On Thu, Apr 28, 2022 at 12:39:54PM -0600, Jonathan Corbet wrote:
> Joel Savitz <jsavitz@xxxxxxxxxx> writes:
>
> > Friendly ping.
>
> This was waiting for an ack from an RCU person. Looking now, though, I
> see that you didn't copy any RCU people. Adding Paul and the author of
> the patch you reference (and appending patch below).
Thank you for calling this to my attention. ;-)
> Thanks,
>
> jon
>
> Joel Savitz <jsavitz@xxxxxxxxxx> (March 24) (kernel lwn)
> Subject: [PATCH] Documentation/sysctl: document max_rcu_stall_to_panic
> To: linux-kernel@xxxxxxxxxxxxxxx
> Cc: Joel Savitz <jsavitz@xxxxxxxxxx>, Jonathan Corbet <corbet@xxxxxxx>, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>, Huang Ying <ying.huang@xxxxxxxxx>, Eric Biggers <ebiggers@xxxxxxxxxx>, Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx>, Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>, Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>, "Jason A. Donenfeld" <Jason@xxxxxxxxx>, Daniel Borkmann <daniel@xxxxxxxxxxxxx>, Rob Herring <robh@xxxxxxxxxx>, Wang Qing <wangqing@xxxxxxxx>, linux-doc@xxxxxxxxxxxxxxx
> Date: Thu, 24 Mar 2022 18:11:56 -0400
>
> commit dfe564045c65 ("rcu: Panic after fixed number of stalls")
> introduced a new systctl but no accompanying documentation.
>
> Add a simple entry to the documentation.
>
> Signed-off-by: Joel Savitz <jsavitz@xxxxxxxxxx>
Acked-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
> ---
> Documentation/admin-guide/sysctl/kernel.rst | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst
> index 803c60bf21d3..4e48139b9a34 100644
> --- a/Documentation/admin-guide/sysctl/kernel.rst
> +++ b/Documentation/admin-guide/sysctl/kernel.rst
> @@ -781,6 +781,13 @@ is useful to define the root cause of RCU stalls using a vmcore.
> 1 panic() after printing RCU stall messages.
> = ============================================================
>
> +max_rcu_stall_to_panic
> +======================
> +
> +When ``panic_on_rcu_stall`` is set to 1, this value determines the
> +number of times that RCU can stall before panic() is called.
> +
> +When ``panic_on_rcu_stall`` is set to 0, this value is has no effect.
>
> perf_cpu_time_max_percent
> =========================
