Import my recent 1:1 threading working. some features improved includes:

 1. fast simple type mutex.
 2. __thread tls works.
 3. asynchronous cancellation works ( using signal ).
 4. thread synchronization is fully based on umtx, mainly, condition
    variable and other synchronization objects were rewritten by using
    umtx directly. those objects can be shared between processes via
    shared memory, it has to change ABI which does not happen yet.
 5. default stack size is increased to 1M on 32 bits platform, 2M for
    64 bits platform.
As the result, some mysql super-smack benchmarks show performance is
improved massivly.

Okayed by: jeff, mtm, rwatson, scottl

1 files changed, 107 insertions, 87 deletions

diff --git a/lib/libthr/thread/thr_cancel.c b/lib/libthr/thread/thr_cancel.c
index 5880e1f..5a3960e 100644
--- a/lib/libthr/thread/thr_cancel.c
+++ b/lib/libthr/thread/thr_cancel.c
@@ -1,143 +1,163 @@
 /*
- * David Leonard <d@openbsd.org>, 1999. Public domain.
+ * Copyright (c) 2005, David Xu <davidxu@freebsd.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice unmodified, this list of conditions, and the following
+ *    disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
  * $FreeBSD$
+ *
  */
-#include <sys/errno.h>
+
 #include <pthread.h>
-#include <stdlib.h>
-#include "thr_private.h"
 
-/*
- * Static prototypes
- */
-static void	testcancel(void);
+#include "thr_private.h"
 
 __weak_reference(_pthread_cancel, pthread_cancel);
 __weak_reference(_pthread_setcancelstate, pthread_setcancelstate);
 __weak_reference(_pthread_setcanceltype, pthread_setcanceltype);
 __weak_reference(_pthread_testcancel, pthread_testcancel);
 
-/*
- * Posix requires this function to be async-cancel-safe, so it
- * may not aquire any type of resource or call any functions
- * that might do so.
- */
+int _pthread_setcanceltype(int type, int *oldtype);
+
 int
 _pthread_cancel(pthread_t pthread)
 {
-	/* Don't continue if cancellation has already been set. */
-	if (atomic_cmpset_int(&pthread->cancellation, (int)CS_NULL,
-	    (int)CS_PENDING) != 1)
-		return (0);
+	struct pthread *curthread = _get_curthread();
+	int oldval, newval = 0;
+	int oldtype;
+	int ret;
 
 	/*
-	 * Only wakeup threads that are in cancellation points or
-	 * have set async cancel.
-	 * XXX - access to pthread->flags is not safe. We should just
-	 *	 unconditionally wake the thread and make sure that
-	 *	 the the library correctly handles spurious wakeups.
+	 * POSIX says _pthread_cancel should be async cancellation safe,
+	 * so we temporarily disable async cancellation.
 	 */
-	if ((pthread->cancellationpoint || pthread->cancelmode == M_ASYNC) &&
-	    (pthread->flags & PTHREAD_FLAGS_NOT_RUNNING) != 0)
-		PTHREAD_WAKE(pthread);
+	_pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &oldtype);
+	if ((ret = _thr_ref_add(curthread, pthread, 0)) != 0) {
+		_pthread_setcanceltype(oldtype, NULL);
+		return (ret);
+	}
+
+	do {
+		oldval = pthread->cancelflags;
+		if (oldval & THR_CANCEL_NEEDED)
+			break;
+		newval = oldval | THR_CANCEL_NEEDED;
+	} while (!atomic_cmpset_acq_int(&pthread->cancelflags, oldval, newval));
+
+	if (!(oldval & THR_CANCEL_NEEDED) && SHOULD_ASYNC_CANCEL(newval))
+		_thr_send_sig(pthread, SIGCANCEL);
+
+	_thr_ref_delete(curthread, pthread);
+	_pthread_setcanceltype(oldtype, NULL);
 	return (0);
 }
 
-/*
- * Posix requires this function to be async-cancel-safe, so it
- * may not aquire any type of resource or call any functions
- * that might do so.
- */
+static inline void
+testcancel(struct pthread *curthread)
+{
+	int newval;
+
+	newval = curthread->cancelflags;
+	if (SHOULD_CANCEL(newval))
+		pthread_exit(PTHREAD_CANCELED);
+}
+
 int
 _pthread_setcancelstate(int state, int *oldstate)
 {
-	int ostate;
+	struct pthread *curthread = _get_curthread();
+	int oldval, ret;
 
