Date: Fri, 22 Sep 2017 11:33:29 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Andy Lutomirski <luto@kernel.org>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Will Deacon <will.deacon@arm.com>,
        Alan Stern <stern@rowland.harvard.edu>,
        Michael Ellerman <mpe@ellerman.id.au>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        linux-arch <linux-arch@vger.kernel.org>,
        Dave Watson <davejwatson@fb.com>,
        maged michael <maged.michael@gmail.com>
Subject: Re: Rough notes from sys_membarrier() lightning BoF
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On Thu, Sep 21, 2017 at 10:23:39AM -0700, James Bottomley wrote:

> ?We have one system that locks up if
> multiple CPUs have outstanding coherency operations on the private bus,
> but that's only one annoying CPU (which we manage with a special lock
> inside the PA-RISC mmu code).

Hehe, yeah. I saw that code recently and had a WTF moment ;-)