Changeset 33a3be8 in mainline

Timestamp:

2023-02-05T14:43:59Z (2 years ago)

Author:

Jiří Zárevúcky <zarevucky.jiri@…>

Branches:

master, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

07700ed

Parents:

c030818

git-author:

Jiří Zárevúcky <zarevucky.jiri@…> (2022-08-15 19:35:23)

git-committer:

Jiří Zárevúcky <zarevucky.jiri@…> (2023-02-05 14:43:59)

Message:

Modify semantics of WAKEUP_ALL slightly

Previous implementation saves the wakeup if no threads have
been woken up. IMO that is a counterintuitive behaviour and
limits usefulness of the function.

For context, the only current consumer of WAKEUP_ALL is condvar
broadcast, in which case there is always one extra spurious
wakeup going out. Condvar allows spurious wakeups, so it's
not an issue here, but there are other possible uses where
it can be a problem.

File:

• kernel/generic/src/synch/waitq.c (modified) (1 diff)

kernel/generic/src/synch/waitq.c

@@ -519 +519 @@
 loop:
         if (list_empty(&wq->sleepers)) {
-                wq->missed_wakeups++;
-                if ((count) && (mode == WAKEUP_ALL))
-                        wq->missed_wakeups--;
+                if (mode != WAKEUP_ALL) {
+                        wq->missed_wakeups++;
+                }
 
                 return;