D60246.diff
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	diff --git a/sys/kern/kern_timeout.c b/sys/kern/kern_timeout.c
	--- a/sys/kern/kern_timeout.c
	+++ b/sys/kern/kern_timeout.c
	@@ -676,11 +676,27 @@
	if (c_iflags & CALLOUT_TRYLOCK) {
	if (__predict_false(class->lc_trylock(c_lock,
	lock_status) == 0)) {
	+ /*
	+ * Retry after half of the precision, but not
	+ * sooner than a tick from the current time.
	+ * Every failure halves the precision, so the
	+ * retry delay would otherwise shrink to zero.
	+ * Immediate retries can starve a
	+ * lower-priority lock owner on the same CPU,
	+ * preventing it from running to release the
	+ * lock.
	+ *
	+ * Use the current time because cc_lastscan may
	+ * be stale by the time the lock is attempted.
	+ * Keep the precision at least a tick as well,
	+ * so that the retries of many contended
	+ * callouts can share a timer interrupt.
	+ */
	cc_exec_curr(cc, direct) = NULL;
	- callout_cc_add(c, cc,
	- cc->cc_lastscan + c->c_precision / 2,
	- qmax(c->c_precision / 2, 1), c_func, c_arg,
	- (direct) ? C_DIRECT_EXEC : 0);
	+ callout_cc_add(c, cc, sbinuptime() +
	+ qmax(c->c_precision / 2, tick_sbt),
	+ qmax(c->c_precision / 2, tick_sbt), c_func,
	+ c_arg, (direct) ? C_DIRECT_EXEC : 0);
	return;
	}
	CC_UNLOCK(cc);