From: Andi Kleen <ak@suse.de>
To: Eric Dumazet <dada1@cosmosbay.com>
Cc: Andrew Morton <akpm@osdl.org>, Mikael Starvik <starvik@axis.com>,
David Howells <dhowells@redhat.com>,
Kyle McMartin <kyle@parisc-linux.org>,
Anton Blanchard <anton@samba.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Paul Mundt <lethal@linux-sh.org>,
"David S. Miller" <davem@davemloft.net>,
William Lee Irwin III <wli@holomorphy.com>,
Andi Kleen <ak@muc.de>, Christian Zankel <chris@zankel.net>,
Philippe Elie <phil.el@wanadoo.fr>,
Nathan Scott <nathans@sgi.com>, Jens Axboe <axboe@suse.de>,
linux-arch@vger.kernel.org
Subject: Re: percpu data changes
Date: Fri, 3 Feb 2006 12:07:13 +0100 [thread overview]
Message-ID: <200602031207.14816.ak@suse.de> (raw)
In-Reply-To: <43E33802.6090502@cosmosbay.com>
On Friday 03 February 2006 12:01, Eric Dumazet wrote:
> Andi Kleen a écrit :
> > On Friday 03 February 2006 10:17, Andrew Morton wrote:
> >> It seems that powerpc has gone and changed their implementation of percpu
> >> data so that there is no memory allocated for not-possible CPUs. To save a
> >> bit of RAM.
> >>
> >> This means that any code which does
> >>
> >> for (i = 0; i < NR_CPUS; i++)
> >> touch(percpudata(i))
> >>
> >> will explode on powerpc.
> >
> > It also explodes since some time on x86-64.
> >
> > But I added a workaround now (or rather sent one and Linus dropped it)
> > to point the not possible CPUs to the reference data and not free it.
> > With that violating that protocol is mostly harmless.
> >
> > Later the plan was to point it to unmapped data to catch all users.
>
> Maybe you can port the following i386 patch to x86_64 ? (I dont have a x86_64
> test machine at this moment)
Yes good idea. I will add it after 2.6.16.
-Andi
next prev parent reply other threads:[~2006-02-03 11:30 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-03 9:17 percpu data changes Andrew Morton
2006-02-03 9:18 ` Andrew Morton
2006-02-03 9:35 ` Andrew Morton
2006-02-03 9:38 ` David S. Miller
2006-02-03 9:36 ` William Lee Irwin III
2006-02-03 9:40 ` David S. Miller
2006-02-03 9:51 ` Andi Kleen
2006-02-03 11:01 ` Eric Dumazet
2006-02-03 11:07 ` Andi Kleen [this message]
2006-02-03 15:36 ` Kyle McMartin
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