2019-07-05 04:42:44

by Yi Wang

Subject: [PATCH v2] sched: fix unlikely use of sched_info_on()

sched_info_on() is called with unlikely hint, however, the test
is to be a constant(1) on which compiler will do nothing when
make defconfig, so remove the hint.

Also, fix a lack of {}.

Signed-off-by: Yi Wang <[email protected]>
---
v2: remove the hint rather than replace with likely, and fix a
coding style.

kernel/sched/stats.h | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h
index aa0de24..ba683fe 100644
--- a/kernel/sched/stats.h
+++ b/kernel/sched/stats.h
@@ -157,9 +157,10 @@ static inline void sched_info_dequeued(struct rq *rq, struct task_struct *t)
{
unsigned long long now = rq_clock(rq), delta = 0;

- if (unlikely(sched_info_on()))
+ if (sched_info_on()) {
if (t->sched_info.last_queued)
delta = now - t->sched_info.last_queued;
+ }
sched_info_reset_dequeued(t);
t->sched_info.run_delay += delta;

@@ -192,7 +193,7 @@ static void sched_info_arrive(struct rq *rq, struct task_struct *t)
*/
static inline void sched_info_queued(struct rq *rq, struct task_struct *t)
{
- if (unlikely(sched_info_on())) {
+ if (sched_info_on()) {
if (!t->sched_info.last_queued)
t->sched_info.last_queued = rq_clock(rq);
}
@@ -239,7 +240,7 @@ static inline void sched_info_depart(struct rq *rq, struct task_struct *t)
static inline void
sched_info_switch(struct rq *rq, struct task_struct *prev, struct task_struct *next)
{
- if (unlikely(sched_info_on()))
+ if (sched_info_on())
__sched_info_switch(rq, prev, next);
}

--
1.8.3.1

2019-07-05 12:10:36

by Peter Zijlstra

Subject: Re: [PATCH v2] sched: fix unlikely use of sched_info_on()

On Fri, Jul 05, 2019 at 12:35:07PM +0800, Yi Wang wrote:
> sched_info_on() is called with unlikely hint, however, the test
> is to be a constant(1) on which compiler will do nothing when
> make defconfig, so remove the hint.
>
> Also, fix a lack of {}.
>
> Signed-off-by: Yi Wang <[email protected]>

Thanks!

2019-07-25 18:07:17

by tip-bot for Vasyl Gomonovych

Subject: [tip:sched/core] sched/stats: Fix unlikely() use of sched_info_on()

Commit-ID: 65d74e91694e1afac40c96fb64a9ef120757729e
Gitweb: https://git.kernel.org/tip/65d74e91694e1afac40c96fb64a9ef120757729e
Author: Yi Wang <[email protected]>
AuthorDate: Fri, 5 Jul 2019 12:35:07 +0800
Committer: Ingo Molnar <[email protected]>
CommitDate: Thu, 25 Jul 2019 15:51:55 +0200

sched/stats: Fix unlikely() use of sched_info_on()

sched_info_on() is called with unlikely hint, however, the test
is to be a constant(1) on which compiler will do nothing when
make defconfig, so remove the hint.

Also, fix a lack of {}.

Signed-off-by: Yi Wang <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
kernel/sched/stats.h | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h
index aa0de240fb41..ba683fe81a6e 100644
--- a/kernel/sched/stats.h
+++ b/kernel/sched/stats.h
@@ -157,9 +157,10 @@ static inline void sched_info_dequeued(struct rq *rq, struct task_struct *t)
{
unsigned long long now = rq_clock(rq), delta = 0;

- if (unlikely(sched_info_on()))
+ if (sched_info_on()) {
if (t->sched_info.last_queued)
delta = now - t->sched_info.last_queued;
+ }
sched_info_reset_dequeued(t);
t->sched_info.run_delay += delta;

@@ -192,7 +193,7 @@ static void sched_info_arrive(struct rq *rq, struct task_struct *t)
*/
static inline void sched_info_queued(struct rq *rq, struct task_struct *t)
{
- if (unlikely(sched_info_on())) {
+ if (sched_info_on()) {
if (!t->sched_info.last_queued)
t->sched_info.last_queued = rq_clock(rq);
}
@@ -239,7 +240,7 @@ __sched_info_switch(struct rq *rq, struct task_struct *prev, struct task_struct
static inline void
sched_info_switch(struct rq *rq, struct task_struct *prev, struct task_struct *next)
{
- if (unlikely(sched_info_on()))
+ if (sched_info_on())
__sched_info_switch(rq, prev, next);
}