Markers Use RCU sched

rcu_barrier_sched and call_rcu_sched has been introduced in 2.6.26 for the Markers. Change the marker code to use them.

It can be seen as a fix since the marker code was using an ugly, temporary, #ifdef hack to work around CONFIG_PREEMPT_RCU.

Signed-off-by Mathieu Desnoyers <[email protected]>

CC Paul McKenney <[email protected]>

CC Andrew Morton <[email protected]>

---
 kernel/marker.c |   25 ++++++++-----------------
 1 file changed, 8 insertions(+), 17 deletions(-)

Index: linux-2.6-lttng/kernel/marker.c
===================================================================

kernel/marker.c +8 -17

@@ -443,7 +443,7 @@
 	hlist_del(&e->hlist);
 	/* Make sure the call_rcu has been executed */
 	if (e->rcu_pending)
-		rcu_barrier();
+		rcu_barrier_sched();
 	kfree(e);
 	return 0;
 }

@@ -478,7 +478,7 @@
 	hlist_del(&(*entry)->hlist);
 	/* Make sure the call_rcu has been executed */
 	if ((*entry)->rcu_pending)
-		rcu_barrier();
+		rcu_barrier_sched();
 	kfree(*entry);
 	*entry = e;
 	trace_mark(core_marker_format, "name %s format %s",

@@ -657,7 +657,7 @@
 	 * make sure it's executed now.
 	 */
 	if (entry->rcu_pending)
-		rcu_barrier();
+		rcu_barrier_sched();
 	old = marker_entry_add_probe(entry, probe, probe_private);
 	if (IS_ERR(old)) {
 		ret = PTR_ERR(old);

@@ -672,10 +672,7 @@
 	entry->rcu_pending = 1;
 	/* write rcu_pending before calling the RCU callback */
 	smp_wmb();
-#ifdef CONFIG_PREEMPT_RCU
-	synchronize_sched();	/* Until we have the call_rcu_sched() */
-#endif
-	call_rcu(&entry->rcu, free_old_closure);
+	call_rcu_sched(&entry->rcu, free_old_closure);
 end:
 	mutex_unlock(&markers_mutex);
 	return ret;

@@ -706,7 +703,7 @@
 	if (!entry)
 		goto end;
 	if (entry->rcu_pending)
-		rcu_barrier();
+		rcu_barrier_sched();
 	old = marker_entry_remove_probe(entry, probe, probe_private);
 	mutex_unlock(&markers_mutex);
 	marker_update_probes();		/* may update entry */

@@ -718,10 +715,7 @@
 	entry->rcu_pending = 1;
 	/* write rcu_pending before calling the RCU callback */
 	smp_wmb();
-#ifdef CONFIG_PREEMPT_RCU
-	synchronize_sched();	/* Until we have the call_rcu_sched() */
-#endif
-	call_rcu(&entry->rcu, free_old_closure);
+	call_rcu_sched(&entry->rcu, free_old_closure);
 	remove_marker(name);	/* Ignore busy error message */
 	ret = 0;
 end:

@@ -788,7 +782,7 @@
 		goto end;
 	}
 	if (entry->rcu_pending)
-		rcu_barrier();
+		rcu_barrier_sched();
 	old = marker_entry_remove_probe(entry, NULL, probe_private);
 	mutex_unlock(&markers_mutex);
 	marker_update_probes();		/* may update entry */

@@ -799,10 +793,7 @@
 	entry->rcu_pending = 1;
 	/* write rcu_pending before calling the RCU callback */
 	smp_wmb();
-#ifdef CONFIG_PREEMPT_RCU
-	synchronize_sched();	/* Until we have the call_rcu_sched() */
-#endif
-	call_rcu(&entry->rcu, free_old_closure);
+	call_rcu_sched(&entry->rcu, free_old_closure);
 	remove_marker(entry->name);	/* Ignore busy error message */
 end:
 	mutex_unlock(&markers_mutex);

Signature · 3 lines

-- 
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68