System and method for handling shared resource writes arriving via non-maskable interrupts (NMI) in single thread non-mission critical systems with limited memory space

• US 7,003,610 B2
• Filed: 09/20/2002
• Issued: 02/21/2006
• Est. Priority Date: 09/20/2002
• Status: Expired due to Fees

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: LSI Logic Corporation (Broadcom, Inc.)
• Inventors: Yang, Jinchao, Owens, Jason, Lesslie, Lance
• Primary Examiner(s): Perveen, Rehana
• Assistant Examiner(s): VU, TRISHA U
• Application Number:
  US10/251,344
• Publication Number:
  US 20040059855A1
• Time in Patent Office: 1,250 Days
• Field of Search: 710/260, 710/263, 710/264, 718100-105
• US Class Current: 710/260
• CPC Class Codes: G06F 13/102 where the programme performs an interfacing function, e.g. device driver G06F13/105 takes precedence; scheduling within device drivers G06F9/52; contention policies within device drivers G06F9/4881

Abstract

A system and method for handling shared resource writes arriving via non-maskable interrupts in single thread non-mission critical system with limited memory space includes a queue for providing temporary storage of a write request. The queue is accessible by lower or higher priority processes for the servicing of the write requests. Upon completion of service to the write requests the system returns control to the standard operations of the single thread system.

Claims

1. A method for handling write requests within a single thread system, comprising:

establishing a write request storage location disposed in a single thread system, for storing and providing access to a write request;

receiving of the write request by an interrupt handler disposed in a single thread system;

registering of the write request, by the interrupt handler, on the write request storage location disposed in the single thread system; and

servicing the write requests from the storage location disposed within the single thread system.

2. The method of claim 1, wherein the write request storage location is at least one of a queue and a linked list, for storing the write request.

3. The method of claim 2, wherein the queue includes a start index, an end index, a request count and a service count.

4. The method of claim 3, wherein the queue is a global limited size queue including a total size limiting routine.

5. The method of claim 2, wherein the linked list includes a head node and a tail node.

6. The method of claim 1, wherein the interrupt handler determines whether the maximum capacity of the write request storage location has been reached before registering the write request upon the storage location.

7. The method of claim 1, wherein servicing of the write request is accomplished by at least one of the interrupt handler and a polling process, which initiate a write-handler routine.

8. The method of claim 7, wherein the polling process, before performing its read/write operations, initiates the write-handler routine.

9. The method of claim 7, wherein the interrupt handler, after determining that there are no shared resource access conflicts between variables currently being modified and variables to be modified by the write request, initiates the write-handler routine.

10. The method of claim 7, wherein a context switch is coupled to the interrupt handler, the context switch being capable of giving operation execution priority to the interrupt handler for initiating the write-handler routine.

11. The method of claim 7, wherein the polling process initiates the write-handler routine after determining that there are no shared resource access conflicts between variables currently being modified and variables to be modified by the write request.

12. The method of claim 7, wherein at least one of the interrupt handler and the polling process may re-organize the write requests received so that non-shared resource conflict writes are serviced immediately without being registered in at least one of the queue and the linked list.

13. The method of claim 1, wherein the single thread system is a single thread non-mission critical system.

14. A system for handling a write request in a single thread system, comprising:

a write request queue disposed in the single thread system, for providing a storage location for and access to the write request; and

an interrupt handler disposed within the single thread system, for receiving the write request and registering the write request on the write request queue; and

a polling process disposed in the single thread system, for servicing the write request registered on the write request queue by initiating a write-handler routine,

wherein the system registers the write request in the write request queue prior to initiating the write-handler routine.

15. The system of claim 14, wherein the write request queue includes a start index, end index, request count and a service count.

16. The system of claim 15, wherein the write request queue is a global limited size queue including a size limiting index.

17. The system of claim 14, wherein the write request queue is a linked list including a head node and a tail node.

18. The system of claim 14, wherein the system further comprises a first and a second context switch coupled to the interrupt handler, the first context switch being capable of giving operational priority to the interrupt handler and the second context switch being capable of returning operational priority to the polling process.

19. The system of claim 18, wherein the interrupt handler registers the write request on the write request queue after the interrupt handler determines there is room on the write request queue.

20. The system of claim 14, wherein the polling process, at the beginning of its routine, initiates the write-handler routine.

21. The system of claim 14, wherein the interrupt handler, after determining that there are no shared resource access conflicts between variables currently being modified and variables to be modified by the write request, initiates the write-handler routine.

22. The system of claim 14 wherein the interrupt handler may re-organize the write requests received so that non-conflicting shared resource writes are serviced immediately without being registered in at least one of the write request queue and the linked list.

23. The system of claim 14 wherein the single thread system is a single thread non-mission critical system with limited memory space.

24. A system for handling write requests in a single thread system, comprising:

a write request queue disposed in the single thread system, for providing a storage location for and access to the write request;

an interrupt handler disposed within the single thread system, for receiving write requests, registering the write request on the write request queue and initiating a write-handler routine; and

a polling process disposed in the single thread system, for servicing the write requests registered on the write request queue by initiating the write-handler routine,

wherein the system registers the write request in the write request queue prior to initiating the write-handler routine.

25. The system of claim 24, wherein the write request queue includes a start index, end index, request count and a service count.

26. The system of claim 25, wherein the write request queue is a global limited size queue including a size limiting index.

27. The system of claim 24, wherein the write request queue is a linked list including a head node and a tail node.

28. The system of claim 24, wherein the system further comprises a first and a second context switch coupled to the interrupt handler, the first context switch being capable of giving operational priority to the interrupt handler and the second context switch being capable of returning operational priority to the polling process.

29. The system of claim 28, wherein the interrupt handler registers the write request on the write request queue after the interrupt handler determines there is room on the write request queue.

30. The system of claim 24, wherein the interrupt handler, after determining that there are no shared resource access conflicts between variables currently being modified and variables to be modified by the write request, initiates the write-handler routine to service the write request.

31. The system of claim 24, wherein the polling process, before performing its read/write operations, initiates the write-handler routine.

32. The system of claim 24, wherein the interrupt handler may re-organize the write requests received so that non-conflicting shared resource writes are serviced immediately without being registered in at least one of the write request queue and the linked list.

33. The system of claim 24, wherein the single thread system is a single thread non-mission critical system with limited memory space.