From: Peter Zijlstra <peterz@infradead.org>
To: paulmck@linux.vnet.ibm.com
Cc: linux-kernel@vger.kernel.org, mingo@elte.hu,
laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca,
josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de,
rostedt@goodmis.org, Valdis.Kletnieks@vt.edu,
dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com,
fweisbec@gmail.com, patches@linaro.org
Subject: Re: [PATCH RFC tip/core/rcu 6/6] rcu: Reduce cache-miss initialization latencies for large systems
Date: Fri, 27 Apr 2012 00:04:05 +0200 [thread overview]
Message-ID: <1335477845.2463.131.camel@laptop> (raw)
In-Reply-To: <20120426202940.GL2407@linux.vnet.ibm.com>
On Thu, 2012-04-26 at 13:29 -0700, Paul E. McKenney wrote:
> On Thu, Apr 26, 2012 at 09:47:44PM +0200, Peter Zijlstra wrote:
> > On Thu, 2012-04-26 at 21:41 +0200, Peter Zijlstra wrote:
> > >
> > > I can very easily give you the size (nr cpus in) a node, still as long
> > > as you iterate the cpu space linearly that's not going to be much
> > > help.
> > >
> > Oh, I forgot, the numa masks etc are available, depending on
> > CONFIG_NUMA, as cpumask_of_node(n).
>
> These change with each CPU-hotplug operation? Or is a given CPU
> hotplug operation guaranteed to change only those node masks that
> the CPU was (or will be, in the case of online) a member?
I'd have to check, but its either the last or they don't change at all
and you have to mask out the offline cpus yourself.
NUMA topology doesn't actually change due to hotplug, so there's no
reason to update masks that do not (or should not) contain the cpu under
operation.
next prev parent reply other threads:[~2012-04-26 22:04 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-23 16:41 [PATCH RFC 0/6] Miscellaneous RCU fixes for 3.5 Paul E. McKenney
2012-04-23 16:42 ` [PATCH RFC tip/core/rcu 1/6] rcu: Stabilize use of num_online_cpus() for GP short circuit Paul E. McKenney
2012-04-23 16:42 ` [PATCH RFC tip/core/rcu 2/6] rcu: List-debug variants of rcu list routines Paul E. McKenney
2012-04-23 16:42 ` [PATCH RFC tip/core/rcu 3/6] rcu: Replace list_first_entry_rcu() with list_first_or_null_rcu() Paul E. McKenney
2012-04-23 16:42 ` [PATCH RFC tip/core/rcu 4/6] rcu: Clarify help text for RCU_BOOST_PRIO Paul E. McKenney
2012-04-26 12:46 ` Peter Zijlstra
2012-04-26 17:28 ` Paul E. McKenney
2012-04-23 16:42 ` [PATCH RFC tip/core/rcu 5/6] rcu: Make __kfree_rcu() less dependent on compiler choices Paul E. McKenney
2012-04-26 12:48 ` Peter Zijlstra
2012-04-26 13:29 ` Jan Engelhardt
2012-04-26 13:50 ` Peter Zijlstra
2012-04-23 16:42 ` [PATCH RFC tip/core/rcu 6/6] rcu: Reduce cache-miss initialization latencies for large systems Paul E. McKenney
2012-04-26 12:51 ` Peter Zijlstra
2012-04-26 14:12 ` Paul E. McKenney
2012-04-26 15:28 ` Peter Zijlstra
2012-04-26 16:15 ` Paul E. McKenney
2012-04-26 19:41 ` Peter Zijlstra
2012-04-26 19:47 ` Peter Zijlstra
2012-04-26 20:29 ` Paul E. McKenney
2012-04-26 22:04 ` Peter Zijlstra [this message]
2012-04-26 20:28 ` Paul E. McKenney
2012-04-26 22:01 ` Peter Zijlstra
2012-04-27 14:17 ` Paul E. McKenney
2012-04-27 4:36 ` Mike Galbraith
2012-04-27 15:15 ` Paul E. McKenney
2012-04-28 4:42 ` Mike Galbraith
2012-04-28 17:21 ` Paul E. McKenney
2012-04-29 3:54 ` Mike Galbraith
2012-04-24 15:35 ` [PATCH RFC tip/core/rcu 1/6] rcu: Stabilize use of num_online_cpus() for GP short circuit Srivatsa S. Bhat
2012-04-24 16:50 ` Paul E. McKenney
2012-04-24 17:46 ` Srivatsa S. Bhat
2012-05-07 3:47 ` Rusty Russell
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