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

[Konstantin Belousov]

On Sat, Mar 16, 2019 at 03:55:07AM +0300, Rozhuk Ivan wrote:
> 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,
Another case of what ?

> 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.
So what is the problem ?