Clearing specified blocks of main storage

Patent metadata

Field	Value
Publication number	US-2016216902-A1
Application number	US-201615014063-A
Country	US
Kind code	A1
Filing date	Feb 3, 2016
Priority date	Jan 27, 2015
Publication date	Jul 28, 2016
Grant date	—

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.

First claim

What is claimed is:

1 . A method in a data processing system comprising:
determining, by a processor, from an instruction stream, an extended asynchronous data mover (EADM) start subchannel instruction, wherein the EADM start subchannel instruction comprises: a subsystem identification operand and an EADM operation request block operand configured to designate a location of an EADM operation request block; executing, by the processor, the EADM start subchannel instruction, wherein executing the EADM start subchannel instruction comprises notifying a system assist processor (SAP), wherein the SAP comprises:
an equivalent architecture as a CPU on which operating systems and application programs execute; and
performing memory clearing operations in a similar manner as the CPU on which operating systems and application programs execute;
receiving, by the SAP, an asynchronous data mover (ADM) request block; determining, by the SAP, whether the ADM request block specifies a main-storage-clearing operation command, wherein the main-storage-clearing operation command operates asynchronously from a program on a CPU; responsive to determining the ADM request block specifies the main-storage-clearing operation command, obtaining one or more move specification blocks (MSBs), wherein an address associated with the one or more MSBs is designated by the ADM request block; determining, by the SAP, based on the one or more MSBs, an address and a size of a main storage block to clear; responsive to determining the address and the size of the main storage block, clearing, by the SAP, the main storage block, wherein if the SAP is associated with a predetermined time period for clearing the main storage block, then a set of partially completed instructions are placed on a queue, by the SAP, to continue the clearing of the main storage block at a later time; responsive to clearing, by the SAP, the main storage block, notifying, asynchronously, the CPU, when the SAP successfully completes the main-storage-clearing operation command; and responsive to determining that the main-storage-clearing operation command did not complete successfully, providing an indication, in an ADM response block, of an error associated with at least one of: a request block, the one or more MSBs, and a memory access.

Assignees

• IBM

Inventors

• Coneski Anthony F
• Glendening Beth A
• Greiner Dan F
• Sutton Peter G
• Tuttle Scott B
• Tzortzatos Elpida

Classifications

• G06F12/023 Primary

  Free address space management · CPC title

• G06F3/0683

  Plurality of storage devices · CPC title

• G06F3/065

  Replication mechanisms · CPC title

• G06F3/0652

  Erasing, e.g. deleting, data cleaning, moving of data to a wastebasket · CPC title

• G06F3/0617 Primary

  in relation to availability · CPC title