Don't you call it Zaduszki or is that all saints day on the following day?
Zaduszki are celebrated on the 2 October, and have their roots in a pagan holiday called "Dziady". On that day our ancestors were meting on the graves of their relatives to feast and pray for them. Aside from sharing the food with their ancestors they were also setting up bonfires on their graves, paths and crossroads to keep their dead worm and show the wandering restless souls the way home. The other tradition was to set bonfire on the grave of a person who died in a tragic way, as it was believed that that person may become a vampire, and it was just a precaution to stop the daemon from haunting their living family members.(vampires are typical Slavic daemons, and maybe when I have some free time, I will write something more about them)
Besides at that day Slavs believed that earth was full of wandering restless souls, and some people were summing them in order to help them achieve redemption, etc…
At present some of the old tradition prevailed in Zaduszki, like for example lighting candles on the graves of ones relatives.