From: Oleg Nesterov <oleg@redhat.com>
To: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>, Tejun Heo <tj@kernel.org>,
Ingo Molnar <mingo@redhat.com>,
lkml <linux-kernel@vger.kernel.org>,
Dmitry Shmidt <dimitrysh@google.com>,
Rom Lemarchand <romlem@google.com>,
Colin Cross <ccross@google.com>, Todd Kjos <tkjos@google.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: Re: Severe performance regression w/ 4.4+ on Android due to cgroup locking changes
Date: Thu, 14 Jul 2016 19:13:12 +0200 [thread overview]
Message-ID: <20160714171311.GB13434@redhat.com> (raw)
In-Reply-To: <CALAqxLWRNd=9gaVWUeH=u5iMVdGPmP_gZMwNf2Tk9BKn9BL1VA@mail.gmail.com>
On 07/14, John Stultz wrote:
>
> So I am seeing synchronize_sched called, and its taking the
> !rcu_gp_is_expedited path when I see the particularly bad latencies.
>
> I wonder if I just mucked up applying the patch?
Probably yes...
Just in case, could you try the patch below? Of course, without other
optimizations from Peter, this change makes cgroup_threadgroup_rwsem
much worse than a plain rw_semaphore.
Oleg.
--- x/kernel/cgroup.c
+++ x/kernel/cgroup.c
@@ -5605,6 +5605,8 @@ int __init cgroup_init(void)
BUG_ON(cgroup_init_cftypes(NULL, cgroup_dfl_base_files));
BUG_ON(cgroup_init_cftypes(NULL, cgroup_legacy_base_files));
+ rcu_sync_enter(&cgroup_threadgroup_rwsem.rss);
+
get_user_ns(init_cgroup_ns.user_ns);
mutex_lock(&cgroup_mutex);
next prev parent reply other threads:[~2016-07-14 17:12 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-13 0:00 Severe performance regression w/ 4.4+ on Android due to cgroup locking changes John Stultz
2016-07-13 8:21 ` Peter Zijlstra
2016-07-13 14:42 ` Paul E. McKenney
2016-07-13 18:13 ` Dmitry Shmidt
2016-07-13 18:32 ` Paul E. McKenney
2016-07-13 18:21 ` Tejun Heo
2016-07-13 18:33 ` Tejun Heo
2016-07-13 20:13 ` John Stultz
2016-07-13 20:18 ` Tejun Heo
2016-07-13 20:26 ` Peter Zijlstra
2016-07-13 20:39 ` Tejun Heo
2016-07-13 20:51 ` Peter Zijlstra
2016-07-13 21:01 ` Tejun Heo
2016-07-13 21:03 ` Paul E. McKenney
2016-07-13 21:05 ` Tejun Heo
2016-07-13 21:18 ` Paul E. McKenney
2016-07-13 21:42 ` Paul E. McKenney
2016-07-13 21:46 ` John Stultz
2016-07-13 22:17 ` Paul E. McKenney
2016-07-13 22:39 ` John Stultz
2016-07-13 23:02 ` Paul E. McKenney
2016-07-13 23:04 ` Paul E. McKenney
2016-07-14 11:35 ` Tejun Heo
2016-07-14 12:04 ` Peter Zijlstra
2016-07-14 12:08 ` Tejun Heo
2016-07-14 12:20 ` Peter Zijlstra
2016-07-14 15:07 ` Tejun Heo
2016-07-14 15:24 ` Tejun Heo
2016-07-14 16:32 ` Peter Zijlstra
2016-07-14 17:34 ` Oleg Nesterov
2016-07-14 16:54 ` John Stultz
2016-07-13 22:25 ` John Stultz
2016-07-13 22:01 ` Tejun Heo
2016-07-13 22:33 ` Paul E. McKenney
2016-07-14 6:49 ` Peter Zijlstra
2016-07-14 11:20 ` Tejun Heo
2016-07-14 12:11 ` Peter Zijlstra
2016-07-14 15:14 ` Tejun Heo
2016-07-14 13:18 ` Peter Zijlstra
2016-07-14 14:14 ` Peter Zijlstra
2016-07-14 14:58 ` Oleg Nesterov
2016-07-14 16:14 ` Peter Zijlstra
2016-07-14 16:37 ` Peter Zijlstra
2016-07-14 17:05 ` Oleg Nesterov
2016-07-14 16:23 ` Paul E. McKenney
2016-07-14 16:45 ` Peter Zijlstra
2016-07-14 17:15 ` Paul E. McKenney
2016-07-14 16:43 ` John Stultz
2016-07-14 16:49 ` Peter Zijlstra
2016-07-14 17:02 ` John Stultz
2016-07-14 17:13 ` Oleg Nesterov [this message]
2016-07-14 17:30 ` John Stultz
2016-07-14 17:41 ` Oleg Nesterov
2016-07-14 17:51 ` John Stultz
2016-07-14 18:09 ` Oleg Nesterov
2016-07-14 18:36 ` Peter Zijlstra
2016-07-14 19:35 ` Peter Zijlstra
2016-07-13 20:57 ` John Stultz
2016-07-13 20:52 ` Paul E. McKenney
2016-07-13 20:57 ` Peter Zijlstra
2016-07-13 21:08 ` Paul E. McKenney
2016-07-13 21:01 ` Dmitry Shmidt
2016-07-13 21:03 ` John Stultz
2016-07-13 21:05 ` Paul E. McKenney
2016-07-13 20:31 ` Dmitry Shmidt
2016-07-13 20:44 ` Colin Cross
2016-07-13 20:54 ` Tejun Heo
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