Hybrid address translation cache using DRAM
Splitting an address translation cache (ATC) into two portions can reduce costs and maintain efficient retrieval of data. One portion can be disposed in a first location while a second portion can be disposed in a second location distinct from the first location. The first location can be in the controller. The second location can be in a host memory buffer (HMB) or in a memory device separate from the controller. To obtain translated addresses, untranslated addresses can be searched in the first portion and the corresponding translated addresses can be retrieved from the second portion. When invalidating untranslated addresses, the untranslated addresses of the first portion can be deleted without a need to delete corresponding translated addresses in the second portion. To improve ATC storage capacity, grouping of untranslated addresses is possible using most significant bytes (MSBs).
1. A data storage device, comprising:
a memory device; and
a controller coupled to the memory device, wherein the controller is configured to:
obtain a translation corresponding to an untranslated address;
store the untranslated address in a first location of an address translation cache (ATC);
retrieve the untranslated address from the first location of the ATC;
store the translated address in a second location of the ATC, wherein the first location is separate and distinct from the second location; and
retrieve the translated address corresponding to the untranslated address from the second location of the ATC, wherein retrieving the untranslated address and retrieving the translated address occur sequentially.
2. The data storage device of claim 1 , wherein the first location is volatile memory.
3. The data storage device of claim 2 , wherein the volatile memory is static random access memory (SRAM).
4. The data storage device of claim 3 , wherein the SRAM is disposed in a host interface module (HIM).
5. The data storage device of claim 2 , wherein the first location and the second location are each volatile memory.
6. The data storage device of claim 5 , wherein the second location is dynamic random access memory (DRAM).
7. The data storage device of claim 2 , wherein the second location is host memory buffer (HMB).
8. The data storage device of claim 1 , wherein the controller is further configured to:
determine that address translation service (ATS) is needed;
search for the untranslated address in the first location;
determine that the untranslated address is in the first location; and
retrieve the translated address from the second location.
9. The data storage device of claim 1 , wherein the controller is further configured to:
receive an invalidation request to invalidate the untranslated address;
search for the untranslated address in the first location; and
delete the untranslated address in the first location.
10. The data storage device of claim 9 , wherein the controller is configured to not delete the translated address from the second location in response to the deleting the untranslated address in the first location.
11. The data storage device of claim 1 , wherein the controller is further configured to compress the untranslated address.
12. The data storage device of claim 1 , wherein the controller is further configured to determine whether the untranslated address has one or more most significant byte (MSB) in common with another untranslated address in the ATC.
13. A data storage device, comprising:
a memory device; and
a controller coupled to the memory device, wherein the controller is configured to:
determine that address translation service (ATS) is needed for an untranslated address;
search a first portion of an address translation cache (ATC) for the untranslated address;
determine whether there is a match for the untranslated address in the first portion of the ATC;
retrieve the untranslated address from the first portion of the ATC;
search a second portion of the ATC for a translated address corresponding to the untranslated address; and
retrieve the translated address from the second portion of the ATC, wherein retrieving the untranslated address and retrieving the translated address occur sequentially.
14. The data storage device of claim 13 , wherein the first portion is disposed in a first location and the second portion is disposed in a second location, and wherein the first location and the second location are distinct locations.
15. The data storage device of claim 13 , wherein the controller is configured to retrieve the second portion from a host memory buffer (HMB).
16. The data storage device of claim 13 , wherein the controller is configured to retrieve the second portion from the memory device.
17. The data storage device of claim 13 , wherein the controller is configured to delete the untranslated address from the first portion in response to an invalidation request, and wherein the translated address remains in the second portion after the deletion.
18. A data storage device, comprising:
means to store data; and
a controller coupled to the means to store data, wherein the controller is configured to:
store and retrieve an untranslated address from a first portion of an address translation cache (ATC); and
store and retrieve a corresponding translated address from a second portion of the ATC, wherein the first portion and the second portion are distinct locations, wherein retrieving the untranslated address and retrieving the translated address occur sequentially.
19. A data storage device, comprising:
means to store data; and
a controller coupled to the means to store data, wherein the controller is configured to:
store and retrieve an untranslated address from a first portion of an address translation cache (ATC); and
store and retrieve a corresponding translated address from a second portion of the ATC, wherein the first portion and the second portion are distinct locations, wherein the untranslated address is a first untranslated address, wherein the controller is configured to simultaneously retrieve the corresponding translated address and a second untranslated address.