Another method of paging space garbage collection is by
scrubbing memory, which is implemented with the psgc kernel
process.
The psgc kernel process frees up paging space disk blocks
for modified memory pages that have not yet been paged out again or
for unmodified pages for which a paging space disk block exists.
The
psgc kernel process uses the following tunable parameters
that you can tune with the
vmo command:
Tuning the npsscrubmin parameter includes
the following fields:
| Item |
Descriptor |
| Purpose: |
Specifies the number of
free paging space blocks at which scrubbing of memory pages starts
to free disk blocks from pages from the deferred page space allocation
policy. |
| Values: |
Default:
MAX (768, the value of the npsrpgmin parameter) |
| Range: |
0 to total
number of paging space blocks in the system. |
Tuning the npsscrubmax parameter
includes the following fields:
| Item |
Descriptor |
| Purpose: |
Specifies the number of
free paging space blocks at which scrubbing of memory pages stops
to free disk blocks from pages from the deferred page space allocation
policy. |
| Values: |
Default:
MAX (1024, the value of the npsrpgmax parameter) |
| Range: |
0 to total
number of paging space blocks in the system. |
Tuning the scrub parameter includes
the following fields:
| Item |
Descriptor |
| Purpose: |
Enables or disables the
freeing of paging space disk blocks from pages in memory from pages
of the deferred page space allocation Policy. |
| Values: |
Default:
0, which completely disables memory scrubbing. If the value is set
to 1, scrubbing of memory of paging space disk blocks is enabled when
the number of system free paging space blocks is below the value of
the npsscrubmin parameter and above the value of the npsscrubmax parameter. |
| Range: |
0 | 1 |
Tuning the scrubclean parameters
includes the following fields:
| Item |
Descriptor |
| Purpose: |
Enables or disables the
freeing of paging space disk blocks from pages in memory from pages
of the deferred page space allocation policy that are not modified. |
| Values: |
Default:
0, which signifies free paging space disk blocks only for modified
pages in memoryIf the value is set to 1, frees paging space disk blocks
for modified or unmodified pages. |
| Range: |
0 | 1 |