mm, vma: use percpu sheaves for vm_area_struct cache

Create the vm_area_struct cache with percpu sheaves of size 32 to
improve its performance.

Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

mm/vma_init.c

@@ -16,6 +16,7 @@ void __init vma_state_init(void)
 	struct kmem_cache_args args = {
 		.use_freeptr_offset = true,
 		.freeptr_offset = offsetof(struct vm_area_struct, vm_freeptr),
+		.sheaf_capacity = 32,
 	};
 
 	vm_area_cachep = kmem_cache_create("vm_area_struct",