请用python帮我写一个代码,设计有 n 个进程共享 1 个系统资源的系统,基于银行家算法和安全性算法,进 程可动态的申请和释放资源,系统按各进程的申请动态的分配资源。要求打印资源动态分配矩阵
时间: 2024-11-03 16:20:42 浏览: 19
操作系统课程设计——银行家算法
在Python中,我们可以使用`multiprocessing`库模拟多进程环境,并结合一些数据结构来实现基于银行家算法的安全性检查。以下是简化的示例代码:
```python
import heapq
from multiprocessing import Process, Manager
# 定义资源列表
resources = [0] * 4 # 假设有4种资源,每种初始都是0
limits = [10, 8, 6, 4] # 每种资源的最大可用量
processes = []
def allocate_resources(process_id, needed):
global resources, limits
if can_allocate(process_id, needed):
for i in range(len(needed)):
resources[i] += needed[i]
print(f"Process {process_id}: Requested {i+1} resource(s) ({needed[i]}), current allocation: {resources[i]}")
return True
else:
print(f"Process {process_id}: Allocation denied due to insufficient resources.")
return False
def release_resources(process_id, released):
global resources
for i in range(len(released)):
resources[i] -= released[i]
print(f"Process {process_id}: Released {i+1} resource(s) ({released[i]}), new allocation: {resources[i]}")
def can_allocate(process_id, needed):
global resources, limits
available = []
for i, limit in enumerate(limits):
if resources[i] + needed[i] <= limit:
available.append(limit - resources[i])
if not available:
return False
# 使用堆来查找最有利的资源组合
min_heap = [-value for value in available] # 负数表示最小值,因为我们需要最大可用资源
heapq.heapify(min_heap)
while len(min_heap) > 0 and sum(needed) > 0:
# 如果当前分配的资源可以满足所有请求,则接受分配
if -heapq.heappop(min_heap) >= needed[0]:
for i in range(len(needed)):
if needed[i] > 0:
min_heap.append(-(available[i] - needed[i]))
break
processes[process_id].running = False
sum_needed = sum(needed)
else:
# 否则,回退并尝试下一个最小可用资源
pass
return len(min_heap) == 0 or processes[process_id].running # 返回是否分配成功
if __name__ == "__main__":
manager = Manager()
processes_data = manager.list() # 存储进程信息
for i in range(5): # 假设有5个进程
process = Process(target=run_process, args=(i, processes_data))
process.start()
processes.append(process)
# 等待所有进程结束
for process in processes:
process.join()
def run_process(process_id, processes_data):
running = True # 标记进程是否还在运行
while running:
request = input(f"Enter resources needed for Process {process_id} (separated by comma, leave blank to finish): ")
if request == "":
running = False
else:
requested = list(map(int, request.split(",")))
if allocate_resources(process_id, requested):
processes_data.append((process_id, requested))
else:
break
release_resources(process_id, requested) # 无论分配成功与否,都需要释放已申请的资源
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