Garbage Collection with Demotion of Valid Data to a Lower Memory Tier

摘要

Method and apparatus for managing data in a memory. In accordance with some embodiments, a first tier of a multi-tier memory structure is arranged into a plurality of garbage collection units (GCUs). Each GCU is formed from a plurality of non-volatile memory cells, and is managed as a unit. A plurality of data sets is stored in a selected GCU. A garbage collection operation is performed upon the selected GCU by identifying at least one of the plurality of data sets as a valid data set, migrating the valid data set to a non-volatile second tier of the multi-tier memory structure, and invalidating a programmed state of each of the plurality of non-volatile memory cells to prepare the selected GCU for storage of new data. In some embodiments, the invalidating operation involves setting all of the memory cells in the selected GCU to a known storage state.

主权项

1. A method comprising:
arranging a non-volatile first tier of a multi-tier memory structure into a plurality of garbage collection units (GCUs) each comprising a plurality of non-volatile memory cells managed as a unit; storing a plurality of data sets in a selected GCU; and performing a garbage collection operation upon the selected GCU by identifying at least one of the plurality of data sets as a valid data set, migrating the valid data set to a different, non-volatile second tier of the multi-tier memory structure, and invalidating a data state of each of the plurality of non-volatile memory cells in the selected GCU to prepare the selected GCU to store new data.