-	ostate = (curthread->cancelmode == M_OFF) ? PTHREAD_CANCEL_DISABLE :
-	    PTHREAD_CANCEL_ENABLE;
+	oldval = curthread->cancelflags;
+	if (oldstate != NULL)
+		*oldstate = ((oldval & THR_CANCEL_DISABLE) ?
+		    PTHREAD_CANCEL_DISABLE : PTHREAD_CANCEL_ENABLE);
 	switch (state) {
-	case PTHREAD_CANCEL_ENABLE:
-		curthread->cancelmode = curthread->cancelstate;
-		break;
 	case PTHREAD_CANCEL_DISABLE:
-		if (curthread->cancelmode != M_OFF) {
-			curthread->cancelstate = curthread->cancelmode;
-			curthread->cancelmode = M_OFF;
-		}
+		atomic_set_int(&curthread->cancelflags, THR_CANCEL_DISABLE);
+		ret = 0;
+		break;
+	case PTHREAD_CANCEL_ENABLE:
+		atomic_clear_int(&curthread->cancelflags, THR_CANCEL_DISABLE);
+		testcancel(curthread);
+		ret = 0;
 		break;
 	default:
-		return (EINVAL);
+		ret = EINVAL;
 	}
-	if (oldstate != NULL)
-		*oldstate = ostate;
-	return (0);
+
+	return (ret);
 }
 
-/*
- * Posix requires this function to be async-cancel-safe, so it
- * may not aquire any type of resource or call any functions that
- * might do so.
- */
 int
 _pthread_setcanceltype(int type, int *oldtype)
 {
-	enum cancel_mode omode;
+	struct pthread	*curthread = _get_curthread();
+	int oldval, ret;
 
-	omode = curthread->cancelstate;
+	oldval = curthread->cancelflags;
+	if (oldtype != NULL)
+		*oldtype = ((oldval & THR_CANCEL_AT_POINT) ?
+				 PTHREAD_CANCEL_ASYNCHRONOUS :
+				 PTHREAD_CANCEL_DEFERRED);
 	switch (type) {
 	case PTHREAD_CANCEL_ASYNCHRONOUS:
-		if (curthread->cancelmode != M_OFF)
-			curthread->cancelmode = M_ASYNC;
-		curthread->cancelstate = M_ASYNC;
+		atomic_set_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
+		testcancel(curthread);
+		ret = 0;
 		break;
 	case PTHREAD_CANCEL_DEFERRED:
-		if (curthread->cancelmode != M_OFF)
-			curthread->cancelmode = M_DEFERRED;
-		curthread->cancelstate = M_DEFERRED;
+		atomic_clear_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
+		ret = 0;
 		break;
 	default:
-		return (EINVAL);
+		ret = EINVAL;
 	}
-	if (oldtype != NULL) {
-		if (omode == M_DEFERRED)
-			*oldtype = PTHREAD_CANCEL_DEFERRED;
-		else if (omode == M_ASYNC)
-			*oldtype = PTHREAD_CANCEL_ASYNCHRONOUS;
-	}
-	return (0);
+
+	return (ret);
 }
 
 void
 _pthread_testcancel(void)
 {
-	testcancel();
+	testcancel(_get_curthread());
 }
 
-static void
-testcancel()
+int
+_thr_cancel_enter(struct pthread *curthread)
 {
-	if (curthread->cancelmode != M_OFF) {
-
-		/* Cleanup a canceled thread only once. */
-		if (atomic_cmpset_int(&curthread->cancellation,
-		    (int)CS_PENDING, (int)CS_SET) == 1) {
-			_thread_exit_cleanup();
-			pthread_exit(PTHREAD_CANCELED);
-			PANIC("cancel");
-		}
-	}
-}
+	int oldval;
 
-void
-_thread_enter_cancellation_point(void)
-{
-	testcancel();
-	curthread->cancellationpoint = 1;
+	oldval = curthread->cancelflags;
+	if (!(oldval & THR_CANCEL_AT_POINT)) {
+		atomic_set_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
+		testcancel(curthread);
+	}
+	return (oldval);
 }
 
 void
-_thread_leave_cancellation_point(void)
+_thr_cancel_leave(struct pthread *curthread, int previous)
 {
-	curthread->cancellationpoint = 0;
-	testcancel();
+	if (!(previous & THR_CANCEL_AT_POINT))
+		atomic_clear_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
 }