Re: [PATCH] slab: deal with NULL pointers passed to kmem_cache_free

["Pekka Enberg" <penberg@cs.helsinki.fi>]

On 3/19/2007, "Andrew Morton" <akpm@linux-foundation.org> wrote:
> Would prefer to do:
> 
> static inline void kmem_cache_free_if_not_null(struct kmem_cache *cachep,
> 						void *objp)
> {
> 	if (objp)
> 		kmem_cache_free(cachep, objp);
> }
> 
> so that we don't add extra overhead to all the thousands of existing,
> well-behaved callsites.

That bloats kernel text all the same so it's much cleaner to just make
the callers explicitly check for NULL then. That said, I'm sorry but I
just don't buy the "overhead" part of your argument since it's one
branch and no extra data cache pressure especially as we're already
doing the BUG_ON and page flag checking.

But, since you're NAKing my patch, we need to get the mempool for from
the original thread in to fix the oops.

                                     Pekka