slub: remove obsolete comments of put_cpu_partial()

Commit d6e0b7fa1186 ("slub: make dead caches discard free slabs
immediately") makes put_cpu_partial() run with preemption disabled and
interrupts disabled when calling unfreeze_partials().

The comment: "put_cpu_partial() is done without interrupts disabled and
without preemption disabled" looks obsolete, so remove it.

Link: http://lkml.kernel.org/r/1516968550-1520-1-git-send-email-miles.chen@mediatek.com
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/slub.c

@@ -2222,9 +2222,7 @@ static void unfreeze_partials(struct kmem_cache *s,
 
 /*
  * Put a page that was just frozen (in __slab_free) into a partial page
- * slot if available. This is done without interrupts disabled and without
- * preemption disabled. The cmpxchg is racy and may put the partial page
- * onto a random cpus partial slot.
+ * slot if available.
  *
  * If we did not find a slot then simply move all the partials to the
  * per node partial list.