Re: pthread library related

[christos%zoulas.com@localhost (Christos Zoulas)]

On May 30, 10:33am, charles.cui1984%gmail.com@localhost (Charles Cui) wrote:
-- Subject: Re: pthread library related

Inline comments.

christos

diff --git a/lib/libpthread/pthread.h b/lib/libpthread/pthread.h
index 5970378..ed16d7c 100644
--- a/lib/libpthread/pthread.h
+++ b/lib/libpthread/pthread.h
@@ -94,6 +94,9 @@ int	pthread_mutex_destroy(pthread_mutex_t *);
 int	pthread_mutex_lock(pthread_mutex_t *);
 int	pthread_mutex_trylock(pthread_mutex_t *);
 int	pthread_mutex_unlock(pthread_mutex_t *);
+int	pthread_mutex_timedlock(pthread_mutex_t *, const struct timespec*__restrict);
+int	pthread_mutex_getprioceiling(const pthread_mutex_t *__restrict, int*__restrict);
+int	pthread_mutex_setprioceiling(pthread_mutex_t* __restrict, int, int*__restrict);

Wrap lines, whitespace "const struct timespec *__restrict" etc. (space after
the type name)

+int	pthread_mutexattr_getprotocol(const pthread_mutexattr_t * __restrict, int*__restrict);
+int	pthread_mutexattr_setprotocol(pthread_mutexattr_t* , int);
+int	pthread_mutexattr_getprioceiling(const pthread_mutexattr_t *__restrict,int*__restrict);
+int	pthread_mutexattr_setprioceiling(pthread_mutexattr_t*, int);

Again

 int	pthread_cond_init(pthread_cond_t * __restrict,
 	    const pthread_condattr_t * __restrict);
 int	pthread_cond_destroy(pthread_cond_t *);
@@ -116,7 +122,7 @@ int	pthread_cond_broadcast(pthread_cond_t *);
 int	pthread_condattr_init(pthread_condattr_t *);
 #if defined(_NETBSD_SOURCE)
 int     pthread_condattr_setclock(pthread_condattr_t *, clockid_t);
-int	pthread_condattr_getclock(pthread_condattr_t *);
+int	pthread_condattr_getclock(const pthread_condattr_t *__restrict attr, clockid_t *__restrict clock_id);

Again (wrap)

 int
-pthread_condattr_getclock(pthread_condattr_t *attr)
+pthread_condattr_getclock(const pthread_condattr_t *__restrict attr, clockid_t *__restrict clock_id)

Wrap

 {
 	if (attr == NULL || attr->ptca_private == NULL)
 		return EINVAL;
-	return *(int *)attr->ptca_private;
+	*clock_id = *(clockid_t*)attr->ptca_private;

Whitespace before *

+	return 0;
 }
 
 int
diff --git a/lib/libpthread/pthread_mutex.c b/lib/libpthread/pthread_mutex.c
index e755ade..ec46070 100644
--- a/lib/libpthread/pthread_mutex.c
+++ b/lib/libpthread/pthread_mutex.c
@@ -51,6 +51,7 @@ __RCSID("$NetBSD: pthread_mutex.c,v 1.59 2014/02/03 15:51:01 rmind Exp $");
 
 #include <sys/types.h>
 #include <sys/lwpctl.h>
+#include <sys/sched.h>
 #include <sys/lock.h>
 
 #include <errno.h>
@@ -67,10 +68,12 @@ __RCSID("$NetBSD: pthread_mutex.c,v 1.59 2014/02/03 15:51:01 rmind Exp $");
 #define	MUTEX_WAITERS_BIT		((uintptr_t)0x01)
 #define	MUTEX_RECURSIVE_BIT		((uintptr_t)0x02)
 #define	MUTEX_DEFERRED_BIT		((uintptr_t)0x04)
+#define	MUTEX_PROTECT_BIT		((uintptr_t)0x08)
 #define	MUTEX_THREAD			((uintptr_t)-16L)
 
 #define	MUTEX_HAS_WAITERS(x)		((uintptr_t)(x) & MUTEX_WAITERS_BIT)
 #define	MUTEX_RECURSIVE(x)		((uintptr_t)(x) & MUTEX_RECURSIVE_BIT)
+#define	MUTEX_PROTECT(x)		((uintptr_t)(x) & MUTEX_PROTECT_BIT)
 #define	MUTEX_OWNER(x)			((uintptr_t)(x) & MUTEX_THREAD)
 
