Paging Related Tunables

In certain revisions of the Solaris 2.6 kernel patch (105181-10 for SPARC platforms and 105182-09 for Intel platforms) and in the Solaris 7 release, a new parameter is introduced: priority paging. A new starting point for pageout thread activity (cachefree) is also used. When available memory is between cachefree and lotsfree, priority paging modifies the page-checking algorithm to skip the page, if it came from an executable (text, stack, or data). After memory falls below lotsfree, every page is considered equally. The facility is not enabled by default, but can be enabled by either setting cachefree to a value greater than lotsfree or by setting the priority_paging variable to a non-zero value, which sets cachefree to 2 times lotsfree.

priority_paging (Solaris 2.6 and 7 Releases)

Description

Enables priority paging feature. When set, this variable sets cachefree to 2 times lotsfree, thereby enabling priority paging.

Data Type

Signed integer

Default

0

Range

0 (priority paging disabled unless cachefree set separately) or 1 (enabled)

Units

Toggle (on/off)

Dynamic?

No. Sets the value of cachefree at boot time only. Runtime enabling can be achieved by setting cachefree with adb while the system is running.

Validation

None

When to Change

Should always be enabled unless the system is tight on memory, and does excessive I/O where the contents of the files are needed in the future.

Commitment Level

Obsolete

cachefree (Solaris 2.6 and Solaris 7 Releases)

Description

Enables priority paging feature, provided cachefree is greater than lotsfree. This variable is available for systems running the Solaris 2.6 release, with at a minimum, revision 10 of patch 105181 installed, and for systems running the Solaris 7 release. By default, this feature (cachefree equals lotsfree) is disabled.

Data Type

Unsigned long

Default

Value of lotsfree unless priority_paging is set, which means cachefree is 2 times lotsfree

Range

lotsfree to physical memory on system

Units

Pages

Dynamic?

Yes

Validation

If less than lotsfree, it is reset to the value of lotsfree.

When to Change

Should always be enabled unless the system is tight on memory, and does excessive I/O where the contents of the files are needed in the future.

Commitment Level

Obsolete