Partial R-block recycling

• US 8,972,776 B2
• Filed: 03/07/2013
• Issued: 03/03/2015
• Est. Priority Date: 03/06/2013
• Status: Expired due to Fees

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Inventors: Baryudin, Leonid, Tang, Alex G., Cohen, Earl T.
• Primary Examiner(s): CHU, GABRIEL L
• Application Number:
  US13/788,303
• Publication Number:
  US 20140258769A1
• Time in Patent Office: 726 Days
• Field of Search: None
• US Class Current: 714/6.2
• CPC Class Codes: G06F 11/0793 Remedial or corrective actions recovery from an exception in an instruction pipeline G06F9/3861; by retry G06F11/1402; for recovering from a failure of a protocol instance or entity H04L69/40
• CPC Class Codes: G06F 11/1008 in individual solid state devices G06F11/1004 takes precedence
• CPC Class Codes: G06F 12/02 Addressing or allocation; Relocation program address sequencing G06F9/00; arrangements for selecting an address in a digital store G11C8/00
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2211/109 Sector level checksum or ECC, i.e. sector or stripe level checksum or ECC in addition to the RAID parity calculation
• CPC Class Codes: G06F 2212/7205 Cleaning, compaction, garbage collection, erase control
• CPC Class Codes: G11C 16/3418 Disturbance prevention or evaluation; Refreshing of disturbed memory data
• CPC Class Codes: G11C 2029/0409 Online test
• CPC Class Codes: G11C 2029/0411 Online error correction
• CPC Class Codes: G11C 29/82 for EEPROMs

Abstract

An apparatus includes a non-volatile memory and a controller. The non-volatile memory includes a plurality of R-blocks. The controller is coupled to the non-volatile memory. The controller is configured to (i) write data using the R-blocks as a unit of allocation and (ii) perform recycling operations selectively on either an entire one of the R-blocks or a portion less than all of one of the R-blocks.

Claims

1. An apparatus comprising:

a non-volatile memory comprising a plurality of R-blocks; and

a controller coupled to said non-volatile memory, wherein said controller is configured to (i) write data using said R-blocks as a unit of allocation and (ii) perform recycling operations selectively on either an entire one of said R-blocks or a portion less than all of one of said R-blocks.

2. The apparatus according to claim 1, wherein said controller is further configured to perform said recycling operations on said entire one of said R-blocks as part of garbage collection.

3. The apparatus according to claim 1, wherein said controller is further configured to perform said recycling operations on said portion less than all of one of said R-blocks as part of error handling.

4. The apparatus according to claim 3, wherein:

said error handling is enabled in response to detection of a program error in a block of said non-volatile memory; and

said portion less than all of one of said R-blocks is a portion of said block of said non-volatile memory.

5. The apparatus according to claim 3, wherein:

said error handling is enabled in response to detection of a program error in a block of said non-volatile memory; and

said portion less than all of one of said R-blocks is an R-page.

6. The apparatus according to claim 3, wherein:

said error handling is enabled in response to detection of a read disturb condition of a block of said non-volatile memory; and

said portion less than all of one of said R-blocks is said block of said non-volatile memory affected by said read disturb condition.

7. The apparatus according to claim 1, wherein said controller is configured to perform said recycling operations on a granularity less than that of an entire one of said R-blocks by performing said recycling operations on said portion less than all of one of said R-blocks.

8. The apparatus according to claim 1, wherein:

said portion less than all of one of said R-blocks comprises a plurality of pages of said non-volatile memory, with said plurality of pages storing at least a portion of one or more valid data items; and

said controller is configured to perform said recycling operations on said portion less than all of one of said R-blocks by making a determination whether a particular one of said one or more valid data items spans into or out of the portion less than all of one of said R-blocks and, based upon the determination, selectively performing recycling operations that recycle all of the one or more valid data items.

9. The apparatus according to claim 1, wherein said portion less than all of one of said R-blocks comprises at least one of a single non-volatile memory block, a portion of said single non-volatile memory block, a single R-page, a single e-page.

10. A method for recycling non-volatile memory (NVM) blocks in an R-block comprising the steps of:

reading a NVM page in a selected NVM block;

locating data unit within said NVM page;

determining whether said data unit within said NVM page spans outside said selected NVM block;

determining whether said data unit is valid;

if said data unit is valid, also determining which, if any, neighbor NVM pages are affected;

if neighbor NVM pages are affected, reading any neighbor NVM pages so all portions of said data unit are available along with any related meta-data associated with the span of said data unit;

recycling the valid data unit by re-writing the data unit to another NVM location outside the area being recycled.

11. The method according to claim 10, wherein said R-block comprises a combination of NVM blocks providing cross-die redundancy for error correction.

12. The method according to claim 10, wherein said span of said data unit comprises one or both of (i) a data unit starting in one or more previous NVM blocks and (ii) a data unit continuing into one or more subsequent NVM blocks.

13. The method according to claim 12, wherein meta-data within the data indicates spanning of data units.

14. The method according to claim 13, further comprising parsing the meta-data to determine whether previous NVM blocks, subsequent NVM blocks, or both previous and subsequent NVM blocks are needed.

15. The method according to claim 10, further comprising calculating the neighbor NVM pages based on worst case spanning conditions.

16. A method for recycling a single R-page comprising:

reading one or more NVM pages in a selected R-page;

locating data units within the one or more NVM pages;

determining if data units in the one or more NVM pages span outside the selected R-page;

determining which data units are valid;

for each data unit that is valid, also determining which neighbor NVM pages are affected;

if neighbor NVM pages are affected, reading the neighbor NVM pages so all portions of said data units along with any related meta-data associated with the span of data units are available;

recycling the valid data units by re-writing the data units to another NVM location.

17. The method according to claim 16, wherein said R-page comprises a set of NVM pages and each neighbor NVM page as defined by a write order can be on one or both of a different NVM block and a different NVM die.

18. The method according to claim 16, wherein said R-page contains cross-die or cross-block redundancy.

19. The method according to claim 16, wherein the NVM pages in the selected R-page are read in sequence or concurrently.

20. The method according to claim 16, further comprising updating the map information with a new location and size for each data unit being rewritten after the re-write.