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.Dd September 9, 2019
.Dt VM_PAGE_WIRE 9
.Os
.Sh NAME
.Nm vm_page_wire ,
.Nm vm_page_unwire ,
.Nm vm_page_unwire_noq
.Nd "wire and unwire pages"
.Sh SYNOPSIS
.In sys/param.h
.In vm/vm.h
.In vm/vm_page.h
.Ft void
.Fn vm_page_wire "vm_page_t m"
.Ft bool
.Fn vm_page_wire_mapped "vm_page_t m"
.Ft void
.Fn vm_page_unwire "vm_page_t m" "int queue"
.Ft bool
.Fn vm_page_unwire_noq "vm_page_t m"
.Sh DESCRIPTION
The
.Fn vm_page_wire
and
.Fn vm_page_wire_mapped
functions wire the page, which prevents it from being reclaimed by the page
daemon or when its containing object is destroyed.
Both functions require that the page belong to an object.
The
.Fn vm_page_wire_mapped
function is for use by the
.Xr pmap 9
layer following a lookup.
This function may fail if mappings of the page are concurrently
being destroyed, in which case it will return false.
.Pp
The
.Fn vm_page_unwire
and
.Fn vm_page_unwire_noq
functions release a wiring of a page.
The
.Fn vm_page_unwire
function takes a queue index and will insert the page into the
corresponding page queue upon releasing its last wiring.
If the page does not belong to an object and no other references
to the page exist,
.Fn vm_page_unwire
will free the page.
.Fn vm_page_unwire_noq
releases the wiring and returns true if it was the last wiring
of the page.
.Sh AUTHORS
This manual page was written by
.An Chad David Aq Mt davidc@acns.ab.ca .