Re: [PATCH] nommu: Push kobjsize() slab-specific logic down to ksize().

[Matt Mackall <mpm@selenic.com>]

On Tue, 2008-05-20 at 11:51 -0700, Christoph Lameter wrote:
> On Tue, 20 May 2008, Matt Mackall wrote:
> 
> > > Hmm. That means we are sanctioning using ksize on arbitrary objects? SLUB 
> > > supports that but SLAB wont and neither will SLOB. I think we need to stay 
> > > with the strict definition that is needed by SLOB.
> > 
> > Of course SLUB won't be able to tell you the size of objects allocated
> > statically, through bootmem, etc.
> 
> Right the function actually give misleading results even if you just pass 
> a pointer to an int at an address that is page backed but not using a slab 
> allocator. Then PAGE_SIZE will be returned?
> 
> So the semantics are screwed up here. kobjsize() should only be called for 
> slab objects. 
> 
> Remove kobjsize completely and replace with calls to ksize? Callers must 
> not call ksize() on non slab objects.

What'd you think of my idea of adding WARN_ONs to SLAB and SLUB for
these cases? That is, warn whenever ksize() gets a non-kmalloced
address?

-- 
Mathematics is the supreme nostalgia of our time.

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