Thread based lock manager

• US 20040002974A1
• Filed: 06/27/2002
• Published: 01/01/2004
• Est. Priority Date: 06/27/2002
• Status: Abandoned Application

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Kravitz, Jody, Chen, Shyh-Jye, Tejaswini
• Application Number:
  US10/180,135
• Publication Number:
  US 20040002974A1
• Time in Patent Office: Days
• US Class Current: 707/8
• CPC Class Codes: G06F 9/52 Program synchronisation; Mutual exclusion, e.g. by means of semaphores

Abstract

An arrangement is provided for thread based lock management. A lock manager is first initialized. A thread sends a request with respect to a lock associated with a shared resource to the thread based lock manager. Upon receiving the request, the lock manager determines the request type and associated lock operation requested. The request is then accordingly processed based on the request type. A reply is generated based on the outcome of the processing and returned to the thread.

Claims

1. A method, comprising:

initializing a lock manager;

sending a request from a thread with respect to a lock associated with a shared resource;

determining the request type;

processing the request based on the request type; and

returning a reply to the thread based on the outcome of the processing.

2. The method according to claim 1, wherein the request type includes at least some of:

a lock creation request;

a lock deletion request;

a lock relinquishing request;

a lock taking request; and

a lock clean request.

3. The method according to claim 2, wherein the shared resource includes:

memory resource;

peripherals;

hardware resource; and

objects.

4. The method according to claim 3, wherein the reply includes at least one of:

a lock identification representing a lock;

a success message indicating that the request is successfully processed;

or

an error message indicating that said processing is in error.

5. The method according to claim 4, wherein said processing comprises:

creating the lock associated with the shared resource if the request type is lock creation;

deleting the lock associated with the shared resource if the request type is lock deletion;

relinquishing the lock associated with the shared resource if the request type is lock relinquishing;

taking the lock associated with the shared resource if the request type is lock taking; and

cleaning at least one lock created by the thread if the request type is lock cleaning.

6. The method according to claim 5, wherein said creating the lock comprises:

examining the availability of the lock;

returning an error message if the lock is not available;

extracting a lock identification if the lock is available;

storing context information related to the thread in a storage associated with the lock; and

returning the lock identification.

7. The method according to claim 6, wherein said deleting the lock comprises:

examining whether the thread is the creator of the lock;

returning an error message if the thread is not the creator of the lock;

checking whether the lock is in use, if the thread is the creator of the lock;

marking the lock for deletion, if the lock is currently in use;

clearing the context information related to the creator of the lock stored in a storage associated with the lock, if the lock currently is not in use;

setting the lock free, if the lock currently is not in use; and

returning a success message to indicate that deletion of the lock is successful.

8. The method according to claim 7, wherein said relinquishing the lock comprises:

marking a lock counter associated with the lock to indicate that the lock is available;

returning a success message to indicate that the lock is successfully relinquished;

examining whether there is a pending lock taking request waiting for the availability of the lock; and

taking the lock, if there is at least one pending lock taking request.

9. The method according to claim 8, wherein said taking the lock comprises:

examining whether the lock is available;

adding the lock taking request to a waiting queue associated with the lock, if the lock is not available;

marking the lock counter associated with the lock to indicate that the lock is in use;

storing context information related to the thread in the storage associated with the lock; and

returning a success message to indicate that the lock is successfully taken.

10. The method according to claim 9, wherein said cleaning at least one lock created by the thread comprises:

identifying a lock created by the thread;

deleting the lock identified by said identifying;

repeating said identifying and said deleting until all the at least one lock created by the thread are deleted;

removing context information associated with the thread after said repeating.

11. The method according to claim 1, further comprising updating resource use information associated with the shared resource.

12. A system, comprising:

a plurality of threads;

at least one shared resource that can be shared among the plurality of threads; and

a lock management mechanism for managing at least one lock associated with the at least one shared resource to facilitate the at least one thread to share the resources.

13. The system according to claim 12, wherein the lock management mechanism comprises:

a request receiver for receiving a request from a thread with respect to a lock, the thread being one of the plurality of threads;

a request processing mechanism for processing the request to determine the request type based on the request received from the thread;

a lock manager for performing an operation with respect to the lock, the operation being determined based on the request type; and

a lock manager initialization mechanism for initializing the lock manager prior to the operation.

14. The system according to claim 13, wherein the lock manager comprises:

a lock creation mechanism for performing the operation of creating the lock;

a lock deletion mechanism for performing the operation of deleting the lock;

a lock cleaning mechanism for performing the operation of deleting any lock created by the thread;

a lock relinquishing mechanism for performing the operation of relinquishing the lock; and

a lock taking mechanism for performing the operation of taking the possession of the lock for the thread.

