get_phys_pages - Linux
Overview
get_phys_pages is a Linux utility that provides information about physical pages in the system’s memory. It’s primarily designed for kernel developers and system administrators to analyze system memory usage and optimize memory allocation.
Syntax
get_phys_pages [options] <pid>
Options/Flags
-c, --count: Display the number of physical pages for the specified process.-m, --memory: Show information about physical memory usage by page tables.-d, --direct: Directly access the physical memory without using page tables.-s, --sort: Sort the output by the physical page address.-v, --verbose: Provide detailed information about each physical page.
Examples
- Display the number of physical pages used by a process:
get_phys_pages -c 1234
- Show memory footprint of page tables:
get_phys_pages -m
- Get direct physical memory access:
get_phys_pages -d -s
- List physical pages for a process in a verbose format:
get_phys_pages -v 1234
Common Issues
- Invalid PID: If the provided PID does not exist,
get_phys_pageswill return an error. - Permission Denied: The user running the command must have root privileges to access physical memory.
- Kernel Module Not Loaded: On some systems, you may need to load the "kallsyms" kernel module before using
get_phys_pages.
Integration
get_phys_pages can be combined with other Linux commands for more advanced analysis. For example:
get_phys_pages -c 1234 | grep foo
Related Commands
top: Monitor system resource usage, including physical memory.free: Display information about physical memory and swap space.grep: Search and filter output, useful for finding specific information inget_phys_pagesresults.