z/OS MVS Programming: Extended Addressability Guide
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Paging data space storage areas into and out of central storage

z/OS MVS Programming: Extended Addressability Guide
SA23-1394-00

If you expect to be processing through one or more 4K blocks of data space storage, you can use DSPSERV LOAD to load these pages into central storage. By loading an area of a data space into central storage, you reduce the number of page faults that occur while you sequentially process through that area. DSPSERV LOAD requires that you specify the STOKEN of the data space (on the STOKEN parameter), the beginning address of the area (on the START parameter), and the size of the area (on the BLOCKS parameter). The beginning address does not have to be on a 4K-byte boundary, nor does the size have to be an increment of 4K blocks. (Note that DSPSERV LOAD performs the same action for a data space as the PGSER macro with the LOAD parameter does for an address space.)

Issuing DSPSERV LOAD does not guarantee that the pages will be in central storage; the system honors your request according to the availability of central storage. Also, after the pages are loaded, page faults might occur elsewhere in the system and cause the system to move those pages out of central storage.

If you finish processing through one or more 4K block of data space storage, you can use DSPSERV OUT to page the area out of central storage. The system will make these real storage frames available for reuse. DSPSERV OUT requires that you specify the STOKEN, the beginning address of the area, and the size of the area. (Note that DSPSERV OUT corresponds to the PGSER macro with the OUT parameter.)

When your program has no further need for the data in a certain area of a data space, it can use DSPSERV RELEASE to free that storage.

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