topic Re: What is the maximum memory per process in Operating System - Linux

What is the maximum memory per process

Md. Minhaz Khan — Tue, 01 Feb 2011 10:12:16 GMT

Dear Experts,

What is the maximum memory per process that
we can have in Red Hat Linux. In HP-UX we can control process size with maxdsiz,maxdsiz_64bit, maxssiz, maxssiz_64bit.

How can we control Process memory utilization in Linux. Please help.

Note: We are using RHEL 5.3,5.4,5.5

Thanks
Minhaz

Re: What is the maximum memory per process

Alzhy — Tue, 01 Feb 2011 15:02:31 GMT

32bit processes can use as much as ~4GB
64bit processes way way more than your RAM

The above HP-UX kernel parms are non-existent on RHEL 5. Instead, each user or globaly can be set limits to data. segment and stack memory in /etc/security/limits.conf

man limits.conf(5)

HTH.

Re: What is the maximum memory per process

Matti_Kurkela — Tue, 01 Feb 2011 15:18:40 GMT

The HP-UX kernel parameters maxdsiz, maxdsiz_64bit, maxssiz and maxssiz_64bit all control the POSIX standard ulimit values on HP-UX.

maxdsiz* = data segment size limit
maxssiz* = stack size limit

In HP-UX, there are separate limits for 32- and 64-bit programs. In Linux, both types of programs use the same limits.

In RedHat Enterprise Linux, the ulimit values can be configured using /etc/security/limits.conf. The file includes comments that describe the file format, and some examples. You can specify different limits for different users or user groups, if you wish.

You can view the current limits in Linux with:
ulimit -a -H

In Linux, the default limits are "unlimited" (i.e. limited only by the amount of available memory & swap space).

For more information, see "man limits.conf".

When you change the limit definitions, only new sessions started after the change will get the new limits; any existing sessions will still have the old limits.

MK

Re: What is the maximum memory per process

Md. Minhaz Khan — Wed, 02 Feb 2011 10:17:59 GMT

Dear MK & Alzhy,

Thanks a lot for your help. I have read "man limits.conf" & what i understood is, if we give below entry for user "minhaz" then is it maximum limit for per-process physical memory consumption under "minhaz" user or all processes that run under "minhaz" can not exceed the limit 128 MB:

/etc/security/limits.conf
=========================
minhaz hard as 131072

Thanks
Minhaz

Re: What is the maximum memory per process

Alzhy — Wed, 02 Feb 2011 15:15:44 GMT

Salam:

Si. Exactamente