From: Prakash Sangappa <prakash.sangappa@oracle.com>
To: Randy Dunlap <rdunlap@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
Boqun Feng <boqun.feng@gmail.com>,
Jonathan Corbet <corbet@lwn.net>,
Madadi Vineeth Reddy <vineethr@linux.ibm.com>,
K Prateek Nayak <kprateek.nayak@amd.com>,
Steven Rostedt <rostedt@goodmis.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Arnd Bergmann <arnd@arndb.de>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ron Geva <rongevarg@gmail.com>, Waiman Long <longman@redhat.com>
Subject: Re: [patch V6 07/11] rseq: Implement time slice extension enforcement timer
Date: Tue, 16 Dec 2025 17:55:07 +0000 [thread overview]
Message-ID: <7B4AF4F8-EE20-44CC-BC79-693529F19BA6@oracle.com> (raw)
In-Reply-To: <d1dcaa6c-98fc-4d02-a958-209c54d8374b@infradead.org>
> On Dec 15, 2025, at 11:18 PM, Randy Dunlap <rdunlap@infradead.org> wrote:
>
> 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.
>
Well, this prctl call is to enable the time slice extension mechanism for the thread.
Actually requesting to delay scheduling(time slice extension) is done
by updating a member in rseq structure. Perhaps this needs to be clarified.
-Prakash
> --
> ~Randy
>
next prev parent reply other threads:[~2025-12-16 17:55 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-15 16:52 [patch V6 00/11] rseq: Implement time slice extension mechanism Thomas Gleixner
2025-12-15 16:52 ` [patch V6 01/11] rseq: Add fields and constants for time slice extension Thomas Gleixner
2025-12-15 18:24 ` Thomas Gleixner
2025-12-16 14:36 ` Mathieu Desnoyers
2025-12-18 23:21 ` Thomas Gleixner
2026-01-07 21:11 ` Mathieu Desnoyers
2026-01-11 17:11 ` Thomas Gleixner
2026-01-13 23:45 ` Florian Weimer
2026-01-14 21:59 ` Thomas Gleixner
2026-01-17 16:16 ` Mathieu Desnoyers
2026-01-19 10:21 ` Peter Zijlstra
2026-01-19 10:30 ` Mathieu Desnoyers
2026-01-19 11:03 ` Peter Zijlstra
2026-01-19 11:10 ` Mathieu Desnoyers
2026-01-19 11:27 ` Peter Zijlstra
2026-01-19 10:46 ` Florian Weimer
2026-01-17 9:36 ` Peter Zijlstra
2026-01-19 10:10 ` Peter Zijlstra
2026-01-22 10:16 ` [tip: sched/core] " tip-bot2 for Thomas Gleixner
2025-12-15 16:52 ` [patch V6 02/11] rseq: Provide static branch for time slice extensions Thomas Gleixner
2025-12-15 18:24 ` Thomas Gleixner
2026-01-22 10:16 ` [tip: sched/core] " tip-bot2 for Thomas Gleixner
2025-12-15 16:52 ` [patch V6 03/11] rseq: Add statistics " Thomas Gleixner
2025-12-15 18:24 ` Thomas Gleixner
2026-01-22 10:16 ` [tip: sched/core] " tip-bot2 for Thomas Gleixner
2025-12-15 16:52 ` [patch V6 04/11] rseq: Add prctl() to enable " Thomas Gleixner
2025-12-15 18:24 ` Thomas Gleixner
2026-01-22 10:16 ` [tip: sched/core] " tip-bot2 for Thomas Gleixner
2025-12-15 16:52 ` [patch V6 05/11] rseq: Implement sys_rseq_slice_yield() Thomas Gleixner
2025-12-15 18:24 ` Thomas Gleixner
2025-12-16 14:59 ` Mathieu Desnoyers
2026-01-22 10:16 ` [tip: sched/core] " tip-bot2 for Thomas Gleixner
2025-12-15 16:52 ` [patch V6 06/11] rseq: Implement syscall entry work for time slice extensions Thomas Gleixner
2025-12-15 18:24 ` Thomas Gleixner
2025-12-16 15:05 ` Mathieu Desnoyers
2025-12-18 22:28 ` Thomas Gleixner
2025-12-18 22:30 ` Mathieu Desnoyers
2026-01-22 10:16 ` [tip: sched/core] " tip-bot2 for Thomas Gleixner
2025-12-15 16:52 ` [patch V6 07/11] rseq: Implement time slice extension enforcement timer Thomas Gleixner
2025-12-15 18:24 ` Thomas Gleixner
2025-12-16 7:18 ` Randy Dunlap
2025-12-16 17:55 ` Prakash Sangappa [this message]
2025-12-16 8:26 ` [patch V6.1 " Thomas Gleixner
2025-12-16 15:13 ` [patch V6 " Mathieu Desnoyers
2025-12-18 15:05 ` Peter Zijlstra
2025-12-18 23:26 ` Thomas Gleixner
2025-12-19 10:05 ` Peter Zijlstra
2026-01-16 18:15 ` Peter Zijlstra
2026-01-18 10:46 ` Thomas Gleixner
2026-01-19 10:01 ` Peter Zijlstra
2025-12-18 15:18 ` Peter Zijlstra
2025-12-18 23:25 ` Thomas Gleixner
2026-01-17 9:57 ` Peter Zijlstra
2026-01-23 17:38 ` Prakash Sangappa
2026-01-23 17:41 ` Prakash Sangappa
2026-01-27 18:48 ` Peter Zijlstra
2026-01-22 10:16 ` [tip: sched/core] " tip-bot2 for Thomas Gleixner
2025-12-15 16:52 ` [patch V6 08/11] rseq: Reset slice extension when scheduled Thomas Gleixner
2025-12-15 18:24 ` Thomas Gleixner
2025-12-16 15:17 ` Mathieu Desnoyers
2026-01-22 10:16 ` [tip: sched/core] " tip-bot2 for Thomas Gleixner
2025-12-15 16:52 ` [patch V6 09/11] rseq: Implement rseq_grant_slice_extension() Thomas Gleixner
2025-12-15 18:24 ` Thomas Gleixner
2025-12-16 15:25 ` Mathieu Desnoyers
2025-12-18 23:28 ` Thomas Gleixner
2026-01-11 10:22 ` Thomas Gleixner
2026-01-22 10:15 ` [tip: sched/core] " tip-bot2 for Thomas Gleixner
2025-12-15 16:52 ` [patch V6 10/11] entry: Hook up rseq time slice extension Thomas Gleixner
2025-12-15 18:24 ` Thomas Gleixner
2025-12-16 15:37 ` Mathieu Desnoyers
2025-12-19 11:07 ` Peter Zijlstra
2026-01-11 11:01 ` Thomas Gleixner
2026-01-17 9:51 ` Peter Zijlstra
2026-01-22 10:15 ` [tip: sched/core] " tip-bot2 for Thomas Gleixner
2025-12-15 16:52 ` [patch V6 11/11] selftests/rseq: Implement time slice extension test Thomas Gleixner
2025-12-15 18:24 ` Thomas Gleixner
2026-01-22 10:15 ` [tip: sched/core] " tip-bot2 for Thomas Gleixner
2025-12-15 18:24 ` [patch V6 00/11] rseq: Implement time slice extension mechanism Thomas Gleixner
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