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Date: Tue, 15 Nov 2016 15:55:36 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
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Subject: Re: [PATCH RFC tip/core/rcu] SRCU rewrite
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On Tue, Nov 15, 2016 at 06:26:27AM -0800, Paul E. McKenney wrote:
> On Tue, Nov 15, 2016 at 02:59:12PM +0100, Peter Zijlstra wrote:

> > The smp_mb()s in read_{un,}lock() and the lock in call_srcu() come to
> > mind.
> 
> There is some possibility of weakening the srcu_read_unlock() ordering,
> but one step at a time.
> 
> Has the lock in call_srcu() been causing trouble?  Easy to fix if so,
> but as you noted in another email today, we don't need complexity for
> complexity's sake.  And no reports of problems with this have reached
> me thus far.

It was a cause for concern in the optimistic fault series, but since
that never got sorted, it hasn't shown up in practise afaik.