From: Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] Export symbol ksize()
Date: Sun, 15 Feb 2009 13:36:38 -0800
Message-ID: <20090215133638.5ef517ac.akpm@linux-foundation.org>
References: <1234272104-10211-1-git-send-email-kirill@shutemov.name>
	<84144f020902100535i4d626a9fj8cbb305120cf332a@mail.gmail.com>
	<20090210134651.GA5115@epbyminw8406h.minsk.epam.com>
	<Pine.LNX.4.64.0902101605070.20991@melkki.cs.Helsinki.FI>
	<20090212104349.GA13859@gondor.apana.org.au>
	<1234435521.28812.165.camel@penberg-laptop>
	<20090212105034.GC13859@gondor.apana.org.au>
	<1234454104.28812.175.camel@penberg-laptop>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
        "Kirill A. Shutemov"
 <kirill@shutemov.name>,
        Christoph Lameter <cl@linux-foundation.org>,
        Matt
 Mackall <mpm@selenic.com>, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, linux-crypto@vger.kernel.org,
        Geert.Uytterhoeven@sonycom.com
To: Pekka Enberg <penberg@cs.helsinki.fi>
Return-path: <owner-linux-mm@kvack.org>
In-Reply-To: <1234454104.28812.175.camel@penberg-laptop>
Sender: owner-linux-mm@kvack.org
List-Id: linux-crypto.vger.kernel.org

On Thu, 12 Feb 2009 17:55:04 +0200 Pekka Enberg <penberg@cs.helsinki.fi> wrote:

> On Thu, Feb 12, 2009 at 12:45:21PM +0200, Pekka Enberg wrote:
> > > 
> > > Because the API was being widely abused in the nommu code, for example.
> > > I'd rather not add it back for this special case which can be handled
> > > otherwise.
> 
> On Thu, 2009-02-12 at 18:50 +0800, Herbert Xu wrote:
> > I'm sorry but that's like banning the use of heaters just because
> > they can abused and cause fires.
> > 
> > I think I've said this to you before but in networking we very much
> > want to use ksize because the standard case of a 1500-byte packet
> > has loads of extra room given by kmalloc which all goes to waste
> > right now.
> > 
> > If we could use ksize then we can stuff loads of metadata in that
> > space.
> 
> OK, fair enough, I applied Kirill's patch. Thanks.
> 

Could we please have more details regarding this:

> The ksize() function is not exported to modules because it has non-standard
> behavour across different slab allocators. 

How does the behaviour differ?  It this documented?  Can we fix it?

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>