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From: Gautham R Shenoy <ego@in.ibm.com>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org,
	mingo@elte.hu, akpm@linux-foundation.org, dipankar@in.ibm.com,
	josht@linux.vnet.ibm.com, tytso@us.ibm.com, dvhltc@us.ibm.com,
	tglx@linutronix.de
Subject: Re: [PATCH RFC] Priority boosting for preemptible RCU
Date: Fri, 24 Aug 2007 13:51:21 +0530	[thread overview]
Message-ID: <20070824082121.GA16301@in.ibm.com> (raw)
In-Reply-To: <20070823155526.GB8371@linux.vnet.ibm.com>

On Thu, Aug 23, 2007 at 08:55:26AM -0700, Paul E. McKenney wrote:
> > Even if we use another cpumask_t, whenever a cpu goes down or comes up,
> > that will be reflected in this map, no? So what's the additional
> > advantage of using it?
> 
> The additional map allows the code to use something other than the
> lock_cpu_hotplug/unlock_cpu_hotplug, and also is robust against any
> changes to the hotplug synchronization mechanism.  Might well be
> better just to use the current hotplug synchronization mechanism,
> but I was feeling paranoid.  ;-)

If it was doing something more complicated in the critical section other
than summing stuff up, I would probably recommend going for another map
instead of using the current hotplug synchronization. But for this case
the current hotplug synchronization would work just fine.

I can very well understand your paranoia, but let me assure you, you are
not the only one ;-)

Regards
gautham.
> 
> 						Thanx, Paul

-- 
Gautham R Shenoy
Linux Technology Center
IBM India.
"Freedom comes with a price tag of responsibility, which is still a bargain,
because Freedom is priceless!"

  reply	other threads:[~2007-08-24  8:21 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-08-22 19:02 [PATCH RFC] Priority boosting for preemptible RCU Paul E. McKenney
2007-08-22 19:43 ` Andrew Morton
2007-08-22 20:23   ` Josh Triplett
2007-08-22 21:22   ` Paul E. McKenney
2007-08-22 21:41     ` Andrew Morton
2007-08-22 22:00       ` Paul E. McKenney
2007-08-24 10:09   ` Andy Whitcroft
2007-08-23  4:26 ` Gautham R Shenoy
2007-08-23  8:54   ` Paul E. McKenney
2007-08-23 10:14     ` Gautham R Shenoy
2007-08-23 13:15       ` Paul E. McKenney
2007-08-23 14:22         ` Gautham R Shenoy
2007-08-23 15:55           ` Paul E. McKenney
2007-08-24  8:21             ` Gautham R Shenoy [this message]
2007-08-24 17:27               ` Paul E. McKenney

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