From: Joel Fernandes <joelaf@google.com>
To: paulmck@kernel.org
Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org>,
Nishanth Aravamudan <naravamudan@digitalocean.com>,
Julien Desfossez <jdesfossez@digitalocean.com>,
Peter Zijlstra <peterz@infradead.org>,
Tim Chen <tim.c.chen@linux.intel.com>,
Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Paul Turner <pjt@google.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
vpillai <vpillai@digitalocean.com>,
LKML <linux-kernel@vger.kernel.org>,
"Cc: Frederic Weisbecker" <fweisbec@gmail.com>,
Kees Cook <keescook@chromium.org>, Greg Kerr <kerrnel@google.com>,
Phil Auld <pauld@redhat.com>, Aaron Lu <aaron.lwe@gmail.com>,
Aubrey Li <aubrey.intel@gmail.com>,
aubrey.li@linux.intel.com,
Valentin Schneider <valentin.schneider@arm.com>,
Mel Gorman <mgorman@techsingularity.net>,
Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH RFC] sched: Use sched-RCU in core-scheduling balancing logic
Date: Thu, 21 May 2020 21:26:05 -0400 [thread overview]
Message-ID: <CAJWu+opfReuX=uEV+2yhor81yjzSe1O0JP9=TxPd2O-mxxFyyw@mail.gmail.com> (raw)
In-Reply-To: <20200521225202.GD2869@paulmck-ThinkPad-P72>
On Thu, May 21, 2020 at 6:52 PM Paul E. McKenney <paulmck@kernel.org> wrote:
>
> On Wed, May 20, 2020 at 06:48:18PM -0400, Joel Fernandes (Google) wrote:
> > rcu_read_unlock() can incur an infrequent deadlock in
> > sched_core_balance(). Fix this by using sched-RCU instead.
> >
> > This fixes the following spinlock recursion observed when testing the
> > core scheduling patches on PREEMPT=y kernel on ChromeOS:
> >
> > [ 3.240891] BUG: spinlock recursion on CPU#2, swapper/2/0
> > [ 3.240900] lock: 0xffff9cd1eeb28e40, .magic: dead4ead, .owner: swapper/2/0, .owner_cpu: 2
> > [ 3.240905] CPU: 2 PID: 0 Comm: swapper/2 Not tainted 5.4.22htcore #4
> > [ 3.240908] Hardware name: Google Eve/Eve, BIOS Google_Eve.9584.174.0 05/29/2018
> > [ 3.240910] Call Trace:
> > [ 3.240919] dump_stack+0x97/0xdb
> > [ 3.240924] ? spin_bug+0xa4/0xb1
> > [ 3.240927] do_raw_spin_lock+0x79/0x98
> > [ 3.240931] try_to_wake_up+0x367/0x61b
> > [ 3.240935] rcu_read_unlock_special+0xde/0x169
> > [ 3.240938] ? sched_core_balance+0xd9/0x11e
> > [ 3.240941] __rcu_read_unlock+0x48/0x4a
> > [ 3.240945] __balance_callback+0x50/0xa1
> > [ 3.240949] __schedule+0x55a/0x61e
> > [ 3.240952] schedule_idle+0x21/0x2d
> > [ 3.240956] do_idle+0x1d5/0x1f8
> > [ 3.240960] cpu_startup_entry+0x1d/0x1f
> > [ 3.240964] start_secondary+0x159/0x174
> > [ 3.240967] secondary_startup_64+0xa4/0xb0
> > [ 14.998590] watchdog: BUG: soft lockup - CPU#0 stuck for 11s! [kworker/0:10:965]
> >
> > Cc: vpillai <vpillai@digitalocean.com>
> > Cc: Aaron Lu <aaron.lwe@gmail.com>
> > Cc: Aubrey Li <aubrey.intel@gmail.com>
> > Cc: peterz@infradead.org
> > Cc: paulmck@kernel.org
> > Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
> > Change-Id: I1a4bf0cd1426b3c21ad5de44719813ad4ee5805e
>
> With some luck, the commit removing the need for this will hit
> mainline during the next merge window. Fingers firmly crossed...
