From: nicolas saenz julienne <nsaenz@kernel.org>
To: Frederic Weisbecker <frederic@kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Phil Auld <pauld@redhat.com>, Alex Belits <abelits@marvell.com>,
Xiongfeng Wang <wangxiongfeng2@huawei.com>,
Neeraj Upadhyay <quic_neeraju@quicinc.com>,
Thomas Gleixner <tglx@linutronix.de>,
Yu Liao <liaoyu15@huawei.com>, Boqun Feng <boqun.feng@gmail.com>,
"Paul E . McKenney" <paulmck@kernel.org>,
Marcelo Tosatti <mtosatti@redhat.com>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Uladzislau Rezki <uladzislau.rezki@sony.com>,
Joel Fernandes <joel@joelfernandes.org>
Subject: Re: [PATCH 00/19] rcu/context-tracking: Merge RCU eqs-dynticks counter to context tracking
Date: Fri, 11 Mar 2022 12:37:55 +0100 [thread overview]
Message-ID: <c6333d9ebf5fcf03c1cf62071336c110a013a762.camel@kernel.org> (raw)
In-Reply-To: <20220302154810.42308-1-frederic@kernel.org>
On Wed, 2022-03-02 at 16:47 +0100, Frederic Weisbecker wrote:
> This mixes up the RCU dynticks counter and the context tracking state
> updates into a single atomic instruction. This may serve several
> purposes:
>
> 1) Improve CPU isolation with deferring some disturbances until sensitive
> userspace workload completes and goes to the kernel. This can take
> several forms, for example smp_call_function_housekeeping() or
> on_each_housekeeping_cpu() to enqueue and execute work on all
> housekeeping CPUs. Then an atomic operation on ct->state can defer
> the work on nohz_full CPUs until they run in kernel (or IPI them
> if they are in kernel mode), see this proposal by Peter:
> https://lore.kernel.org/all/20210929151723.162004989@infradead.org/#r
>
> 2) Unearth sysidle (https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git/commit/?h=sysidle.2017.05.11a&id=fe5ac724d81a3c7803e60c2232718f212f3f38d4)
> This feature allowed to shutdown the tick on the last housekeeping
> CPU once the rest of the system is fully idle. We needed some proper
> fully ordered context tracking for that.
>
> Inspired by Peterz: https://lore.kernel.org/all/20210929151723.162004989@infradead.org
>
> git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
> rcu/context-tracking
>
> HEAD: e4eaff86ec91c1cbde9a113cf5232dac9f897337
>
> Thanks,
> Frederic
> ---
I've been testing patches 1 to 18 on my nohz_full setup. Everything is looking
good so far.
Regards,
Nicolas
prev parent reply other threads:[~2022-03-11 11:38 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-02 15:47 Frederic Weisbecker
2022-03-02 15:47 ` [PATCH 01/19] context_tracking: Rename __context_tracking_enter/exit() to __ct_user_enter/exit() Frederic Weisbecker
2022-03-10 19:27 ` Paul E. McKenney
2022-03-02 15:47 ` [PATCH 02/19] context_tracking: Rename context_tracking_user_enter/exit() to user_enter/exit_callable() Frederic Weisbecker
2022-03-05 13:59 ` Peter Zijlstra
2022-03-09 20:53 ` Frederic Weisbecker
2022-03-02 15:47 ` [PATCH 03/19] context_tracking: Rename context_tracking_enter/exit() to ct_user_enter/exit() Frederic Weisbecker
2022-03-05 14:02 ` Peter Zijlstra
