diff mbox series

[5/6] delayacct: Add static_branch in scheduler hooks

Message ID 20210505111525.248028369@infradead.org (mailing list archive)
State New, archived
Headers show
Series sched,delayacct: Some cleanups | expand

Commit Message

Peter Zijlstra May 5, 2021, 10:59 a.m. UTC 
Cheaper when delayacct is disabled.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 include/linux/delayacct.h |    8 ++++++++
 kernel/delayacct.c        |    3 +++
 2 files changed, 11 insertions(+)

Comments

Johannes Weiner May 6, 2021, 2:05 p.m. UTC | #1 
On Wed, May 05, 2021 at 12:59:45PM +0200, Peter Zijlstra wrote:
> Cheaper when delayacct is disabled.
> 
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Education Directorate May 10, 2021, 8:42 a.m. UTC | #2 
On Wed, May 05, 2021 at 12:59:45PM +0200, Peter Zijlstra wrote:
> Cheaper when delayacct is disabled.
> 
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---

Acked-by: Balbir Singh <bsingharora@gmail.com>
Mel Gorman May 12, 2021, 11:13 a.m. UTC | #3 
On Wed, May 05, 2021 at 12:59:45PM +0200, Peter Zijlstra wrote:
> Cheaper when delayacct is disabled.
> 
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>

Acked-by: Mel Gorman <mgorman@suse.de>
diff mbox series

Patch

--- a/include/linux/delayacct.h
+++ b/include/linux/delayacct.h
@@ -58,8 +58,10 @@  struct task_delay_info {
 
 #include <linux/sched.h>
 #include <linux/slab.h>
+#include <linux/jump_label.h>
 
 #ifdef CONFIG_TASK_DELAY_ACCT
+DECLARE_STATIC_KEY_TRUE(delayacct_key);
 extern int delayacct_on;	/* Delay accounting turned on/off */
 extern struct kmem_cache *delayacct_cache;
 extern void delayacct_init(void);
@@ -114,6 +116,9 @@  static inline void delayacct_tsk_free(st
 
 static inline void delayacct_blkio_start(void)
 {
+	if (!static_branch_likely(&delayacct_key))
+		return;
+
 	delayacct_set_flag(DELAYACCT_PF_BLKIO);
 	if (current->delays)
 		__delayacct_blkio_start();
@@ -121,6 +126,9 @@  static inline void delayacct_blkio_start
 
 static inline void delayacct_blkio_end(struct task_struct *p)
 {
+	if (!static_branch_likely(&delayacct_key))
+		return;
+
 	if (p->delays)
 		__delayacct_blkio_end(p);
 	delayacct_clear_flag(DELAYACCT_PF_BLKIO);
--- a/kernel/delayacct.c
+++ b/kernel/delayacct.c
@@ -14,6 +14,7 @@ 
 #include <linux/delayacct.h>
 #include <linux/module.h>
 
+DEFINE_STATIC_KEY_TRUE(delayacct_key);
 int delayacct_on __read_mostly = 1;	/* Delay accounting turned on/off */
 struct kmem_cache *delayacct_cache;
 
@@ -28,6 +29,8 @@  void delayacct_init(void)
 {
 	delayacct_cache = KMEM_CACHE(task_delay_info, SLAB_PANIC|SLAB_ACCOUNT);
 	delayacct_tsk_init(&init_task);
+	if (!delayacct_on)
+		static_branch_disable(&delayacct_key);
 }
 
 void __delayacct_tsk_init(struct task_struct *tsk)