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| author |   Peter Zijlstra <peterz@infradead.org> | 2021-05-04 22:43:36 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2021-05-12 11:43:25 +0200 |
| commit | eee4d9fee2544389e5ce5697ed92db67c86d7a9f (patch) | |
| tree | 3f6f000928209912313d34bc3ca383cea1f94fd7 | |
| parent | kvm: Select SCHED_INFO instead of TASK_DELAY_ACCT (diff) | |
| download | linux-dev-eee4d9fee2544389e5ce5697ed92db67c86d7a9f.tar.xz linux-dev-eee4d9fee2544389e5ce5697ed92db67c86d7a9f.zip | |
delayacct: Add static_branch in scheduler hooks
Cheaper when delayacct is disabled.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Link: https://lkml.kernel.org/r/20210505111525.248028369@infradead.org
| -rw-r--r-- | include/linux/delayacct.h | 8 | ||||
| -rw-r--r-- | kernel/delayacct.c | 3 |
2 files changed, 11 insertions, 0 deletions
diff --git a/include/linux/delayacct.h b/include/linux/delayacct.h index 21651f946751..57fefa54b53a 100644 --- 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(struct task_struct *tsk) static inline void delayacct_blkio_start(void) { + if (!static_branch_likely(&delayacct_key)) + return; + delayacct_set_flag(current, DELAYACCT_PF_BLKIO); if (current->delays) __delayacct_blkio_start(); @@ -121,6 +126,9 @@ static inline void delayacct_blkio_start(void) 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(p, DELAYACCT_PF_BLKIO); diff --git a/kernel/delayacct.c b/kernel/delayacct.c index 3a0b910386d1..63012fd39ae2 100644 --- 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) |