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30.Dd April 24, 2022
31.Dt VNODE_PAGER_PURGE_RANGE 9
32.Os
33.Sh NAME
34.Nm vnode_pager_purge_range
35.Nd "invalidate the cached content within the given byte range"
36.Sh SYNOPSIS
37.In sys/param.h
38.In vm/vm.h
39.In vm/vm_extern.h
40.Ft void
41.Fo vnode_pager_purge_range
42.Fa "struct vnode *vp"
43.Fa "vm_ooffset_t start"
44.Fa "vm_ooffset_t end"
45.Fc
46.Sh DESCRIPTION
47.Nm
48invalidates the cached content within the given byte range from the
49specified vnode
50.Fa vp .
51The range to be purged is
52.Eo [
53.Fa start , end
54.Ec ) .
55If the
56.Fa end
57parameter is the value zero, the affected range starts from
58.Fa start
59continues to the end of the object.
60Pages within the specified range will be removed from the object's queue.
61If
62.Fa start
63or
64.Fa end
65is not aligned to a page boundary, the invalidated part of the page is zeroed.
66This function only cleans the resident pages in the affected region, it is up to
67the callers to ensure reading the backing store gets back zeroes.
68.Pp
69In case the vnode
70.Fa vp
71does not have a VM object allocated, the effect of calling this function is a
72no-op.
73.Sh LOCKS
74The vnode must be locked on entry and will still be locked on exit.
75.Sh SEE ALSO
76.Xr vnode 9
77.Sh HISTORY
78The
79.Nm
80manual page first appeared in
81.Fx 14 .
82.Sh AUTHORS
83This
84manual page was written by
85.An Ka Ho Ng Aq Mt khng@FreeBSD.org .
86