On Sat, 28 Jul 2012, JoonSoo Kim wrote:
> 2012/7/28 Christoph Lameter <c...@linux.com>:
> > On Sat, 28 Jul 2012, Joonsoo Kim wrote:
> >
> >> Subject and commit log are changed from v1.
> >
> > That looks a bit better. But the changelog could use more cleanup and
> > clearer expression.
> >
> >> @@ -2490,25 +2492,17 @@ static void __slab_free(struct kmem_cache *s,
> >> struct page *page,
> >> return;
> >> }
> >>
> >> + if (unlikely(!new.inuse && n->nr_partial > s->min_partial))
> >> + goto slab_empty;
> >> +
> >
> > So we can never encounter a empty slab that was frozen before? Really?
>
> In my suggestion, 'was_frozen = 1' is "always" handled without taking a lock.
Yepo that is true with this patch.
> Then, never hit following code.
> + if (unlikely(!new.inuse && n->nr_partial > s->min_partial))
> + goto slab_empty;
> +
Correct.
> Instead, hit following code.
> if (likely(!n)) {
>
> /*
> * If we just froze the page then put it onto the
> * per cpu partial list.
> */
> if (new.frozen && !was_frozen) {
> put_cpu_partial(s, page, 1);
> stat(s, CPU_PARTIAL_FREE);
> }
> /*
> * The list lock was not taken therefore no list
> * activity can be necessary.
> */
> if (was_frozen)
> stat(s, FREE_FROZEN);
> return;
> }
>
> So, even if we encounter a empty slab that was frozen before, we just
> do "stat(s, FREE_FROZEN)".
> Please let me know my answer is sufficient.
Yes.
Acked-by: Christoph Lameter <c...@linux.com>
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