linux-kernel - Re: [PATCH 1/2] rcuperf: Remove useless while loops around wait

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Date:   Mon, 25 May 2020 11:04:14 -0700
From:   "Paul E. McKenney" <paulmck@...nel.org>
To:     "Joel Fernandes (Google)" <joel@...lfernandes.org>
Cc:     linux-kernel@...r.kernel.org, Davidlohr Bueso <dave@...olabs.net>,
        Josh Triplett <josh@...htriplett.org>,
        Lai Jiangshan <jiangshanlai@...il.com>,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        rcu@...r.kernel.org, Steven Rostedt <rostedt@...dmis.org>
Subject: Re: [PATCH 1/2] rcuperf: Remove useless while loops around wait_event

On Mon, May 25, 2020 at 12:36:47AM -0400, Joel Fernandes (Google) wrote:
> wait_event() already retries if the condition for the wake up is not
> satisifed after wake up. Remove them from the rcuperf test.
> 
> Signed-off-by: Joel Fernandes (Google) <joel@...lfernandes.org>

Queued the series, thank you, Joel!

							Thanx, Paul

> ---
>  kernel/rcu/rcuperf.c | 14 ++++----------
>  1 file changed, 4 insertions(+), 10 deletions(-)
> 
> diff --git a/kernel/rcu/rcuperf.c b/kernel/rcu/rcuperf.c
> index 16dd1e6b7c09f..246da8fe199e8 100644
> --- a/kernel/rcu/rcuperf.c
> +++ b/kernel/rcu/rcuperf.c
> @@ -576,11 +576,8 @@ static int compute_real(int n)
>  static int
>  rcu_perf_shutdown(void *arg)
>  {
> -	do {
> -		wait_event(shutdown_wq,
> -			   atomic_read(&n_rcu_perf_writer_finished) >=
> -			   nrealwriters);
> -	} while (atomic_read(&n_rcu_perf_writer_finished) < nrealwriters);
> +	wait_event(shutdown_wq,
> +		   atomic_read(&n_rcu_perf_writer_finished) >= nrealwriters);
>  	smp_mb(); /* Wake before output. */
>  	rcu_perf_cleanup();
>  	kernel_power_off();
> @@ -693,11 +690,8 @@ kfree_perf_cleanup(void)
>  static int
>  kfree_perf_shutdown(void *arg)
>  {
> -	do {
> -		wait_event(shutdown_wq,
> -			   atomic_read(&n_kfree_perf_thread_ended) >=
> -			   kfree_nrealthreads);
> -	} while (atomic_read(&n_kfree_perf_thread_ended) < kfree_nrealthreads);
> +	wait_event(shutdown_wq,
> +		   atomic_read(&n_kfree_perf_thread_ended) >= kfree_nrealthreads);
>  
>  	smp_mb(); /* Wake before output. */
>  
> -- 
> 2.27.0.rc0.183.gde8f92d652-goog
>