From 51dc8e7f688867e73eb7edc6bc65fdc77c9d5fff Mon Sep 17 00:00:00 2001
From: Kristof Provost <kp@FreeBSD.org>
Date: Thu, 11 Mar 2021 09:32:01 +0100
Subject: [PATCH] Document that uma_zfree_pcpu() allows NULL now

While here also document that for counter_u64_free().

Reviewed by:	rpokala@
MFC after:	1 week
Sponsored by:	Rubicon Communications, LLC ("Netgate")
Differential Revision:	https://reviews.freebsd.org/D29215
---
 share/man/man9/counter.9 |  7 +++++--
 share/man/man9/zone.9    | 18 +++++++++++++++++-
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/share/man/man9/counter.9 b/share/man/man9/counter.9
index 1eb36b571249..04376ba9c994 100644
--- a/share/man/man9/counter.9
+++ b/share/man/man9/counter.9
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd March 6, 2020
+.Dd March 11, 2021
 .Dt COUNTER 9
 .Os
 .Sh NAME
@@ -98,10 +98,13 @@ or
 .Va M_WAITOK .
 If
 .Va M_NOWAIT
-is specified the operation may fail.
+is specified the operation may fail and return
+.Dv NULL .
 .It Fn counter_u64_free c
 Free the previously allocated counter
 .Fa c .
+It is safe to pass
+.Dv NULL .
 .It Fn counter_u64_add c v
 Add
 .Fa v
diff --git a/share/man/man9/zone.9 b/share/man/man9/zone.9
index 91c965ff69ce..7da40b13469b 100644
--- a/share/man/man9/zone.9
+++ b/share/man/man9/zone.9
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd August 20, 2020
+.Dd March 11, 2021
 .Dt UMA 9
 .Os
 .Sh NAME
@@ -385,6 +385,22 @@ specify an argument for the
 and
 .Dv dtor
 functions of the zone, respectively.
+The variants
+.Fn uma_zalloc_pcpu
+and
+.Fn uma_zfree_pcpu
+allocate and free
+.Va mp_ncpu
+shadow copies as described for
+.Dv UMA_ZONE_PCPU .
+If
+.Fa item
+is
+.Dv NULL ,
+then
+.Fn uma_zfree_pcpu
+does nothing.
+.Pp
 The
 .Fn uma_zalloc_domain
 function allows callers to specify a fixed