	US 12,235,754 B2
	Victim zone selection for zone compaction during garbage collection in zns devices
Navin Kochar, Karnataka (IN); Sampath Kumar Raja Murthy, Karnataka (IN); and Suhaib Mohammed Adhoni, Karnataka (IN)
Assigned to SANDISK TECHNOLOGIES, INC., Milpitas, CA (US)
Filed by Western Digital Technologies, Inc., San Jose, CA (US)
Filed on Jul. 7, 2023, as Appl. No. 18/349,098.
Claims priority of provisional application 63/383,230, filed on Nov. 10, 2022.
Prior Publication US 2024/0160563 A1, May 16, 2024
Int. Cl. G06F 16/00 (2019.01); G06F 12/02 (2006.01)

CPC G06F 12/0253 (2013.01)

16 Claims

1. A storage device, comprising:

a non-volatile memory including a plurality of first blocks, a plurality of second blocks, and a plurality of third blocks; and

a controller configured to:

allocate a first sub-drive and a second sub-drive in the non-volatile memory, wherein the first sub-drive includes a first plurality of superblocks for storing data overwrites associated with a zoned namespace (ZNS) and for storing other data associated with a namespace other than the ZNS, the first plurality of superblocks including the first superblock, wherein the second sub-drive includes a second plurality of superblocks for storing sequential data associated with the ZNS, the second plurality of superblocks in the second sub-drive including the second superblock and the third superblock;

create a first superblock including the first blocks, a second superblock including the second blocks;

determine whether a total quantity of data in the first sub-drive exceeds a threshold percentage of a capacity of the non-volatile memory, the total quantity including at least the first quantity and the second quantity;

relocate, during a first garbage collection for a first zone prior to a second garbage collection for a second zone, first data overwrites associated with the first zone from the first superblock in the first sub-drive to the second superblock in the second sub-drive in response to the total quantity exceeding the threshold percentage, the first zone including a first range of logical addresses, and the second zone including a second range of logical addresses different than the first range of logical addresses; and

relocate, during the second garbage collection, the second data overwrites from the first superblock in the first sub-drive to the third superblock in the second sub-drive in response to the total quantity of the data in the first sub-drive continuing to exceed the threshold percentage after the first garbage collection,

wherein the first garbage collection occurs prior to the second garbage collection in response to a first quantity of the first data overwrites in the first superblock being larger than a second quantity of second data overwrites associated with the second zone in the first superblock.