The mobilization only includes people who formerly served in the military (at least 1-2 years of training). A certain percentage of them are "reservists" who work normal jobs but are summoned for a month-long military training every year to be ready in the case of war, and so they will probably be prioritized (at least according to Putin & Shoigu).

This is not cannon fodder. Russia is running out of willing soldiers, not soldiers in general.