How Do I Check Reserved Memory in Linux?

Linux is a powerful and versatile operating system, but to harness its full potential, you need to understand and manage various aspects of its performance. One crucial aspect is checking reserved memory. In this article, we’ll dive deep into the world of Linux memory management and explore how to effectively monitor and check reserved memory.

Understanding Reserved Memory

Reserved memory in Linux refers to the portion of system memory that is allocated for specific purposes and cannot be used for other tasks. It plays a critical role in maintaining system stability and ensuring that essential processes have the memory they need to run smoothly.

Importance of Monitoring Reserved Memory

Monitoring reserved memory is essential for several reasons. It helps you:

  • Ensure optimal system performance.
  • Detect and troubleshoot memory-related issues.
  • Prevent memory leaks that can lead to system crashes.
  • Make informed decisions about resource allocation.

How to Check Reserved Memory in Linux

To check reserved memory in Linux, you can use various commands and tools. Let’s explore some of the most commonly used methods:

Using the free Command

The free command provides a quick overview of your system’s memory usage, including reserved memory. Open your terminal and type:

free -h

This will display memory statistics in a human-readable format, including total, used, and reserved memory.

Interpreting free Command Output

Understanding the free command’s output is crucial. It provides information on total memory (RAM), used memory, free memory, shared memory, and buffers/cache. Reserved memory is often included in the “used” section.

Using top Command

Another way to monitor memory usage, including reserved memory, is by using the top command:


This interactive tool displays real-time system statistics, including memory usage. Look for the “RES” column to find information about reserved memory.

Viewing Memory Information in htop

For a more user-friendly alternative to top, you can use htop. Install it if necessary and run:


htop provides a visual representation of memory usage, making it easier to identify reserved memory.

Using vmstat for Memory Analysis

For in-depth memory analysis, consider using the vmstat command:

vmstat 1

This command provides a continuous stream of memory statistics, including reserved memory, at one-second intervals.

Analyzing Memory with pmap

For detailed process memory analysis, pmap is a powerful tool:

pmap <process_id>

Replace <process_id> with the ID of the process you want to analyze. pmap will provide information about the memory used by that specific process, including reserved memory.

Reserved Memory in Virtual Machines

If you’re running Linux within a virtual machine (VM), understanding and managing reserved memory becomes even more critical. VMs have their own memory allocation settings, and you need to ensure that the host and guest systems are well-balanced in terms of memory allocation.

Identifying Memory Leaks

Memory leaks can be a common issue in Linux systems. They occur when a program allocates memory but doesn’t release it when it’s no longer needed. To identify memory leaks, you can use tools like Valgrind and AddressSanitizer.

To optimize memory usage, it’s essential to monitor trends over time. Collecting historical data allows you to identify patterns and make informed decisions about resource allocation. Tools like Prometheus and Grafana can help with this.

Kernel Parameters for Memory Management

Linux provides various kernel parameters that allow you to fine-tune memory management. Adjusting these parameters can optimize reserved memory allocation for your specific use case.

Best Practices for Memory Optimization

Here are some best practices to manage reserved memory effectively:

  • Regularly monitor memory usage.
  • Investigate any unexpected spikes in memory usage.
  • Implement proper resource limits for processes.
  • Use swap space judiciously.
  • Keep your kernel and system libraries updated.

Troubleshooting Memory Issues

If you encounter memory-related issues, don’t panic. Common problems include out-of-memory errors and sluggish performance. Check your logs, use diagnostic tools, and consult relevant documentation or forums for solutions.

Comparing Different Linux Distributions

It’s worth noting that memory management can vary between different Linux distributions. Factors like default configurations and package choices can impact how memory is reserved and used. Make sure to consider these differences when optimizing memory.

Third-party Tools for Memory Monitoring

In addition to built-in Linux commands, several third-party tools are available for memory monitoring. Tools like New Relic, Datadog, and Zabbix offer advanced features and analytics for in-depth memory management.

Community Resources and Forums

The Linux community is vast, and there are numerous forums, blogs, and websites where you can seek help, share your experiences, and stay updated on the latest developments in Linux memory management. Some popular resources include the Linux subreddit, Stack Overflow, and the forum.

  • RAM (Random Access Memory): The physical memory in your computer that applications use for temporary data storage.
  • Swap Space: A designated area on your hard drive that acts as an extension of RAM when physical memory is exhausted.
  • Memory Leak: A situation where a program fails to release memory it no longer needs, causing a gradual increase in memory usage.
  • Kernel Parameters: Configuration settings that govern the behavior of the Linux kernel, including memory management.


How do I check if my system is running out of reserved memory?

You can use the free command or check system logs for out-of-memory errors.

Can I increase the amount of reserved memory in Linux?

Yes, you can adjust kernel parameters to allocate more reserved memory if needed.

What should I do if I suspect a memory leak?

Use memory analysis tools like Valgrind to identify and fix memory leaks in your programs.

Are there any GUI-based tools for monitoring memory usage in Linux?

Yes, tools like GNOME System Monitor and KDE System Guard provide graphical interfaces for monitoring system resources.

Which Linux distribution is best for memory-intensive tasks?

It depends on your specific requirements, but distributions like CentOS and Ubuntu Server are often recommended for server environments.

How can I check memory usage for a specific process?

Use the pmap command followed by the process ID to analyze the memory usage of a particular process.

How do I check reserved memory in Linux?

You can check reserved memory in Linux using the “free” command or by examining the “/proc/meminfo” file.

What is reserved RAM in Linux?

Reserved RAM in Linux is memory that is allocated but not currently in use by running processes; it may include reserved memory for the kernel, hardware devices, or other system functions.


Checking reserved memory in Linux is a critical aspect of system administration and performance optimization. By mastering the tools and techniques discussed in this article, you can ensure that your Linux system operates smoothly, efficiently utilizes memory, and avoids memory-related issues.

Remember to regularly monitor memory usage, investigate any anomalies, and stay informed about the latest developments in Linux memory management. With the right knowledge and tools at your disposal, you can confidently manage reserved memory in Linux and maintain a high-performance system.

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