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.Dd August 2, 2021
.Dt VNODE_PAGER_PURGE_RANGE 9
.Os
.Sh NAME
.Nm vnode_pager_purge_range
.Nd "invalidate the cached contents within the given byte range"
.Sh SYNOPSIS
.In sys/param.h
.In vm/vm.h
.In vm/vm_extern.h
.Ft void
.Fo vnode_pager_purge_range
.Fa "struct vnode *vp"
.Fa "vm_ooffset_t start"
.Fa "vm_ooffset_t end"
.Fc
.Sh DESCRIPTION
.Nm
invalidates the cached contents within the given byte range from the
specified vnode
.Fa vp .
The range to be purged is
.Eo [
.Fa start , end
.Ec ) .
If the
.Fa end
parameter is the value zero, the affected range starts from
.Fa start
continues to the end of the object.
Pages within the specified range will be removed from the object's queue.
If
.Fa start
or
.Fa end
is not aligned to a page boundary, the invalidated part of the page is zeroed.
This function only cleans the resident pages in the affected region, it is up to
the callers to ensure reading the backing store gets back zeroes.
.Pp
In case the vnode
.Fa vp
does not have a VM object allocated, the effect of calling this function is a
no-op.
.Sh LOCKS
The vnode must be locked on entry and will still be locked on exit.
.Sh SEE ALSO
.Xr vnode 9
.Sh HISTORY
The
.Nm
manual page first appeared in
.Fx 14 .
.Sh AUTHORS
This
manual page was written by
.An Ka Ho Ng Aq Mt khng@FreeBSD.org .