io_uring: enable kmemcg account for io_uring requests

This puts io_uring under the memory cgroups accounting and limits for
requests.
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -10350,7 +10350,8 @@ static int __init io_uring_init(void)
 
 	BUILD_BUG_ON(ARRAY_SIZE(io_op_defs) != IORING_OP_LAST);
 	BUILD_BUG_ON(__REQ_F_LAST_BIT >= 8 * sizeof(int));
-	req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC);
+	req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC |
+				SLAB_ACCOUNT);
 	return 0;
 };
 __initcall(io_uring_init);