International Business Machines Corporation

Wenjeng Ko

Cheng-Chung Song

Brian D Hatfield

Lei Liu

Daniel Anson Heffley

William Griswold Sherman

Embodiments for managing read-only memory. A system includes a memory device including a real memory and a tracking mechanism configured to track relationships between multiple virtual memory addresses and real memory. The system further includes a processor configured to perform the below method and/or execute the below computer program product. One method includes mapping a first virtual memory address to a real memory in a memory device and mapping a second virtual memory address to the real memory.

Systems and methods for managing read-only memory

Embodiments for managing read-only memory. A system includes a memory device including a real memory and a tracking mechanism configured to track relationships between multiple virtual memory addresses and real memory. The system further includes a processor configured to perform the below method and/or execute the below computer program product. One method includes mapping a first virtual memory address to a real memory in a memory device and mapping a second virtual memory address to the real memory. Here, the first virtual memory address is authorized to modify data in the real memory and the second virtual memory address is not authorized to modify the data in the real memory.

A system includes a memory device including a real memory and a tracking mechanism configured to track relationships between multiple virtual memory addresses and real memory. The system further includes a processor configured to perform the below method and/or execute the below computer program product. One method includes mapping a first virtual memory address to a real memory in a memory device and mapping a second virtual memory address to the real memory. Here, the first virtual memory address is authorized to modify data in the real memory and the second virtual memory address is not authorized to modify the data in the real memory. One computer storage medium includes a computer program product for performing the above method.

A first virtual memory address is mapped to a real memory in a memory device, and a second virtual memory address is mapped to the real memory. Here, the first virtual memory address is authorized to modify data in the real memory and the second virtual memory address is not authorized to modify the data in the real memory.

A method, apparatus and program storage device for providing an anchor pointer in an operating system context structure for improving the efficiency of accessing thread specific data is provided. A kernel thread context structure is maintained in memory. A thread accesses a pointer memory in the kernel thread context structure and sets a value within the pointer memory that addresses data specific to the thread.

Method, apparatus and program storage device for providing an anchor pointer in an operating system context structure for improving the efficiency of accessing thread specific data

A method, apparatus and program storage device for providing light weight system calls to improve user mode performance is disclosed. A range of system call code for the light weight system calls is provided in a system call table. The light weight system calls skip the code for saving and restore processor context.

Method, apparatus and program storage device for providing light weight system calls to improve user mode performance

A method, apparatus and program storage device for providing a no context switch attribute that allows a user mode thread to become a near interrupt disabled priority is disclosed. A thread includes a no context switch attribute. Control of a thread based on the no context switch attribute is much more efficient than the real-time priority because the no context switch attribute bypasses the overhead of scheduling. Moreover, the no context switch attribute may be used to detect whether a thread performs any undesirable operations that can cause the thread to become suspended while in a critical section. The no context switch attribute is configurable to indicate whether execution of the thread can be suspended.

Handling of user mode thread using no context switch attribute to designate near interrupt disabled priority status

A method, system and program product save state data in a multi-processor system. A problem in the multi-processor system is detected and a statesave thread is spawned for each processor in the system. Each statesave thread directs a processor, in parallel with the other processors to attempt to identify a component in the system having a status of 'incomplete', indicating that state data of the component remains to be offloaded. When a component having a status of 'incomplete' is identified, the processor executes statesave code to offload state data from the identified component. Upon completion of the state data offload from the identified component, the processor changes the status of the component to &#x201c;complete&#x201d;. The foregoing processes are repeated until no components are identified in the system having a status of &#x201c;incomplete&#x201d;.

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Tucson, AZ, United States of America

Wenjeng Ko