Rebase to OpenSolaris b103, in the process we are removing any code which did not...

[zfs.git] / zfs / lib / libumem / umem_update_thread.c

diff --git a/zfs/lib/libumem/umem_update_thread.c b/zfs/lib/libumem/umem_update_thread.c
index 033d606..178c6e7 100644 (file)
--- a/zfs/lib/libumem/umem_update_thread.c
+++ b/zfs/lib/libumem/umem_update_thread.c
@@ -2,9 +2,8 @@
  * CDDL HEADER START
  *
  * The contents of this file are subject to the terms of the
- * Common Development and Distribution License, Version 1.0 only
- * (the "License").  You may not use this file except in compliance
- * with the License.
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
  *
  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  * or http://www.opensolaris.org/os/licensing.
@@ -19,30 +18,22 @@
  *
  * CDDL HEADER END
  */
+
 /*
- * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
-/*
- * Portions Copyright 2006 OmniTI, Inc.
- */
 
-/* #pragma ident       "@(#)umem_update_thread.c       1.2     05/06/08 SMI" */
+#pragma ident  "%Z%%M% %I%     %E% SMI"
 
-#include "config.h"
 #include "umem_base.h"
 #include "vmem_base.h"
 
 #include <signal.h>
 
-/*
- * we use the _ version, since we don't want to be cancelled.
- */
-extern int _cond_timedwait(cond_t *cv, mutex_t *mutex, const timespec_t *delay);
-
 /*ARGSUSED*/
-static THR_RETURN
-THR_API umem_update_thread(void *arg)
+static void *
+umem_update_thread(void *arg)
 {
        struct timeval now;
        int in_update = 0;
@@ -110,12 +101,16 @@ THR_API umem_update_thread(void *arg)
                 * next update, or someone wakes us.
                 */
                if (umem_null_cache.cache_unext == &umem_null_cache) {
+                       int cancel_state;
                        timespec_t abs_time;
                        abs_time.tv_sec = umem_update_next.tv_sec;
                        abs_time.tv_nsec = umem_update_next.tv_usec * 1000;
 
-                       (void) _cond_timedwait(&umem_update_cv,
+                       (void) pthread_setcancelstate(PTHREAD_CANCEL_DISABLE,
+                           &cancel_state);
+                       (void) cond_timedwait(&umem_update_cv,
                            &umem_update_lock, &abs_time);
+                       (void) pthread_setcancelstate(cancel_state, NULL);
                }
        }
        /* LINTED no return statement */
@@ -124,30 +119,47 @@ THR_API umem_update_thread(void *arg)
 int
 umem_create_update_thread(void)
 {
-#ifndef _WIN32
        sigset_t sigmask, oldmask;
-#endif
+       thread_t newthread;
 
        ASSERT(MUTEX_HELD(&umem_update_lock));
        ASSERT(umem_update_thr == 0);
 
-#ifndef _WIN32
        /*
         * The update thread handles no signals
         */
        (void) sigfillset(&sigmask);
        (void) thr_sigsetmask(SIG_BLOCK, &sigmask, &oldmask);
-#endif
-       if (thr_create(NULL, 0, umem_update_thread, NULL,
-           THR_BOUND | THR_DAEMON | THR_DETACHED, &umem_update_thr) == 0) {
-#ifndef _WIN32
+
+       /*
+        * drop the umem_update_lock; we cannot hold locks acquired in
+        * pre-fork handler while calling thr_create or thr_continue().
+        */
+
+       (void) mutex_unlock(&umem_update_lock);
+
+       if (thr_create(NULL, NULL, umem_update_thread, NULL,
+           THR_BOUND | THR_DAEMON | THR_DETACHED | THR_SUSPENDED,
+           &newthread) == 0) {
                (void) thr_sigsetmask(SIG_SETMASK, &oldmask, NULL);
-#endif
+
+               (void) mutex_lock(&umem_update_lock);
+               /*
+                * due to the locking in umem_reap(), only one thread can
+                * ever call umem_create_update_thread() at a time.  This
+                * must be the case for this code to work.
+                */
+
+               ASSERT(umem_update_thr == 0);
+               umem_update_thr = newthread;
+               (void) mutex_unlock(&umem_update_lock);
+               (void) thr_continue(newthread);
+               (void) mutex_lock(&umem_update_lock);
+
                return (1);
+       } else { /* thr_create failed */
+               (void) thr_sigsetmask(SIG_SETMASK, &oldmask, NULL);
+               (void) mutex_lock(&umem_update_lock);
        }
-       umem_update_thr = 0;
-#ifndef _WIN32
-       (void) thr_sigsetmask(SIG_SETMASK, &oldmask, NULL);
-#endif
        return (0);
 }