2019-06-21 08:43:30

by Patrick Bellasi

[permalink] [raw]
Subject: [PATCH v10 07/16] sched/core: uclamp: Reset uclamp values on RESET_ON_FORK

A forked tasks gets the same clamp values of its parent however, when
the RESET_ON_FORK flag is set on parent, e.g. via:

sys_sched_setattr()
sched_setattr()
__sched_setscheduler(attr::SCHED_FLAG_RESET_ON_FORK)

the new forked task is expected to start with all attributes reset to
default values.

Do that for utilization clamp values too by checking the reset request
from the existing uclamp_fork() call which already provides the required
initialization for other uclamp related bits.

Signed-off-by: Patrick Bellasi <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Peter Zijlstra <[email protected]>
---
kernel/sched/core.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 7d4272440890..2c49b23efc87 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1071,6 +1071,14 @@ static void uclamp_fork(struct task_struct *p)

for_each_clamp_id(clamp_id)
p->uclamp[clamp_id].active = false;
+
+ if (likely(!p->sched_reset_on_fork))
+ return;
+
+ for_each_clamp_id(clamp_id) {
+ uclamp_se_set(&p->uclamp_req[clamp_id],
+ uclamp_none(clamp_id), false);
+ }
}

static void __init init_uclamp(void)
--
2.21.0


Subject: [tip:sched/core] sched/uclamp: Reset uclamp values on RESET_ON_FORK

Commit-ID: a87498ace58e23b62a572dc7267579ede4c8495c
Gitweb: https://git.kernel.org/tip/a87498ace58e23b62a572dc7267579ede4c8495c
Author: Patrick Bellasi <[email protected]>
AuthorDate: Fri, 21 Jun 2019 09:42:08 +0100
Committer: Ingo Molnar <[email protected]>
CommitDate: Mon, 24 Jun 2019 19:23:47 +0200

sched/uclamp: Reset uclamp values on RESET_ON_FORK

A forked tasks gets the same clamp values of its parent however, when
the RESET_ON_FORK flag is set on parent, e.g. via:

sys_sched_setattr()
sched_setattr()
__sched_setscheduler(attr::SCHED_FLAG_RESET_ON_FORK)

the new forked task is expected to start with all attributes reset to
default values.

Do that for utilization clamp values too by checking the reset request
from the existing uclamp_fork() call which already provides the required
initialization for other uclamp related bits.

Signed-off-by: Patrick Bellasi <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Alessio Balsini <[email protected]>
Cc: Dietmar Eggemann <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Morten Rasmussen <[email protected]>
Cc: Paul Turner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Quentin Perret <[email protected]>
Cc: Rafael J . Wysocki <[email protected]>
Cc: Steve Muckle <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Todd Kjos <[email protected]>
Cc: Vincent Guittot <[email protected]>
Cc: Viresh Kumar <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
kernel/sched/core.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index e9a669266fa9..ecc304ab906f 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1082,6 +1082,14 @@ static void uclamp_fork(struct task_struct *p)

for_each_clamp_id(clamp_id)
p->uclamp[clamp_id].active = false;
+
+ if (likely(!p->sched_reset_on_fork))
+ return;
+
+ for_each_clamp_id(clamp_id) {
+ uclamp_se_set(&p->uclamp_req[clamp_id],
+ uclamp_none(clamp_id), false);
+ }
}

static void __init init_uclamp(void)