Invention Grant
- Patent Title: Almost fair busy lock
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Application No.: US14860965Application Date: 2015-09-22
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Publication No.: US09697055B2Publication Date: 2017-07-04
- Inventor: Marco Greco
- Applicant: International Business Machines Corporation
- Applicant Address: US NY Armonk
- Assignee: International Business Machines Corporation
- Current Assignee: International Business Machines Corporation
- Current Assignee Address: US NY Armonk
- Agent Leonard T. Guzman
- Priority: GB1420412.7 20141118
- Main IPC: G06F9/46
- IPC: G06F9/46 ; G06F9/52 ; G06F9/48

Abstract:
Managing exclusive control of a shareable resource includes publishing a claim non atomically to a lock by a thread that is next to own the lock in an ordered set of threads that have requested to own the lock. The claim includes a structure capable of being read and written only in a single memory access. A determination is made of whether the next owning thread has been pre-empted. Responsive to the determination, the next owning thread of the lock acquires the lock if the next owning thread has not been pre-empted and retries acquisition of the lock if the next owning thread has been pre-empted. Responsive to the next owning thread being pre-empted, a subsequent owning thread acquires the lock unfairly and atomically, consistently modifies the lock such that a next lock owner can determine that the next lock owner has been preempted.
Public/Granted literature
- US20160139966A1 ALMOST FAIR BUSY LOCK Public/Granted day:2016-05-19
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