PRIORITIZED LOCK REQUESTS TO REDUCE BLOCKING

• US 20140181342A1
• Filed: 12/21/2012
• Published: 06/26/2014
• Est. Priority Date: 12/21/2012
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Kodavalla, Hanumantha Rao, Prakash, Naveen, Antonopoulos, Panagiotis
• Granted Patent: US 9,164,793 B2
• Time in Patent Office: Days
• US Class Current: 710/200
• CPC Class Codes: G06F 2209/522 Manager
• CPC Class Codes: G06F 2209/523 Mode
• CPC Class Codes: G06F 9/466 Transaction processing
• CPC Class Codes: G06F 9/526 Mutual exclusion algorithms

Abstract

A method includes requesting a lock on a resource. The request for the lock on the resource is specified as a low priority non-blocking request that does not block one or more other requests such that one or more other requests can request a lock on the resource and obtain the lock on the resource in priority to the low priority non-blocking request. Based on the low priority request, the method includes maintaining the low priority request in a non-blocking fashion until a predetermined condition occurs. As a result of the predetermined condition occurring, the method includes handling the low priority request such that it is no longer treated as a low priority non-blocking request. Embodiments may further include a kill request which kills any operations on the resource, aborts any transactions having a lock on the resource, and locks the resource.

Claims

1. In a transactional computing environment, a method of requesting a lock on a resource, the method comprising:

requesting a lock on a resource, wherein the request for the lock on the resource is specified as a low priority non-blocking request that does not block one or more other requests such that one or more other requests can request a lock on the resource and obtain the lock on the resource in priority to the low priority non-blocking request including when the one or more other requests are made after the low priority non-blocking request;

based on the low priority request, maintaining the low priority request in a non-blocking fashion until a predetermined condition occurs; and

as a result of the predetermined condition occurring, handling the low priority request such that it is no longer treated as a low priority non-blocking request.

2. The method of claim 1, wherein handling the low priority request such that it is no longer treated as a low priority non-blocking request comprises renewing the low priority request as a normal priority request for a lock on the resource that is handled in accordance with ordinary operating of a transactional computing system

3. The method of claim 1, wherein handling the low priority request such that it is no longer treated as a low priority non-blocking request comprises renewing the low priority request as a high priority kill request for a lock on the resource, wherein the high priority kill request configured to:

kill any operations being performed on the resource;

abort any transactions having a lock on the resource; and

lock the resource to prevent other agents from operating on the resource or requesting a lock on the resource.

4. The method of claim 1, wherein handling the low priority request such that it is no longer treated as a low priority non-blocking request comprises aborting the low priority request.

5. The method of claim 1, wherein the predetermined condition comprises expiration of a given period of time.

6. The method of claim 1, wherein the predetermined condition comprises the occurrence of a specific time.

7. The method of claim 1, wherein the predetermined condition comprises use of a predetermined amount of storage as a result of the low priority non-blocking request being maintained.

8. The method of claim 1, wherein the predetermined condition comprises a predetermined number of lock requests by other agents occurring.

9. The method of claim 1, wherein the predetermined condition comprises user input.

10. The method of claim 1, wherein the method is performed in a lock partitioning scenario, and wherein requesting a low priority non-blocking request on a resource comprises requesting a lock on a first partition, and once this lock is acquired, attempting to lock all other partitions.

11. The method of claim 10, further comprising, determining that one of the other partitions cannot be locked, and as a result, unlocking any locked partitions and repeating requesting a low priority non-blocking request on a resource by requesting locks on the partitions beginning by requesting a lock from the partition where the previous request failed.

14. The system of claim 11, wherein handling the low priority request such that it is no longer treated as a low priority non-blocking request comprises renewing the low priority request as a normal priority request for a lock on the resource that is handled in accordance with ordinary operating of a transactional computing system.

15. The system of claim 11, wherein handling the low priority request such that it is no longer treated as a low priority non-blocking request comprises renewing the low priority request as a high priority kill request for a lock on the resource, wherein the high priority kill request configured to:

kill any operations being performed on the resource;

abort any transactions having a lock on the resource; and

lock the resource to prevent other agents from operating on the resource or requesting a lock on the resource.

17. The system of claim 11, wherein handling the low priority request such that it is no longer treated as a low priority non-blocking request comprises aborting the low priority request.

18. The method of claim 1, wherein the predetermined condition comprises expiration of a given period of time.

19. The system of claim 11, wherein the predetermined condition comprises the occurrence of a specific time.

20. The system of claim 11, wherein the predetermined condition comprises use of a predetermined amount of storage as a result of the low priority non-blocking request being maintained.

12. In a transactional computing environment, a method of requesting a lock on a resource, the method comprising:

identify a resource;

issuing a kill lock request as single command, wherein issuing the kill lock request comprises;

killing any operations being performed on the resource;

aborting any transactions having a lock on the resource; and

locking the resource to prevent other agents from operating on the resource or requesting a lock on the resource.

13. A system for requesting a lock on a resource, the system comprising

one or more processors;

one or more computer readable media, wherein the one or more computer readable media comprise computer executable instructions that when executed by at least one of the one or more processors cause at least one of the one or more processors to perform the following;

requesting a lock on a resource, wherein the request for the lock on the resource is specified as a low priority non-blocking request that does not block one or more other requests such that one or more other requests can request a lock on the resource and obtain the lock on the resource in priority to the low priority non-blocking request including when the one or more other requests are made after the low priority non-blocking request;

based on the low priority request, maintaining the low priority request in a non-blocking fashion until a predetermined condition occurs; and

as a result of the predetermined condition occurring, handling the low priority request such that it is no longer treated as a low priority non-blocking request; and

.

a plurality of queues, the plurality of queues comprising;

a grant queue, wherein the grant queue stores all the locks which are currently granted for a particular resource

a kill queue, wherein the kill queue stores high priority requests which may be granted by killing any operations being performed on a resource, aborting any transactions having a lock on a resource, and locking the resource to prevent other agents from operating on the resource or requesting a lock on the resource;

a convert queue, wherein the convert queue stores all lock requests for a particular resource which are waiting to be granted, but were made by transactions which are already holding a lock on a resource and need to upgrade to a more exclusive lock;

a wait queue, wherein the wait queue stores all new normal priority lock requests for a particular resource which are waiting to be granted;

a low priority wait queue, wherein the low priority wait queue stores requests that have to wait for all high priority requests, normal priority requests, and existing low priority requests; and

a low priority convert queue, wherein the low priority convert queue stores requests that have to wait for existing high priority requests and normal priority requests but do not have to wait for existing low priority requests.

16. The method of claim 13, wherein renewing the low priority request as a high priority kill request comprises adding the request to the kill queue.