From: Ankur Arora <ankur.a.arora@oracle.com>
To: Joel Fernandes <joel@joelfernandes.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ankur Arora <ankur.a.arora@oracle.com>,
paulmck@kernel.org, linux-kernel@vger.kernel.org,
peterz@infradead.org, torvalds@linux-foundation.org,
akpm@linux-foundation.org, luto@kernel.org, bp@alien8.de,
dave.hansen@linux.intel.com, hpa@zytor.com, mingo@redhat.com,
juri.lelli@redhat.com, vincent.guittot@linaro.org,
willy@infradead.org, mgorman@suse.de, jpoimboe@kernel.org,
mark.rutland@arm.com, jgross@suse.com, andrew.cooper3@citrix.com,
bristot@kernel.org, mathieu.desnoyers@efficios.com,
geert@linux-m68k.org, glaubitz@physik.fu-berlin.de,
anton.ivanov@cambridgegreys.com, mattst88@gmail.com,
krypton@ulrich-teichert.org, rostedt@goodmis.org,
David.Laight@aculab.com, richard@nod.at, mjguzik@gmail.com,
jon.grimm@amd.com, bharata@amd.com, raghavendra.kt@amd.com,
boris.ostrovsky@oracle.com, konrad.wilk@oracle.com,
rcu@vger.kernel.org
Subject: Re: [PATCH 15/30] rcu: handle quiescent states for PREEMPT_RCU=n, PREEMPT_COUNT=y
Date: Mon, 11 Mar 2024 20:16:12 -0700 [thread overview]
Message-ID: <87msr4f8cj.fsf@oracle.com> (raw)
In-Reply-To: <5b78a338-cb82-4ac4-8004-77a3eb150604@joelfernandes.org>
Joel Fernandes <joel@joelfernandes.org> writes:
> Hi, Thomas,
> Thanks for your reply! I replied below.
>
> On 3/11/2024 3:12 PM, Thomas Gleixner wrote:
>> On Mon, Mar 11 2024 at 11:25, Joel Fernandes wrote:
[ ... ]
>> What's wrong with the combination of PREEMPT_AUTO=y and PREEMPT_RCU=n?
>> Paul and me agreed long ago that this needs to be supported.
>
> There's nothing wrong with it. Its just a bit quirky (again just a point of
> view), that for a configuration that causes preemption (similar to
> CONFIG_PREEMPT=y), that PREEMPT_RCU can be disabled. After all, again with
> CONFIG_PREEMPT=y, PREEMPT_RCU cannot be currently disabled.
I think the argument was that PREEMPT_RCU=y is suboptimal for certain
workloads, and those configurations might prefer the stronger
forward-progress guarantees that PREEMPT_RCU=n provides.
See this:
https://lore.kernel.org/lkml/73ecce1c-d321-4579-b892-13b1e0a0620a@paulmck-laptop/T/#m6aab5a6fd5f1fd4c3dc9282ce564e64f2fa6cdc3
and the surrounding thread.
