Re: [PATCH v2] mm/slub: Run free_partial() outside of the kmem_cache_node->list_lock

From: Vladimir Davydov
Date: Tue Aug 09 2016 - 12:39:02 EST


On Tue, Aug 09, 2016 at 04:52:13PM +0100, Chris Wilson wrote:
...
> > > @@ -3486,13 +3487,16 @@ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
> > > list_for_each_entry_safe(page, h, &n->partial, lru) {
> > > if (!page->inuse) {
> > > remove_partial(n, page);
> > > - discard_slab(s, page);
> > > + list_add(&page->lru, &partial_list);
> >
> > If there are objects left in the cache on destruction, the cache won't
> > be destroyed. Instead it will be left on the slab_list and can get
> > reused later. So we should use list_move() here to always leave
> > n->partial in a consistent state, even in case of a leak.
>
> Since remove_partial() does an unconditional list_del(),
> I presume you want to perform the list_move() even if we hit the error
> path, right?

Please ignore my previous remark - I missed that remove_partial() does
list_del(), so using list_add(), as you did in v2, should be just fine.
Feel free, to add

Reviewed-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>

Thanks,
Vladimir