VOP_INACTIVE(9): reclaiming space for open but deleted files?

[Rozhuk Ivan]

On Fri, 15 Mar 2019 17:19:20 +0200
Konstantin Belousov <kostikbel at gmail.com> wrote:

> On Fri, Mar 15, 2019 at 08:44:57AM -0600, Alan Somers wrote:
> > VOP_INACTIVE(9) says that the vop can "be used to reclaim space for
> > ‘open but deleted’ files".  What does that mean?  How can you
> > reclaim space for open files?  I assume it's just a mistake, but I
> > want to check before I fix the man page.  SVN archaeology shows
> > that the line has been present since a mass import of man pages in
> > 1997.  
> 
> VOP_INACTIVE() call means that the last use count for the vnode is
> dereferenced. This can only happen when there is no more open files
> using the vnode.
> 

I was seen another use case: app allocate file to 10gb,
mmap() 4mb, write(), unmap()...many times. 10gb writed. close().
And FreeBSD keep all 10g ram as incative/wired, and dot not allow use it.
Untill file readed or deleted.
That was on 10x, without swap.