Changeset ad58fd2 in mainline for kernel/generic/include/time/timeout.h

Timestamp:

2022-08-15T16:31:58Z (3 years ago)

Author:

Jiří Zárevúcky <zarevucky.jiri@…>

Branches:

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

Children:

46b305a

Parents:

742f95ec

git-author:

Jiří Zárevúcky <zarevucky.jiri@…> (2022-08-15 16:26:16)

git-committer:

Jiří Zárevúcky <zarevucky.jiri@…> (2022-08-15 16:31:58)

Message:

Make timeout→cpu immutable

We ensure timeout→cpu is only changed in timeout_register(),
which by its nature is externally synchronized with timeout_unregister(),
and internally synchronized with clock(). Thus in both those contexts,
timeout→cpu is always a valid constant pointing to the CPU of last
call to timeout_register().

Doing so removes the need for synchronization using timeout→lock.
Instead, timeout→link is synchronized by timeout→cpu→timeoutlock,
and all other fields of timeout_t are also immutable outside
timeout_register(), which means they are safely synchronized by
a combination of timeout→cpu→timoutlock and external sychronization
of timeout_register/unregister.

File:

• kernel/generic/include/time/timeout.h (modified) (2 diffs)

kernel/generic/include/time/timeout.h

@@ -45 +45 @@
         IRQ_SPINLOCK_DECLARE(lock);
 
-        /** Link to the list of active timeouts on CURRENT->cpu */
+        /** Link to the list of active timeouts on timeout->cpu */
         link_t link;
         /** Timeout will be activated when current clock tick reaches this value. */
@@ -61 +61 @@
 extern void timeout_init(void);
 extern void timeout_initialize(timeout_t *);
-extern void timeout_reinitialize(timeout_t *);
 extern void timeout_register(timeout_t *, uint64_t, timeout_handler_t, void *);
 extern bool timeout_unregister(timeout_t *);