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Date: Sat, 16 Dec 2023 11:35:04 -0800
From: "Paul E. McKenney" <paulmck@kernel.org>
To: Kent Overstreet <kent.overstreet@linux.dev>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-fsdevel@vger.kernel.org, tglx@linutronix.de, x86@kernel.org,
	tj@kernel.org, peterz@infradead.org, mathieu.desnoyers@efficios.com,
	keescook@chromium.org, dave.hansen@linux.intel.com,
	mingo@redhat.com, will@kernel.org, longman@redhat.com,
	boqun.feng@gmail.com, brauner@kernel.org
Subject: Re: [PATCH 50/50] Kill sched.h dependency on rcupdate.h
Message-ID: <a22b69cc-40e3-451c-a18e-ee610aef5150@paulmck-laptop>
Reply-To: paulmck@kernel.org
References: <20231216024834.3510073-1-kent.overstreet@linux.dev>
 <20231216033552.3553579-1-kent.overstreet@linux.dev>
 <20231216033552.3553579-7-kent.overstreet@linux.dev>
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In-Reply-To: <20231216033552.3553579-7-kent.overstreet@linux.dev>

On Fri, Dec 15, 2023 at 10:35:51PM -0500, Kent Overstreet wrote:
> by moving cond_resched_rcu() to rcupdate.h, we can kill another big
> sched.h dependency.
> 
> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Could you please instead move the cond_resched_rcu() function to
include/linux/rcupdate_wait.h?  This would avoid breaking Ingo's
separation that makes it possible to include rcupdate.h without also
pulling in sched.h.

							Thanx, Paul

> ---
>  include/linux/rcupdate.h | 11 +++++++++++
>  include/linux/sched.h    | 13 +++----------
>  2 files changed, 14 insertions(+), 10 deletions(-)
> 
> diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
> index f7206b2623c9..8ebfa57e0164 100644
> --- a/include/linux/rcupdate.h
> +++ b/include/linux/rcupdate.h
> @@ -1058,4 +1058,15 @@ extern int rcu_normal;
>  
>  DEFINE_LOCK_GUARD_0(rcu, rcu_read_lock(), rcu_read_unlock())
>  
> +#if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_PREEMPT_RCU)
> +#define cond_resched_rcu()		\
> +do {					\
> +	rcu_read_unlock();		\
> +	cond_resched();			\
> +	rcu_read_lock();		\
> +} while (0)
> +#else
> +#define cond_resched_rcu()
> +#endif
> +
>  #endif /* __LINUX_RCUPDATE_H */
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index d528057c99e4..b781ac7e0a02 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -10,8 +10,11 @@
>  #include <uapi/linux/sched.h>
>  
>  #include <asm/current.h>
> +#include <linux/thread_info.h>
> +#include <linux/preempt.h>
>  
>  #include <linux/irqflags_types.h>
> +#include <linux/smp_types.h>
>  #include <linux/pid_types.h>
>  #include <linux/sem_types.h>
>  #include <linux/shm.h>
> @@ -22,7 +25,6 @@
>  #include <linux/timer_types.h>
>  #include <linux/seccomp_types.h>
>  #include <linux/nodemask_types.h>
> -#include <linux/rcupdate.h>
>  #include <linux/refcount_types.h>
>  #include <linux/resource.h>
>  #include <linux/latencytop.h>
> @@ -2058,15 +2060,6 @@ extern int __cond_resched_rwlock_write(rwlock_t *lock);
>  	__cond_resched_rwlock_write(lock);					\
>  })
>  
> -static inline void cond_resched_rcu(void)
> -{
> -#if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_PREEMPT_RCU)
> -	rcu_read_unlock();
> -	cond_resched();
> -	rcu_read_lock();
> -#endif
> -}
> -
>  #ifdef CONFIG_PREEMPT_DYNAMIC
>  
>  extern bool preempt_model_none(void);
> -- 
> 2.43.0
>