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Date: Thu, 3 Oct 2013 11:46:07 -0700
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>, Mel Gorman <mgorman@suse.de>,
        Rik van Riel <riel@redhat.com>,
        Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
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        Johannes Weiner <hannes@cmpxchg.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Steven Rostedt <rostedt@goodmis.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] hotplug: Optimize cpu_hotplug_{begin,done}() using
 rcu_sync
Message-ID: <20131003184607.GQ5790@linux.vnet.ibm.com>
Reply-To: paulmck@linux.vnet.ibm.com
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On Thu, Oct 03, 2013 at 08:41:51PM +0200, Peter Zijlstra wrote:
> On Thu, Oct 03, 2013 at 09:48:38AM -0700, Paul E. McKenney wrote:
> > > -enum { readers_fast = 0, readers_slow, readers_block };
> > > +enum { readers_slow, readers_block };
> > 
> > It took me a bit to realize that readers_fast is obsoleted by the
> > rcu_sync_is_idle() above.  ;-)
> 
> Yeah.. I pondered changing/adding to the rcu_sync interface to allow
> using gp_count like status to avoid the extra variable, but decided
> against it for now.

Should be OK as is -- people who haven't reviewed the old version with
readers_fast are unlikely to be confused by the current setup.

							Thanx, Paul