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Date: Thu, 22 May 2008 08:45:55 +0900
From: Paul Mundt <lethal@linux-sh.org>
To: Pekka J Enberg <penberg@cs.helsinki.fi>
Cc: linux-kernel@vger.kernel.org, clameter@sgi.com, mpm@selenic.com,
       dhowells@redhat.com
Subject: Re: [RFC/PATCH 1/3] SLAB: Add PageSlab checking to ksize()
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	Pekka J Enberg <penberg@cs.helsinki.fi>,
	linux-kernel@vger.kernel.org, clameter@sgi.com, mpm@selenic.com,
	dhowells@redhat.com
References: <Pine.LNX.4.64.0805212124250.22291@sbz-30.cs.Helsinki.FI>
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On Wed, May 21, 2008 at 09:25:26PM +0300, Pekka J Enberg wrote:
> From: Pekka Enberg <penberg@cs.helsinki.fi>
> 
> The ksize() function is meant for objects allocated from the slab caches, not
> for arbitrary objects. Add a BUG_ON() to enforce that.
> 
> Cc: Christoph Lameter <clameter@sgi.com>
> Cc: Matt Mackall <mpm@selenic.com>
> Cc: Paul Mundt <lethal@linux-sh.org>
> Cc: David Howells <dhowells@redhat.com>
> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>

This series seems to work ok with all of SLAB/SLUB/SLOB when also
applying the kobjsize() patch. Without the kobjsize() patch in place,
SLAB and SLUB both work, while SLOB still triggers the >= MAX_ORDER
BUG_ON() for page cache pages. Note that this is still an improvement
over SLUB blowing up, as it was before, even without the kobjsize()
change.