Re: [PATCH 1/2] SLUB: Fix merged slab cache names

[Pekka Enberg]

 On 14.9.2010 20.26, Christoph Lameter wrote:
> On Tue, 14 Sep 2010, Pekka Enberg wrote:
>
> > diff --git a/include/linux/slab.h b/include/linux/slab.h
> > index 59260e2..df201cf 100644
> > --- a/include/linux/slab.h
> > +++ b/include/linux/slab.h
> > @@ -76,6 +76,8 @@
> >   # define SLAB_FAILSLAB		0x00000000UL
> >   #endif
> >
> > +#define SLAB_DYNAMIC_NAME	0x04000000UL	/* s->name is kmalloc()'d */
> > +
> Put this into mm/slub.c as slub only flag? What is the difference from
> refcount == 1?
I can put it in mm/slub.c but I was worried about someone reusing the 
bit for something else.

Do you mean refcount == 2? You don't know during kmem cache release time 
if someone was merged to the cache or not.
> > @@ -3218,6 +3221,18 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size,
> >   	down_write(&slub_lock);
> >   	s = find_mergeable(size, align, flags, name, ctor);
> >   	if (s) {
> > +		if (!(s->flags&  SLAB_DYNAMIC_NAME)) {
> > +			const char *new_name;
> > +
> > +			new_name = kstrdup(s->name, GFP_KERNEL);
> Ok. Keeping the original name. Why dont we do strdup by default and always
> do a kfree(s->name) on close?
I tried that. It gets very nasty during bootstrap.

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