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Date: Tue, 17 Mar 2015 05:01:10 -0700
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
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        Thomas Gleixner <tglx@linutronix.de>,
        David Howells <dhowells@redhat.com>, Nick Piggin <npiggin@kernel.dk>
Subject: Re: [RFC PATCH] sys_membarrier(): system/process-wide memory barrier
 (x86) (v12)
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On Tue, Mar 17, 2015 at 04:56:08AM -0700, Paul E. McKenney wrote:
> On Tue, Mar 17, 2015 at 07:30:59AM +0100, Peter Zijlstra wrote:
> > On Tue, Mar 17, 2015 at 01:45:25AM +0000, Mathieu Desnoyers wrote:
> 
> [ . . . ]
> 
> > > Then we can add
> > > the expedited-private implementation after rq->curr becomes
> > > available through RCU.
> > 
> > Yeah, or not at all; I'm still trying to get Paul to remove the
> > expedited nonsense from the kernel RCU bits; and now you want it in
> > userspace too :/
> 
> Well, the expedited RCU primitives got added for some use cases, and
> those use cases are still with us.  ;-)

And, as I was meaning to say -before- I hit send...  I still have some
changes in mind to make the expedited RCU primitives at least somewhat
more friendly, for example, moving from try_stop_cpus() to something
like on_each_cpu_mask().

							Thanx, Paul