Notes on memtype parameter in proc.mem items

Overview

The memtype parameter is supported on Linux, AIX, FreeBSD, and Solaris platforms.

Three common values of memtype are supported on all of these platforms: pmem, rss and vsize. Additionally, platform-specific memtype values are supported on some platforms.

AIX

See values supported for memtype parameter on AIX in the table.

Supported value Description Source in procentry64 structure Tries to be compatible with
vsize 1 Virtual memory size pi_size
pmem Percentage of real memory pi_prm ps -o pmem
rss Resident set size pi_trss + pi_drss ps -o rssize
size Size of process (code + data) pi_dvm ps gvw SIZE column
dsize Data size pi_dsize
tsize Text (code) size pi_tsize ps gvw TSIZ column
sdsize Data size from shared library pi_sdsize
drss Data resident set size pi_drss
trss Text resident set size pi_trss

Notes for AIX:

  1. When choosing parameters for proc.mem[] item key on AIX, try to specify narrow process selection criteria. Otherwise, there is a risk of getting unwanted processes counted into proc.mem[] result.

Example:

$ zabbix_agentd -t proc.mem[,,,NonExistingProcess,rss]
proc.mem[,,,NonExistingProcess,rss]           [u|2879488]

This example shows that specifying only the command line (regular expression to match) parameter results in Zabbix agent self-accounting, which is probably not what you want.

  1. Do not use ps -ef to browse processes — it shows only non-kernel processes. Use ps -Af to see all processes which will be seen by Zabbix agent.

  2. Let's go through example of topasrec how Zabbix agent proc.mem[] selects processes.

$ ps -Af | grep topasrec
root 10747984        1   0   Mar 16      -  0:00 /usr/bin/topasrec  -L -s 300 -R 1 -r 6 -o /var/perf daily/ -ypersistent=1 -O type=bin -ystart_time=04:08:54,Mar16,2023

proc.mem[] has arguments:

proc.mem[<name>,<user>,<mode>,<cmdline>,<memtype>]

where:

  • The first criterion is a process name (argument <name>). In our example Zabbix agent will see it as topasrec. In order to match, you need to either specify topasrec or to leave it empty.
  • The second criterion is a user name (argument <user>). To match, you need to either specify root or to leave it empty.
  • The third criterion used in process selection is an argument <cmdline>. Zabbix agent will see its value as /usr/bin/topasrec -L -s 300 -R 1 -r 6 -o /var/perf/daily/ -ypersistent=1 -O type=bin -ystart_time=04:08:54,Mar16,2023. To match, you need to either specify a regular expression which matches this string or to leave it empty.

Arguments <mode> and <memtype> are applied after using the three criteria mentioned above.

FreeBSD

See values supported for memtype parameter on FreeBSD in the table.

Supported value Description Source in kinfo_proc structure Tries to be compatible with
vsize Virtual memory size kp_eproc.e_vm.vm_map.size or ki_size ps -o vsz
pmem Percentage of real memory calculated from rss ps -o pmem
rss Resident set size kp_eproc.e_vm.vm_rssize or ki_rssize ps -o rss
size 1 Size of process (code + data + stack) tsize + dsize + ssize
tsize Text (code) size kp_eproc.e_vm.vm_tsize or ki_tsize ps -o tsiz
dsize Data size kp_eproc.e_vm.vm_dsize or ki_dsize ps -o dsiz
ssize Stack size kp_eproc.e_vm.vm_ssize or ki_ssize ps -o ssiz

Linux

See values supported for memtype parameter on Linux in the table.

Supported value Description Source in /proc/<pid>/status file
vsize 1 Virtual memory size VmSize
pmem Percentage of real memory (VmRSS/total_memory) * 100
rss Resident set size VmRSS
data Size of data segment VmData
exe Size of code segment VmExe
hwm Peak resident set size VmHWM
lck Size of locked memory VmLck
lib Size of shared libraries VmLib
peak Peak virtual memory size VmPeak
pin Size of pinned pages VmPin
pte Size of page table entries VmPTE
size Size of process code + data + stack segments VmExe + VmData + VmStk
stk Size of stack segment VmStk
swap Size of swap space used VmSwap

Notes for Linux:

  1. Not all memtype values are supported by older Linux kernels. For example, Linux 2.4 kernels do not support hwm, pin, peak, pte and swap values.
  2. We have noticed that self-monitoring of the Zabbix agent active check process with proc.mem[...,...,...,...,data] shows a value that is 4 kB larger than reported by VmData line in the agent's /proc/<pid>/status file. At the time of self-measurement the agent's data segment increases by 4 kB and then returns to the previous size.

Solaris

See values supported for memtype parameter on Solaris in the table.

Supported value Description Source in psinfo structure Tries to be compatible with
vsize 1 Size of process image pr_size ps -o vsz
pmem Percentage of real memory pr_pctmem ps -o pmem
rss Resident set size
It may be underestimated (see rss description in man ps).		 pr_rssize ps -o rss
Footnotes

1 Default value.