Abstract: Embodiments of the present invention provide systems and methods for clearing specified blocks of main storage. In one embodiment, an EADM start subchannel is executed. The instructions of the execution of the EADM start subchannel may include a SAP receiving an ADM request block, which specifies a main-storage-clearing operation command. The address and size of a block of main memory to be cleared by the SAP is specified in an MSB designated by the ADM request block.

Abstract: Technical solutions for reducing page invalidation broadcasts in virtual storage management are described. One general aspect includes a method including allocating, by a storage manager, a virtual memory page to a memory buffer that is used by an application being executed by a multiprocessor system, the virtual memory page being allocated from an address space of the application. The method also includes recording, by a memory management unit, a mapping between the virtual memory page and a physical location in a memory. The method also includes in response to a request, from the application, to deallocate the memory buffer, delaying invalidation of the mapping between the virtual memory page and the physical location in a memory, based on a count of free frames in the address space of the application.

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 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: A computer system includes a translation look-aside (TLB) buffer and a processing unit. The TLB is configured to store an entry that comprises virtual address information, real address information associated with the virtual address information, and additional information corresponding to at least one of the virtual address information and the real address information. The processing unit is configured to control the TLB to modify the additional information while maintaining the entry in a valid state accessible by the processing unit for a translation look-aside operation corresponding to the virtual address information and the real address information.

Abstract: Embodiments relate to methods, computer systems and computer program products for improving software performance by identifying and preloading data pages. Embodiments include executing an instruction that requests a data page from the one or more auxiliary storage devices. Based on determining that the instruction is present in the long-running instruction list, embodiments include examining one or more characteristics of a plurality of data pages that will be requested by the instruction. Based on determining that the plurality of data pages are located on a single auxiliary storage device and that the plurality of data pages can be efficiently retrieved by the single auxiliary storage device, embodiments include initiating a pre-load operation to move the plurality of data pages to the main memory.

Abstract: A fault occurs in a virtual environment that includes a base space, a first subspace, and a second subspace, each with a virtual address associated with content in auxiliary storage memory. The fault is resolved by copying the content from auxiliary storage to central storage memory and updating one or more base space dynamic address translation (DAT) tables, and not updating DAT tables of the first and second subspace. A subsequent fault at the first subspace virtual address is resolved by copying the base space DAT table information to the first subspace DAT tables and not updating the second subspace DAT tables. A fault occurring with association to the virtual address of the first subspace is resolved for the base space and the base space DAT table information is copied to the first subspace DAT tables, and the second subspace DAT tables are not updated.

Abstract: A method, system, and computer program product to verify serialization of storage frames within an address space via multi-threaded programs is described. The method includes dynamically scaling a number of units of work based on a number of available processors, each of the units of work configured to execute actions, and dynamically scaling an amount and page size of virtual storage accessed by each of the units of work based on a total available memory. The method also includes obtaining, at each of the units of work, different types of storage pages and accessing storage pages corresponding with the respective different types of virtual storage pages associated with the different frame sizes and attributes and performing a respective action, and verifying, for each of the units of work performing the respective action, a state and data content of the storage pages.

Abstract: Embodiments of the disclosure include a method for reserving large pages in a large frame area (LFAREA) of a main memory. The method includes pre-scanning a plurality of storage increments and counting a number of available large pages that are online and issuing a message that indicates the number of available large pages. The method also includes receiving and parsing an LFAREA request including a target number of large pages to be reserved. The method further includes calculating an optimal number of large pages to be reserved, based upon the target number of available pages and a system limit. The method includes determining if the LFAREA request is valid and if the LFAREA request can be satisfied and scanning the plurality of the storage increments and reserving the optimal number of pages in the LFAREA.

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 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 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 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: Embodiments of the disclosure include a method for optimizing large page processing. The method includes receiving an indication that a real memory includes a first page. The first page includes a plurality of smaller pages. The method also includes determining a page frame table entry associated with a first smaller page of the first page and storing data associated with the first page in the page frame table entry associated with the first smaller page. The page frame table entry associated with the first smaller page of the first page is a data repository for the plurality of smaller pages of the first page.

Abstract: Embodiments relate to methods, systems and computer program products for defragmenting storage class memory by comparing a utilization rate of the storage class memory to a threshold value. If the utilization rate of the storage class memory is greater than the threshold value, the potentially wasted storage space is then compared to the combined storage capacity of the unclaimed extents of the storage class memory. If the potentially wasted storage space is greater than the combined storage capacity of the unclaimed extents of the storage class memory, a determination is made whether a defragmentation was recently performed. Based on determining that the defragmentation was not recently performed, or that it was recently performed and was productive, performing a defragmentation of the storage class memory.

Abstract: A method includes making in a real storage, a copy of a first page content stored in a first page data structure by creating a second page content in a second data structure, the second page content pointing to actual data pointed to by the first page content, storing the second page content in the second data structure, marking the first page content in the first page data structure with a page protection bit, wherein the page protection bit prevents a modification of the virtual page, in response to an attempt to modify the virtual page, copying the virtual page in the event the first page content in the first page data structure is marked with the page protection bit, storing the copied virtual page in a second virtual storage, and altering the second page content in the second data structure to point to the stored virtual page.

Abstract: A method includes copying a first virtual storage by making, a point-in-time copy of a first page content stored in a first structure by creating a second page content in a second structure, the second page content pointing to actual data pointed to by the first page content, storing the second page content in the second data structure, marking the first page content in the first structure with a bit, copying the virtual page in the event the first page content in the first structure is marked with the bit, storing the copied virtual page in a second virtual storage, altering the second page content to point to the stored virtual page, and using the second virtual storage to perform the core dump process, wherein the second virtual storage is referenced via the second page content stored in the real storage.

Abstract: Embodiments relate to methods, computer systems and computer program products for improving software performance by identifying and preloading data pages. Embodiments include executing an instruction that requests a data page from the one or more auxiliary storage devices. Based on determining that the instruction is present in the long-running instruction list, embodiments include examining one or more characteristics of a plurality of data pages that will be requested by the instruction. Based on determining that the plurality of data pages are located on a single auxiliary storage device and that the plurality of data pages can be efficiently retrieved by the single auxiliary storage device, embodiments include initiating a pre-load operation to move the plurality of data pages to the main memory.

Abstract: Dedicated large page memory pools are provided to, at least in part, facilitate access to large pages. The large page memory is managed by: establishing multiple large page memory pools, each large page memory pool of the multiple large page memory pools including a number of large pages; and dedicating each large page memory pool of the multiple large page memory pools to a respective processor of multiple processors of the computing environment, wherein processors of the multiple processors can concurrently access pages from the respective large page memory pools of the multiple large page memory pools.

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.