Method, apparatus and computer program product for managing data access

• US 11,593,272 B2
• Filed: 09/24/2019
• Issued: 02/28/2023
• Est. Priority Date: 10/31/2018
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Inventors: Jia, Ruiyong, Dong, Jibing, Zhuo, Baote, Ma, Chun, Kang, Jianbin
• Primary Examiner(s): Faal, Baboucarr
• Application Number:
  US16/579,988
• Publication Number:
  US 20200133875A1
• Time in Patent Office: 1,253 Days
• CPC Class Codes: G06F 12/0804 with main memory updating G06F12/0806 takes precedence
• CPC Class Codes: G06F 12/0868 Data transfer between cache memory and other subsystems, e.g. storage devices or host systems
• CPC Class Codes: G06F 12/10 Address translation
• CPC Class Codes: G06F 2212/1016 Performance improvement
• CPC Class Codes: G06F 2212/1041 Resource optimization
• CPC Class Codes: G06F 2212/286 Mirrored cache memory
• CPC Class Codes: G06F 2212/608 Details relating to cache mapping
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/064 Management of blocks
• CPC Class Codes: G06F 3/0656 Data buffering arrangements
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

In response to receiving a read request for target data, an external address of the target data is obtained from the read request, which is an address unmapped to a storage system; hit information of the target data in cache of the storage system is determined based on the external address; and based on the hit information, an address from the external address and an internal address for providing the target data is determined. The internal address is determined based on the external address and a mapping relationship. Therefore, it can shorten the data access path, accelerate the responding speed for the data access request, and allow the cache to prefetch the data more efficiently.

Claims

1. A method of managing data access, comprising:

in response to receiving a read request for target data, obtaining an external address of the target data from the read request, the external address being an address unmapped to a storage system, the storage system including a first cache, a second cache, and a mapping layer of a data input/output (I/O) stack, the mapping layer managing a mapping relationship between the external address and an internal address of the storage system;

determining, based on the external address, hit information of the target data in the first cache of the storage system, the first cache storing user data, the first cache being disposed above the mapping layer of the data I/O stack;

determining, based on the hit information, an address from the external address and the internal address for providing the target data, the internal address being determined based on the external address and the mapping relationship, the second cache storing metadata associated with the mapping relationship, the second cache being located between the mapping layer of the data I/O stack and a memory of the storage system,

wherein determining the address for providing the target data comprises, in response to the hit information indicating a hit on the target data, determining the external address as an address for providing the target address; and

providing, based on the external address, the target data from the first cache for the read request.

2. The method of claim 1, wherein determining the address for providing the target data comprises:

in response to the hit information indicating that the target data is missed, determining the internal address based on the external address and the mapping relationship; and

determining the internal address as the address for providing the target data.

3. The method of claim 2, further comprises:

obtaining the target data from the memory of the storage system based on the internal address;

storing the target data in association with the external address into the first cache; and

providing, based on the external address, the target data from the first cache for the read request.

4. A method of managing data access, comprising:

in response to receiving a write request for target data, obtaining the target data and an external address of the target data from the write request, the external address being an address unmapped to a storage system, the storage system including a first cache, a second cache, and a mapping layer of a data input/output (I/O) stack, the mapping layer managing a mapping relationship between the external address and an internal address of the storage system;

storing the target data in association with the external address into the first cache in the storage system, the first cache storing user data, the first cache being disposed above the mapping layer of the data I/O stack; and

in response to a cache flush request for the first cache, determining the mapping relationship for mapping the external address to the internal address of the storage system, the second cache storing metadata associated with the mapping relationship, the second cache being located between the mapping layer of the data I/O stack and a memory of the storage system;

determining, based on the external address and the mapping relationship, the internal address for storing data in the first cache into a memory of the storage system; and

storing the data into the memory of the storage system based on the internal address.

