Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Systems, methods, and computer storage mediums for managing read-only memory are provided. 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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 “complete”. The foregoing processes are repeated until no components are identified in the system having a status of “incomplete”.

Abstract: DMA mapping for adapters configured to communicated with respect to a computer processor memory structure via DMA and configured to have DMA mapping space for control information and data. The adapters are separated into groups. The control information DMA mapping of the adapters is separated into at least three types: type “H” mapping, type “D” mapping, and shared mapping. The type “H” mapping and the shared mapping are applied to one group of adapters for the DMA mapping space for control information, such as host adapters, and the type “D” mapping and the shared mapping are applied to another group, such as device adapters, and the type “H” mapping of the one group and the type “D” mapping of another group are overlayed in the DMA mapping space for control information for the respective adapters.

Abstract: DMA mapping for adapters configured to communicate with respect to a computer processor memory structure via DMA and configured to have DMA mapping space for control information and data. The adapters are separated into groups. The control information DMA mapping of the adapters is separated into at least three types: type “H” mapping, type “D” mapping, and shared mapping. The type “H” mapping and the shared mapping are applied to one group of adapters for the DMA mapping space for control information, such as host adapters, and the type “D” mapping and the shared mapping are applied to another group, such as device adapters, and the type “H” mapping of the one group and the type “D” mapping of the another group are overlayed in the DMA mapping space for control information for the respective adapters.

Abstract: 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 “complete”. The foregoing processes are repeated until no components are identified in the system having a status of “incomplete”.

Abstract: In a data processing system having multiple input/output adapters, a DMA memory block is assigned to each adapter. The DMA memory block has a data area and a generic common control area. All adapters have the same translation control entry for the control area. The control area includes a mapped page assigned to each adapter request and an unmapped buffer space interposed between the mapped pages. By mapping the generic DMA memory, memory space which is not required by an adapter is not mapped unnecessarily. Because the generic DMA memory space is part of each adapter's DMA memory space, adapters are unable to write to partitions to which they do not belong and the possibility of cross-partition memory writes is reduced. Moreover, runaway writes to dedicated DMA memory space may be caught as soon as they occur.

Abstract: 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.

Abstract: 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.

Abstract: 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 specific context structure and sets a value within the pointer memory that addresses data specific to the thread.