# US 2026/0064584 A1 · Lookup table for contiguous page detection in live migration > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2026/0064584 A1 - Document ID: US20260064584A1 - Status: Published application - Kind: A1 - Application number: 18/888,773 - Filed: 2024-09-18 - Published: 2026-03-05 - Earliest claimed: 2024-08-29 - Assignees: Micron Technology, Inc. - Applicants: Micron Technology, Inc. - Inventors: Hua Ye - Web page: https://patentgrep.com/patent/US20260064584A1 ## CPC - G06F 12/0246: {in block erasable memory, e.g. flash memory} - G06F 12/0292: {using tables or multilevel address translation means (G06F12/023 takes precedence; address translation in virtual memory systems G06F12/10)} - G06F 13/1668: {Details of memory controller} - G06F 2212/657: Virtual address space management - G06F 2212/7201: Logical to physical mapping or translation of blocks or pages - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract A first set of characteristics corresponding to a first memory device and a second set of characteristics corresponding to a second memory device are received. A first usage threshold for the first memory device based on the first set of characteristics and a second usage threshold for the second memory device based on the second set of characteristics are determined. Data is stored at the first memory device or the second memory device based on the first usage threshold for the first memory device and the second usage threshold for the second memory device. ## Claims ### Claim 1 A system comprising: a plurality of memory devices; and a processing device, operatively coupled with the plurality of memory devices, to perform operations comprising: for each namespace of a plurality of namespaces of the plurality of memory devices, identifying a corresponding set of bitmaps; identifying, for the set of bitmaps, a plurality of physical addresses, wherein each physical address of the plurality of physical addresses identifies a memory location of the memory device storing a page of the set of bitmaps; for each physical address of the plurality of physical addresses, storing a namespace identifier of the respective namespace and a respective physical address identifying a memory location of the memory device, the memory location storing a page of the set of bitmaps in an entry of a plurality of entries of a reverse namespace lookup data structure; receiving a host command to track migration of a target namespace of the plurality of namespaces; and initializing, using the reverse namespace lookup data structure, a set of bitmaps of the target namespace. ### Claim 2 (depends on 1) The system of claim 1, wherein identifying, for the set of bitmaps, the plurality of physical addresses comprises: for each bitmap of the set of bitmaps, identifying a corresponding logical page pointer data structure, wherein each entry of the logical page pointer data structure includes a logical page number of a logical page of the bitmap and a physical address which identifies a memory location of the memory device storing data of the logical page of the respective bitmap; obtaining, from each entry of the logical page pointer data structure associated with the respective bitmap, a corresponding physical address. ### Claim 3 (depends on 1) The system of claim 1, wherein each entry of the reverse namespace lookup data structure is indexed by a physical address. ### Claim 4 (depends on 1) The system of claim 1, wherein initializing, using the reverse namespace lookup data structure, the set of bitmaps of the target namespace comprises: for each entry of the reverse namespace lookup data structure, comparing a namespace identifier of the target namespace with a namespace identifier of a respective entry; responsive to determining that the namespace identifier of the target namespace matches the namespace identifier of the respective entry, determining whether a namespace identifier of consecutive entries of the reverse namespace lookup data structure following the respective entry matches the namespace identifier of the target namespace. ### Claim 5 (depends on 4) The system of claim 4, wherein the processing device is to perform operations further comprising: responsive to determining the namespace identifier of consecutive entries of the reverse namespace lookup data structure following the respective entry matches the namespace identifier of the target namespace, writing a known value to bits within a memory location addressed by a range of physical addresses associated with the respective entry and the consecutive entries. ### Claim 6 (depends on 4) The system of claim 4, wherein the processing device is to perform operations further comprising: responsive to determining a namespace identifier of a subsequent entry of the reverse namespace lookup data structure following the respective entry does not match the namespace identifier of the target namespace, writing a known value to bits within a memory location addressed by a physical address associated with the respective entry. ### Claim 7 (depends on 1) The system of claim 1, wherein a first bitmap of the set of bitmaps tracks memory pages copied from a source namespace to a destination namespace, a second bitmap of the set of bitmaps tracks memory pages modified at the source namespace during migration, and a third bitmap of the set of bitmaps tracks memory pages modified at the source namespace during migration when the second bitmap is unavailable. ### Claim 8 A method comprising: for each namespace of a plurality of namespaces of a plurality of memory devices, identifying a corresponding set of bitmaps; identifying, for the set of bitmaps, a plurality of physical addresses, wherein each physical address of the plurality of physical addresses identifies a memory location of the memory device storing a page of the set of bitmaps; for each physical address of the plurality of physical addresses, storing a namespace identifier of the respective namespace and a respective physical address identifying a memory location of the memory device, the memory location storing a page of the set of bitmaps in an entry of a plurality of entries of a reverse namespace lookup data structure; receiving a host command to track migration of a target namespace of the plurality of namespaces; and initializing, using the reverse namespace lookup data structure, a set of bitmaps of the target namespace. ### Claim 9 (depends on 8) The method of claim 