_likely(&psi_disabled)) {
/*
* Lame to do this here, but the scheduler cannot be locked
* from the outside, so we move cgroups from inside sched/.
@@ -673,7 +685,7 @@ int psi_show(struct seq_file *m, struct psi_group *group, enum psi_res res)
{
int full;
- if (psi_disabled)
+ if (static_branch_likely(&psi_disabled))
return -EOPNOTSUPP;
update_stats(group);
diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h
index 4904c4677000..aa0de240fb41 100644
--- a/kernel/sched/stats.h
+++ b/kernel/sched/stats.h
@@ -66,7 +66,7 @@ static inline void psi_enqueue(struct task_struct *p, bool wakeup)
{
int clear = 0, set = TSK_RUNNING;
- if (psi_disabled)
+ if (static_branch_likely(&psi_disabled))
return;
if (!wakeup || p->sched_psi_wake_requeue) {
@@ -86,7 +86,7 @@ static inline void psi_dequeue(struct task_struct *p, bool sleep)
{
int clear = TSK_RUNNING, set = 0;
- if (psi_disabled)
+ if (static_branch_likely(&psi_disabled))
return;
if (!sleep) {
@@ -102,7 +102,7 @@ static inline void psi_dequeue(struct task_struct *p, bool sleep)
static inline void psi_ttwu_dequeue(struct task_struct *p)
{
- if (psi_disabled)
+ if (static_branch_likely(&psi_disabled))
return;
/*
* Is the task being migrated during a wakeup? Make sure to
@@ -128,7 +128,7 @@ static inline void psi_ttwu_dequeue(struct task_struct *p)
static inline void psi_task_tick(struct rq *rq)
{
- if (psi_disabled)
+ if (static_branch_likely(&psi_disabled))
return;
if (unlikely(rq->curr->flags & PF_MEMSTALL))