xref: /freebsd/share/man/man9/vm_page_grab.9 (revision fa9896e082a1046ff4fbc75fcba4d18d1f2efc19)
121642577SAlfred Perlstein.\"
221642577SAlfred Perlstein.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. All rights reserved.
300cf6892SKonstantin Belousov.\" Copyright (c) 2013 The FreeBSD Foundation
400cf6892SKonstantin Belousov.\"
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600cf6892SKonstantin Belousov.\" under sponsorship from the FreeBSD Foundation.
721642577SAlfred Perlstein.\"
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3100cf6892SKonstantin Belousov.Dd August 23, 2013
3221642577SAlfred Perlstein.Dt VM_PAGE_GRAB 9
3321642577SAlfred Perlstein.Os
3421642577SAlfred Perlstein.Sh NAME
3521642577SAlfred Perlstein.Nm vm_page_grab
3621642577SAlfred Perlstein.Nd "returns a page from an object"
3721642577SAlfred Perlstein.Sh SYNOPSIS
3821642577SAlfred Perlstein.In sys/param.h
3921642577SAlfred Perlstein.In vm/vm.h
4021642577SAlfred Perlstein.In vm/vm_page.h
4121642577SAlfred Perlstein.Ft vm_page_t
4221642577SAlfred Perlstein.Fn vm_page_grab "vm_object_t object" "vm_pindex_t pindex" "int allocflags"
4321642577SAlfred Perlstein.Sh DESCRIPTION
4421642577SAlfred PerlsteinThe
4521642577SAlfred Perlstein.Fn vm_page_grab
4621642577SAlfred Perlsteinfunction returns the page at
4721642577SAlfred Perlstein.Fa pindex
4821642577SAlfred Perlsteinfrom the given object.
491f620c2eSRuslan ErmilovIf the page exists and is busy,
5021642577SAlfred Perlstein.Fn vm_page_grab
5121642577SAlfred Perlsteinwill sleep while waiting for it.
521f620c2eSRuslan ErmilovIf the page does not exist, it is allocated.
5300cf6892SKonstantin BelousovThe function sleeps until the allocation request can be satisfied.
5421642577SAlfred Perlstein.Pp
5500cf6892SKonstantin BelousovThe function requires the
5600cf6892SKonstantin Belousov.Fa object
5700cf6892SKonstantin Belousovto be locked on entry, and returns with the object locked.
5800cf6892SKonstantin BelousovIf the
5921642577SAlfred Perlstein.Fn vm_page_grab
6000cf6892SKonstantin Belousovfunction sleeps for any reason, the object lock is temporary dropped.
6100cf6892SKonstantin Belousov.Pp
6200cf6892SKonstantin BelousovThe
6300cf6892SKonstantin Belousov.Fn vm_page_grab
6400cf6892SKonstantin Belousovsupports all of the flags supported by
652a6b4327SJohn-Mark Gurney.Xr vm_page_alloc 9 .
6600cf6892SKonstantin BelousovIn addition,
6700cf6892SKonstantin Belousov.Fn vm_page_grab
6800cf6892SKonstantin Belousovsupports the following flags:
6900cf6892SKonstantin Belousov.Bl -tag -width ".Dv VM_ALLOC_IGN_SBUSY"
7000cf6892SKonstantin Belousov.It Dv VM_ALLOC_IGN_SBUSY
7100cf6892SKonstantin BelousovWhen waiting for the busy state of the existing page to drain,
7200cf6892SKonstantin Belousovonly test for exclusive busy; ignore the shared busy counter.
7300cf6892SKonstantin Belousov.El
7400cf6892SKonstantin Belousov.Sh RETURN VALUES
7500cf6892SKonstantin BelousovThe
7600cf6892SKonstantin Belousov.Fn vm_page_grab
7700cf6892SKonstantin Belousovalways returns the page.
7821642577SAlfred Perlstein.Sh SEE ALSO
7921642577SAlfred Perlstein.Xr vm_page_alloc 9
8021642577SAlfred Perlstein.Sh AUTHORS
81571dba6eSHiten PandyaThis manual page was written by
82*8a7314fcSBaptiste Daroussin.An Chad David Aq Mt davidc@acns.ab.ca .
83