Managing memory maintenance operations in a memory system having backing storage media

Patent metadata

Field	Value
Publication number	US-11526445-B2
Application number	US-202016868088-A
Country	US
Kind code	B2
Filing date	May 6, 2020
Priority date	May 13, 2019
Publication date	Dec 13, 2022
Grant date	Dec 13, 2022

Abstract

Memory controllers, devices, modules, systems and associated methods are disclosed. In one embodiment, a memory system is disclosed. The memory system includes volatile memory configured as a cache. The cache stores first data at first storage locations. Backing storage media couples to the cache. The backing storage media stores second data in second storage locations corresponding to the first data. Logic uses a presence or status of first data in the first storage locations to cease maintenance operations to the stored second data in the second storage locations.

First claim

We claim:

1. A memory system, comprising:
volatile memory configured as a cache, the cache to store first data at first storage locations;
backing storage media coupled to the cache, the backing storage media to store second data in second storage locations corresponding to the first data; and
logic to cease maintenance operations to the stored second data in the second storage locations when a status of the first data in the first storage locations indicates an unmanaged state where the first data no longer corresponds to the second data, wherein the memory maintenance operations include at least one of logical-to-physical address translation, block memory management, wear leveling and erroneous data management.

2. The memory system of claim 1 , wherein:
the first storage locations comprise a first page of volatile memory storage cells; and
the second storage locations comprise a second page of storage class memory (SCM) storage cells.

3. The memory system of claim 2 , wherein:
the volatile memory storage cells comprise dynamic random access memory (DRAM).

4. The memory system of claim 2 , wherein:
the SCM storage cells comprise non-volatile memory cells.

5. The memory system of claim 4 , wherein:
the non-volatile memory cells comprise flash memory cells.

6. The memory system of claim 1 , wherein the logic comprises a local processor, the memory system further comprising:
a cache manager running on the local processor to manage operations directed to the cache; and
a backing store media manager running on the local processor to manage the backing store media.

7. The memory system of claim 6 , further comprising:
storage configured as a lookup table to store page allocation information identifying managed/unmanaged backing store pages corresponding to a status of data stored in the cache;
wherein the backing store media manager updates the backing store page allocation table as it detects data status changes; and
wherein the maintenance operations are directed solely to managed pages as identified in the lookup table.

8. The memory system of claim 1 , wherein the logic comprises a system controller host, and wherein the memory system further comprises:
an interface to receive commands generated by the system controller host, the commands specifying page-related status information for data in the cache; and
wherein application of the maintenance operations is based on the page-related status information.

9. A memory module, comprising:
a substrate;
a memory sub-system including
multiple volatile memory devices configured as a cache, the cache to store first data at first storage locations;
backing storage media coupled to the cache, the backing storage media to store second data in second storage locations corresponding to the first data; and
wherein maintenance operations to the stored second data in the second storage locations are ceased when a status of the first data in the first storage locations indicates an unmanaged state where the first data no longer corresponds to the second data, wherein the memory maintenance operations include at least one of logical-to-physical address translation, block memory management, wear leveling and erroneous data management.

10. The memory module of claim 9 , wherein:
the maintenance operations comprise at least one from the group comprising memory address translation, memory block management, wear leveling operations, and data error management operations.

11. The memory module of claim 9 , wherein:
the backing storage media comprises multiple flash memory devices.

12. The memory module of claim 9 , further comprising:
a local processor;
a cache manager running on the local processor to manage operations directed to the cache; and
a backing storage media manager running on the local processor to manage the backing storage media.

13. The memory module of claim 12 , further comprising:
storage configured as a lookup table to store page allocation information identifying managed/unmanaged backing store pages corresponding to a status of data stored in the cache;
wherein the backing storage media manager is operative to detect changes to data status of pages in the cache;
wherein the backing storage media manager updates the backing store page allocation table in response to detected data status changes; and
wherein the maintenance operations are solely directed to managed pages as identified in the lookup table.

14. The memory module of claim 9 , further comprising:
an interface to receive commands generated external to the memory module, the commands specifying page-related status information for data in the cache; and
wherein the maintenance operations are selectively directed to the backing storage media based on the page-related status information.

15. The memory module of claim 9 , wherein:
the page-related status information includes at least one from the group comprising data unallocation, data load and unallocation, and data read-only.

16. A method of operation in a memory system, the method comprising:
storing first data at first volatile memory storage locations in a cache;
selectively storing a copy of the first data a s in a second location of a backing storage media for the cache, and
ceasing maintenance operations to the stored second data in the second storage locations when a status of first data in the first storage locations indicates an unmanaged state where the first data no longer corresponds to the second data, wherein the memory maintenance operations include at least one of logical-to-physical address translation, block memory management, wear leveling and erroneous data management.

17. The method of claim 16 , wherein:
the ceasing maintenance operations is controlled locally on a memory module, the cache and backing storage media disposed on the memory module.

18. The method of claim 17 , wherein the memory module includes a local processor and a backing storage media memory manager running on the processor, and wherein the method further comprises:
detecting changes to data status of pages in the cache with the backing storage media memory manager;
updating a backing store page allocation table with the backing storage media memory manager in response to detected data status changes; and
wherein the maintenance operations are solely directed to managed pages as identified in the lookup table.

19. The method of claim 16 , wherein:
the ceasing maintenance operations is controlled remotely by a system controller host.

Assignees

• Rambus Inc

Inventors

• Williams Collins
• Miller Michael
• Wright Kenneth

Classifications

• G06F12/0871

  Allocation or management of cache space · CPC title

• G11C14/0018

  whereby the nonvolatile element is an EEPROM element, e.g. a floating gate or metal-nitride-oxide-silicon [MNOS] transistor · CPC title

• G06F12/0815 Primary

  Cache consistency protocols · CPC title

• G06F2212/7202

  Allocation control and policies · CPC title

• G06F2212/7203

  Temporary buffering, e.g. using volatile buffer or dedicated buffer blocks · CPC title