Re: [PATCH] percpu_ida: Use _irqsave() instead of local_irq_save() + spin_lock

[Matthew Wilcox]

On Fri, May 04, 2018 at 04:22:16PM -0700, Andrew Morton wrote:
> I'm feeling a bit hostile toward lib/percpu_ida.c in general ;) It has
> very few users and seems rather complicated (what's with that
> schedule() in percpu_ida_alloc?).  I'm suspecting and hoping that if
> someone can figure out what the requirements were, this could all be
> zapped and reimplemented using something else which we already have.

Note that I have no code in percpu_ida ... it's quite different from
the regular IDA.  But I have noticed the stunning similarity between the
percpu_ida and the code in lib/sbitmap.c.  I have no idea which one is
better, but they're essentially doing the same thing.