Technical Reference: Kernel and Subsystems, Volume 1

vm_releasep Kernel Service

Purpose

Releases virtual memory resources for the specified page range.

Syntax

#include <sys/types.h>
#include <sys/errno.h>
#include  <sys/vmuser.h>

int vm_releasep ( vmid, pfirst, npages) vmid_t vmid; int pfirst; int npages;

Description

The vm_releasep kernel service releases pages for the specified page range in the virtual memory object. The values in the pfirst and npages parameters must be nonnegative.

Each page of the virtual memory object that intersects the page range (pfirst, pfirst + npages -1) is logically reset to 0, and any page frame is discarded. A page frame in the I/O state is marked for discard at I/O completion.

For working storage, paging-space disk blocks are freed and the storage-protect key is reset to the default value.

Note

All of the pages to be released must be in the same virtual memory object.

Note

The vm_releasep subroutine is not supported for use on large pages.

Parameters

vmid	Specifies the virtual memory object identifier.
pfirst	Specifies the first page number in the specified page range.
npages	Specifies the number of pages in the specified page range.

Execution Environment

The vm_releasep kernel service can be called from the process environment only.

Return Values

0	Indicates a successful operation.
EINVAL	Indicates one of the following errors: An invalid virtual memory object ID. The starting page is negative. Number of pages is negative. Page range crosses a virtual memory object boundary. One or more large pages lie in the target page range.

Related Information

The vm_release kernel service.

Memory Kernel Services and Understanding Virtual Memory Manager Interfaces in AIX 5L Version 5.2 Kernel Extensions and Device Support Programming Concepts.