Re: [PATCH RFC v1 1/2] rcu/tree: Add basic support for kfree_rcu batching

[Joel Fernandes]

On Thu, Aug 08, 2019 at 01:51:29PM -0700, Paul E. McKenney wrote:
[snip]
> > Also, I am thinking that whenever we do per-slab optimization, then the
> > kmem_cache_free_bulk() can be optimized further. If all pointers are on the
> > same slab, then we can just do virt_to_cache on the first pointer and avoid
> > repeated virt_to_cache() calls. That might also give a benefit -- but I could
> > be missing something.
> 
> A sort might be required to make that work nicely, which would add some
> overhead.  Probably not that much, though, the increased locality would
> have a fighting chance of overcoming the sort's overhead.
> 
> > Right now kmem_cache_free_bulk() just looks like a kmem_cache_free() in a
> > loop except the small benefit of not disabling/enabling IRQs across each
> > __cache_free, and the reduced cache miss benefit of using the array.
> 
> C'mon!  Show some respect for the awesome power of temporal locality!!!  ;-)

Good point. I will try to respect it more in the future ;-) After all, it is
quite a useful concept.

thanks,

 - Joel