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Message-ID: <20240711130004.2157737-10-vschneid@redhat.com>
Date: Thu, 11 Jul 2024 15:00:03 +0200
From: Valentin Schneider <vschneid@...hat.com>
To: linux-kernel@...r.kernel.org,
rcu@...r.kernel.org
Cc: Ingo Molnar <mingo@...hat.com>,
Peter Zijlstra <peterz@...radead.org>,
Juri Lelli <juri.lelli@...hat.com>,
Vincent Guittot <vincent.guittot@...aro.org>,
Dietmar Eggemann <dietmar.eggemann@....com>,
Steven Rostedt <rostedt@...dmis.org>,
Ben Segall <bsegall@...gle.com>,
Mel Gorman <mgorman@...e.de>,
Phil Auld <pauld@...hat.com>,
Clark Williams <williams@...hat.com>,
Tomas Glozar <tglozar@...hat.com>,
"Paul E. McKenney" <paulmck@...nel.org>,
Frederic Weisbecker <frederic@...nel.org>,
Neeraj Upadhyay <neeraj.upadhyay@...nel.org>,
Joel Fernandes <joel@...lfernandes.org>,
Josh Triplett <josh@...htriplett.org>,
Boqun Feng <boqun.feng@...il.com>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Lai Jiangshan <jiangshanlai@...il.com>,
Zqiang <qiang.zhang1211@...il.com>,
Alexander Gordeev <agordeev@...ux.ibm.com>,
Catalin Marinas <catalin.marinas@....com>,
Arnd Bergmann <arnd@...db.de>,
Guo Ren <guoren@...nel.org>,
Palmer Dabbelt <palmer@...osinc.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Oleg Nesterov <oleg@...hat.com>,
Jens Axboe <axboe@...nel.dk>
Subject: [RFC PATCH v3 09/10] sched/fair: Add a class->task_woken callback in preparation for per-task throttling
Later commits will change CFS bandwidth control throttling from a
per-cfs_rq basis to a per-task basis. This means special care needs to be
taken around any transition a task can have into and out of a cfs_rq.
To ease reviewing, the transitions are patched with dummy-helpers that are
implemented later on.
Add a class->task_woken callback to handle tasks being woken into
potentially throttled cfs_rq's. Conversely, a task flagged for
throttle-at-kernel-exit may block and need to have its pending throttle
removed if runtime was replenished by the time it got woken up.
Signed-off-by: Valentin Schneider <vschneid@...hat.com>
---
kernel/sched/fair.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index b2242307677ca..0cec3e70f1277 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5776,6 +5776,17 @@ static void task_throttle_cancel_irq_work_fn(struct irq_work *work)
/* Write me */
}
+static void task_woken_fair(struct rq *rq, struct task_struct *p)
+{
+ if (!cfs_bandwidth_used())
+ return;
+
+ if (task_needs_throttling(p))
+ task_throttle_setup(p);
+ else
+ task_throttle_cancel(p);
+}
+
void init_cfs_throttle_work(struct task_struct *p)
{
/* Protect against double add, see throttle_cfs_rq() and throttle_cfs_rq_work() */
@@ -13288,6 +13299,10 @@ DEFINE_SCHED_CLASS(fair) = {
.task_change_group = task_change_group_fair,
#endif
+#ifdef CONFIG_CFS_BANDWIDTH
+ .task_woken = task_woken_fair,
+#endif
+
#ifdef CONFIG_SCHED_CORE
.task_is_throttled = task_is_throttled_fair,
#endif
--
2.43.0
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