Add a way to force 1:1 mode for libpthread. To do this, define

LIBPTHREAD_SYSTEM_SCOPE in the environment.

You can still force libpthread to be built in strictly 1:1 by
adding -DSYSTEM_SCOPE_ONLY to CFLAGS.  This is kept for archs
that don't yet support M:N mode.

Requested by:   rwatson
Reviewed by:    davidxu

5 files changed, 41 insertions, 42 deletions

diff --git a/lib/libpthread/thread/thr_create.c b/lib/libpthread/thread/thr_create.c
index 9682fcf..8c4592a 100644
--- a/lib/libpthread/thread/thr_create.c
+++ b/lib/libpthread/thread/thr_create.c
@@ -126,9 +126,8 @@ _pthread_create(pthread_t * thread, const pthread_attr_t * attr,
 				 */
 			}
 		}
-#ifdef SYSTEM_SCOPE_ONLY
-		new_thread->attr.flags |= PTHREAD_SCOPE_SYSTEM;
-#endif
+		if (_thread_scope_system != 0)
+			new_thread->attr.flags |= PTHREAD_SCOPE_SYSTEM;
 		if (create_stack(&new_thread->attr) != 0) {
 			/* Insufficient memory to create a stack: */
 			ret = EAGAIN;
diff --git a/lib/libpthread/thread/thr_exit.c b/lib/libpthread/thread/thr_exit.c
index 22aa875..ec8e9ec 100644
--- a/lib/libpthread/thread/thr_exit.c
+++ b/lib/libpthread/thread/thr_exit.c
@@ -126,11 +126,8 @@ _pthread_exit(void *status)
 	KSE_LOCK_ACQUIRE(curkse, &_thread_list_lock);
 	/* Use thread_list_lock */
 	_thread_active_threads--;
-#ifdef SYSTEM_SCOPE_ONLY
-	if (_thread_active_threads == 0) {
-#else
-	if (_thread_active_threads == 1) {
-#endif
+	if ((_thread_scope_system == 0 && _thread_active_threads == 1) ||
+	    (_thread_scope_system != 0 && _thread_active_threads == 0)) {
 		KSE_LOCK_RELEASE(curkse, &_thread_list_lock);
 		_kse_critical_leave(crit);
 		exit(0);
diff --git a/lib/libpthread/thread/thr_init.c b/lib/libpthread/thread/thr_init.c
index 36e7e69..6c371b0 100644
--- a/lib/libpthread/thread/thr_init.c
+++ b/lib/libpthread/thread/thr_init.c
@@ -258,11 +258,7 @@ _libpthread_init(struct pthread *curthread)
 	_kse_init();
 
 	/* Initialize the initial kse and kseg. */
-#ifdef SYSTEM_SCOPE_ONLY
-	_kse_initial = _kse_alloc(NULL, 1);
-#else
-	_kse_initial = _kse_alloc(NULL, 0);
-#endif
+	_kse_initial = _kse_alloc(NULL, _thread_scope_system);
 	if (_kse_initial == NULL)
 		PANIC("Can't allocate initial kse.");
 	_kse_initial->k_kseg = _kseg_alloc(NULL);
@@ -467,6 +463,14 @@ init_private(void)
 	/* Clear pending signals and get the process signal mask. */
 	SIGEMPTYSET(_thr_proc_sigpending);
 
+	/* Are we in M:N mode (default) or 1:1 mode? */
+#ifdef SYSTEM_SCOPE_ONLY
+	_thread_scope_system = 1;
+#else
+	if (getenv("LIBPTHREAD_SYSTEM_SCOPE") != NULL)
+		_thread_scope_system = 1;
+#endif
+
 	/*
 	 * _thread_list_lock and _kse_count are initialized
 	 * by _kse_init()
diff --git a/lib/libpthread/thread/thr_kern.c b/lib/libpthread/thread/thr_kern.c
index c159f1b..ddcae89 100644
--- a/lib/libpthread/thread/thr_kern.c
+++ b/lib/libpthread/thread/thr_kern.c
@@ -75,13 +75,8 @@ __FBSDID("$FreeBSD$");
  * same number of KSEs and KSE groups as threads. Once these levels are
  * reached, any extra KSE and KSE groups will be free()'d.
  */
-#ifdef SYSTEM_SCOPE_ONLY
-#define	MAX_CACHED_KSES		100
-#define	MAX_CACHED_KSEGS	100
-#else
-#define	MAX_CACHED_KSES		50
-#define	MAX_CACHED_KSEGS	50
-#endif
+#define	MAX_CACHED_KSES		((_thread_scope_system == 0) ? 50 : 100)
+#define	MAX_CACHED_KSEGS	((_thread_scope_system == 0) ? 50 : 100)
 
