From: Sebastien Dugue <sebastien.dugue@bull.net>
To: benh@kernel.crashing.org
Cc: Peter Zijlstra <peterz@infradead.org>,
Nick Piggin <nickpiggin@yahoo.com.au>,
Linux-rt <linux-rt-users@vger.kernel.org>,
linux-ppc <linuxppc-dev@ozlabs.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <michael@ellerman.id.au>,
Tim Chavez <tinytim@us.ibm.com>,
Jean Pierre Dion <jean-pierre.dion@bull.net>,
Gilles Carry <Gilles.Carry@ext.bull.net>
Subject: Re: [PATCH 2/2][RT] powerpc - Make the irq reverse mapping radix tree lockless
Date: Fri, 25 Jul 2008 10:47:30 +0200 [thread overview]
Message-ID: <20080725104730.2211e057@bull.net> (raw)
In-Reply-To: <1216975221.11188.102.camel@pasglop>
On Fri, 25 Jul 2008 18:40:21 +1000 Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:
> On Fri, 2008-07-25 at 10:36 +0200, Sebastien Dugue wrote:
> > On Fri, 25 Jul 2008 18:27:20 +1000 Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:
> >
> > > On Fri, 2008-07-25 at 09:49 +0200, Peter Zijlstra wrote:
> > > >
> > > >
> > > > The only advantage of the concurrent radix tree over this model is that
> > > > it can potentially do multiple modification operations at the same time.
> > >
> > > Yup, we do not need that for the irq revmap... concurrent lookup is all we need.
> > >
> >
> > Shouldn't we care about concurrent insertion and deletion in the tree? I agree
> > that concern might be a bit artificial but in theory that can happen.
>
> Yes, we just need to protect it with a big hammer, like a spinlock, it's
> not a performance critical code path.
Agreed. Will look into this in the next few days.
Thanks,
Sebastien.
next prev parent reply other threads:[~2008-07-25 8:47 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-24 10:23 [PATCH 0/2][RT] powerpc - fix bug in irq reverse mapping radix tree (Resend) Sebastien Dugue
2008-07-24 10:48 ` [PATCH 1/2][RT] powerpc - XICS: move the call to irq_radix_revmap from xics_startup to xics_host_map Sebastien Dugue
2008-07-24 10:50 ` [PATCH 2/2][RT] powerpc - Make the irq reverse mapping radix tree lockless Sebastien Dugue
2008-07-24 11:11 ` Nick Piggin
2008-07-24 12:18 ` Sebastien Dugue
2008-07-25 7:49 ` Peter Zijlstra
2008-07-25 8:27 ` Benjamin Herrenschmidt
2008-07-25 8:36 ` Sebastien Dugue
2008-07-25 8:40 ` Benjamin Herrenschmidt
2008-07-25 8:47 ` Sebastien Dugue [this message]
2008-07-25 8:34 ` Sebastien Dugue
2008-07-25 5:13 ` Benjamin Herrenschmidt
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