Messages in this thread | | | From | Nick Piggin <> | Subject | Re: [regression] nf_iterate(), BUG: unable to handle kernel NULL pointer dereference | Date | Fri, 25 Jul 2008 19:09:07 +1000 |
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On Friday 25 July 2008 05:21, Matt Mackall wrote: > On Thu, 2008-07-24 at 16:32 +0300, Pekka Enberg wrote: > > 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. > > > > On 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. > > On the other hand, I can imagine useful allocator changes where this > would not be a constant of requested size. For instance, imagine we had > a classless bucket allocator, but with a heuristic to try a larger > bucket when it wasn't cheap/possible to allocate a right-sized object > (because of memory pressure, etc.) and larger ones were available. > This sort of thing is a pretty small change for SLAB/SLUB.
If that comes up, you could make the API take the pointer as well, then just filter out the new argument in allocators that don't use it. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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