Thanks
--
ankur
next prev parent reply other threads:[~2024-03-12 3:17 UTC|newest]
Thread overview: 155+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-13 5:55 [PATCH 00/30] PREEMPT_AUTO: support lazy rescheduling Ankur Arora
2024-02-13 5:55 ` [PATCH 01/30] preempt: introduce CONFIG_PREEMPT_AUTO Ankur Arora
2024-02-13 5:55 ` [PATCH 02/30] thread_info: selector for TIF_NEED_RESCHED[_LAZY] Ankur Arora
2024-02-19 15:16 ` Thomas Gleixner
2024-02-20 22:50 ` Ankur Arora
2024-02-21 17:05 ` Thomas Gleixner
2024-02-21 18:26 ` Steven Rostedt
2024-02-21 20:03 ` Thomas Gleixner
2024-02-13 5:55 ` [PATCH 03/30] thread_info: tif_need_resched() now takes resched_t as param Ankur Arora
2024-02-14 3:17 ` kernel test robot
2024-02-14 14:08 ` Mark Rutland
2024-02-15 4:08 ` Ankur Arora
2024-02-19 12:30 ` Mark Rutland
2024-02-20 22:09 ` Ankur Arora
2024-02-19 15:21 ` Thomas Gleixner
2024-02-20 22:21 ` Ankur Arora
2024-02-21 17:07 ` Thomas Gleixner
2024-02-21 21:22 ` Ankur Arora
2024-02-13 5:55 ` [PATCH 04/30] sched: make test_*_tsk_thread_flag() return bool Ankur Arora
2024-02-14 14:12 ` Mark Rutland
2024-02-15 2:04 ` Ankur Arora
2024-02-13 5:55 ` [PATCH 05/30] sched: *_tsk_need_resched() now takes resched_t as param Ankur Arora
2024-02-19 15:26 ` Thomas Gleixner
2024-02-20 22:37 ` Ankur Arora
2024-02-21 17:10 ` Thomas Gleixner
2024-02-13 5:55 ` [PATCH 06/30] entry: handle lazy rescheduling at user-exit Ankur Arora
2024-02-19 15:29 ` Thomas Gleixner
2024-02-20 22:38 ` Ankur Arora
2024-02-13 5:55 ` [PATCH 07/30] entry/kvm: handle lazy rescheduling at guest-entry Ankur Arora
2024-02-13 5:55 ` [PATCH 08/30] entry: irqentry_exit only preempts for TIF_NEED_RESCHED Ankur Arora
2024-02-13 5:55 ` [PATCH 09/30] sched: __schedule_loop() doesn't need to check for need_resched_lazy() Ankur Arora
2024-02-13 5:55 ` [PATCH 10/30] sched: separate PREEMPT_DYNAMIC config logic Ankur Arora
2024-02-13 5:55 ` [PATCH 11/30] sched: runtime preemption config under PREEMPT_AUTO Ankur Arora
2024-02-13 5:55 ` [PATCH 12/30] rcu: limit PREEMPT_RCU to full preemption " Ankur Arora
2024-02-13 5:55 ` [PATCH 13/30] rcu: fix header guard for rcu_all_qs() Ankur Arora
2024-02-13 5:55 ` [PATCH 14/30] preempt,rcu: warn on PREEMPT_RCU=n, preempt=full Ankur Arora
2024-02-13 5:55 ` [PATCH 15/30] rcu: handle quiescent states for PREEMPT_RCU=n, PREEMPT_COUNT=y Ankur Arora
2024-03-10 10:03 ` Joel Fernandes
2024-03-10 18:56 ` Paul E. McKenney
2024-03-11 0:48 ` Joel Fernandes
2024-03-11 3:56 ` Paul E. McKenney
2024-03-11 15:01 ` Joel Fernandes
2024-03-11 20:51 ` Ankur Arora
2024-03-11 22:12 ` Thomas Gleixner
2024-03-11 5:18 ` Ankur Arora
2024-03-11 15:25 ` Joel Fernandes
2024-03-11 19:12 ` Thomas Gleixner
2024-03-11 19:53 ` Paul E. McKenney
2024-03-11 20:29 ` Thomas Gleixner
2024-03-12 0:01 ` Paul E. McKenney
2024-03-12 0:08 ` Joel Fernandes
