Method and device for data read and write

Patent metadata

Field	Value
Publication number	US-10489058-B2
Application number	US-201815995192-A
Country	US
Kind code	B2
Filing date	Jun 1, 2018
Priority date	Jun 2, 2017
Publication date	Nov 26, 2019
Grant date	Nov 26, 2019

Abstract

Embodiments of the present disclosure relate to method and device for data read/write. The method comprises: in response to receiving a first read/write request for a first target area, determining whether there is a second read/write request under execution in conflict with the first read/write request, a second target area for the second read/write request at least partially overlapping with the first target area, and at least one of the first read/write request and the second read/write request being a write request; and in response to determining there being the second read/write request in conflict, suspending the first read/write request while maintaining a sub-area of the first target area in an unlocked state, the sub-area not overlapping with the second target area.

First claim

We claim:

1. A method for data read and write, comprising:
in response to receiving a first read/write request for a first target area, determining whether there is a second read/write request under execution in conflict with the first read/write request, a second target area for the second read/write request at least partially overlapping with the first target area, and at least one of the first read/write request and the second read/write request being a write request;
in response to determining there being the second conflicted read/write request, suspending the first read/write request while maintaining a sub-area of the first target area in an unlocked state, the sub-area not overlapping with the second target area;
in response to receiving a third read/write request in conflict with the first read/write request after the first read/write request and the third read/write request being executed prior to the first read/write request, incrementing a counter associated with the first read/write request; and
in response that a value of the counter reaches a predetermined threshold, promoting an execution priority of the first read/write request.

2. The method of claim 1 , further comprising:
in response to determining there not being the second conflicted read/write request, executing the first read/write request without checking whether the first read/write request is in conflict with other read/write requests which are currently suspended.

3. The method of claim 1 , further comprising:
in response to completion of the first read/write request, only activating a currently waiting request which is in conflict with the first read/write request.

4. The method of claim 1 , further comprising:
in response to receiving a fourth read/write request, a fourth target area for the fourth read/write request at least partially overlapping with the first target area, and the fourth target area being available,
comparing the execution priority of the first read/write request with an execution priority of the fourth read/write request; and
in response that the execution priority of the fourth read/write request is lower than the execution priority of the first read/write request, suspending the fourth read/write request.

5. An electronic device, comprising:
at least one processing unit;
at least one memory coupled to the at least one processing unit and stored with instructions executed by the at least processing unit, the instructions, when executed by the at least one processing unit, causing the device to execute actions comprising:
in response to receiving a first read/write request for a first target area, determining whether there is a second read/write request under execution in conflict with the first read/write request, a second target area for the second read/write request at least partially overlapping with the first target area and at least one of the first read/write request, and the second read/write request being a write request;
in response to determining there being the second conflicted read/write request in conflict, suspending the first read/write request while maintaining a sub-area of the first target area in an unlocked state, the sub-area not overlapping with the second target area;
in response to receiving a third read/write request in conflict with the first read/write request after the first read/write request and the third read/write request being executed prior to the first read/write request, incrementing a counter associated with the first read/write request; and
in response that a value of the counter reaches a predetermined threshold, promoting an execution priority of the first read/write request.

6. The device of claim 5 , the actions further comprise:
in response to determining there not being the second conflicted read/write request in conflict, executing the first read/write request without checking whether the first read/write request is in conflict with other read/write requests which are currently suspended.

7. The device of claim 5 , the actions further comprise:
in response to completion of the first read/write request, only activating a currently waiting request which is in conflict with the first read/write request.

8. The device of claim 5 , the actions further comprise:
in response to receiving a fourth read/write request, a fourth target area for the fourth read/write request at least partially overlapping with the first target area, and the fourth target area being available,
comparing the execution priority of the first read/write request with an execution priority of the fourth read/write request; and
in response that the execution priority of the fourth read/write request is lower than the execution priority of the first read/write request, suspending the fourth read/write request.

9. A computer program product for data read and write, the computer program product comprising:
a non-transitory computer readable medium encoded with computer-executable code, the code configured for the execution of:
in response to receiving a first read/write request for a first target area, determining whether there is a second read/write request under execution in conflict with the first read/write request, a second target area for the second read/write request at least partially overlapping with the first target area, and at least one of the first read/write request and the second read/write request being a write request;
in response to determining there being the second conflicted read/write request, suspending the first read/write request while maintaining a sub-area of the first target area in an unlocked state, the sub-area not overlapping with the second target area,
in response to receiving a third read/write request in conflict with the first read/write request after the first read/write request and the third read/write request being executed prior to the first read/write request, incrementing a counter associated with the first read/write request; and
in response that a value of the counter reaches a predetermined threshold, promoting an execution priority of the first read/write request.

10. The computer program product of claim 9 , the code further configured for the execution of:
in response to determining there not being the second conflicted read/write request, executing the first read/write request without checking whether the first read/write request is in conflict with other read/write requests which are currently suspended.

11. The computer program product of claim 9 , the code further configured for the execution of:
in response to completion of the first read/write request, only activating a currently waiting request which is in conflict with the first read/write request.

12. The computer program product of claim 9 , the code further configured for the execution of:
in response to receiving a fourth read/write request, a fourth target area for the fourth read/write request at least partially overlapping with the first target area, and the fourth target area being available,
comparing the execution priority of the first read/write request with an execution priority of the fourth read/write request; and
in response that the execution priority of the fourth read/write request is lower than the execution priority of the first read/write request, suspending the fourth read/write request.

13. The method of claim 1 , wherein:
in response to receiving a first write request for a file system, splitting the first write request into at least one sub-request on the basis of logic data unit of the file system;
determining whether there is a first sub-request for a data block whose size

Assignees

• Emc Ip Holding Co Llc

Inventors

• Zhao Bean Bin
• Hu Wilson Guoyu
• Wu Jun
• Lv Shuo
• Zhou Qiaosheng
• Zhang Lester Ming

Classifications

• G06F3/0673

  Single storage device · CPC title

• G06F16/1767

  Concurrency control, e.g. optimistic or pessimistic approaches · CPC title

• G06F3/0613

  in relation to throughput · CPC title

• G06F3/0659

  Command handling arrangements, e.g. command buffers, queues, command scheduling · CPC title

• G06F9/526 Primary

  Mutual exclusion algorithms · CPC title