Abstract: A method of determining and using the optimal page size in the execution of an application wherein the number of virtual to real address caching mechanism misses per unit time is calculated for available page sizes and wherein the optimal page size is determined based on the determined number of mechanism misses. In a more specific aspect of this invention, mechanism misses per unit time are calculated for only those applications which are more likely to consume computer system resources. In yet another more specific aspect of this invention, the mechanism misses for a selected application are determined for each of a number of memory address regions.

Abstract: A method and system for efficiently migrating in-use small pages to enable promotion of contiguous small pages into large pages in a memory environment that includes small pages pinned to real memory and/or and small pages mapped to direct memory access (DMA) within real memory. The operating system is designed with a two-phase page promotion engine/utility that enables coalescing contiguous small virtual memory pages to create large virtual memory pages by migrating in-use small memory pages including those that are pinned and/or mapped to DMA.

Abstract: System, method and computer program product for supporting a plurality of Access Control List types for a file system in an operating system in a data processing system. An Access Control List supporting system for managing access to a file system in a data processing system has at least one file system in an operating system of the data processing system, and an Access Control List management framework in the operating system and external to the at least one file system for managing access to the at least one file system. The Access Control List supporting system of the invention removes ACL management and access check-related functions from the at least one file system to an external Access Control List management framework, thus enabling an operating system to support a plurality of Access Control List types using the same Access Control List management framework and enabling new Access Control List types to be added to the operating system dynamically while the operating system is running.

Abstract: A method, information processing system, and computer readable medium for efficiently distributing a computer system's main memory among applications running in that operating system instance. More specifically, threshold values used by a page replacement algorithm of the virtual memory manager are automatically tuned in response to the load on the memory of a computer system. One such threshold value is the lower threshold of free memory which is changed as a function of the load on the memory. For example, such a load might be represented as the number of threads that were added to a waiting queue during a defined interval of time divided by the number of clock tics in that interval. This representation is known as the thread wait rate. This rate is then compared to a target rate to determine if the lower threshold value should be changed. When the free memory space falls below the lower threshold, a page replacement daemon is used to page out memory to make more memory space available.