svn commit: r345491 - in head/sys: conf fs/tmpfs modules/tmpfs

[Ian Lepore]

On Mon, 2019-03-25 at 05:42 -0700, Cy Schubert wrote:
> In message <201903250746.x2P7kKUu019786 at repo.freebsd.org>, Allan
> Jude 
> writes:
> > Author: allanjude
> > Date: Mon Mar 25 07:46:20 2019
> > New Revision: 345491
> > URL: https://svnweb.freebsd.org/changeset/base/345491
> > 
> > Log:
> >   Make TMPFS_PAGES_MINRESERVED a kernel option
> >   
> >   TMPFS_PAGES_MINRESERVED controls how much memory is reserved for
> > the system
> >   and not used by tmpfs.
> >   
> >   On very small memory systems, the default value may be too high
> > and this
> >   prevents these small memory systems from using reroot, which is
> > required
> >   for them to install firmware updates.
> >   
> >   Submitted by:	Hiroki Mori <yamori813 at yahoo.co.jp>
> >   Reviewed by:	mizhka
> >   Differential Revision:	https://reviews.freebsd.org/D13583
> > 
> > Modified:
> >   head/sys/conf/options
> >   head/sys/fs/tmpfs/tmpfs.h
> >   head/sys/fs/tmpfs/tmpfs_vfsops.c
> >   head/sys/modules/tmpfs/Makefile
> > 
> 
> Would this be a good candidate for a sysctl or tuneable?
> 

The small-memory embedded systems most affected by this often don't use
loader(8) at all, so tunables aren't an option, and sysctl may be too
late.  No reason it can't be a tunable as well, but it'll probably need
to remain as a compile-time option too.

-- Ian