 #if __GNUC_PREREQ__(3, 0)
@@ -80,7 +83,7 @@ __RCSID("$NetBSD: pthread_mutex.c,v 1.59 2014/02/03 15:51:01 rmind Exp $");
 #endif
 
 static void	pthread__mutex_wakeup(pthread_t, pthread_mutex_t *);
-static int	pthread__mutex_lock_slow(pthread_mutex_t *);
+static int	pthread__mutex_lock_slow(pthread_mutex_t *, const struct timespec*);

wrap and space

 static int	pthread__mutex_unlock_slow(pthread_mutex_t *);
 static void	pthread__mutex_pause(void);
 
@@ -103,16 +106,21 @@ __strong_alias(__libc_mutexattr_settype,pthread_mutexattr_settype)
 int
 pthread_mutex_init(pthread_mutex_t *ptm, const pthread_mutexattr_t *attr)
 {
-	intptr_t type;
+	uintptr_t type, proto, val, ceil;
 
 	if (__predict_false(__uselibcstub))
 		return __libc_mutex_init_stub(ptm, attr);
 
-	if (attr == NULL)
+	if (attr == NULL) {
 		type = PTHREAD_MUTEX_NORMAL;
-	else
-		type = (intptr_t)attr->ptma_private;
-
+		proto = PTHREAD_PRIO_NONE;
+		ceil = 0;
+	} else {
+		val = (uintptr_t)attr->ptma_private;
+		type = val & 0xff;
+		proto = (val & 0xff00) >> 8;
+		ceil = (val & 0xff0000) >> 16;
+	}
 	switch (type) {
 	case PTHREAD_MUTEX_ERRORCHECK:
 		__cpu_simple_lock_set(&ptm->ptm_errorcheck);
@@ -127,10 +135,17 @@ pthread_mutex_init(pthread_mutex_t *ptm, const pthread_mutexattr_t *attr)
 		ptm->ptm_owner = NULL;
 		break;
 	}
-
+	switch (proto) {
+	case PTHREAD_PRIO_PROTECT:
+		val = (uintptr_t)ptm->ptm_owner;
+		val |= MUTEX_PROTECT_BIT;
+		ptm->ptm_owner = (void*)val;

space

+		break;
+	}
 	ptm->ptm_magic = _PT_MUTEX_MAGIC;
 	ptm->ptm_waiters = NULL;
 	ptm->ptm_recursed = 0;
+	ptm->ptm_ceiling = (unsigned char)ceil;
 
 	return 0;
 }
@@ -168,7 +183,24 @@ pthread_mutex_lock(pthread_mutex_t *ptm)
 #endif
 		return 0;
 	}
-	return pthread__mutex_lock_slow(ptm);
+	return pthread__mutex_lock_slow(ptm, NULL);
+}
+
+int
+pthread_mutex_timedlock(pthread_mutex_t* ptm, const struct timespec *ts)
+{
+	pthread_t self;
+	void *val;
+
+	self = pthread__self();
+	val = atomic_cas_ptr(&ptm->ptm_owner, NULL, self);
+	if (__predict_true(val == NULL)) {
+#ifndef PTHREAD__ATOMIC_IS_MEMBAR
+		membar_enter();
+#endif
+		return 0;
+	}
+	return pthread__mutex_lock_slow(ptm, ts);
 }
 
 /* We want function call overhead. */
@@ -258,11 +290,12 @@ again:
 }
 
 NOINLINE static int
-pthread__mutex_lock_slow(pthread_mutex_t *ptm)
+pthread__mutex_lock_slow(pthread_mutex_t *ptm, const struct timespec *ts)
 {
 	void *waiters, *new, *owner, *next;
 	pthread_t self;
 	int serrno;
+	int error;
 
 	pthread__error(EINVAL, "Invalid mutex",
 	    ptm->ptm_magic == _PT_MUTEX_MAGIC);
@@ -282,6 +315,10 @@ pthread__mutex_lock_slow(pthread_mutex_t *ptm)
 			return EDEADLK;
 	}
 
