From mboxrd@z Thu Jan  1 00:00:00 1970
From: Pekka Enberg <penberg@cs.helsinki.fi>
Subject: Re: [regression] nf_iterate(), BUG: unable to handle kernel NULL
	pointer dereference
Date: Thu, 24 Jul 2008 16:32:22 +0300
Message-ID: <1216906342.12021.0.camel@penberg-laptop>
References: <20080724060448.GA10203@elte.hu>
	 <200807242256.09107.nickpiggin@yahoo.com.au>
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	 <200807242313.47041.nickpiggin@yahoo.com.au>
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Cc: Herbert Xu <herbert@gondor.apana.org.au>,
	Patrick McHardy <kaber@trash.net>, Ingo Molnar <mingo@elte.hu>,
	David Miller <davem@davemloft.net>, w@1wt.eu,
	davidn@davidnewall.com, torvalds@linux-foundation.org,
	akpm@linux-foundation.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, stefanr@s5r6.in-berlin.de,
	rjw@sisk.pl, ilpo.jarvinen@helsinki.fi,
	Dave Jones <davej@redhat.com>, Matt Mackall <mpm@selenic.com>,
	Christoph Lameter <cl@linux-foundation.org>
To: Nick Piggin <nickpiggin@yahoo.com.au>
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On Thu, Jul 24, 2008 at 10:56:08PM +1000, Nick Piggin wrote:
> > > OTOH, skb allocation uses kmalloc don't they? So you could still =
use
> > > SLOB ksize for that I guess.

On Thursday 24 July 2008 23:04, Herbert Xu wrote:
> > Yes I was referring to the data portion which is kmalloc'ed.
> > That is also why I'm interested in ksize because a priori we
> > don't know exactly how big it's going to be.  However, we do
> > know that statistically 1500 will dominate.
> >
> > I'm not interested in ksize for kmem_cache at all.  So in fact
> > we could have something simpler that's based on kmalloc's rounding
> > algorithm instead.

=EF=BB=BFOn Thu, 2008-07-24 at 23:13 +1000, Nick Piggin wrote:
> Yes you could definitely have a function that returns allocated
> bytes for a given kmalloc size. Should be about as fast or faster
> than extracting the size from the kaddr...

Yup, makes sense.