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US 8,943,276 B2Granted
Efficient discard scans
AssigneeInternational Business Machines Corporation
InventorsMichael T. Benhase, Lokesh M. Gupta, Carol S. Mellgren, Kenneth W. Todd
Life of this patent
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Abstract
A plurality of tracks is examined for meeting criteria for a discard scan. In lieu of waiting for a completion of a track access operation, at least one of the plurality of tracks is marked for demotion. An additional discard scan may be subsequently performed for tracks not previously demoted. The discard and additional discard scans may proceed in two phases.
Claims7
A method for performing a discard scan operation by a processor device in a computing storage environment, comprising:
- examining a plurality of tracks for meeting a criteria for a discard scan;
- in lieu of waiting for a completion of a track access operation, marking at least one of the plurality of tracks for demotion by setting a bit in the hash table indicating a beginning of an extent range and an end of the extent range in the at least one of the plurality of tracks
- in response to the track access operation not being complete after the step of marking, taking a spin lock and setting a flag on one track of the plurality of tracks and releasing the spin lock after setting the flag, and
- in response to the track access operation not being complete and after the step of marking, continuing to perform the step of marking on another one of the plurality of tracks for demotion by setting another bit in the hash table.
1 more element
Dependencies are inferred from the claim text.