+	/*priority protect*/
+	if (MUTEX_PROTECT(owner) && _sched_protect(ptm->ptm_ceiling) == -1) {
+		return errno;
+	}
 	serrno = errno;
 	for (;; owner = ptm->ptm_owner) {
 		/* Spin while the owner is running. */
@@ -339,12 +376,23 @@ pthread__mutex_lock_slow(pthread_mutex_t *ptm)
 		 */
 		while (self->pt_mutexwait) {
 			self->pt_blocking++;
-			(void)_lwp_park(CLOCK_REALTIME, TIMER_ABSTIME, NULL,
+			error = _lwp_park(CLOCK_REALTIME, TIMER_ABSTIME, ts,
 			    self->pt_unpark, __UNVOLATILE(&ptm->ptm_waiters),
 			    __UNVOLATILE(&ptm->ptm_waiters));
 			self->pt_unpark = 0;
 			self->pt_blocking--;
 			membar_sync();
+			if (__predict_true(error != -1)) {
+				continue;
+			}
+			if (errno == ETIMEDOUT && self->pt_mutexwait) {
+				/*Remove self from waiters list*/
+				pthread__mutex_wakeup(self, ptm);
+				/*priority protect*/
+				if (MUTEX_PROTECT(owner))
+					(void)_sched_protect(-1);
+				return ETIMEDOUT;
+			}
 		}
 	}
 }
@@ -460,6 +508,10 @@ pthread__mutex_unlock_slow(pthread_mutex_t *ptm)
 	 */
 	if (new != owner) {
 		owner = atomic_swap_ptr(&ptm->ptm_owner, new);
+		if (__predict_false(MUTEX_PROTECT(owner))) {
+			/*restore elevated priority*/
+			(void)_sched_protect(-1);
+		}
 		if (MUTEX_HAS_WAITERS(owner) != 0) {
 			pthread__mutex_wakeup(self, ptm);
 			return 0;
@@ -591,16 +643,21 @@ pthread_mutexattr_destroy(pthread_mutexattr_t *attr)
 int
 pthread_mutexattr_gettype(const pthread_mutexattr_t *attr, int *typep)
 {
+	uintptr_t val;
+
 	pthread__error(EINVAL, "Invalid mutex attribute",
 	    attr->ptma_magic == _PT_MUTEXATTR_MAGIC);
 
-	*typep = (int)(intptr_t)attr->ptma_private;
+	val = (uintptr_t)attr->ptma_private & ~0x00ffL;
+	*typep = (int)val;

I'd use a constant for 0x00ff, instead of repeating it everywhere.
In fact I'd define and use accessor macros for fields setting and getting


 	return 0;
 }
 
 int
 pthread_mutexattr_settype(pthread_mutexattr_t *attr, int type)
 {
+	uintptr_t val;
+
 	if (__predict_false(__uselibcstub))
 		return __libc_mutexattr_settype_stub(attr, type);
 
@@ -611,7 +668,8 @@ pthread_mutexattr_settype(pthread_mutexattr_t *attr, int type)
 	case PTHREAD_MUTEX_NORMAL:
 	case PTHREAD_MUTEX_ERRORCHECK:
 	case PTHREAD_MUTEX_RECURSIVE:
-		attr->ptma_private = (void *)(intptr_t)type;
+		val = (uintptr_t)attr->ptma_private & ~0x00ffL;
+		attr->ptma_private = (void*)(val | type);
 		return 0;
 	default:
 		return EINVAL;
@@ -619,6 +677,67 @@ pthread_mutexattr_settype(pthread_mutexattr_t *attr, int type)
 }
 