Sounds good, thank you Paul :-)
- Joel
>
> Thanx, Paul
>
> > ---
> > kernel/sched/core.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> > index 780514d03da47..b8ca6fcaaaf06 100644
> > --- a/kernel/sched/core.c
> > +++ b/kernel/sched/core.c
> > @@ -4897,7 +4897,7 @@ static void sched_core_balance(struct rq *rq)
> > struct sched_domain *sd;
> > int cpu = cpu_of(rq);
> >
> > - rcu_read_lock();
> > + rcu_read_lock_sched();
> > raw_spin_unlock_irq(rq_lockp(rq));
> > for_each_domain(cpu, sd) {
> > if (!(sd->flags & SD_LOAD_BALANCE))
> > @@ -4910,7 +4910,7 @@ static void sched_core_balance(struct rq *rq)
> > break;
> > }
> > raw_spin_lock_irq(rq_lockp(rq));
> > - rcu_read_unlock();
> > + rcu_read_unlock_sched();
> > }
> >
> > static DEFINE_PER_CPU(struct callback_head, core_balance_head);
> > --
> > 2.26.2.761.g0e0b3e54be-goog
> >
next prev parent reply other threads:[~2020-05-22 1:26 UTC|newest]
Thread overview: 110+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-04 16:59 [RFC PATCH 00/13] Core scheduling v5 vpillai
2020-03-04 16:59 ` [RFC PATCH 01/13] sched: Wrap rq::lock access vpillai
2020-03-04 16:59 ` [RFC PATCH 02/13] sched: Introduce sched_class::pick_task() vpillai
2020-03-04 16:59 ` [RFC PATCH 03/13] sched: Core-wide rq->lock vpillai
2020-04-01 11:42 ` [PATCH] sched/arm64: store cpu topology before notify_cpu_starting Cheng Jian
2020-04-01 13:23 ` Valentin Schneider
2020-04-06 8:00 ` chengjian (D)
2020-04-09 9:59 ` Sudeep Holla
2020-04-09 10:32 ` Valentin Schneider
2020-04-09 11:08 ` Sudeep Holla
2020-04-09 17:54 ` Joel Fernandes
2020-04-10 13:49 ` chengjian (D)
2020-04-14 11:36 ` [RFC PATCH 03/13] sched: Core-wide rq->lock Peter Zijlstra
2020-04-14 21:35 ` Vineeth Remanan Pillai
2020-04-15 10:55 ` Peter Zijlstra
2020-04-14 14:32 ` Peter Zijlstra
2020-03-04 16:59 ` [RFC PATCH 04/13] sched/fair: Add a few assertions vpillai
2020-03-04 16:59 ` [RFC PATCH 05/13] sched: Basic tracking of matching tasks vpillai
2020-03-04 16:59 ` [RFC PATCH 06/13] sched: Update core scheduler queue when taking cpu online/offline vpillai
2020-03-04 16:59 ` [RFC PATCH 07/13] sched: Add core wide task selection and scheduling vpillai
2020-04-14 13:35 ` Peter Zijlstra
2020-04-16 23:32 ` Tim Chen
2020-04-17 10:57 ` Peter Zijlstra
2020-04-16 3:39 ` Chen Yu
2020-04-16 19:59 ` Vineeth Remanan Pillai
2020-04-17 11:18 ` Peter Zijlstra
2020-04-19 15:31 ` Chen Yu
2020-05-21 23:14 ` Joel Fernandes
2020-05-21 23:16 ` Joel Fernandes
2020-05-22 2:35 ` Joel Fernandes
2020-05-22 3:44 ` Aaron Lu
2020-05-22 20:13 ` Joel Fernandes
2020-03-04 16:59 ` [RFC PATCH 08/13] sched/fair: wrapper for cfs_rq->min_vruntime vpillai
2020-03-04 16:59 ` [RFC PATCH 09/13] sched/fair: core wide vruntime comparison vpillai
2020-04-14 13:56 ` Peter Zijlstra
2020-04-15 3:34 ` Aaron Lu
2020-04-15 4:07 ` Aaron Lu
2020-04-15 21:24 ` Vineeth Remanan Pillai
2020-04-17 9:40 ` Aaron Lu
2020-04-20 8:07 ` [PATCH updated] sched/fair: core wide cfs task priority comparison Aaron Lu
2020-04-20 22:26 ` Vineeth Remanan Pillai
2020-04-21 2:51 ` Aaron Lu
2020-04-24 14:24 ` [PATCH updated v2] " Aaron Lu
