Re: [PATCH] slub: change cmpxchg_double_slab in get_freelist() to__cmpxchg_double_slab

From: Pekka Enberg
Date: Fri Jun 01 2012 - 02:39:36 EST


On Mon, 14 May 2012, David Rientjes wrote:
> > On Fri, 11 May 2012, Joonsoo Kim wrote:
> >
> > > get_freelist() is only called by __slab_alloc with interrupt disabled,
> > > so __cmpxchg_double_slab is suitable.
> > >
> > > Signed-off-by: Joonsoo Kim <js1304@xxxxxxxxx>
> >
> > Acked-by: David Rientjes <rientjes@xxxxxxxxxx>

On Thu, 31 May 2012, David Rientjes wrote:
> Pekka, did you want to pick this up so it can get into linux-next?

We now made get_freelist() *require* interrupts to be disabled which
deserves a comment, no?

Also, what do we gain from patches like this? It's somewhat
counterintuitive that we have a function with "cmpxchg" in it which is not
always atomic (i.e. you need to have interrupts disabled).

IIRC, there was even a long rant about this by Linus but I'm unable to
find it in my email archives.

Pekka
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