second chance page replacement policy/algorithm

second-chance_PR.py

import sys
from threading import Thread
import time

#def only_a_second_chance():

def second_chance(page_requests, mem_size, page_faults, m, thread_name):
    #mem_size = int(sys.argv[1]) # N, physical memory

    mem_size = mem_size
    page_faults = page_faults
    m = []*mem_size #popula a lista com os slots, ou indexes totais

    for index in page_requests:
        s = index.split(':') #: trata o texto e separa set/destroy/create do numero da pagina
        page = s[1]
        print("PAGE = {}".format(page))

        # verifica se ja existe em memoria
        if page not in m:

            # se houver espaco de memoria, insira a nova pagina no fim
            if len(m) < mem_size:
                m = m + [page] #m.append(page)
                page_faults += 1
                print("{} {} exists in memory /// {}".format(thread_name, page, time.ctime(time.time())))

            # se nao houver espaco de memoria, remove a primeira pagina da lista e adiciona a nova no final
            else:
                m.pop(0)
                m.append(page)
                page_faults += 1
                print("{} {} DONT exist in memory /// {}".format(thread_name, page, time.ctime(time.time())))

        # se nao existir, adiciona sem problema algum, nao acusando page fault
        else:
            m.remove(page)
            m.append(page)
            print("{} {} nao existia in memory, agora existe /// {}".format(thread_name, page, time.ctime(time.time())))

    print("|> Mem State: {}".format(m))
    print("|> Page Faults: {}".format(page_faults))


def main():
    #python <filename.py> <memory_capacity> <requested_accesses.txt>
    try:
        with open(sys.argv[2], 'r') as file:
            page_requests = file.read().split()
        file.close()
        print("passou try")

    except IndexError:
        print("caiu no IndexError")
        if len(sys.argv) != 3:
            print("Usage: $ python optimal.py <Number of physical memory pages> <access sequence file>")
            sys.exit()
    print("Escopo Atual: funcao main()")

    mem_size = int(sys.argv[1]) # N, physical memory
    page_faults = 0
    m = []#*mem_size #popula a lista com os slots, ou indexes totais

    Thread(target=second_chance(page_requests, mem_size, page_faults, m, "T1")).start()
    Thread(target=second_chance(page_requests, mem_size, page_faults, m, "T2")).start()



if __name__ == "__main__":
    main()