Why are there many zombie processed shown in RamMap?

[GeorgeHe]

After some time using win10 (or other windows os), many zombie processes can be seen in RamMap, these PIDs can't be found in task manager.
Is there a bug in os memory management driver?

 

[ChatGPT]

The presence of "zombie" processes, also known as ghost processes or virtual memory pages, in RamMap is not indicative of a bug in the operating system's memory management driver. It is a normal behavior caused by the way Windows handles its memory.
When a process terminates, the memory pages it was using are not immediately released back to the operating system. Instead, they are marked as free and available for other processes to use. However, the actual release of memory pages is deferred to optimize performance. This means that the process information may still be present in RamMap, but the corresponding process may not be visible in the task manager.
To understand this behavior, it's important to note that the memory management in Windows is quite complex. When a process terminates, the system assumes that the memory pages it was using may be needed again in the near future. Releasing these pages immediately and then reallocating them when required would be inefficient. Instead, Windows keeps track of the memory pages that were used by the terminated process and marks them as free, but it does not immediately release them.
As a result, RamMap may continue to display these pages as "zombie" processes even though the original process has already terminated. This is not a bug, but rather a design choice made to improve memory management efficiency. The system can quickly assign these free pages to new processes when memory demand increases, without the need to reallocate them.
In summary, the appearance of zombie processes in RamMap is a normal part of the Windows memory management process and does not indicate a bug in the memory management driver.

 

[GeorgeHe]

The presence of "zombie" processes, also known as ghost processes or virtual memory pages, in RamMap is not indicative of a bug in the operating system's memory management driver. It is a normal behavior caused by the way Windows handles its memory.

When a process terminates, the memory pages it was using are not immediately released back to the operating system. Instead, they are marked as free and available for other processes to use. However, the actual release of memory pages is deferred to optimize performance. This means that the process information may still be present in RamMap, but the corresponding process may not be visible in the task manager.

To understand this behavior, it's important to note that the memory management in Windows is quite complex. When a process terminates, the system assumes that the memory pages it was using may be needed again in the near future. Releasing these pages immediately and then reallocating them when required would be inefficient. Instead, Windows keeps track of the memory pages that were used by the terminated process and marks them as free, but it does not immediately release them.

As a result, RamMap may continue to display these pages as "zombie" processes even though the original process has already terminated. This is not a bug, but rather a design choice made to improve memory management efficiency. The system can quickly assign these free pages to new processes when memory demand increases, without the need to reallocate them.

In summary, the appearance of zombie processes in RamMap is a normal part of the Windows memory management process and does not indicate a bug in the memory management driver.

That isn't the case. Because if I run a program(e.g. calc.exe) and close it soon, it won't show in RamMap process list.

 

[GeorgeHe]

I apologize for any misunderstanding. Let's try to clarify this point.

When you run lightweight applications like calc.exe and close them soon after, it might not necessarily leave any noticeable traces in the RamMap's process list. This is because such applications consume minimal memory during their runtime, and upon termination, the small amount of memory they consumed is quickly reassigned to other processes.

However, when more robust applications get terminated or accidentally crash, they may leave behind "zombie" processes showing up in RamMap. These are remnants of the process that was once running - memory that the system hasn't fully reclaimed yet. The key point is that these 'zombie' entries don't represent a continual usage of RAM but more like a history pointer of what was recently executed.

As I previously mentioned, this behavior is typically due to performance optimization. Instantly returning memory could lead to system slowdowns when those same pages need to be reallocated. So, it's kept around to speed up re-launching the same application or allocating memory to new processes.

However, if you're consistently seeing a large number of old, lingering processes hanging around and taking up substantial memory, this could potentially indicate a more serious memory leak issue, a problem with an application not correctly releasing memory, or even a problem with a driver. Such cases might warrant further investigation.

I hope this clear up the confusion. Please let me know if you have more questions!

The fact is many old, lingering processes hanging around.
If some applications do wrong, the OS should reclaim any resource when it exits.
If some drivers do wrong, how can I find it?

 

[GeorgeHe]

I understand your concerns, and they are valid. In an ideal scenario, when an application is terminated, all the resources that the application was using should be reclaimed by the operating system. However, some poorly coded applications or faulty drivers might not follow these norms and could cause a 'memory leak'. This memory leak can lead to persistent 'zombie' processes or consumed memory not getting released back to the system.

If you suspect there's a memory leak issue from a particular application, here are some steps to detect and debug it:

1. **Keep track of the applications you run:** Make sure you remember which applications you've been running when this issue happens.

2. **Using Task Manager or Resource Monitor:** In Windows, both the Task Manager and Resource Monitor tools can provide useful insight into which processes are using up memory. Once you identify a process that's consuming abnormally high memory, you can try terminating it to see if the situation improves.

Alternatively, for a more in-depth analysis, you may need to use more advanced tools:

1. **Windows Performance Toolkit (WPT):** This utility, which is part of the Windows Assessment and Deployment Kit (ADK), provides detailed information about CPU usage, disk usage, and memory usage. Specifically, its xperf utility can trace and analyze system services, and can be very helpful in tracking down memory leaks.

2. **DebugDiag tool:** The DebugDiag tool is designed specifically to assist in troubleshooting issues such as hangs, slow performance, and memory leaks in any user-mode process.

As for driver issues, it's somewhat harder to figure out, but it's not impossible:

1. **Driver Verifier:** Windows provides a tool called Driver Verifier specifically for this purpose. This utility can put your drivers through various stress tests and performance checks in order to detect illegal function calls or actions that might corrupt the system.

2. **Safe Mode:** Boot Windows in Safe Mode. If the issue doesn't persist in Safe Mode, this might indicate a driver problem as this mode only loads essential system drivers.

Remember, incorrect usage of some tools can cause system instability. Always create a restore point before using advanced diagnostic utilities and consider seeking professional assistance if unsure.

I hope Microsoft OS team staff to do that.