Managing lock rankings

• US 7,809,897 B1
• Filed: 02/19/2009
• Issued: 10/05/2010
• Est. Priority Date: 08/17/2006
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: OSR Open Systems Resources, Inc.
• Inventors: Viscarola, Peter G., Noone, Scott J., Mason, W. Anthony, Cariddi, Mark J.
• Primary Examiner(s): Verbrugge, Kevin
• Application Number:
  US12/388,712
• Time in Patent Office: 593 Days
• Field of Search: None
• US Class Current: 711/151
• CPC Class Codes: G06F 9/524 Deadlock detection or avoidance

Abstract

Methods of monitoring a computer system. The methods may comprise the steps of calculating a first checksum of a data location and receiving a request from an operation running on the computer system for a lock corresponding to the data location. The methods may also comprise the steps of calculating a second checksum of the data location, and generating an indication if the first checksum and the second checksum are not equivalent. Also, methods of detecting a lock ranking violation in a computer system. The methods may comprise the steps of receiving a request from an operation for a first lock associated with a first data storage location and reviewing a list of locks issued to the operation. The methods may also comprise the step of determining whether the operation possesses a lock ranked higher than the first lock.

Claims

1. A method of monitoring a computer system, the method comprising:

calculating, by the computer system, a first checksum of a data location;

receiving a request from an operation running on the computer system for a first lock corresponding to the data location;

determining, by the computer system, whether the operation possesses a lock ranked higher than the first lock;

calculating, by the computer system, a second checksum of the data location; and

conditioned upon the first checksum and the second checksum being equivalent and on the operation not possessing a lock ranked higher than the first lock, issuing the first lock to the operation.

2. The method of claim 1, further comprising generating a report setting forth information about at least one transaction involving the data location.

3. The method of claim 1, further comprising, conditioned upon the first checksum and the second checksum not being equivalent, aborting an application including the operation that made the request for the lock.

4. The method of claim 1, further comprising:

receiving notice that the operation has released the first lock; and

calculating a third checksum of the data location.

5. The method of claim 1, wherein the data location comprises a single addressable location.

6. The method of claim 1, wherein the data location comprises a plurality of addressable locations.

7. A computer readable medium having instructions stored thereon that when executed by a processor, cause the processor to perform the steps of:

calculating a first checksum of a data location;

receiving a request from an operation running on the computer system for a first lock corresponding to the data location;

determining whether the operation possesses a lock ranked higher than the first lock;

calculating a second checksum of the data location; and

conditioned upon the first checksum and the second checksum being equivalent and on the operation not possessing a lock ranked higher than the first lock, issuing the first lock to the operation.