Messages in this thread | | | Date | Sun, 27 Jan 2008 23:35:49 +0200 | From | "Pekka Enberg" <> | Subject | Re: lib/idr.c: initialize struct idr_layer |
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Hi Vegard,
On Jan 27, 2008 11:30 PM, Vegard Nossum <vegard.nossum@gmail.com> wrote: > > Depends on how you track object initialization. An object returned by > > kmem_cache_alloc() is always initialized if the cache it comes from has a > > constructor. > > I think there's a pretty big chance I'm wrong (or misunderstanding > something) here, so I'll just ask: > setup_object() from mm/slub.c is what calls the ctor. Shouldn't this > be called from slab_alloc() as well? (I'm marking the data > "uninitialized" there before returning the object.) Otherwise you > might get back an object that is initialized with the previous owner's > data. Or is this intentional?
It's intentional. The caller of kmem_cache_free() is expected to put the object in such a state that it can be recycled immediately when kmem_cache_alloc() for that cache is called. You can find the design rationale for that in Bonwick's original paper on slab: http://citeseer.ist.psu.edu/bonwick94slab.html
Pekka
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