Author: attilio
Date: Wed Jul 7 12:00:11 2010
New Revision: 209761
URL: http://svn.freebsd.org/changeset/base/209761
Log:
- Simplify logic in handling ticks wrap-up
- Fix a bug where thread may be in sleeping state but the wchan won't
be set, leading to an empty container for sleepq_type(). [0]
Sponsored by: Sandvine Incorporated
[0] Submitted by: Bryan Venteicher
<bryanv at daemoninthecloset dot org>
MFC after: 3 days
X-MFC: 209577
Modified:
head/sys/kern/kern_clock.c
Modified: head/sys/kern/kern_clock.c
==============================================================================
--- head/sys/kern/kern_clock.c Wed Jul 7 11:19:06 2010 (r209760)
+++ head/sys/kern/kern_clock.c Wed Jul 7 12:00:11 2010 (r209761)
@@ -202,8 +202,14 @@ deadlkres(void)
FOREACH_PROC_IN_SYSTEM(p) {
PROC_LOCK(p);
FOREACH_THREAD_IN_PROC(p, td) {
+
+ /*
+ * Once a thread is found in "interesting"
+ * state a possible ticks wrap-up needs to be
+ * checked.
+ */
thread_lock(td);
- if (TD_ON_LOCK(td)) {
+ if (TD_ON_LOCK(td) && ticks < td->td_blktick) {
/*
* The thread should be blocked on a
@@ -212,11 +218,6 @@ deadlkres(void)
*/
MPASS(td->td_blocked != NULL);
- /* Handle ticks wrap-up. */
- if (ticks < td->td_blktick) {
- thread_unlock(td);
- continue;
- }
tticks = ticks - td->td_blktick;
thread_unlock(td);
if (tticks > blkticks) {
@@ -232,13 +233,9 @@ deadlkres(void)
panic("%s: possible deadlock detected for %p, blocked for %d ticks\n",
__func__, td, tticks);
}
- } else if (TD_IS_SLEEPING(td)) {
-
- /* Handle ticks wrap-up. */
- if (ticks < td->td_blktick) {
- thread_unlock(td);
- continue;
- }
+ } else if (TD_IS_SLEEPING(td) &&
+ TD_ON_SLEEPQ(td) &&
+ ticks < td->td_blktick) {
/*
* Check if the thread is sleeping on a
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