persianyagami90xs / qmemstat

Inspect Pagemaps of Programs

QMemstat

QMemstat is a tool to inspect the address space of a process.

The Linux kernel exposes quite detailed information about the memory pages that processes use, and information about the pages themselves, which can be put together to get detailed information about a given process. qmemstat uses this information from the kernel and shows it in a more convenient format. Since the kernel interfaces used are root-only for security reasons, qmemstat needs to run as root, or at least a "server" needs to run as root for qmemstat.

Tools

QMemstat contains two related tools:

memstat

Command-line tool. It must be run as root.

memstat has two modes:

• display memory use information: memstat <pid>|<process-name> outputs the following three numbers:
  • VSZ (virtual set size): the size of the address space of the process
  • RSS (resident set size): the size of physical memory in the address space of the process
  • PSS (proportional set size): like RSS, but for shared memory pages the size is divided by the number of users. This is the most accurate "actual memory used" value.
• server mode: memstat <pid>|<process> --server <port-number> continuously grabs address space information and provides it to qmemstat (see below).

qmemstat

GUI tool which shows information about a process's address space, and which updates the information continuously.

It has two modes:

• standalone: qmemstat <pid>|<process-name> (must be run as root) shows a graphical view of the address space of the process.
  • Hold down the left mouse button to see the flags of the page under the cursor in the panel on the left.
• as a client to memstat running in server mode (does not need root): qmemstat --client <server-address> <port-number> Otherwise it works like standalone mode.