15. The system according to claim 14, further comprising an awakening mechanism for awaking another thread that is waiting for the availability of the lock that the thread requests to relinquish.

16. A lock management mechanism, comprising:

a request receiver for receiving a request from a thread with respect to a lock;

a request processing mechanism for processing the request to determine the request type based on the request received from the thread;

a lock manager for performing an operation with respect to the lock, the operation being determined based on the request type; and

a lock manager initialization mechanism for initializing the lock manager before the request is received.

17. The system according to claim 16, wherein the lock manager comprises:

a lock creation mechanism for performing the operation of creating the lock;

a lock deletion mechanism for performing the operation of deleting the lock;

a lock cleaning mechanism for performing the operation of deleting any lock created by the thread;

a lock relinquishing mechanism for performing the operation of relinquishing the lock; and

a lock taking mechanism for performing the operation of taking the possession of the lock for the thread.

18. The system according to claim 17, further comprising an awakening mechanism for awaking another thread that is waiting for the availability of the lock that the thread requests to relinquish.

19. An article comprising a storage medium having stored thereon instructions that, when executed by a machine, result in the following:

initializing a lock manager;

sending a request from a thread with respect to a lock associated with a shared resource;

determining the request type;

processing the request based on the request type; and

returning a reply to the thread based on the outcome of the processing.

20. The article comprising a storage medium having stored thereon instructions according to claim 19, wherein the request type includes:

a lock creation request;

a lock deletion request;

a lock relinquishing request;

a lock possession request; and

a lock clean request.

21. The article comprising a storage medium having stored thereon instructions according to claim 20, wherein the shared resource includes:

memory resource;

peripherals;

hardware resource; and

objects.

22. The article comprising a storage medium having stored thereon instructions according to claim 21, wherein the reply includes at least some of:

a lock identification representing a lock;

a success message indicating that the request is successfully processed;

or

an error message indicating that said processing is in error.

23. The article comprising a storage medium having stored thereon instructions according to claim 22, wherein said processing comprises:

creating the lock associated with the shared resource if the request type is lock creation;

deleting the lock associated with the shared resource if the request type is lock deletion;

relinquishing the lock associated with the shared resource if the request type is lock relinquishing;

taking the lock associated with the shared resource if the request type is lock taking; and

cleaning at least one lock created by the thread if the request type is lock cleaning.

24. The article comprising a storage medium having stored thereon instructions according to claim 23, wherein said creating the lock comprises:

examining the availability of the lock;

returning an error message if the lock is not available;

extracting a lock identification if the lock is available;

storing context information related to the thread in a storage associated with the lock; and

returning the lock identification.

25. The article comprising a storage medium having stored thereon instructions according to claim 24, wherein said deleting the lock comprises:

examining whether the thread is the creator of the lock;

returning an error message if the thread is not the creator of the lock;

checking whether the lock is in use, if the thread is the creator of the lock;

marking the lock for deletion, if the lock is currently in use;

clearing the context information related to the creator of the lock stored in a storage associated with the lock, if the lock currently is not in use;

setting the lock free, if the lock currently is not in use; and

returning a success message to indicate that deletion of the lock is successful.

26. The article comprising a storage medium having stored thereon instructions according to claim 25, wherein said relinquishing the lock comprises:

marking a lock counter associated with the lock to indicate that the lock is available;

returning a success message to indicate that the lock is successfully relinquished;

examining whether there is a pending lock taking request waiting for the availability of the lock; and

taking the lock, if there is at least one pending lock taking request.

27. The article comprising a storage medium having stored thereon instructions according to claim 26, wherein said taking the lock comprises:

examining whether the lock is available;

adding the lock taking request to a waiting queue associated with the lock, if the lock is not available;

marking the lock counter associated with the lock to indicate that the lock is in use;

storing context information related to the thread in the storage associated with the lock; and

returning a success message to indicate that the lock is successfully taken.

28. The article comprising a storage medium having stored thereon instructions according to claim 27, wherein said cleaning at least one lock created by the thread comprises:

identifying a lock created by the thread;

deleting the lock identified by said identifying;

repeating said identifying and said deleting until all the at least one lock created by the thread are deleted;

removing context information associated with the thread after said repeating.

29. The article comprising a storage medium having stored thereon instructions according to claim 19, the instructions, when executed by a machine, further result in updating resource use information associated with the shared resource.