Patent Number: 7,823,150

Title: Computer-implemented method, system and program product for establishing multiple read-only locks on a shared data object

Abstract: Under the present invention, a locking primitive associated with a shared data object is automatically transformed to allow multiple read-only locks if certain conditions are met. To this extent, when a read-only lock on a shared data object is desired, a thread identifier of an object header lock word (hereinafter "lock word") associated with the shared data object is examined to determine if a read-write lock on the shared data object already exists. If not, then the thread identifier is set to a predetermined value indicative of read-only locks, and a thread count in the lock word is incremented. If another thread attempts a read-only lock, the thread identifier will be examined for the predetermined value. If it is present, the thread count will be incremented again, and a second read-only lock will be simultaneously established.

Inventors: Grcevski; Nikola (Toronto, CA), Stoodley; Kevin A. (Richmond Hill, CA), Stoodley; Mark G. (Thornhill, CA), Sundaresan; Vijay (North York, CA)

Assignee: International Business Machines Corporation

International Classification: G06F 9/46 (20060101)

Expiration Date: 2018-10-26 0:00:00