K 10
svn:author
V 5
markj
K 8
svn:date
V 27
2020-01-09T19:17:42.942180Z
K 7
svn:log
V 681
UMA: Don't destroy zones after the system shutdown process starts.

Some kernel subsystems, notably ZFS, will destroy UMA zones from a
shutdown eventhandler.  This causes the zone to be drained.  For slabs
that are mapped into KVA this can be very expensive and so it needlessly
delays the shutdown process.

Add a new state to the "booted" variable, BOOT_SHUTDOWN.  Once
kern_reboot() starts invoking shutdown handlers, turn uma_zdestroy()
into a no-op, provided that the zone does not have a custom finalization
routine.

PR:		242427
Reviewed by:	jeff, kib, rlibby
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D23066

END