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From: "Paul E. McKenney" <paulmck@kernel.org>
To: Frederic Weisbecker <frederic@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Boqun Feng <boqun.feng@gmail.com>,
	Lai Jiangshan <jiangshanlai@gmail.com>,
	Neeraj Upadhyay <neeraju@codeaurora.org>,
	Josh Triplett <josh@joshtriplett.org>,
	Stable <stable@vger.kernel.org>,
	Joel Fernandes <joel@joelfernandes.org>
Subject: Re: [PATCH 12/13] rcu/nocb: Prepare for finegrained deferred wakeup
Date: Mon, 15 Mar 2021 20:02:39 -0700	[thread overview]
Message-ID: <20210316030239.GA13675@paulmck-ThinkPad-P72> (raw)
In-Reply-To: <20210223001011.127063-13-frederic@kernel.org>

On Tue, Feb 23, 2021 at 01:10:10AM +0100, Frederic Weisbecker wrote:
> Provide a way to tune the deferred wakeup level we want to perform from
> a safe wakeup point. Currently those sites are:
> 
> * nocb_timer
> * user/idle/guest entry
> * CPU down
> * softirq/rcuc
> 
> All of these sites perform the wake up for both RCU_NOCB_WAKE and
> RCU_NOCB_WAKE_FORCE.
> 
> In order to merge nocb_timer and nocb_bypass_timer together, we plan to
> add a new RCU_NOCB_WAKE_BYPASS that really want to be deferred until
> a timer fires so that we don't wake up the NOCB-gp kthread too early.
> 
> To prepare for that, integrate a wake up level/limit that a callsite is
> deemed to perform.

This appears to need the following in order to build for non-NOCB
configurations.  I will fold it in and am retesting.

							Thanx, Paul

------------------------------------------------------------------------

commit 55f59dd75a11455cf558fd387fbf9011017dcc8a
Author: Paul E. McKenney <paulmck@kernel.org>
Date:   Mon Mar 15 20:00:34 2021 -0700

    squash! rcu/nocb: Prepare for fine-grained deferred wakeup
    
    [ paulmck: Fix non-NOCB rcu_nocb_need_deferred_wakeup() definition. ]
    Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 0cc7f68..dfb048e 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -2926,7 +2926,7 @@ static void __init rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp)
 {
 }
 
-static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp)
+static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp, int level)
 {
 	return false;
 }

  reply	other threads:[~2021-03-16  3:03 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-23  0:09 [PATCH 00/13] rcu/nocb updates v2 Frederic Weisbecker
2021-02-23  0:09 ` [PATCH 01/13] rcu/nocb: Fix potential missed nocb_timer rearm Frederic Weisbecker
2021-02-24 18:37   ` Paul E. McKenney
2021-02-24 22:06     ` Frederic Weisbecker
2021-02-25  0:14       ` Paul E. McKenney
2021-02-25  0:48         ` Frederic Weisbecker
2021-02-25  1:07           ` Paul E. McKenney
2021-03-02  1:48       ` Paul E. McKenney
2021-03-02 12:34         ` Frederic Weisbecker
2021-03-02 18:17           ` Paul E. McKenney
2021-03-03  1:35             ` Frederic Weisbecker
2021-03-03  2:06               ` Paul E. McKenney
2021-03-03  2:17                 ` Frederic Weisbecker
2021-03-03 11:15             ` Neeraj Upadhyay
2021-02-23  0:10 ` [PATCH 02/13] rcu/nocb: Disable bypass when CPU isn't completely offloaded Frederic Weisbecker
2021-02-23  0:10 ` [PATCH 03/13] rcu/nocb: Remove stale comment above rcu_segcblist_offload() Frederic Weisbecker
2021-02-23  0:10 ` [PATCH 04/13] rcu/nocb: Move trace_rcu_nocb_wake() calls outside nocb_lock when possible Frederic Weisbecker
2021-02-23  0:10 ` [PATCH 05/13] rcu/nocb: Merge nocb_timer to the rdp leader Frederic Weisbecker
2021-03-03  1:15   ` [PATCH 05/13] rcu/nocb: Use the rcuog CPU's ->nocb_timer Paul E. McKenney
2021-03-10 22:05     ` Frederic Weisbecker
2021-03-16  0:02       ` Paul E. McKenney
2021-02-23  0:10 ` [PATCH 06/13] timer: Revert "timer: Add timer_curr_running()" Frederic Weisbecker
2021-02-23  0:10 ` [PATCH 07/13] rcu/nocb: Directly call __wake_nocb_gp() from bypass timer Frederic Weisbecker
2021-02-23  0:10 ` [PATCH 08/13] rcu/nocb: Allow de-offloading rdp leader Frederic Weisbecker
2021-02-23  0:10 ` [PATCH 09/13] rcu/nocb: Cancel nocb_timer upon nocb_gp wakeup Frederic Weisbecker
2021-02-23  0:10 ` [PATCH 10/13] rcu/nocb: Delete bypass_timer " Frederic Weisbecker
2021-03-03  1:24   ` Paul E. McKenney
2021-03-10 22:17     ` Frederic Weisbecker
2021-03-15 14:53       ` Boqun Feng
2021-03-15 22:56         ` Frederic Weisbecker
2021-03-16  0:02           ` Paul E. McKenney
2021-02-23  0:10 ` [PATCH 11/13] rcu/nocb: Only cancel nocb timer if not polling Frederic Weisbecker
2021-03-03  1:22   ` Paul E. McKenney
2021-03-10 22:08     ` Frederic Weisbecker
2021-02-23  0:10 ` [PATCH 12/13] rcu/nocb: Prepare for finegrained deferred wakeup Frederic Weisbecker
2021-03-16  3:02   ` Paul E. McKenney [this message]
2021-03-16 11:45     ` Frederic Weisbecker
2021-03-16 14:02       ` Paul E. McKenney
2021-02-23  0:10 ` [PATCH 13/13] rcu/nocb: Unify timers Frederic Weisbecker

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