2022-03-09 21:21 ` Frederic Weisbecker
2022-03-02 15:47 ` [PATCH 04/19] context_tracking: Rename context_tracking_cpu_set() to context_tracking_cpu_track_user() Frederic Weisbecker
2022-03-05 14:03 ` Peter Zijlstra
2022-03-09 21:11 ` Frederic Weisbecker
2022-03-02 15:47 ` [PATCH 05/19] context_tracking: Split user tracking Kconfig Frederic Weisbecker
2022-03-10 19:43 ` Paul E. McKenney
2022-03-11 15:49 ` Frederic Weisbecker
2022-03-02 15:47 ` [PATCH 06/19] context_tracking: Take idle eqs entrypoints over RCU Frederic Weisbecker
2022-03-05 14:05 ` Peter Zijlstra
2022-03-09 21:12 ` Frederic Weisbecker
2022-03-02 15:47 ` [PATCH 07/19] context_tracking: Take IRQ " Frederic Weisbecker
2022-03-10 19:46 ` Paul E. McKenney
2022-03-02 15:47 ` [PATCH 08/19] context_tracking: Take NMI " Frederic Weisbecker
2022-03-10 19:47 ` Paul E. McKenney
2022-03-02 15:48 ` [PATCH 09/19] rcu/context-tracking: Remove rcu_irq_enter/exit() Frederic Weisbecker
2022-03-05 14:16 ` Peter Zijlstra
2022-03-09 22:25 ` Frederic Weisbecker
2022-03-02 15:48 ` [PATCH 10/19] rcu/context_tracking: Move dynticks counter to context tracking Frederic Weisbecker
2022-03-10 20:00 ` Paul E. McKenney
2022-03-02 15:48 ` [PATCH 11/19] rcu/context_tracking: Move dynticks_nesting " Frederic Weisbecker
2022-03-10 20:01 ` Paul E. McKenney
2022-03-12 23:23 ` Peter Zijlstra
2022-03-02 15:48 ` [PATCH 12/19] rcu/context_tracking: Move dynticks_nmi_nesting " Frederic Weisbecker
2022-03-10 20:02 ` Paul E. McKenney
2022-03-02 15:48 ` [PATCH 13/19] rcu/context-tracking: Move deferred nocb resched " Frederic Weisbecker
2022-03-10 20:04 ` Paul E. McKenney
2022-03-02 15:48 ` [PATCH 14/19] rcu/context-tracking: Move RCU-dynticks internal functions to context_tracking Frederic Weisbecker
2022-03-10 20:07 ` Paul E. McKenney
2022-03-11 16:02 ` Frederic Weisbecker
2022-03-11 16:14 ` Paul E. McKenney
2022-03-12 23:10 ` Peter Zijlstra
2022-03-02 15:48 ` [PATCH 15/19] rcu/context-tracking: Remove unused and/or unecessary middle functions Frederic Weisbecker
2022-03-09 16:40 ` nicolas saenz julienne
2022-03-11 15:19 ` Frederic Weisbecker
2022-03-02 15:48 ` [PATCH 16/19] context_tracking: Convert state to atomic_t Frederic Weisbecker
2022-03-09 17:17 ` nicolas saenz julienne
2022-03-11 15:24 ` Frederic Weisbecker
2022-03-12 22:54 ` Peter Zijlstra
2022-03-21 13:32 ` Will Deacon
2022-03-02 15:48 ` [PATCH 17/19] rcu/context-tracking: Use accessor for dynticks counter value Frederic Weisbecker
2022-03-10 20:08 ` Paul E. McKenney
2022-03-02 15:48 ` [PATCH 18/19] rcu/context_tracking: Merge dynticks counter and context tracking states Frederic Weisbecker
2022-03-10 20:32 ` Paul E. McKenney
2022-03-11 16:35 ` Frederic Weisbecker
2022-03-11 17:28 ` Paul E. McKenney
2022-03-02 15:48 ` [PATCH 19/19] context_tracking: Exempt CONFIG_HAVE_CONTEXT_TRACKING_USER_OFFSTACK from non-active tracking Frederic Weisbecker
2022-03-08 16:15 ` nicolas saenz julienne
2022-03-11 15:16 ` Frederic Weisbecker
2022-03-11 11:37 ` nicolas saenz julienne [this message]
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