Patent ID: 8966178
Filing Date: 2015-02-24
Classification: G06F

Abstract:
1. A computer program product for managing data in a cache system comprising a first cache, a second cache, and a storage system, the computer program product comprising a computer readable storage medium having computer readable program code embodied therein that executes to perform operations, the operations comprising: in response to the first cache being full, destaging modified non-sequential tracks indicated in a modified list from the first cache to the storage; indicating the non-sequential modified tracks destaged from the first cache to the storage as unmodified non-sequential tracks in the first cache; indicating the unmodified non-sequential tracks in the first cache in a first unmodified list, wherein the first unmodified list only indicates unmodified non-sequential tracks in the first cache; determining tracks that are indicated in the first unmodified list of unmodified tracks in the first cache stored in the storage system to demote from the first cache, wherein each stride in the first cache and the second cache is populated with tracks of data, and wherein the tracks are maintained in the storage system; forming a first stride including the determined tracks from the first unmodified list to demote based on a configuration of the second cache; determining a second stride in the second cache in which to include the tracks in the first stride; adding the tracks from the first stride to the second stride in the second cache; indicating the tracks added to the second stride in the second cache in a second unmodified list of unmodified tracks in the second cache; determining tracks from the second unmodified list in strides in the second cache to demote from the second cache; and demoting the determined tracks from the second unmodified list to the second cache.