From 8f93d79d0536fb19b3e3894d8c888fb3084e9aab Mon Sep 17 00:00:00 2001
From: Jeff Roberson <jeff@FreeBSD.org>
Date: Mon, 10 Mar 2008 03:16:51 +0000
Subject: [PATCH] - Handle kdb switch panics outside of mi_switch() to remove
some instructions from the common path and make the code more clear.
Whether this has any impact on performance may depend on optimization
levels.
Sponsored by: Nokia
---
sys/kern/kern_synch.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/sys/kern/kern_synch.c b/sys/kern/kern_synch.c
index ad13c2b47461..983d5a6347a9 100644
--- a/sys/kern/kern_synch.c
+++ b/sys/kern/kern_synch.c
@@ -365,6 +365,15 @@ wakeup_one(ident)
sleepq_release(ident);
}
+static void
+kdb_switch(void)
+{
+ thread_unlock(curthread);
+ kdb_backtrace();
+ kdb_reenter();
+ panic("%s: did not reenter debugger", __func__);
+}
+
/*
* The machine independent parts of context switching.
*/
@@ -394,12 +403,8 @@ mi_switch(int flags, struct thread *newtd)
/*
* Don't perform context switches from the debugger.
*/
- if (kdb_active) {
- thread_unlock(td);
- kdb_backtrace();
- kdb_reenter();
- panic("%s: did not reenter debugger", __func__);
- }
+ if (kdb_active)
+ kdb_switch();
if (flags & SW_VOL)
td->td_ru.ru_nvcsw++;
else