 #define	KSE_SET_MBOX(kse, thrd) \
 	(kse)->k_kcb->kcb_kmbx.km_curthread = &(thrd)->tcb->tcb_tmbx
@@ -412,19 +407,20 @@ _kse_setthreaded(int threaded)
 		 */
 		_kse_initial->k_flags |= KF_STARTED;
 
-#ifdef SYSTEM_SCOPE_ONLY
-		/*
-		 * For bound thread, kernel reads mailbox pointer once,
-		 * we'd set it here before calling kse_create
-		 */
-		_tcb_set(_kse_initial->k_kcb, _thr_initial->tcb);
-		KSE_SET_MBOX(_kse_initial, _thr_initial);
-		_kse_initial->k_kcb->kcb_kmbx.km_flags |= KMF_BOUND;
-#else
-		_thr_initial->attr.flags &= ~PTHREAD_SCOPE_SYSTEM;
-		_kse_initial->k_kseg->kg_flags &= ~KGF_SINGLE_THREAD;
-		_kse_initial->k_kcb->kcb_kmbx.km_curthread = NULL;
-#endif
+		if (_thread_scope_system == 0) {
+			_thr_initial->attr.flags &= ~PTHREAD_SCOPE_SYSTEM;
+			_kse_initial->k_kseg->kg_flags &= ~KGF_SINGLE_THREAD;
+			_kse_initial->k_kcb->kcb_kmbx.km_curthread = NULL;
+		}
+		else {
+			/*
+			 * For bound thread, kernel reads mailbox pointer
+			 * once, we'd set it here before calling kse_create.
+			 */
+			_tcb_set(_kse_initial->k_kcb, _thr_initial->tcb);
+			KSE_SET_MBOX(_kse_initial, _thr_initial);
+			_kse_initial->k_kcb->kcb_kmbx.km_flags |= KMF_BOUND;
+		}
 
 		/*
 		 * Locking functions in libc are required when there are
@@ -443,15 +439,17 @@ _kse_setthreaded(int threaded)
 			_kse_initial->k_kcb->kcb_kmbx.km_lwp;
 		_thread_activated = 1;
 
-#ifndef SYSTEM_SCOPE_ONLY
-		/* Set current thread to initial thread */
-		_tcb_set(_kse_initial->k_kcb, _thr_initial->tcb);
-		KSE_SET_MBOX(_kse_initial, _thr_initial);
-		_thr_start_sig_daemon();
-		_thr_setmaxconcurrency();
-#else
-		__sys_sigprocmask(SIG_SETMASK, &_thr_initial->sigmask, NULL);
-#endif
+		if (_thread_scope_system == 0) {
+			/* Set current thread to initial thread */
+			_tcb_set(_kse_initial->k_kcb, _thr_initial->tcb);
+			KSE_SET_MBOX(_kse_initial, _thr_initial);
+			_thr_start_sig_daemon();
+			_thr_setmaxconcurrency();
+		}
+		else {
+			__sys_sigprocmask(SIG_SETMASK, &_thr_initial->sigmask,
+			    NULL);
+		}
 	}
 	return (0);
 }
diff --git a/lib/libpthread/thread/thr_private.h b/lib/libpthread/thread/thr_private.h
index 7a3ae50..b2d1987 100644
--- a/lib/libpthread/thread/thr_private.h
+++ b/lib/libpthread/thread/thr_private.h
@@ -992,6 +992,7 @@ SCLASS struct pthread	*_thr_initial	SCLASS_PRESET(NULL);
 /* For debugger */
 SCLASS int		_libkse_debug		SCLASS_PRESET(0);
 SCLASS int		_thread_activated	SCLASS_PRESET(0);
+SCLASS int		_thread_scope_system	SCLASS_PRESET(0);
 
 /* List of all threads: */
 SCLASS TAILQ_HEAD(, pthread)	_thread_list