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From: Joel Fernandes <joel@joelfernandes.org>
Date: Tue, 23 Apr 2024 13:58:01 -0400
Message-ID: <CAEXW_YRjuWMLvmZ_oVHEe837gPAyjBs5OMvZc=T1PXYB0apNmQ@mail.gmail.com>
Subject: Re: [PATCH V2 03/11] rcu: Reorder tree_exp.h after tree_plugin.h
To: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: linux-kernel@vger.kernel.org, rcu@vger.kernel.org, x86@kernel.org, 
	Lai Jiangshan <jiangshan.ljs@antgroup.com>, "Paul E. McKenney" <paulmck@kernel.org>, 
	Peter Zijlstra <peterz@infradead.org>, Frederic Weisbecker <frederic@kernel.org>, 
	Neeraj Upadhyay <quic_neeraju@quicinc.com>, Josh Triplett <josh@joshtriplett.org>, 
	Boqun Feng <boqun.feng@gmail.com>, Steven Rostedt <rostedt@goodmis.org>, 
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>, Zqiang <qiang.zhang1211@gmail.com>
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On Sun, Apr 7, 2024 at 5:03=E2=80=AFAM Lai Jiangshan <jiangshanlai@gmail.co=
m> wrote:
>
> From: Lai Jiangshan <jiangshan.ljs@antgroup.com>
>
> Enable tree_exp.h using some rcu preempt macros introduced in
> the next patch. The new macros touch core rcu-preempt fields
> and are better to be implemented in tree_plugin.h.
>
> Cc: "Paul E. McKenney" <paulmck@kernel.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Frederic Weisbecker <frederic@kernel.org>
> Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
> ---
>  kernel/rcu/tree.c        | 2 +-
>  kernel/rcu/tree_plugin.h | 1 +
>  2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> index d9642dd06c25..57d1ae26861f 100644
> --- a/kernel/rcu/tree.c
> +++ b/kernel/rcu/tree.c
> @@ -5245,6 +5245,6 @@ void __init rcu_init(void)
>  }
>
>  #include "tree_stall.h"
> -#include "tree_exp.h"
>  #include "tree_nocb.h"
>  #include "tree_plugin.h"
> +#include "tree_exp.h"
> diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
> index b1264096d03a..d899b4afc21c 100644
> --- a/kernel/rcu/tree_plugin.h
> +++ b/kernel/rcu/tree_plugin.h
> @@ -103,6 +103,7 @@ static void __init rcu_bootup_announce_oddness(void)
>  #ifdef CONFIG_PREEMPT_RCU
>
>  static void rcu_report_exp_rnp(struct rcu_node *rnp, bool wake);
> +static bool sync_rcu_exp_done(struct rcu_node *rnp);
>  static void rcu_read_unlock_special(struct task_struct *t);

OK with me, but not sure if the reordering of header inclusion is
needed? You could get the same results by just adding declarations of
the new helpers to tree_exp.h.

Not sure if tree_plugin.h needs to be included last, I for some reason
thought it needed to be - but looks like not. I found a thread that
shed some light into the header file including C code thing as well,
which may or may not help:
https://lore.kernel.org/all/8ab3ca72-e20c-4b18-803f-bf6937c2cd70@paulmck-la=
ptop/#t

Thanks.