Re: git: ef6fcc5e2b07 - main - nfsd: Add VNET_SYSUNINIT() macros for vnet cleanup

  Rick,

On Tue, Feb 21, 2023 at 07:29:30PM -0800, Rick Macklem wrote:
R> I did that for one of the ones related to nfsd (sys/fs/nfsserver/nfs_fha_new.c).

This one actually doesn't look correct to me. What happens here is that the sysctls
will affect only the default VNET.

I think the VNET-itezation of this file went a bit wrong. You don't need to convert
static structures to malloced when you VNET-ize a module. The infrastructure should
take care of memory management.

The dynamic sysctl context seems to be unneeded from the very beginning. It was
always attached to the static softc. Suggested patch:

https://reviews.freebsd.org/D38742

It gets rid of one case of IS_DEFAULT_VNET.

Tested very little: run two jails and observed difference in sysctl.

R> It so happens it doesn't work for this case.  If you look at the patch, you'll
R> see that the variable is vnet'd. It happens that it is only malloc'd for prisons
R> other than prison0. (For prison0, it points to a global structure that is not
R> malloc'd and is shared with the NFS client, which is not vnet'd.

I think all of this instances can be fixed.

For example nfsstatsv1, which is now malloced for non-default vnets and static for 
the default. Lots of modules still incorrectly update the global one.

This patch makes it right:

https://reviews.freebsd.org/D38743

Tested very little: run two jails, use some NFS, observe difference in nfsstat.

Removes another IS_DEFAULT_VNET.

Note that D38743 is still far from perfect. NFS would benefit a lot if used macros
for per-VNET per-CPU (raceless!) stats, that are used in TCP/IP. Sorry, they aren't
documented :( You can find them in vnet.h starting from VNET_PCPUSTAT_DECLARE()
and look for example usage in TCP/IP.

Please fill free to commandeer those reviews from me and finalize them if you
agree with general idea.

-- 
Gleb Smirnoff