Algoritmi za čiščenje pomnilnika

ČESEN, ANDREJ (author), Dobravec, Tomaž (mentor)

Diplomsko delo je posvečeno implementaciji avtomatskega upravljanja pomnilnika za programski jezik C. Metoda čiščenja označi-počisti se je prilagodila za nekooperativen jezik, ki ne sporoča informacij o tipih podatkov na mestih dostopnih mutatorju. Prepoznavanje kazalcev v korenih in poljih objektov je zato konzervativno, kar omogoča varno delovanje čistilca - če je vsebovana vrednost dovolj podobna kazalcu, se jo smatra kot kazalec (četudi to morda ni). Da se uporabnikove podatke zavaruje pred nenamernim pisanjem čistilca, se je označevalne bite premaknilo iz glav objektov v bitna polja, shranjena v ločenem delu pomnilnika. Na koncu sledi še vrednotenje uporabe čistilca v praksi.

• Language: Slovenian
• Keywords: čiščenje pomnilnika, označi-počisti, označi-strni, prepisovanje, štetje referenc
• Work type: Bachelor thesis/paper
• Organization: FRI - Faculty of Computer and Information Science
• Year: 2014
• PID: 20.500.12556/RUL-29511
• Publication date in RUL: 18.09.2014

Secondary language

• Language: English
• Title: Garbage Collection Algorithms

Abstract

This thesis focuses on an implementation of automatic memory management in C programming language. Mark-sweep method was modified for use in uncooperative programming language, which does not share data type information of memory slots accessible by the mutator. Due to this fact, decisions on pointer identity are conservative which guarantees safe collector operation - if value looks sufficiently like a pointer, it is considered a pointer (although it might not actually be one). Mark bits were moved from object's headers to bitmaps, stored in a seperate part of memory to prevent accidental writes to user's data by the collector. Finally, the usage of garbage collector was evaluated in practice.

• Keywords: garbage collection, mark-sweep, mark-compact, copying, reference counting