Re: [PATCH v16 1/7] sched: Add CONFIG_SCHED_PROXY_EXEC & boot argument to enable/disable

[Juri Lelli <juri.lelli@redhat.com>]

Hi John,

On 11/04/25 23:02, John Stultz wrote:
> Add a CONFIG_SCHED_PROXY_EXEC option, along with a boot argument
> sched_proxy_exec= that can be used to disable the feature at boot
> time if CONFIG_SCHED_PROXY_EXEC was enabled.
> 
> Cc: Joel Fernandes <joelagnelf@nvidia.com>
> Cc: Qais Yousef <qyousef@layalina.io>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Juri Lelli <juri.lelli@redhat.com>
> Cc: Vincent Guittot <vincent.guittot@linaro.org>
> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
> Cc: Valentin Schneider <vschneid@redhat.com>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: Ben Segall <bsegall@google.com>
> Cc: Zimuzo Ezeozue <zezeozue@google.com>
> Cc: Mel Gorman <mgorman@suse.de>
> Cc: Will Deacon <will@kernel.org>
> Cc: Waiman Long <longman@redhat.com>
> Cc: Boqun Feng <boqun.feng@gmail.com>
> Cc: "Paul E. McKenney" <paulmck@kernel.org>
> Cc: Metin Kaya <Metin.Kaya@arm.com>
> Cc: Xuewen Yan <xuewen.yan94@gmail.com>
> Cc: K Prateek Nayak <kprateek.nayak@amd.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
> Cc: Suleiman Souhlal <suleiman@google.com>
> Cc: kernel-team@android.com
> Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
> Signed-off-by: John Stultz <jstultz@google.com>
> ---

...

> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> index 47972f34ea701..154f0aa0c6322 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -1149,10 +1149,15 @@ struct rq {
>  	 */
>  	unsigned int		nr_uninterruptible;
>  
> +#ifdef CONFIG_SCHED_PROXY_EXEC
> +	struct task_struct __rcu	*donor;  /* Scheduling context */
> +	struct task_struct __rcu	*curr;   /* Execution context */
> +#else
>  	union {
>  		struct task_struct __rcu *donor; /* Scheduler context */
>  		struct task_struct __rcu *curr;  /* Execution context */
>  	};
> +#endif
>  	struct sched_dl_entity	*dl_server;
>  	struct task_struct	*idle;
>  	struct task_struct	*stop;
> @@ -1347,10 +1352,17 @@ DECLARE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
>  #define cpu_curr(cpu)		(cpu_rq(cpu)->curr)
>  #define raw_rq()		raw_cpu_ptr(&runqueues)
>  
> +#ifdef CONFIG_SCHED_PROXY_EXEC
> +static inline void rq_set_donor(struct rq *rq, struct task_struct *t)
> +{
> +	rcu_assign_pointer(rq->donor, t);
> +}
> +#else
>  static inline void rq_set_donor(struct rq *rq, struct task_struct *t)
>  {
>  	/* Do nothing */
>  }
> +#endif

Does this chunk belong here?

Thanks,
Juri