Abstract: An abstraction for storage class memory is provided that hides the details of the implementation of storage class memory from a program, and provides a standard channel programming interface for performing certain actions, such as controlling movement of data between main storage and storage class memory or managing storage class memory.

Abstract: An auxiliary storage medium is selected for writing data of a set of one or more pages being paged-out from real memory. The auxiliary storage medium is selected from among a plurality of auxiliary storage media, including differing types of storage media, based on characteristics of the plurality of storage media and/or the attributes of the data being written to the auxiliary storage media.

Abstract: Allocation of pages of memory is managed in computing environments that include multiple sized memory pools. Responsive to a request for a page of memory, one or more memory pools are searched for an available frame of memory to service the request. The search uses a predefined order of search, which includes multiple types of memory pools in a specific order based on the requested size of the page of memory.

Abstract: Large page memory pools are managed. Thresholds are used to determine if the number of pages in a large page memory pool is to be adjusted. If the number of pages is to be increased, a particular technique is provided for adding additional pages to the pool. Further, if there are too many pages in the pool, one or more pages may be removed.

Abstract: An auxiliary storage medium is selected for writing data of a set of one or more pages being paged-out from real memory. The auxiliary storage medium is selected from among a plurality of auxiliary storage media, including differing types of storage media, based on characteristics of the plurality of storage media and/or the attributes of the data being written to the auxiliary storage media.

Abstract: Auxiliary storage is segmented into different types of extents (i.e., ranges of storage), including extents with 4K blocks of storage, extents with 1M blocks of storage, empty extents, and mixed extents that include blocks of storage of various sizes (e.g., 4K blocks and 1M blocks). The auxiliary storage, and in particular, the extents and blocks of storage therein, are managed to reduce storage fragmentation and optimize system performance.

Abstract: A method for automatically determining performance problems in a computer system due to a metric indicating a current memory peak load in the computer system is disclosed.

Abstract: A virtual storage technique is provided to manage a cell pool or a set of cell pools which can be used to satisfy variable-size storage requests. The algorithm uses no locks and relies on an atomic compare-and-swap instruction to serialize updates to the fields that can be simultaneously requested by multiple threads or processes. A free chain is used to manage cells which have already been obtained and freed, while there is an active extent that is used to hand out cells which have not previously been obtained. The algorithm is based on all cell pool extents being the same size, which allows the control information for the extent to be easily located on the extent boundary (e.g. at a 1 MB boundary). Control information for each cell is stored independently of the cell storage in a control array that resides at the head of the extent, along with other control information. This avoids cell overrun from damaging the cell pool control information.

Abstract: A method for automatically determining performance problems in a computer system due to a metric indicating a current memory peak load in the computer system is disclosed.

Abstract: The updating of components of storage keys is managed. A control program indicates whether the updating of selected components of a storage key can be bypassed. If the updating of the selected components can be bypassed, then depending on the circumstances, an update of the storage key may not need to be performed, saving on quiesce operations. The likelihood that the updating of a storage key can be bypassed is enhanced by selecting a block of storage, along with its associated storage key, from a designated queue or designated region of a queue.

Abstract: A sectioned ordered queue in an information handling system comprises a plurality of queue sections arranged in order from a first queue section to a last queue section. Each queue section contains one or more queue entries that correspond to available ranges of real storage locations and are arranged in order from a first queue entry to a last queue entry. Each queue section and each queue entry in the queue sections having a weight factor defined for it. Each queue entry has an effective weight factor formed by combining the weight factor defined for the queue section with the weight factor defined for the queue entry. A new entry is added to the last queue section to indicate a newly available corresponding storage location, and one or more queue entries are deleted from the first section of the queue to indicate that the corresponding storage locations are no longer available.

Abstract: A sectioned ordered queue in an information handling system comprises a plurality of queue sections arranged in order from a first queue section to a last queue section. Each queue section contains one or more queue entries that correspond to available ranges of real storage locations and are arranged in order from a first queue entry to a last queue entry. Each queue section and each queue entry in the queue sections having a weight factor defined for it. Each queue entry has an effective weight factor formed by combining the weight factor defined for the queue section with the weight factor defined for the queue entry. A new entry is added to the last queue section to indicate a newly available corresponding storage location, and one or more queue entries are deleted from the first section of the queue to indicate that the corresponding storage locations are no longer available.

Abstract: In a computing system implementing a virtual memory system having real memory storage frames for storing virtual pages of data and an auxiliary storage system comprising auxiliary storage slots for storing copies of corresponding virtual pages, wherein I/O mechanisms are employed for effectuating transfer of data between auxiliary and real storage, a system and method for managing storage of unvirtualized dataset pages destined for auxiliary storage in a manner so to avoid I/O operations when assigning or moving VIO dataset data. The system and method is used to allow faster access to VIO data set pages by allowing that data to be kept in real storage.

Abstract: A system and method for eliminating excessive spin conditions on systems implementing a LRU algorithm. This is achieved by limiting the amount of time a LRU task is allowed to run in any one invocation. If this time limit is exceeded before the LRU task has completed its processing, the LRU task will reschedule itself to run after a short time interval, record which frames have been processed so far, release its serialization resources, and exit to open a window of enablement. During this window, other processes that were spinning for the serialization resources can have a chance to run. When the LRU task runs again it will re-obtain the serialization resources and continue processing frames that were not previously processed. The above process will be repeated until all the appropriate frames in the system are in LRU order.

Abstract: In a computing system implementing a virtual memory system having real memory storage frames for storing virtual pages of data and an auxiliary storage system comprising auxiliary storage slots for storing copies of corresponding virtual pages, wherein I/O mechanisms are employed for effectuating transfer of data between auxiliary and real storage, a system and method for managing storage of unvirtualized dataset pages destined for auxiliary storage in a manner so to avoid I/O operations when assigning or moving VIO dataset data. The system and method is used to allow faster access to VIO data set pages by allowing that data to be kept in real storage.

Abstract: A system and method for eliminating excessive spin conditions on systems implementing a LRU algorithm. This is achieved by limiting the amount of time a LRU task is allowed to run in any one invocation. If this time limit is exceeded before the LRU task has completed its processing, the LRU task will reschedule itself to run after a short time interval, record which frames have been processed so far, release its serialization resources, and exit to open a window of enablement. During this window, other processes that were spinning for the serialization resources can have a chance to run. When the LRU task runs again it will re-obtain the serialization resources and continue processing frames that were not previously processed. The above process will be repeated until all the appropriate frames in the system are in LRU order.