2024-03-12 3:16 ` Ankur Arora [this message]
2024-03-12 3:24 ` Joel Fernandes
2024-03-12 5:23 ` Ankur Arora
2024-02-13 5:55 ` [PATCH 16/30] rcu: force context-switch " Ankur Arora
2024-02-13 5:55 ` [PATCH 17/30] x86/thread_info: define TIF_NEED_RESCHED_LAZY Ankur Arora
2024-02-14 13:25 ` Mark Rutland
2024-02-14 20:31 ` Ankur Arora
2024-02-19 12:32 ` Mark Rutland
2024-02-13 5:55 ` [PATCH 18/30] sched: prepare for lazy rescheduling in resched_curr() Ankur Arora
2024-02-13 5:55 ` [PATCH 19/30] sched: default preemption policy for PREEMPT_AUTO Ankur Arora
2024-02-13 5:55 ` [PATCH 20/30] sched: handle idle preemption " Ankur Arora
2024-02-13 5:55 ` [PATCH 21/30] sched: schedule eagerly in resched_cpu() Ankur Arora
2024-02-13 5:55 ` [PATCH 22/30] sched/fair: refactor update_curr(), entity_tick() Ankur Arora
2024-02-13 5:55 ` [PATCH 23/30] sched/fair: handle tick expiry under lazy preemption Ankur Arora
2024-02-21 21:38 ` Steven Rostedt
2024-02-28 13:47 ` Juri Lelli
2024-02-29 6:43 ` Ankur Arora
2024-02-29 9:33 ` Juri Lelli
2024-02-29 23:54 ` Ankur Arora
2024-03-01 0:28 ` Paul E. McKenney
2024-02-13 5:55 ` [PATCH 24/30] sched: support preempt=none under PREEMPT_AUTO Ankur Arora
2024-02-13 5:55 ` [PATCH 25/30] sched: support preempt=full " Ankur Arora
2024-02-13 5:55 ` [PATCH 26/30] sched: handle preempt=voluntary " Ankur Arora
2024-03-03 1:08 ` Joel Fernandes
2024-03-05 8:11 ` Ankur Arora
2024-03-06 20:42 ` Joel Fernandes
2024-03-07 19:01 ` Paul E. McKenney
2024-03-08 0:15 ` Joel Fernandes
2024-03-08 0:42 ` Paul E. McKenney
2024-03-08 4:22 ` Ankur Arora
2024-03-08 21:33 ` Paul E. McKenney
2024-03-11 4:50 ` Ankur Arora
2024-03-11 19:26 ` Paul E. McKenney
2024-03-11 20:09 ` Ankur Arora
2024-03-11 20:23 ` Linus Torvalds
2024-03-11 21:03 ` Ankur Arora
2024-03-12 0:03 ` Paul E. McKenney
2024-03-12 12:14 ` Thomas Gleixner
2024-03-12 19:40 ` Paul E. McKenney
2024-03-08 3:49 ` Ankur Arora
2024-03-08 5:29 ` Joel Fernandes
2024-03-08 6:54 ` Juri Lelli
2024-03-11 5:34 ` Ankur Arora
2024-02-13 5:55 ` [PATCH 27/30] sched: latency warn for TIF_NEED_RESCHED_LAZY Ankur Arora
2024-02-13 5:55 ` [PATCH 28/30] tracing: support lazy resched Ankur Arora
2024-02-13 5:55 ` [PATCH 29/30] Documentation: tracing: add TIF_NEED_RESCHED_LAZY Ankur Arora
2024-02-21 21:43 ` Steven Rostedt
2024-02-21 23:22 ` Ankur Arora
2024-02-21 23:53 ` Steven Rostedt
2024-03-01 23:33 ` Joel Fernandes
2024-03-02 3:09 ` Ankur Arora
2024-03-03 19:32 ` Joel Fernandes
2024-02-13 5:55 ` [PATCH 30/30] osnoise: handle quiescent states for PREEMPT_RCU=n, PREEMPTION=y Ankur Arora
2024-02-13 9:47 ` [PATCH 00/30] PREEMPT_AUTO: support lazy rescheduling Geert Uytterhoeven
2024-02-13 21:46 ` Ankur Arora
2024-02-14 23:57 ` Paul E. McKenney
2024-02-15 2:03 ` Ankur Arora
2024-02-15 3:45 ` Paul E. McKenney
2024-02-15 19:28 ` Paul E. McKenney
2024-02-15 20:04 ` Thomas Gleixner
