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maxtsiz(5)

Tunable Kernel Parameters
HP-UX 11i Version 2: December 2007 Update
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NAME

maxtsiz, maxtsiz_64bit — maximum size (in bytes) of the text segment for any user process

VALUES

Default

32 bit: 96MB

64 bit: 1GB

Allowed values

32 bit minimum: 0x40000

32 bit maximum: 0x40000000

64 bit minimum: 0x40000

64 bit maximum: 0x3FFFFFFFFFF

DESCRIPTION

User programs on HP-UX systems are composed of five discrete segments of virtual memory: text (or code), data, stack, shared, and I/O. Each segment occupies an architecturally defined range of the virtual address space which sets the upper limit to their size, but text, data and stack segments may have a smaller maximum enforced via the maxtsiz, maxdsiz and maxssiz tunables.

maxtsiz controls the size of the text segment, which is the read-only executable object code for the process that can be shared by multiple processes executing the same program. For example, all copies of vi on the system use the same text segment.

Who is Expected to Change This Tunable?

Anyone.

Restrictions on Changing

Changes to this tunable take effect immediately.

When Should the Value of This Tunable Be Raised?

maxtsiz should be raised if user processes are receiving the ENOMEM error with the following message:

exec(2): text exceeds maxtsiz

or

exec(2): text exceeds maxtsiz_64bit

What Are the Side Effects of Raising the Value?

None.

When Should the Value of This Tunable Be Lowered?

This tunable should be lowered if you want to limit the text size of running processes, but there is not a system performance reason to do so.

What Are the Side Effects of Lowering the Value?

None.

What Other Tunable Values Should Be Changed at the Same Time?

None.

WARNINGS

All HP-UX kernel tunable parameters are release specific. This parameter may be removed or have its meaning changed in future releases of HP-UX.

Installation of optional kernel software, from HP or other vendors, may cause changes to tunable parameter values. After installation, some tunable parameters may no longer be at the default or recommended values. For information about the effects of installation on tunable values, consult the documentation for the kernel software being installed. For information about optional kernel software that was factory installed on your system, see HP-UX Release Notes at http://docs.hp.com.

AUTHOR

maxtsiz was developed by HP.