Post meta is not accessible within save_post hook

I am using this code to update post meta but it is not working.

function run_when_job_published( $post_id, $post, $update){
   $post_meta = get_post_meta($post_id);
}
add_action('save_post_jobs', 'run_when_job_published', 10, 3);

But here in this function $post_meta is returning an empty array. Actually I want to update one of the meta field during post insertion but I think it is not possible with this hook. I have also tried publish_post hook but in my scenario it is not working. Any suggestion will be much appreciated. Thank you!