linux-kernel - Re: [PATCH rcu 1/6] rcu: Update synchronize_rcu_mult() comment for call_rcu

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Message-ID: <e6ba1856-f54b-943e-d01d-097e88900846@joelfernandes.org>
Date:   Tue, 18 Jul 2023 08:59:24 -0400
From:   Joel Fernandes <joel@...lfernandes.org>
To:     "Paul E. McKenney" <paulmck@...nel.org>, rcu@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, kernel-team@...a.com,
        rostedt@...dmis.org
Subject: Re: [PATCH rcu 1/6] rcu: Update synchronize_rcu_mult() comment for
 call_rcu_hurry()

On 7/17/23 14:03, Paul E. McKenney wrote:
> Those who have worked with RCU for some time will naturally think in
> terms of the long-standing call_rcu() API rather than the much newer
> call_rcu_hurry() API.  But it is call_rcu_hurry() that you should normally
> pass to synchronize_rcu_mult().  This commit therefore updates the header
> comment to point this out.
> 
> Signed-off-by: Paul E. McKenney <paulmck@...nel.org>
> ---
>   include/linux/rcupdate_wait.h | 5 +++++
>   1 file changed, 5 insertions(+)
> 
> diff --git a/include/linux/rcupdate_wait.h b/include/linux/rcupdate_wait.h
> index 699b938358bf..5e0f74f2f8ca 100644
> --- a/include/linux/rcupdate_wait.h
> +++ b/include/linux/rcupdate_wait.h
> @@ -42,6 +42,11 @@ do {									\
>    * call_srcu() function, with this wrapper supplying the pointer to the
>    * corresponding srcu_struct.
>    *
> + * Note that call_rcu_hurry() should be used instead of call_rcu()
> + * because in kernels built with CONFIG_RCU_LAZY=y the delay between the
> + * invocation of call_rcu() and that of the corresponding RCU callback
> + * can be multiple seconds.
> + *
>    * The first argument tells Tiny RCU's _wait_rcu_gp() not to
>    * bother waiting for RCU.  The reason for this is because anywhere
>    * synchronize_rcu_mult() can be called is automatically already a full

Reviewed-by: Joel Fernandes (Google) <joel@...lfernandes.org>

thanks,

  - Joel