- Protect the callout wheel with a separate spin mutex, callout_lock.

- Use the mutex in hardclock to ensure no races between it and
  softclock.
- Make softclock be INTR_MPSAFE and provide a flag,
  CALLOUT_MPSAFE, which specifies that a callout handler does not
  need giant.  There is still no way to set this flag when
  regstering a callout.

Reviewed by:	-smp@, jlemon

1 files changed, 2 insertions, 0 deletions

diff --git a/sys/sys/callout.h b/sys/sys/callout.h
index c83bf44..a90285f 100644
--- a/sys/sys/callout.h
+++ b/sys/sys/callout.h
@@ -61,6 +61,7 @@ struct callout {
 #define	CALLOUT_LOCAL_ALLOC	0x0001 /* was allocated from callfree */
 #define	CALLOUT_ACTIVE		0x0002 /* callout is currently active */
 #define	CALLOUT_PENDING		0x0004 /* callout is waiting for timeout */
+#define	CALLOUT_MPSAFE		0x0008 /* callout handler is mp safe */
 
 struct callout_handle {
 	struct callout *callout;
@@ -72,6 +73,7 @@ extern struct callout *callout;
 extern int	ncallout;
 extern struct callout_tailq *callwheel;
 extern int	callwheelsize, callwheelbits, callwheelmask, softticks;
+extern struct mtx callout_lock;
 
 #define	callout_active(c)	((c)->c_flags & CALLOUT_ACTIVE)
 #define	callout_deactivate(c)	((c)->c_flags &= ~CALLOUT_ACTIVE)