NAME
max_mem_window — maximum number of group-private 32-bit shared memory configurable by users
VALUES
Allowed values
Minimum: 0 shared memory windows
Maximum: 65535 shared memory windows
DESCRIPTION
32-bit processes usually share the global
quadrants 3 and 4 for such things as I/O mappings, shared libraries,
shared mapped files, etc.
However, you may wish to use quadrant 3 in a more limited sharing
fashion with only a select group of processes.
Memory windows allow this functionality.
If this tunable is
set to
0,
32-bit programs always use the global Q3 and Q4 for shared memory.
If this tunable is greater than
0
processes in defined groups use a Q3 private to that group, and then
the globally shared Q4 if Q3 is full.
Who is Expected to Change This Tunable?
Anyone.
Restrictions on Changing
Changes to this tunable take effect at the next reboot.
When Should the Value of This Tunable Be Raised?
This tunable should be raised if more group-private Q3 areas are
needed by the users of the system. Each memory window in active use will
require approximately 1Mb of kernel memory. Windows no longer in use
will have this memory reclaimed by the system.
What Are the Side Effects of Raising the Value?
A little more memory is used in the kernel.
When Should the Value of This Tunable Be Lowered?
If process groups are not being used, or not being used in the
quantity set by the tunable, there is really no point to having
this value higher than what is actually needed.
What Are the Side Effects of Lowering the Value?
The kernel uses a little less memory.
If the value is set to
0,
no group-private Q3's are allowed.
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
max_mem_window
was developed by HP.
