Method and apparatus for storage resource reassignment utilizing an indicator to enhance the likelihood of successful reconfiguration

摘要

An indicator is provided in a Page Frame Table Entry to identify a page frame as “Permanently Non-Preferred” (PNP). The indicator is set for page frames in storage subincrements which have locations corresponding to page frames determined to be “bad” (permanent errors) during system IPL, when reconfiguring storage on-line, or when a storage-related error occurs for such a frame during system execution. Mechanisms are provided to convert even PNP page frames to preferred status when shortages of preferred pages exist; but the mechanism used for choosing PNP frames, and for determining which PNP frames to convert to preferred status when conversion is needed, increase the likelihood of locating a target subincrement to use in copying pages from a preferred storage subincrement when the preferred storage is taken off-line.