Linux: When does Reverse Path Filtering happen?

Question

I know that with rp_filter set to 1, linux would check the route table to see whether the input packet "belongs" to this network (and drop it if not).

So when exactly does this happen? And which routing table does it look up?

• Does it use the routing policy by ip rule?
• When does it happen related to iptables chain? If I set fwmark in iptables' PREROUTING chain, and set routing policy for that fwmark, would it use the different routing table?