From: Andi Kleen <andi@firstfloor.org>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Christoph Lameter <cl@linux-foundation.org>,
Pekka Enberg <penberg@cs.helsinki.fi>,
Ingo Molnar <mingo@elte.hu>,
Jeremy Fitzhardinge <jeremy@goop.org>,
Nick Piggin <nickpiggin@yahoo.com.au>,
Andi Kleen <andi@firstfloor.org>,
"Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>,
Suresh Siddha <suresh.b.siddha@intel.com>,
Jens Axboe <jens.axboe@oracle.com>,
Rusty Russell <rusty@rustcorp.com.au>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] smp_call_function: use rwlocks on queues rather than rcu
Date: Fri, 22 Aug 2008 20:33:46 +0200 [thread overview]
Message-ID: <20080822183346.GS23334@one.firstfloor.org> (raw)
In-Reply-To: <20080822182915.GG6744@linux.vnet.ibm.com>
> Would it make sense to push the freed-by-RCU memory further up the
> hierarchy, so that such memory is not mistaken for recently freed
> hot-in-cache memory?
Right now my impression is that it is not well understood why
the kmalloc makes the IPI that much slower. In theory a kmalloc
shouldn't be all that slow, it's essentially just a
"disable interrupts; unlink object from cpu cache; enable interrupts"
with some window dressing. kfree() is similar.
Does it bounce a cache line on freeing perhaps?
-Andi
next prev parent reply other threads:[~2008-08-22 18:31 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-22 0:29 [PATCH 2/2] smp_call_function: use rwlocks on queues rather than rcu Jeremy Fitzhardinge
2008-08-22 1:53 ` Nick Piggin
2008-08-22 6:28 ` Ingo Molnar
2008-08-22 7:06 ` Pekka Enberg
2008-08-22 7:12 ` Ingo Molnar
2008-08-22 9:12 ` Nick Piggin
2008-08-22 14:01 ` Christoph Lameter
2008-08-22 15:11 ` Paul E. McKenney
2008-08-22 17:14 ` Christoph Lameter
2008-08-22 18:29 ` Paul E. McKenney
2008-08-22 18:33 ` Andi Kleen [this message]
2008-08-22 18:35 ` Jeremy Fitzhardinge
2008-08-23 7:34 ` Andi Kleen
2008-08-24 4:55 ` Jeremy Fitzhardinge
2008-08-24 9:01 ` Andi Kleen
2008-08-22 22:40 ` Paul E. McKenney
2008-08-22 18:36 ` Christoph Lameter
2008-08-22 19:52 ` Paul E. McKenney
2008-08-22 20:03 ` Christoph Lameter
2008-08-22 20:53 ` Paul E. McKenney
2008-08-25 10:31 ` Peter Zijlstra
2008-08-25 15:12 ` Paul E. McKenney
2008-08-25 15:22 ` Peter Zijlstra
2008-08-25 15:46 ` Christoph Lameter
2008-08-25 15:51 ` Peter Zijlstra
2008-08-26 13:43 ` Paul E. McKenney
2008-08-26 14:07 ` Peter Zijlstra
2008-08-27 15:16 ` Paul E. McKenney
2008-08-25 20:04 ` Paul E. McKenney
2008-08-26 5:13 ` Nick Piggin
2008-08-26 13:40 ` [PATCH 2/2] smp_call_function: use rwlocks on queues rather?than rcu Paul E. McKenney
2008-08-25 15:44 ` [PATCH 2/2] smp_call_function: use rwlocks on queues rather than rcu Christoph Lameter
2008-08-25 20:05 ` Paul E. McKenney
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