2020-05-06 14:35 ` Peter Zijlstra
2020-05-08 8:44 ` Aaron Lu
2020-05-08 9:09 ` Peter Zijlstra
2020-05-08 12:34 ` Aaron Lu
2020-05-14 13:02 ` Peter Zijlstra
2020-05-14 22:51 ` Vineeth Remanan Pillai
2020-05-15 10:38 ` Peter Zijlstra
2020-05-15 10:43 ` Peter Zijlstra
2020-05-15 14:24 ` Vineeth Remanan Pillai
2020-05-16 3:42 ` Aaron Lu
2020-05-22 9:40 ` Aaron Lu
2020-06-08 1:41 ` Ning, Hongyu
2020-03-04 17:00 ` [RFC PATCH 10/13] sched: Trivial forced-newidle balancer vpillai
2020-03-04 17:00 ` [RFC PATCH 11/13] sched: migration changes for core scheduling vpillai
2020-06-12 13:21 ` Joel Fernandes
2020-06-12 21:32 ` Vineeth Remanan Pillai
2020-06-13 2:25 ` Joel Fernandes
2020-06-13 18:59 ` Vineeth Remanan Pillai
2020-06-15 2:05 ` Li, Aubrey
2020-03-04 17:00 ` [RFC PATCH 12/13] sched: cgroup tagging interface " vpillai
2020-06-26 15:06 ` Vineeth Remanan Pillai
2020-03-04 17:00 ` [RFC PATCH 13/13] sched: Debug bits vpillai
2020-03-04 17:36 ` [RFC PATCH 00/13] Core scheduling v5 Tim Chen
2020-03-04 17:42 ` Vineeth Remanan Pillai
2020-04-14 14:21 ` Peter Zijlstra
2020-04-15 16:32 ` Joel Fernandes
2020-04-17 11:12 ` Peter Zijlstra
2020-04-17 12:35 ` Alexander Graf
2020-04-17 13:08 ` Peter Zijlstra
2020-04-18 2:25 ` Joel Fernandes
2020-05-09 14:35 ` Dario Faggioli
[not found] ` <38805656-2e2f-222a-c083-692f4b113313@linux.intel.com>
2020-05-09 3:39 ` Ning, Hongyu
2020-05-14 20:51 ` FW: " Gruza, Agata
2020-05-10 23:46 ` [PATCH RFC] Add support for core-wide protection of IRQ and softirq Joel Fernandes (Google)
2020-05-11 13:49 ` Peter Zijlstra
2020-05-11 14:54 ` Joel Fernandes
2020-05-20 22:26 ` [PATCH RFC] sched: Add a per-thread core scheduling interface Joel Fernandes (Google)
2020-05-21 4:09 ` [PATCH RFC] sched: Add a per-thread core scheduling interface(Internet mail) benbjiang(蒋彪)
2020-05-21 13:49 ` Joel Fernandes
2020-05-21 8:51 ` [PATCH RFC] sched: Add a per-thread core scheduling interface Peter Zijlstra
2020-05-21 13:47 ` Joel Fernandes
2020-05-21 20:20 ` Vineeth Remanan Pillai
2020-05-22 12:59 ` Peter Zijlstra
2020-05-22 21:35 ` Joel Fernandes
2020-05-24 14:00 ` Phil Auld
2020-05-28 14:51 ` Joel Fernandes
2020-05-28 17:01 ` Peter Zijlstra
2020-05-28 18:17 ` Phil Auld
2020-05-28 18:34 ` Phil Auld
2020-05-28 18:23 ` Joel Fernandes
2020-05-21 18:31 ` Linus Torvalds
2020-05-21 20:40 ` Joel Fernandes
2020-05-21 21:58 ` Jesse Barnes
2020-05-22 16:33 ` Linus Torvalds
2020-05-20 22:37 ` [PATCH RFC v2] Add support for core-wide protection of IRQ and softirq Joel Fernandes (Google)
2020-05-20 22:48 ` [PATCH RFC] sched: Use sched-RCU in core-scheduling balancing logic Joel Fernandes (Google)
2020-05-21 22:52 ` Paul E. McKenney
2020-05-22 1:26 ` Joel Fernandes [this message]
2020-06-25 20:12 ` [RFC PATCH 00/13] Core scheduling v5 Vineeth Remanan Pillai
2020-06-26 1:47 ` Joel Fernandes
2020-06-26 14:36 ` Vineeth Remanan Pillai
2020-06-26 15:10 ` Joel Fernandes
2020-06-26 15:12 ` Joel Fernandes
2020-06-27 16:21 ` Joel Fernandes
2020-06-30 14:11 ` Phil Auld
2020-06-29 12:33 ` Li, Aubrey
2020-06-29 19:41 ` Vineeth Remanan Pillai
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