drupal 7: my hook module make my site slow?
I see two possible reasons:


You pass form state by value. It should be passed by reference. It is a really, really big array, so copying it when there is no need to may eat up quite a lot of memory, slowing down everything.
You alter $form['name_list']['#options'] in all views exposed forms. But probably most of these forms does not have name_list element at all. So what you do can generate array items that are bad from form api point of view, slowing down form processing, and generate warnings. Server will not show you warnings, but it will save them to error logs, and writing to disk is slow.