From: Peter Zijlstra <peterz@infradead.org>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Oleg Nesterov <oleg@redhat.com>,
Balbir Singh <bsingharora@gmail.com>,
LKML <linux-kernel@vger.kernel.org>,
Nicholas Piggin <nicholas.piggin@gmail.com>
Subject: Re: [RFC][PATCH] Fix a race between rwsem and the scheduler
Date: Thu, 1 Sep 2016 08:57:38 +0200 [thread overview]
Message-ID: <20160901065738.GH10153@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1472680030.2388.95.camel@kernel.crashing.org>
On Thu, Sep 01, 2016 at 07:47:10AM +1000, Benjamin Herrenschmidt wrote:
> > OK, for giggles, could you (or Balbir) check what happens if you take
> > that sync out?
> The problem is no amount of testing can tell you it works for sure :-)
It breaking does prove the negative though, so still interesting.
> I would be nervous not having a real full sync in _switch. All we have
> along the scheduler path is lwsync's and our isync based load construct
> for spin_lock, I'm not sure what other assumptions we have around that
> sync in there...
Only one way to find out ;-)
I'm not saying you should commit that change, just curious if (and how
fast) it would come apart.
At the very least we could update the comment that goes with that sync.
next prev parent reply other threads:[~2016-09-01 6:57 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-30 8:49 [RFC][PATCH] Fix a race between rwsem and the scheduler Balbir Singh
2016-08-30 9:13 ` Nicholas Piggin
2016-08-30 12:19 ` Peter Zijlstra
2016-08-30 13:04 ` Oleg Nesterov
2016-08-30 14:13 ` Peter Zijlstra
2016-08-30 16:57 ` Oleg Nesterov
2016-08-30 18:34 ` Peter Zijlstra
2016-08-30 21:28 ` Benjamin Herrenschmidt
2016-08-31 7:18 ` Peter Zijlstra
2016-08-31 10:56 ` Benjamin Herrenschmidt
2016-08-31 13:31 ` Peter Zijlstra
2016-08-31 21:47 ` Benjamin Herrenschmidt
2016-09-01 6:49 ` Balbir Singh
2016-09-01 6:57 ` Peter Zijlstra [this message]
2016-09-01 14:17 ` Boqun Feng
2016-09-01 15:33 ` Peter Zijlstra
2016-08-30 21:25 ` Benjamin Herrenschmidt
2016-08-31 7:20 ` Peter Zijlstra
2016-08-31 10:55 ` Benjamin Herrenschmidt
2016-08-31 3:41 ` Balbir Singh
2016-08-31 7:28 ` Peter Zijlstra
2016-08-31 10:17 ` Balbir Singh
2016-08-31 10:57 ` Benjamin Herrenschmidt
2016-09-01 1:48 ` Alexey Kardashevskiy
2016-09-01 12:16 ` Alexey Kardashevskiy
2016-08-30 12:58 ` Oleg Nesterov
2016-08-31 3:25 ` Balbir Singh
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