2022-03-25 17:31:00

by Joel Savitz

[permalink] [raw]
Subject: [PATCH] Documentation/sysctl: document max_rcu_stall_to_panic

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 <[email protected]>
---
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
=========================
--
2.27.0


2022-04-29 09:23:25

by Jonathan Corbet

[permalink] [raw]
Subject: Re: [PATCH] Documentation/sysctl: document max_rcu_stall_to_panic

Joel Savitz <[email protected]> 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).

Thanks,

jon

Joel Savitz <[email protected]> (March 24) (kernel lwn)
Subject: [PATCH] Documentation/sysctl: document max_rcu_stall_to_panic
To: [email protected]
Cc: Joel Savitz <[email protected]>, Jonathan Corbet <[email protected]>, Andrew Morton <[email protected]>, Huang Ying <[email protected]>, Eric Biggers <[email protected]>, Dominik Brodowski <[email protected]>, Mauro Carvalho Chehab <[email protected]>, Rasmus Villemoes <[email protected]>, "Jason A. Donenfeld" <[email protected]>, Daniel Borkmann <[email protected]>, Rob Herring <[email protected]>, Wang Qing <[email protected]>, [email protected]
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 <[email protected]>
---
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
=========================

2022-04-30 04:59:11

by Paul E. McKenney

[permalink] [raw]
Subject: Re: [PATCH] Documentation/sysctl: document max_rcu_stall_to_panic

On Thu, Apr 28, 2022 at 12:39:54PM -0600, Jonathan Corbet wrote:
> Joel Savitz <[email protected]> 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 <[email protected]> (March 24) (kernel lwn)
> Subject: [PATCH] Documentation/sysctl: document max_rcu_stall_to_panic
> To: [email protected]
> Cc: Joel Savitz <[email protected]>, Jonathan Corbet <[email protected]>, Andrew Morton <[email protected]>, Huang Ying <[email protected]>, Eric Biggers <[email protected]>, Dominik Brodowski <[email protected]>, Mauro Carvalho Chehab <[email protected]>, Rasmus Villemoes <[email protected]>, "Jason A. Donenfeld" <[email protected]>, Daniel Borkmann <[email protected]>, Rob Herring <[email protected]>, Wang Qing <[email protected]>, [email protected]
> 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 <[email protected]>

Acked-by: Paul E. McKenney <[email protected]>

> ---
> 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
> =========================

2022-05-02 03:47:28

by Jonathan Corbet

[permalink] [raw]
Subject: Re: [PATCH] Documentation/sysctl: document max_rcu_stall_to_panic

"Paul E. McKenney" <[email protected]> writes:

>> 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 <[email protected]>
>
> Acked-by: Paul E. McKenney <[email protected]>

OK, applied, thanks.

jon