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Message-ID: <20240604131856.xo6jxe2geetq6jlg@airbuntu>
Date: Tue, 4 Jun 2024 14:18:56 +0100
From: Qais Yousef <qyousef@...alina.io>
To: John Stultz <jstultz@...gle.com>
Cc: LKML <linux-kernel@...r.kernel.org>,
Connor O'Brien <connoro@...gle.com>,
Joel Fernandes <joelaf@...gle.com>, 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>,
Valentin Schneider <vschneid@...hat.com>,
Steven Rostedt <rostedt@...dmis.org>,
Ben Segall <bsegall@...gle.com>,
Zimuzo Ezeozue <zezeozue@...gle.com>,
Youssef Esmat <youssefesmat@...gle.com>,
Mel Gorman <mgorman@...e.de>,
Daniel Bristot de Oliveira <bristot@...hat.com>,
Will Deacon <will@...nel.org>, Waiman Long <longman@...hat.com>,
Boqun Feng <boqun.feng@...il.com>,
"Paul E. McKenney" <paulmck@...nel.org>,
Metin Kaya <Metin.Kaya@....com>,
Xuewen Yan <xuewen.yan94@...il.com>,
K Prateek Nayak <kprateek.nayak@....com>,
Thomas Gleixner <tglx@...utronix.de>, kernel-team@...roid.com
Subject: Re: [PATCH v10 5/7] sched: Consolidate pick_*_task to
task_is_pushable helper
On 05/06/24 21:54, John Stultz wrote:
> From: Connor O'Brien <connoro@...gle.com>
>
> This patch consolidates rt and deadline pick_*_task functions to
> a task_is_pushable() helper
>
> This patch was broken out from a larger chain migration
> patch originally by Connor O'Brien.
>
> Cc: Joel Fernandes <joelaf@...gle.com>
> Cc: Qais Yousef <qyousef@...alina.io>
> Cc: Ingo Molnar <mingo@...hat.com>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Cc: Juri Lelli <juri.lelli@...hat.com>
> Cc: Vincent Guittot <vincent.guittot@...aro.org>
> Cc: Dietmar Eggemann <dietmar.eggemann@....com>
> Cc: Valentin Schneider <vschneid@...hat.com>
> Cc: Steven Rostedt <rostedt@...dmis.org>
> Cc: Ben Segall <bsegall@...gle.com>
> Cc: Zimuzo Ezeozue <zezeozue@...gle.com>
> Cc: Youssef Esmat <youssefesmat@...gle.com>
> Cc: Mel Gorman <mgorman@...e.de>
> Cc: Daniel Bristot de Oliveira <bristot@...hat.com>
> Cc: Will Deacon <will@...nel.org>
> Cc: Waiman Long <longman@...hat.com>
> Cc: Boqun Feng <boqun.feng@...il.com>
> Cc: "Paul E. McKenney" <paulmck@...nel.org>
> Cc: Metin Kaya <Metin.Kaya@....com>
> Cc: Xuewen Yan <xuewen.yan94@...il.com>
> Cc: K Prateek Nayak <kprateek.nayak@....com>
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Cc: kernel-team@...roid.com
> Tested-by: K Prateek Nayak <kprateek.nayak@....com>
> Tested-by: Metin Kaya <metin.kaya@....com>
> Reviewed-by: Metin Kaya <metin.kaya@....com>
> Reviewed-by: Valentin Schneider <vschneid@...hat.com>
> Signed-off-by: Connor O'Brien <connoro@...gle.com>
> [jstultz: split out from larger chain migration patch,
> renamed helper function]
> Signed-off-by: John Stultz <jstultz@...gle.com>
> ---
> v7:
> * Split from chain migration patch
> * Renamed function
> ---
> kernel/sched/deadline.c | 10 +---------
> kernel/sched/rt.c | 11 +----------
> kernel/sched/sched.h | 10 ++++++++++
> 3 files changed, 12 insertions(+), 19 deletions(-)
>
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index eaedc69c5e30..ae583a427539 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -2179,14 +2179,6 @@ static void task_fork_dl(struct task_struct *p)
> /* Only try algorithms three times */
> #define DL_MAX_TRIES 3
>
> -static int pick_dl_task(struct rq *rq, struct task_struct *p, int cpu)
> -{
> - if (!task_on_cpu(rq, p) &&
> - cpumask_test_cpu(cpu, &p->cpus_mask))
> - return 1;
> - return 0;
> -}
> -
> /*
> * Return the earliest pushable rq's task, which is suitable to be executed
> * on the CPU, NULL otherwise:
> @@ -2205,7 +2197,7 @@ static struct task_struct *pick_earliest_pushable_dl_task(struct rq *rq, int cpu
> if (next_node) {
> p = __node_2_pdl(next_node);
>
> - if (pick_dl_task(rq, p, cpu))
> + if (task_is_pushable(rq, p, cpu) == 1)
Any reason we're checking specifically for == 1? Could the function later
return something other than 0 or 1?
It's explaining if 1 could end up meaning something else in the commit message
and in function docs. Otherwise let's make it a bool and not do explicit check
for return value.
With this
Reviewed-by: Qais Yousef <qyousef@...alina.io>
> return p;
>
> next_node = rb_next(next_node);
> diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
> index 975cb49a64dc..8b6fb77e095b 100644
> --- a/kernel/sched/rt.c
> +++ b/kernel/sched/rt.c
> @@ -1791,15 +1791,6 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
> /* Only try algorithms three times */
> #define RT_MAX_TRIES 3
>
> -static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu)
> -{
> - if (!task_on_cpu(rq, p) &&
> - cpumask_test_cpu(cpu, &p->cpus_mask))
> - return 1;
> -
> - return 0;
> -}
> -
> /*
> * Return the highest pushable rq's task, which is suitable to be executed
> * on the CPU, NULL otherwise
> @@ -1813,7 +1804,7 @@ static struct task_struct *pick_highest_pushable_task(struct rq *rq, int cpu)
> return NULL;
>
> plist_for_each_entry(p, head, pushable_tasks) {
> - if (pick_rt_task(rq, p, cpu))
> + if (task_is_pushable(rq, p, cpu) == 1)
> return p;
> }
>
> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> index 2d41ebe200c7..e46f69ba9ba2 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -3490,6 +3490,16 @@ void move_queued_task_locked(struct rq *rq, struct rq *dst_rq, struct task_struc
> set_task_cpu(task, dst_rq->cpu);
> activate_task(dst_rq, task, 0);
> }
> +
> +static inline
> +int task_is_pushable(struct rq *rq, struct task_struct *p, int cpu)
> +{
> + if (!task_on_cpu(rq, p) &&
> + cpumask_test_cpu(cpu, &p->cpus_mask))
> + return 1;
> +
> + return 0;
> +}
> #endif
>
> #endif /* _KERNEL_SCHED_SCHED_H */
> --
> 2.45.0.rc1.225.g2a3ae87e7f-goog
>
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