Re: [PATCH] mm: slub: Ensure that slab_unlock() is atomic

Peter Zijlstra
2016-03-09T12:22:23Z

On Wed, Mar 09, 2016 at 05:23:26PM +0530, Vineet Gupta wrote:
> > I did not follow through the maze, I think the few archs implementing
> > this simply do not include this file at all.
> >
> > I'll let the first person that cares about this worry about that :-)
>
> Ok - that's be me :-) although I really don't see much gains in case of ARC LLSC.
>
> For us, LD + BCLR + ST is very similar to LLOCK + BCLR + SCOND atleast in terms of
> cache coherency transactions !

The win would be in not having to ever retry the SCOND. Although in this
case, the contending CPU would be doing reads -- which I assume will not
cause a SCOND to fail, so it might indeed not make any difference.