From: Peter Zijlstra <peterz@infradead.org>
To: tglx@linutronix.de, mingo@kernel.org, juri.lelli@redhat.com,
vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
bristot@redhat.com, bsingharora@gmail.com, pbonzini@redhat.com,
maz@kernel.org
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
peterz@infradead.org, riel@surriel.com, hannes@cmpxchg.org
Subject: [PATCH 5/6] delayacct: Add static_branch in scheduler hooks
Date: Wed, 05 May 2021 12:59:45 +0200 [thread overview]
Message-ID: <20210505111525.248028369@infradead.org> (raw)
In-Reply-To: <20210505105940.190490250@infradead.org>
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(+)
--- 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)
next prev parent reply other threads:[~2021-05-05 11:21 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-05 10:59 [PATCH 0/6] sched,delayacct: Some cleanups Peter Zijlstra
2021-05-05 10:59 ` [PATCH 1/6] delayacct: Use sched_clock() Peter Zijlstra
2021-05-05 14:40 ` Rik van Riel
2021-05-06 13:59 ` Johannes Weiner
2021-05-06 14:17 ` Peter Zijlstra
2021-05-06 15:17 ` Johannes Weiner
2021-05-07 12:40 ` Balbir Singh
2021-05-12 10:43 ` Mel Gorman
2021-05-05 10:59 ` [PATCH 2/6] sched: Rename sched_info_{queued,dequeued} Peter Zijlstra
2021-05-05 14:39 ` Rik van Riel
2021-05-06 13:59 ` Johannes Weiner
2021-05-10 8:45 ` Balbir Singh
2021-05-12 10:49 ` Mel Gorman
2021-05-05 10:59 ` [PATCH 3/6] sched: Simplify sched_info_on() Peter Zijlstra
2021-05-06 14:03 ` Johannes Weiner
2021-05-12 11:10 ` Mel Gorman
2021-05-12 11:32 ` Peter Zijlstra
2021-05-12 12:51 ` Mel Gorman
2021-05-05 10:59 ` [PATCH 4/6] kvm: Select SCHED_INFO instead of TASK_DELAY_ACCT Peter Zijlstra
2021-05-05 11:37 ` Paolo Bonzini
2021-05-06 14:38 ` Marc Zyngier
2021-05-07 12:42 ` Balbir Singh
2021-05-12 11:11 ` Mel Gorman
2021-05-05 10:59 ` Peter Zijlstra [this message]
2021-05-06 14:05 ` [PATCH 5/6] delayacct: Add static_branch in scheduler hooks Johannes Weiner
2021-05-10 8:42 ` Balbir Singh
2021-05-12 11:13 ` Mel Gorman
2021-05-05 10:59 ` [PATCH 6/6] [RFC] delayacct: Default disabled Peter Zijlstra
2021-05-12 11:35 ` Mel Gorman
2021-05-05 22:29 ` [PATCH 0/6] sched,delayacct: Some cleanups Balbir Singh
2021-05-06 9:13 ` Peter Zijlstra
2021-05-07 12:38 ` Balbir Singh
2021-05-12 11:34 ` Mel Gorman
2021-05-12 11:38 ` Peter Zijlstra
2021-05-12 12:23 ` Paul Wise
2021-05-12 13:00 ` Mel Gorman
2021-05-13 1:29 ` Paul Wise
2021-06-25 0:50 ` Paul Wise
2021-05-07 9:05 ` Thomas Gleixner
2021-05-10 7:08 ` Ingo Molnar
2021-05-10 12:05 ` [PATCH 7/6] delayacct: Add sysctl to enable at runtime Peter Zijlstra
2021-05-10 12:06 ` Peter Zijlstra
2021-05-12 11:40 ` Mel Gorman
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