Re: SLUB defrag pull request?

From: Miklos Szeredi
Date: Wed Oct 22 2008 - 17:05:52 EST


On Wed, 22 Oct 2008, Pekka Enberg wrote:
> On Wed, Oct 22, 2008 at 11:26 PM, Miklos Szeredi <miklos@xxxxxxxxxx> wrote:
> > Because you don't _need_ a reliable reference to access the contents
> > of the dentry. The dentry is still there after being freed, as long
> > as the underlying slab is there and isn't being reused for some other
> > purpose. But you can easily ensure that from the slab code.
> >
> > Hmm?
>
> Actually, when debugging is enabled, it's customary to poison the
> object, for example (see free_debug_processing() in mm/slub.c). So we
> really can't "easily ensure" that in the allocator unless we by-pass
> all the current debugging code.

Thank you, that does actually answer my question. I would still think
it's a good sacrifice to no let the dentries be poisoned for the sake
of a simpler dentry defragmenter.

Miklos
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