MMG CTLFLAGS

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MMG_CTLFLAGS is a dynamic bitmask system parameter used to enable or disable memory management-related activities. The first two bits, 0 and 1, control the proactive memory reclamation mechanisms. Bit 2 controls deferred memory testing.

Bit Description
0 If this bit is set, reclamation is enabled by trimming from periodically executing, but otherwise idle, processes. This occurs when the size of the free list plus the modified list drops below two times the value of FREEGOAL. This function is disabled if the bit is clear.
1 If this bit is set, reclamation is enabled by outswapping processes that have been idle for longer than LONGWAIT seconds. This occurs when the size of the free list drops below FREEGOAL. This function is disabled if the bit is clear.
2 Controls deferred memory testing (only on AlphaServer 4100 systems). You can use this bit to speed up elapsed bootstrap time by controlling when memory is tested:
  • If the bit is clear (the default), OpenVMS tests memory as a background activity, which might or might not complete before the end of the bootstrap process.
  • If the bit is set, all memory is tested in the bootstrap process by the end of the EXEC_INIT phase (that is, before IPL is lowered from 31).
3 Reserved to OpenVMS use; must be zero.
4 If this bit is clear (the default), all page sizes supported by hardware can be used to map resident memory sections on Integrity servers. If this bit is set, page sizes on Integrity servers are limited to the maximum GH factor available on Alpha systems (512 * <system page size>).
5-7 Reserved for future use.

MMG_CTLFLAGS is an AUTOGEN and DYNAMIC parameter.