svn commit: r356192 - head/sys/geom

[Scott Long]

Good job!

> On Dec 29, 2019, at 7:46 PM, Alexander Motin <mav at FreeBSD.org> wrote:
> 
> Author: mav
> Date: Mon Dec 30 00:46:10 2019
> New Revision: 356192
> URL: https://svnweb.freebsd.org/changeset/base/356192
> 
> Log:
>  Retire nstart/nend counters.
> 
>  Those counters were abused for decade to workaround broken orphanization
>  process in different classes by delaying the call while there are active
>  requests.  But from one side it did not close all the races, while from
>  another was quite expensive on SMP due to trashing twice per request cache
>  lines of consumer and provider and requiring locks.  It lost its sense
>  after I manually went through all the GEOM classes in base and made
>  orphanization wait for either provider close or request completion.
> 
>  Consumer counters are still used under INVARIANTS to detect premature
>  consumer close and detach.  Provider counters are removed completely.
> 
>  Sponsored by:	iXsystems, Inc.
> 
> Modified:
>  head/sys/geom/geom.h
>  head/sys/geom/geom_event.c
>  head/sys/geom/geom_io.c
>  head/sys/geom/geom_subr.c