From owner-p4-projects  Thu Jun 13 11: 1: 7 2002
Delivered-To: p4-projects@freebsd.org
Received: by hub.freebsd.org (Postfix, from userid 32767)
	id 6B5AF37B407; Thu, 13 Jun 2002 11:00:57 -0700 (PDT)
Delivered-To: perforce@freebsd.org
Received: from freefall.freebsd.org (freefall.FreeBSD.org [216.136.204.21])
	by hub.freebsd.org (Postfix) with ESMTP id 0D06A37B430
	for <perforce@freebsd.org>; Thu, 13 Jun 2002 11:00:55 -0700 (PDT)
Received: (from perforce@localhost)
	by freefall.freebsd.org (8.11.6/8.11.6) id g5DI0tp46864
	for perforce@freebsd.org; Thu, 13 Jun 2002 11:00:55 -0700 (PDT)
	(envelope-from green@freebsd.org)
Date: Thu, 13 Jun 2002 11:00:55 -0700 (PDT)
Message-Id: <200206131800.g5DI0tp46864@freefall.freebsd.org>
X-Authentication-Warning: freefall.freebsd.org: perforce set sender to green@freebsd.org using -f
From: Brian Feldman <green@FreeBSD.org>
Subject: PERFORCE change 12837 for review
To: Perforce Change Reviews <perforce@freebsd.org>
Sender: owner-p4-projects@FreeBSD.ORG
Precedence: bulk
List-ID: <p4-projects.FreeBSD.ORG>
List-Archive: <http://docs.freebsd.org/mail/> (Web Archive)
List-Help: <mailto:majordomo@FreeBSD.ORG?subject=help> (List Instructions)
List-Subscribe: <mailto:majordomo@FreeBSD.ORG?subject=subscribe%20p4-projects>
List-Unsubscribe: <mailto:majordomo@FreeBSD.ORG?subject=unsubscribe%20p4-projects>
X-Loop: FreeBSD.ORG

http://people.freebsd.org/~peter/p4db/chv.cgi?CH=12837

Change 12837 by green@green_laptop_1 on 2002/06/13 11:00:16

	Make zombie_thread_lock back into a spin lock and remove the
	condition where it could sleep; then, make the kernel actually
	able to boot by adding it to witness's lock order list!!!

Affected files ...

... //depot/projects/kse/sys/kern/kern_thread.c#67 edit
... //depot/projects/kse/sys/kern/subr_witness.c#27 edit

Differences ...

==== //depot/projects/kse/sys/kern/kern_thread.c#67 (text+ko) ====

@@ -75,7 +75,7 @@
 tdlist_head_t zombie_threads = TAILQ_HEAD_INITIALIZER(zombie_threads);
 struct mtx zombie_thread_lock;
 MTX_SYSINIT(zombie_thread_lock, &zombie_thread_lock,
-    "zombie_thread_lock", MTX_DEF);
+    "zombie_thread_lock", MTX_SPIN);
 
 /*
  * Pepare a thread for use.
@@ -241,9 +241,9 @@
 void
 thread_stash(struct thread *td)
 {
-	mtx_lock(&zombie_thread_lock);
+	mtx_lock_spin(&zombie_thread_lock);
 	TAILQ_INSERT_HEAD(&zombie_threads, td, td_runq);
-	mtx_unlock(&zombie_thread_lock);
+	mtx_unlock_spin(&zombie_thread_lock);
 }
 
 /* 
@@ -252,18 +252,17 @@
 void
 thread_reap(void)
 {
-	struct thread *td_reaped, *td_next;
+	struct thread *td_reaped;
 
-	mtx_lock(&zombie_thread_lock);
-	td_reaped = TAILQ_FIRST(&zombie_threads);
-	while (td_reaped) {
-		td_next = TAILQ_NEXT(td_reaped, td_runq);
+	mtx_lock_spin(&zombie_thread_lock);
+	while (!TAILQ_EMPTY(&zombie_threads)) {
+		td_reaped = TAILQ_FIRST(&zombie_threads);
 		TAILQ_REMOVE(&zombie_threads, td_reaped, td_runq);
+		mtx_unlock_spin(&zombie_thread_lock);
 		thread_free(td_reaped);
-		td_reaped = td_next;
+		mtx_lock_spin(&zombie_thread_lock);
 	}
-	mtx_unlock(&zombie_thread_lock);
-	
+	mtx_unlock_spin(&zombie_thread_lock);
 }
 
 /*

==== //depot/projects/kse/sys/kern/subr_witness.c#27 (text+ko) ====

@@ -225,6 +225,7 @@
 #endif
 	{ "clk", &lock_class_mtx_spin },
 	{ "mutex profiling lock", &lock_class_mtx_spin },
+	{ "zombie_thread_lock", &lock_class_mtx_spin },
 	{ NULL, NULL },
 	{ NULL, NULL }
 };

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe p4-projects" in the body of the message