Integration of application indicated maximum time to cache to least recently used track demoting schemes in a cache management system of a storage controller

A system, comprising:

• a memory;
• and
• a processor coupled to the memory, wherein the processor performs operations, the operations performed by the processor comprising:
• receiving an indication that specifies a maximum retention time in cache for a first plurality of tracks, wherein no maximum retention time is specified for a second plurality of tracks;
• generating a plurality of insertion points in a least recently used (LRU) list, wherein different insertion points in the LRU list correspond to different amounts of maximum retention times in the cache, and wherein the LRU list is configured to demote both tracks of the first plurality of tracks and the second plurality of tracks from the cache;
• determining whether a track is of the first plurality of tracks with maximum retention time specified or is of the second plurality of tracks with no maximum retention time specified;
• in response to determining that the track is of the first plurality of tracks with maximum retention time specified, performing:
• determining an insertion point that is closest to the maximum retention time specified for the track of the first plurality of tracks;
• adding the track of the first plurality of tracks to the determined insertion point in the LRU list;
• starting with the determined insertion point, finding all insertion points that are above the determined insertion point, and moving all insertion points one track lower;
• in response to determining that a list size of the LRU list is a multiple of an insertion interval size that is indicative of how many tracks fit in a specified interval of time, adding a new insertion point to a most recently used (MRU) end of the LRU list;
• and
• in response to determining that the list size of the LRU list is not a multiple of the insertion interval size, performing an exiting from processing the track of the first plurality of tracks;
• and
• in response to determining that the track is of the second plurality of tracks with no maximum retention time specified, adding the track of the second plurality of tracks to the MRU end of the LRU list.

A computer program product, the computer program product comprising a computer readable storage medium having computer readable program code embodied therewith, the computer readable program code configured to perform operations in a computational device, the operations comprising:

• receiving an indication that specifies a maximum retention time in cache for a first plurality of tracks, wherein no maximum retention time is specified for a second plurality of tracks;
• generating a plurality of insertion points in a least recently used (LRU) list, wherein different insertion points in the LRU list correspond to different amounts of maximum retention times in the cache, and wherein the LRU list is configured to demote both tracks of the first plurality of tracks and the second plurality of tracks from the cache;
• determining whether a track is of the first plurality of tracks with maximum retention time specified or is of the second plurality of tracks with no maximum retention time specified;
• in response to determining that the track is of the first plurality of tracks with maximum retention time specified, performing:
• determining an insertion point that is closest to the maximum retention time specified for the track of the first plurality of tracks;
• adding the track of the first plurality of tracks to the determined insertion point in the LRU list;
• starting with the determined insertion point, finding all insertion points that are above the determined insertion point, and moving all insertion points one track lower;
• in response to determining that a list size of the LRU list is a multiple of an insertion interval size that is indicative of how many tracks fit in a specified interval of time, adding a new insertion point to a most recently used (MRU) end of the LRU list;
• and
• in response to determining that the list size of the LRU list is not a multiple of the insertion interval size, performing an exiting from processing the track of the first plurality of tracks;
• and
• in response to determining that the track is of the second plurality of tracks with no maximum retention time specified, adding the track of the second plurality of tracks to the MRU end of the LRU list.

A storage controller, comprising:

• a cache;
• and
• a processor coupled to the cache, wherein the processor is configurable to perform operations,
• the operations comprising:
• receiving an indication that specifies a maximum retention time the cache for a first plurality of tracks, wherein no maximum retention time is specified for a second plurality of tracks;
• generating a plurality of insertion points in a least recently used (LRU) list, wherein different insertion points in the LRU list correspond to different amounts of maximum retention times in the cache, and wherein the LRU list is configured to demote both tracks of the first plurality of tracks and the second plurality of tracks from the cache;
• determining whether a track is of the first plurality of tracks with maximum retention time specified or is of the second plurality of tracks with no maximum retention time specified;
• in response to determining that the track is of the first plurality of tracks with maximum retention time specified, performing:
• determining an insertion point that is closest to the maximum retention time specified for the track of the first plurality of tracks;
• adding the track of the first plurality of tracks to the determined insertion point in the LRU list;
• starting with the determined insertion point, finding all insertion points that are above the determined insertion point, and moving all insertion points one track lower;
• in response to determining that a list size of the LRU list is a multiple of an insertion interval size that is indicative of how many tracks fit in a specified interval of time, adding a new insertion point to a most recently used (MRU) end of the LRU list and
• in response to determining that the list size of the LRU list is not a multiple of the insertion interval size, performing an exiting from processing the track of the first plurality of tracks;
• and
• in response to determining that the track is of the second plurality of tracks with no maximum retention time specified, adding the track of the second plurality of tracks to the MRU end of the LRU list.