From: Benjamin LaHaise <bcrl@kvack.org>
To: Andi Kleen <ak@suse.de>
Cc: dipankar@in.ibm.com, Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org
Subject: Re: [PATCH/RFC] synchronize_rcu(): high latency on idle system
Date: Sat, 12 Jan 2008 12:51:35 -0500 [thread overview]
Message-ID: <20080112175135.GK28570@kvack.org> (raw)
In-Reply-To: <20080112023759.GG21068@bingen.suse.de>
On Sat, Jan 12, 2008 at 03:37:59AM +0100, Andi Kleen wrote:
> > And yes, the
> > network stack shouldn't call synchronize_rcu() quite so much, but fixing that
> > is a little more involved.
>
> ... but the correct solution.
There has to be at least 1 synchronize_rcu() or equivalent in the
unregister_netdev() path. I suspect the easiest way to fix it might be to
use call_rcu() to actually free the network device, as anything else will
limit performance of single threaded teardown (ie, when an l2tp daemon
gets terminated via kill -9). This means an API change that exposes
rcu for unregister_netdev().
-ben
--
"Time is of no importance, Mr. President, only life is important."
Don't Email: <zyntrop@kvack.org>.
next prev parent reply other threads:[~2008-01-12 17:51 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-12 1:26 [PATCH/RFC] synchronize_rcu(): high latency on idle system Benjamin LaHaise
2008-01-12 2:37 ` Andi Kleen
2008-01-12 17:51 ` Benjamin LaHaise [this message]
2008-01-12 18:35 ` Andi Kleen
2008-01-12 9:23 ` Peter Zijlstra
2008-01-12 16:55 ` Paul E. McKenney
2008-01-12 17:33 ` Andi Kleen
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