After we create a boot cache, we may allocate from it until it is bootstraped.
This will move the page from the partial list to the cpu slab list. If this
happens, the loop:

	list_for_each_entry(p, &n->partial, lru)

that we use to scan for all partial pages will yield nothing, and the pages
will keep pointing to the boot cpu cache, which is of course, invalid. To do
that, we should flush the cache to make sure that the cpu slab is back to the
partial list.
Signed-off-by: NGlauber Costa <glommer@parallels.com>
Reported-by: NSteffen Michalke <StMichalke@web.de>
Tested-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: NChristoph Lameter <cl@linux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NPekka Enberg <penberg@kernel.org>