Browse Prior Art Database

Single Address Space Private Virtual Memory Object

IP.com Disclosure Number: IPCOM000115678D
Original Publication Date: 1995-Jun-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Shapiro, B: AUTHOR [+2]

Abstract

Disclosed is a method for improving fork() and full address space replication performance in systems using Mach or Mach-like virtual memory by collecting all the process private data into a single virtual memory object.

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Single Address Space Private Virtual Memory Object

      Disclosed is a method for improving fork() and full address
space replication performance in systems using Mach or Mach-like
virtual memory by collecting all the process private data into a
single virtual memory object.

      A single "private virtual memory object" is created for each
address space.  Associated with this object are all the address space
ranges that contain information which is private to the address space
(stack and data, for example).  The address space private ranges
correspond to the same range in the private virtual memory object, as
illustrated in the Figure.

      Like a virtual memory object in the Mach operating system from
CMU, a private virtual memory object is a unit of backing storage.
It keeps the information needed to find both resident and
non-resident pages.  However, in Mach, a separate virtual memory
object is created for each distinct address range.

      Many of the critical services (for example, a fork() system
call) performed by a Virtual Memory Manager on behalf of clients
(such as the Process Manager) involve operations specifically on the
private contents of an address space.  By managing all the private
virtual memory objects collectively as a single virtual memory
object, a Virtual Memory Manager can perform critical (process
management) services more efficiently.