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.

Unsigned long

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

lotsfree to physical memory on system

Pages

Yes

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

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.

Obsolete

This variable sets cachefree to 2 times lotsfree.

The Solaris 8 release changes the way file system pages are cached. These changes subsume the priority paging capability.

Note - Remove both cachefree and priority_paging settings in the /etc/system file.

Obsolete

See priority_paging (Solaris 2.6 and 7 Releases) for more information.

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

Signed integer

0

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

Toggle (on/off)

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

None

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.

Obsolete

Minimum amount of swap space that TMPFS leaves for the rest of the system.

Signed long

256

0 to maximum swap space size

Bytes

Yes

None

To maintain a reasonable amount of swap space on systems with large amounts of TMPFS usage, you can increase this number. The limit has been reached when the console or system messages file displays the following message.

fs-name: File system full, swap space limit exceeded

Unstable

Defines the number of pages that the system requires be unlocked. If a request to lock pages would force available memory below this value, that request is refused.

Unsigned long

Maximum of the triplet (200, tune_t_minarmem + 100, [10% of memory available at boot time])

Default value to no more than 20% of physical memory. The systems does no enforcement of this range other than that described in the Validation section.

Pages

Yes, unless dynamic reconfiguration operations that add or delete memory occur. At that point, the value is reset to whatever was provided in the /etc/system file or was calculated.

Maximum of the quadruplet (200, tune_t_minarmem + 100, [10% of memory available], and the value from /etc/system). No message is displayed if the value from /etc/system is increased. Done only at boot time.

When memory locking requests or attaching to a shared memory segment with the SHARE_MMU flag fails, yet the amount of memory available seems to be sufficient. Keeping 10% of memory free on a 32-Gbyte system might be excessive.

Excessively large values can cause memory locking requests to fail unnecessarily.

Unstable

Introduced in the Solaris 2.6 release to allow the stack to be marked as non-executable. This helps make buffer-overflow attacks more difficult.

In the Solaris 2.6 release, the value does not affect threaded applications. All 64-bit Solaris applications effectively make all stacks non-executable irrespective of the setting of this variable.

Note - This variable exists on all systems running the Solaris 2.6, 7, or 8 release, but it is only effective on sun4u, sun4m, and sun4d architectures.

Signed integer

0 (disabled)

0 (disabled), 1 (enabled)

Toggle (on/off)

Yes. Does not affect currently running processes--only those created after the value is set.

None

Should be enabled at all times unless applications are deliberately placing executable code on the stack without using mprotect(2) to make the stack executable.

Unstable