linux-kernel - Re: [patch V6 07/11] rseq: Implement time slice extension enforcement timer

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Message-ID: <d1dcaa6c-98fc-4d02-a958-209c54d8374b@infradead.org>
Date: Mon, 15 Dec 2025 23:18:16 -0800
From: Randy Dunlap <rdunlap@...radead.org>
To: Thomas Gleixner <tglx@...utronix.de>, LKML <linux-kernel@...r.kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
 "Paul E. McKenney" <paulmck@...nel.org>, Boqun Feng <boqun.feng@...il.com>,
 Jonathan Corbet <corbet@....net>,
 Prakash Sangappa <prakash.sangappa@...cle.com>,
 Madadi Vineeth Reddy <vineethr@...ux.ibm.com>,
 K Prateek Nayak <kprateek.nayak@....com>,
 Steven Rostedt <rostedt@...dmis.org>,
 Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
 Arnd Bergmann <arnd@...db.de>, linux-arch@...r.kernel.org,
 Peter Zijlstra <peterz@...radead.org>, Ron Geva <rongevarg@...il.com>,
 Waiman Long <longman@...hat.com>
Subject: Re: [patch V6 07/11] rseq: Implement time slice extension enforcement
 timer

Ouch. Would you mind rearranging parts of the first sentence?

On 12/15/25 10:24 AM, Thomas Gleixner wrote:
> --- a/Documentation/admin-guide/sysctl/kernel.rst
> +++ b/Documentation/admin-guide/sysctl/kernel.rst
> @@ -1228,6 +1228,14 @@ reboot-cmd (SPARC only)
>  ROM/Flash boot loader. Maybe to tell it what to do after
>  rebooting. ???
>  
> +rseq_slice_extension_nsec
> +=========================
> +
> +A task can request to delay its scheduling if it is in a critical section
> +via the prctl(PR_RSEQ_SLICE_EXTENSION_SET) mechanism. This sets the maximum
> +allowed extension in nanoseconds before scheduling of the task is enforced.
> +Default value is 30000ns (30us). The possible range is 10000ns (10us) to
> +50000ns (50us).

Maybe
A task that is in a critical section can request to delay its scheduling via
the prctl(PR_RSEQ_SLICE_EXTENSION_SET) mechanism.

-- 
~Randy