git: 0646c56e244e - stable/12 - kqueue: document how timers with low/past timeouts are handled

The branch stable/12 has been updated by kevans:

URL: https://cgit.FreeBSD.org/src/commit/?id=0646c56e244ea51006c252cb91c2577290dba74e

commit 0646c56e244ea51006c252cb91c2577290dba74e
Author:     Kyle Evans <kevans@FreeBSD.org>
AuthorDate: 2021-09-30 18:19:05 +0000
Commit:     Kyle Evans <kevans@FreeBSD.org>
CommitDate: 2021-10-06 07:07:16 +0000

    kqueue: document how timers with low/past timeouts are handled
    
    (cherry picked from commit 4b5554cebb66020f59dc869b835aebbd66e4bb8c)
---
 lib/libc/sys/kqueue.2 | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/lib/libc/sys/kqueue.2 b/lib/libc/sys/kqueue.2
index 95fc86d01a83..620b8e31a61d 100644
--- a/lib/libc/sys/kqueue.2
+++ b/lib/libc/sys/kqueue.2
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd May 1, 2020
+.Dd October 6, 2021
 .Dt KQUEUE 2
 .Os
 .Sh NAME
@@ -563,6 +563,12 @@ On return,
 .Va fflags
 contains the events which triggered the filter.
 .Pp
+Periodic timers with a specified timeout of 0 will be silently adjusted to
+timeout after 1 of the time units specified by the requested precision in
+.Va fflags .
+If an absolute time is specified that has already passed, then it is treated as
+if the current time were specified and the event will fire as soon as possible.
+.Pp
 If an existing timer is re-added, the existing timer will be
 effectively canceled (throwing away any undelivered record of previous
 timer expiration) and re-started using the new parameters contained in