5. A device for managing data access, comprising:

at least one processing unit; and

at least one memory coupled to the at least one processing unit and storing instructions executable by the at least one processing unit, the instructions, when executed by the at least one processing unit, causing the device to perform acts comprising;

in response to receiving a read request for target data, obtaining an external address of the target data from the read request, the external address being an address unmapped to a storage system, the storage system including a first cache, a second cache, and a mapping layer of a data input/output (I/O) stack, the mapping layer managing a mapping relationship between the external address and an internal address of the storage system;

determining, based on the external address, hit information of the target data in the first cache of the storage system, the first cache storing user data, the first cache being disposed above the mapping layer of the data I/O stack;

determining, based on the hit information, an address from the external address and the internal address for providing the target data, the internal address being determined based on the external address and the mapping relationship, the second cache storing metadata associated with the mapping relationship, the second cache being located between the mapping layer of the data I/O stack and a memory of the storage system,

wherein determining the address for providing the target data comprises, in response to the hit information indicating a hit on the target data, determining the external address as an address for providing the target address; and

providing, based on the external address, the target data from the first cache for the read request.

6. The device of claim 5, wherein determining the address for providing the target data comprises:

in response to the hit information indicating that the target data is missed,

determining the internal address based on the external address and the mapping relationship; and

determining the internal address as the address for providing the target data.

7. The device of claim 6, further comprises:

obtaining the target data from the memory of the storage system based on the internal address;

storing the target data in association with the external address into the first cache; and

providing, based on the external address, the target data from the first cache for the read request.

8. A device for managing data access, comprising:

at least one processing unit; and

at least one memory coupled to the at least one processing unit and storing instructions executable by the at least one processing unit, the instructions, when executed by the at least one processing unit, causing the device to perform acts comprising;

in response to receiving a write request for target data, obtaining the target data and an external address of the target data from the write request, the external address being an address unmapped to a storage system, the storage system including a first cache, a second cache, and a mapping layer of a data input/output (I/O) stack, the mapping layer managing a mapping relationship between the external address and an internal address of the storage system;

storing the target data in association with the external address into the first cache in the storage system, the first cache storing user data, the first cache being disposed above the mapping layer of the data I/O stack; and

in response to a cache flush request for the first cache, determining the mapping relationship for mapping the external address to the internal address of the storage system, the second cache storing metadata associated with the mapping relationship, the second cache being located between the mapping layer of the data I/O stack and a memory of the storage system;

determining, based on the external address and the mapping relationship, the internal address for storing data in the first cache into a memory of the storage system; and

storing the data into the memory of the storage system based on the internal address.

9. A computer program product having a non-transitory computer readable medium which stores a set of instructions to manage data access;

the set of instructions, when carried out by computerized circuitry, causing the computerized circuitry to perform a method of;

in response to receiving a read request for target data, obtaining an external address of the target data from the read request, the external address being an address unmapped to a storage system, the storage system including a first cache, a second cache, and a mapping layer of a data input/output (I/O) stack, the mapping layer managing a mapping relationship between the external address and an internal address of the storage system;

determining, based on the external address, hit information of the target data in the first cache of the storage system, the first cache storing user data, the first cache being disposed above the mapping layer of the data I/O stack;

determining, based on the hit information, an address from the external address and the internal address for providing the target data, the internal address being determined based on the external address and the mapping relationship, the second cache storing metadata associated with the mapping relationship, the second cache being located between the mapping layer of the data I/O stack and a memory of the storage system,

wherein determining the address for providing the target data comprises, in response to the hit information indicating a hit on the target data, determining the external address as an address for providing the target address; and

providing, based on the external address, the target data from the first cache for the read request.

10. A computer program product having a non-transitory computer readable medium which stores a set of instructions to manage data access;

the set of instructions, when carried out by computerized circuitry, causing the computerized circuitry to perform a method of;

in response to receiving a write request for target data, obtaining the target data and an external address of the target data from the write request, the external address being an address unmapped to a storage system, the storage system including a first cache, a second cache, and a mapping layer of a data input/output (I/O) stack, the mapping layer managing a mapping relationship between the external address and an internal address of the storage system;

storing the target data in association with the external address into the first cache in the storage system, the first cache storing user data, the first cache being disposed above the mapping layer of the data I/O stack; and

in response to a cache flush request for the first cache, determining the mapping relationship for mapping the external address to the internal address of the storage system, the second cache storing metadata associated with the mapping relationship, the second cache being located between the mapping layer of the data I/O stack and a memory of the storage system;

determining, based on the external address and the mapping relationship, the internal address for storing data in the first cache into a memory of the storage system; and

storing the data into the memory of the storage system based on the internal address.