2024-02-15 20:54 ` Paul E. McKenney
2024-02-15 20:53 ` Ankur Arora
2024-02-15 20:55 ` Paul E. McKenney
2024-02-15 21:24 ` Ankur Arora
2024-02-15 22:54 ` Paul E. McKenney
2024-02-15 22:56 ` Paul E. McKenney
2024-02-16 0:45 ` Ankur Arora
2024-02-16 2:59 ` Paul E. McKenney
2024-02-17 0:55 ` Paul E. McKenney
2024-02-17 3:59 ` Ankur Arora
2024-02-18 18:17 ` Paul E. McKenney
2024-02-19 16:48 ` Paul E. McKenney
2024-02-21 18:19 ` Steven Rostedt
2024-02-21 19:41 ` Paul E. McKenney
2024-02-21 20:11 ` Steven Rostedt
2024-02-21 20:22 ` Paul E. McKenney
2024-02-22 15:50 ` Mark Rutland
2024-02-22 19:11 ` Paul E. McKenney
2024-02-23 11:05 ` Mark Rutland
2024-02-23 15:31 ` Paul E. McKenney
2024-03-02 1:16 ` Paul E. McKenney
2024-03-19 11:45 ` Tasks RCU, ftrace, and trampolines (was: Re: [PATCH 00/30] PREEMPT_AUTO: support lazy rescheduling) Mark Rutland
2024-03-19 23:33 ` Paul E. McKenney
2024-02-21 6:48 ` [PATCH 00/30] PREEMPT_AUTO: support lazy rescheduling Ankur Arora
2024-02-21 17:44 ` Paul E. McKenney
2024-02-16 0:45 ` Ankur Arora
2024-02-21 12:23 ` Raghavendra K T
2024-02-21 17:15 ` Thomas Gleixner
2024-02-21 17:27 ` Raghavendra K T
2024-02-21 21:16 ` Ankur Arora
2024-02-22 4:05 ` Raghavendra K T
2024-02-22 21:23 ` Thomas Gleixner
2024-02-23 3:14 ` Ankur Arora
2024-02-23 6:28 ` Raghavendra K T
2024-02-24 3:15 ` Raghavendra K T
2024-02-27 17:45 ` Ankur Arora
2024-02-22 13:04 ` Raghavendra K T
2024-04-23 15:21 ` Shrikanth Hegde
2024-04-23 16:13 ` Linus Torvalds
2024-04-26 7:46 ` Shrikanth Hegde
2024-04-26 19:00 ` Ankur Arora
2024-05-07 11:16 ` Shrikanth Hegde
2024-05-08 5:18 ` Ankur Arora
2024-05-15 14:31 ` Shrikanth Hegde
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87msr4f8cj.fsf@oracle.com \
--to=ankur.a.arora@oracle.com \
--cc=David.Laight@aculab.com \
--cc=akpm@linux-foundation.org \
--cc=andrew.cooper3@citrix.com \
--cc=anton.ivanov@cambridgegreys.com \
--cc=bharata@amd.com \
--cc=boris.ostrovsky@oracle.com \
--cc=bp@alien8.de \
--cc=bristot@kernel.org \
--cc=dave.hansen@linux.intel.com \
--cc=geert@linux-m68k.org \
--cc=glaubitz@physik.fu-berlin.de \
--cc=hpa@zytor.com \
--cc=jgross@suse.com \
--cc=joel@joelfernandes.org \
--cc=jon.grimm@amd.com \
--cc=jpoimboe@kernel.org \
--cc=juri.lelli@redhat.com \
--cc=konrad.wilk@oracle.com \
--cc=krypton@ulrich-teichert.org \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@kernel.org \
--cc=mark.rutland@arm.com \
--cc=mathieu.desnoyers@efficios.com \
--cc=mattst88@gmail.com \
--cc=mgorman@suse.de \
--cc=mingo@redhat.com \
--cc=mjguzik@gmail.com \
--cc=paulmck@kernel.org \
--cc=peterz@infradead.org \
--cc=raghavendra.kt@amd.com \
--cc=rcu@vger.kernel.org \
--cc=richard@nod.at \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
--cc=vincent.guittot@linaro.org \
--cc=willy@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.