8, wherein identifying, for the set of bitmaps, the plurality of physical addresses comprises: for each bitmap of the set of bitmaps, identifying a corresponding logical page pointer data structure, wherein each entry of the logical page pointer data structure includes a logical page number of a logical page of the bitmap and a physical address which identifies a memory location of the memory device storing data of the logical page of the respective bitmap; obtaining, from each entry of the logical page pointer data structure associated with the respective bitmap, a corresponding physical address. ### Claim 10 (depends on 8) The method of claim 8, wherein each entry of the reverse namespace lookup data structure is indexed by a physical address. ### Claim 11 (depends on 8) The method of claim 8, wherein initializing, using the reverse namespace lookup data structure, the set of bitmaps of the target namespace comprises: for each entry of the reverse namespace lookup data structure, comparing a namespace identifier of the target namespace with a namespace identifier of a respective entry; responsive to determining that the namespace identifier of the target namespace matches the namespace identifier of the respective entry, determining whether a namespace identifier of consecutive entries of the reverse namespace lookup data structure following the respective entry matches the namespace identifier of the target namespace. ### Claim 12 (depends on 11) The method of claim 11, further comprising: responsive to determining the namespace identifier of consecutive entries of the reverse namespace lookup data structure following the respective entry matches the namespace identifier of the target namespace, writing a known value to bits within a memory location addressed by a range of physical addresses associated with the respective entry and the consecutive entries. ### Claim 13 (depends on 11) The method of claim 11, further comprising: responsive to determining a namespace identifier of a subsequent entry of the reverse namespace lookup data structure following the respective entry does not match the namespace identifier of the target namespace, writing a known value to bits within a memory location addressed by a physical address associated with the respective entry. ### Claim 14 (depends on 8) The method of claim 8, wherein a first bitmap of the set of bitmaps tracks memory pages copied from a source namespace to a destination namespace, a second bitmap of the set of bitmaps tracks memory pages modified at the source namespace during migration, and a third bitmap of the set of bitmaps tracks memory pages modified at the source namespace during migration when the second bitmap is unavailable. ### Claim 15 A non-transitory computer-readable storage medium comprising instructions that, when executed by a processing device, cause the processing device to perform operations comprising: for each namespace of a plurality of namespaces of a plurality of memory devices, identifying a corresponding set of bitmaps; identifying, for the set of bitmaps, a plurality of physical addresses, wherein each physical address of the plurality of physical addresses identifies a memory location of the memory device storing a page of the set of bitmaps; for each physical address of the plurality of physical addresses, storing a namespace identifier of the respective namespace and a respective physical address identifying a memory location of the memory device, the memory location storing a page of the set of bitmaps in an entry of a plurality of entries of a reverse namespace lookup data structure; receiving a host command to track migration of a target namespace of the plurality of namespaces; and initializing, using the reverse namespace lookup data structure, a set of bitmaps of the target namespace. ### Claim 16 (depends on 15) The non-transitory computer-readable storage medium of claim 15, wherein identifying, for the set of bitmaps, the plurality of physical addresses comprises: for each bitmap of the set of bitmaps, identifying a corresponding logical page pointer data structure, wherein each entry of the logical page pointer data structure includes a logical page number of a logical page of the bitmap and a physical address which identifies a memory location of the memory device storing data of the logical page of the respective bitmap; obtaining, from each entry of the logical page pointer data structure associated with the respective bitmap, a corresponding physical address. ### Claim 17 (depends on 15) The non-transitory computer-readable storage medium of claim 15, wherein each entry of the reverse namespace lookup data structure is indexed by a physical address. ### Claim 18 (depends on 15) The non-transitory computer-readable storage medium of claim 15, wherein initializing, using the reverse namespace lookup data structure, the set of bitmaps of the target namespace comprises: for each entry of the reverse namespace lookup data structure, comparing a namespace identifier of the target namespace with a namespace identifier of a respective entry; responsive to determining that the namespace identifier of the target namespace matches the namespace identifier of the respective entry, determining whether a namespace identifier of consecutive entries of the reverse namespace lookup data structure following the respective entry matches the namespace identifier of the target namespace. ### Claim 19 (depends on 18) The non-transitory computer-readable storage medium of claim 18, wherein the processing device is to perform operations further comprising: responsive to determining the namespace identifier of consecutive entries of the reverse namespace lookup data structure following the respective entry matches the namespace identifier of the target namespace, writing a known value to bits within a memory location addressed by a range of physical addresses associated with the respective entry and the consecutive entries. ### Claim 20 (depends on 18) The non-transitory computer-readable storage medium of claim 18, wherein the processing device is to perform operations further comprising: responsive to determining a namespace identifier of a subsequent entry of the reverse namespace lookup data structure following the respective entry does not match the namespace identifier of the target namespace, writing a known value to bits within a memory location addressed by a physical address associated with the respective entry.