Memory array page table walk

• US 10,402,340 B2
• Filed: 02/21/2017
• Issued: 09/03/2019
• Est. Priority Date: 02/21/2017
• Status: Active Grant

• Current Assignee: Lodestar Licensing Group LLC
• Original Assignee: Micron Technology, Inc.
• Inventors: Lea, Perry V.
• Primary Examiner(s): Chappell, Daniel C.
• Application Number:
  US15/437,982
• Publication Number:
  US 20180239712A1
• Time in Patent Office: 924 Days
• CPC Class Codes: G06F 12/0864 using pseudo-associative means, e.g. set-associative or hashing
• CPC Class Codes: G06F 12/1009 using page tables, e.g. page table structures
• CPC Class Codes: G06F 12/1027 using associative or pseudo-associative address translation means, e.g. translation look-aside buffer [TLB]
• CPC Class Codes: G06F 12/1045 associated with a data cache
• CPC Class Codes: G06F 2212/1016 Performance improvement
• CPC Class Codes: G06F 2212/1028 Power efficiency
• CPC Class Codes: G06F 2212/651 Multi-level translation tables
• CPC Class Codes: G06F 2212/652 Page size control
• CPC Class Codes: G06F 2212/684 TLB miss handling
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

An example memory array page table walk can include using an array of memory cells configured to store a page table. The page table walk can include using sensing circuitry coupled to the array. The page table walk can include using a controller coupled to the array. The controller can be configured to operate the sensing circuitry to determine a physical address of a portion of data by accessing the page table in the array of memory cells. The controller can be configured to operate the sensing circuitry to cause storing of the portion of data in a buffer.

Claims

1. An apparatus, comprising:

an array comprising memory cells arranged in rows coupled by access lines and columns coupled by sense lines;

sensing circuitry coupled to the array and comprising;

sense amplifiers each corresponding to different sense lines; and

compute components each corresponding to the different sense lines; and

a memory controller coupled to the array, wherein the memory controller is configured to operate the sensing circuitry to;

cause storing of a page table in the array;

determine, in the array and without sending data outside the array, a physical address of a portion of data by accessing the page table; and

cause storing of the portion of data in a buffer.

2. The apparatus of claim 1, wherein the buffer is a translation lookaside buffer (TLB).

3. The apparatus of claim 1, wherein the controller configured to operate the sensing circuitry to determine the physical address comprises the controller configured to cause a page walk through the page table in the array independent of receiving intermediate instructions to perform the page table walk from a host.

4. The apparatus of claim 3, wherein the controller configured to cause storing of the page table in the array comprises the controller configured to cause storing of a series of descriptors with tiered levels that indicate a location of the portion of data.

5. The apparatus of claim 4, wherein each of the tiered levels is a pointer to a sub-section of a subsequent next level of the tiered levels.

6. The apparatus of claim 5, wherein a final tiered level of the tiered levels indicates the physical address of the portion of data.

7. The apparatus of claim 1, wherein the array of memory cells is configured to store the page table rather than a main memory associated with the array of memory cells.

8. A method, comprising:

searching for a physical address corresponding to a virtual address in a lookaside translation buffer (TLB);

determining that the virtual address is not located in the TLB;

performing a page table walk in a memory array comprising memory cells arranged in rows coupled by access lines and columns coupled by sense lines, wherein the page table walk is performed;

independent of intermediate page table walk instructions from a host and without sending data outside the memory array; and

by performing each of a number of logical operations using compute components of sensing circuitry of the memory array on a sense line by sense line bases, wherein the compute components correspond to different respective sense lines; and

locating the physical address based on the page table walk.

9. The method of claim 8, wherein performing the page table walk comprises resolving a first level of the page table to determine a location in a second level of the page table.

10. The method of claim 9, comprising resolving the second level to determine a location in a third level of the page table.

11. The method of claim 10, comprising resolving the third level of the page table to determine a location in a fourth level of the page table.

12. The method of claim 11, comprising resolving the fourth level of the page table to determine the physical address corresponding to the virtual address.

13. The method of claim 8, wherein, in response to determining the physical address, sending the portion of data located at the physical address to be stored in the TLB.

14. The method of claim 8, wherein performing the page table walk comprises comparing the virtual address with each of a plurality of elements of the page table simultaneously.

15. The method of claim 14, wherein comparing the virtual address with each of the plurality of elements comprises comparing the virtual address with a first of the plurality of elements using a plurality of first sensing components.

16. The method of claim 15, wherein the plurality of first sensing components used is a quantity that corresponds to a length of the virtual address and the first of the plurality of elements.

17. The method of claim 15, wherein comparing the virtual address with each of the plurality of elements comprises comparing the virtual address with a second of the plurality of elements using a plurality of second sensing components simultaneously with comparing the virtual address with the first of the plurality of elements.

18. The method of claim 17, wherein, the method includes using the memory array and the sensing circuitry as a fully associative cache to locate the physical address while simultaneously resolving levels of a page table.

19. An apparatus, comprising:

an array of memory cells configured to store a page table and arranged in rows coupled by access lines and columns coupled by sense lines;

sensing circuitry coupled to the array and comprising;

sense amplifiers each corresponding to different sense lines; and

compute components each corresponding to the different sense lines; and

a controller coupled to the array, wherein the controller is configured to operate the sensing circuitry to;

search for an address in a translation lookaside buffer (TLB), wherein the address is associated with a portion of data;

in response to the address being absent from the TLB, perform a walk through the page table without sending data outside the array;

determine a physical address of the portion of data based on the page table walk; and

cause storing of the portion of data in the TLB.

20. The apparatus of claim 19, wherein the array of memory cells and the sensing circuitry are configured to be a fully associative cache to determine the physical address.

21. The apparatus of claim 19, wherein the controller is configured to, in response to the portion of data not being in the array of memory cells, indicate to a host to locate the portion of data in an additional memory location.

22. A method, comprising:

performing a page table walk on a page table stored in a memory array to determine a physical address associated with a portion of data in response to determining that a virtual address associated with the portion of data is not located in a translation lookaside buffer (TLB), wherein the memory array comprises memory cells arranged in rows coupled by access lines and columns coupled by sense lines;

wherein performing the page table walk comprises;

resolving page table levels simultaneously;

using compute components of the sensing circuitry to perform each of a number of logical operations on a sense line by sense line bases, wherein the compute components correspond to different respective sense lines; and

without sending data outside the memory array.

23. The method of claim 22, wherein resolving the page table levels simultaneously using the sensing circuitry comprises comparing the virtual address to each of a plurality of elements in the page table.

24. The method of claim 23, wherein, while comparing the virtual address to each of the plurality of elements, the page table stored in the memory array is used as a fully associative cache.