Re: slab: Remove SLAB_NO_REAP option

[Andrew Morton <akpm@osdl.org>]

Alok Kataria <alok.kataria@calsoftinc.com> wrote:
>
>  On Thu, 2006-02-23 at 14:18, Pekka Enberg wrote:
>  On 2/23/06, Alok Kataria <alok.kataria@calsoftinc.com> wrote:
>  > > There can be some caches which are not used quite often, kmem_cache 
>  > > for instance. Now from performance perspective having SLAB_NO_REAP for 
>  > > such caches is good.
>  >
>  > Yeah, kmem_cache sounds like a realistic user, but I am wondering if
>  > it makes any sense for anyone else to use it?
>  >
>  Right, thats why my question still is why do these iscsi & ocfs  cache 
>  have this flag set.

I'm sure there's no good reason.

>  If we are sure that the flag is still required, we can use the patch 
>  below.

I'm very much hoping that it is not needed.  Would prefer to just toss the
whole thing away.

What's it supposed to do anyway?  Keep wholly-unused pages hanging about in
each slab cache?  If so, it may well be a net loss - it'd be better to push
those pages back into the page allocator so they can get reused for
something else while they're possibly still in-cache.  Similarly, it's
better to fall back to the page allocator for a new slab page because
that's more likely to give us a cache-hot one.

I'm convinced, anyway ;)