International Business Machines Corporation

Michael J Donovan

Steven S Shultz

Xenia Tkatschow

Melissa K Howland

A technique to collectively manage locks by multiple virtual machines and then access shared data protected by the locks. A computer system defines first and second virtual machines and a memory shared by the first and second virtual machines. A lock structure is defined in the shared memory. The lock structure is capable of listing a holder of a lock for shared data in the shared memory. The first virtual machine acquires a lock for the shared data when available by manipulation of the lock structure. After acquiring the lock, the first virtual machine accesses the shared data. The lock structure and the shared data are directly accessible by the first virtual machine. The second virtual machine acquires a lock for the shared data when available by manipulation of the lock structure. After acquiring the lock, the second virtual machine accesses the shared data. The lock structure and shared data are directly accessible by the second virtual machine. In an alternate embodiment of the present invention, the shared data resides in one of the virtual machines while the lock structure remains in shared memory.

Management of locks in a virtual machine environment

A system, computer program product and method for dispatching work items in a virtual machine operating system. The virtual machine operating system defines first and second virtual machines. First and second work queues are created in a memory. The first virtual machine assigns a first work item to the first work queue and a second work item to the second work queue. The first virtual machine schedules work items from the first work queue for execution by the first virtual machine. The first and second work items originate from the first virtual machine. The first and second work queues are directly accessible by the first virtual machine. The second virtual machine assigns a third work item to the first work queue and a fourth work item to the second work queue. The second virtual machine schedules work items from the second work queue for execution by the second virtual machine. The third and fourth work items originate from the second virtual machine. The first and second work queues are directly accessible by the second virtual machine. The first virtual machine is not able to schedule work items from the second work queue, and the second virtual machine is not able to schedule work items from the first work queue. A shared work queue in shared memory is also disclosed.

Multiple virtual machines sharing processor and work queue in memory having program/dispatch functions for assigning and accessing work items while the virtual machine was not idle

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Endicott, NY, United States of America

Michael J Donovan