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Date: Tue, 7 Jun 2016 01:58:37 +0100
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>, "Chen, Tim C" <tim.c.chen@intel.com>,
        Ingo Molnar <mingo@redhat.com>, Davidlohr Bueso <dbueso@suse.de>,
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        Jason Low <jason.low2@hp.com>, Michel Lespinasse <walken@google.com>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Waiman Long <waiman.long@hp.com>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: performance delta after VFS i_mutex=>i_rwsem conversion
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On Tue, Jun 07, 2016 at 01:40:58AM +0100, Al Viro wrote:

> as initial attempt at lockless next_positive(); barriers are probably wrong,
> though...

More than just barriers...  _Absolutely_ untested variant pushed into
vfs.git#untested.dcache_readdir (the last 3 commits in there).  It
compiles, but that's it.