From: Peter Zijlstra <peterz@infradead.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>, John Stultz <john.stultz@linaro.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 18:37:31 +0200 [thread overview]
Message-ID: <20160714163731.GF30154@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20160714145844.GA7760@redhat.com>
On Thu, Jul 14, 2016 at 04:58:44PM +0200, Oleg Nesterov wrote:
>
> But note that we do not need RCU_NONE. All we need is the trivial change
> below.
Hurm, maybe. So having that unbalanced keeps us in GP_PASSED state and
since we'll never drop gp_count back to 0 nothing will ever happen.
Cute, yes.
> Damn, I am trying to find my old rcu-sync patches which I didn't
> send, but can't... OK, this almost off-topic right now, just this "enter"
> is ugly and we can't switch the slow/fast modes dynamically.
>
> The rest of you patch is "optimize the slow path" and we already discussed
> it before, I personally like it. Perhaps you can redo it without RCU_NONE
> part?
Indeed, I rebased that patch on top of the current tree and had to add
support for down_trylock() but otherwise much the same thing.
I can send it out again.
next prev parent reply other threads:[~2016-07-14 16:37 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 [this message]
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
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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