 int
+pthread_mutexattr_getprotocol(const pthread_mutexattr_t *attr, int*proto)
+{
+	uintptr_t val;
+	
+	pthread__error(EINVAL, "Invalid mutex attribute",
+		attr->ptma_magic == _PT_MUTEXATTR_MAGIC);
+
+	val = (uintptr_t)attr->ptma_private & ~0xff00L;
+	*proto = (int)(val >> 8);
+	return 0;
+}
+
+int 
+pthread_mutexattr_setprotocol(pthread_mutexattr_t* attr, int proto)
+{
+	uintptr_t val;
+	
+	pthread__error(EINVAL, "Invalid mutex attribute",
+		attr->ptma_magic == _PT_MUTEXATTR_MAGIC);
+
+	switch (proto) {
+	case PTHREAD_PRIO_NONE:
+	case PTHREAD_PRIO_PROTECT:
+		val = (uintptr_t)attr->ptma_private & ~0xff00L;
+		attr->ptma_private = (void *)(val | (proto << 8));
+		return 0;
+	case PTHREAD_PRIO_INHERIT:
+		return ENOTSUP;
+	default:
+		return EINVAL;
+	}
+}
+
+int 
+pthread_mutexattr_getprioceiling(const pthread_mutexattr_t *attr, int *ceil)
+{
+	uintptr_t val;
+	
+	pthread__error(EINVAL, "Invalid mutex attribute",
+		attr->ptma_magic == _PT_MUTEXATTR_MAGIC);
+
+	val = (uintptr_t)attr->ptma_private & ~0xff0000L;
+	*ceil = (int)(val >> 16);
+	return 0;
+}
+
+int 
+pthread_mutexattr_setprioceiling(pthread_mutexattr_t *attr, int ceil) 
+{
+	uintptr_t val;
+
+	pthread__error(EINVAL, "Invalid mutex attribute",
+		attr->ptma_magic == _PT_MUTEXATTR_MAGIC);

Indent, second level indent is 4 spaces

+
+	/*check range*/
+	val = (uintptr_t)attr->ptma_private & ~0xff0000L;
+	attr->ptma_private = (void*)(val | (ceil << 16));
+	return 0;
+}
+
+int
 pthread_mutexattr_getpshared(const pthread_mutexattr_t *__restrict attr, int* __restrict pshared) {
 	*pshared = PTHREAD_PROCESS_PRIVATE;
 	return 0;
@@ -662,6 +781,28 @@ pthread__mutex_deferwake(pthread_t self, pthread_mutex_t *ptm)
 }
 
 int
+pthread_mutex_getprioceiling(const pthread_mutex_t *ptm, int*ceil) 
+{
+	*ceil = (unsigned int)ptm->ptm_ceiling;
+	return 0;
+}
+
+int
+pthread_mutex_setprioceiling(pthread_mutex_t *ptm, int ceil, int *old_ceil) 
+{
+	int error;
+
+	error = pthread_mutex_lock(ptm);
+	if (error == 0) {
+		*old_ceil = (unsigned int)ptm->ptm_ceiling;
+		/*check range*/
+		ptm->ptm_ceiling = (unsigned char)ceil;
+		pthread_mutex_unlock(ptm);
+	}
+	return error;
+}
+
+int
 _pthread_mutex_held_np(pthread_mutex_t *ptm)
 {
 
diff --git a/lib/libpthread/pthread_types.h b/lib/libpthread/pthread_types.h
index a25be8e..7981348 100644
--- a/lib/libpthread/pthread_types.h
+++ b/lib/libpthread/pthread_types.h
@@ -115,7 +115,7 @@ struct	__pthread_mutex_st {
 #ifdef __CPU_SIMPLE_LOCK_PAD
 	uint8_t		ptm_pad1[3];
 #endif
-	__pthread_spin_t ptm_interlock;	/* unused - backwards compat */
+	__pthread_spin_t ptm_ceiling;
 #ifdef __CPU_SIMPLE_LOCK_PAD
 	uint8_t		ptm_pad2[3];
 #endif
@@ -130,14 +130,14 @@ struct	__pthread_mutex_st {
 
 #ifdef __CPU_SIMPLE_LOCK_PAD
 #define _PTHREAD_MUTEX_INITIALIZER { _PT_MUTEX_MAGIC, 			\
-				    __SIMPLELOCK_UNLOCKED, { 0, 0, 0 },	\
+                                    __SIMPLELOCK_UNLOCKED, { 0, 0, 0 },	\
 				    __SIMPLELOCK_UNLOCKED, { 0, 0, 0 },	\
 				    NULL, NULL, 0, NULL			\
 				  }
 #else
 #define _PTHREAD_MUTEX_INITIALIZER { _PT_MUTEX_MAGIC, 			\
-				    __SIMPLELOCK_UNLOCKED,		\
-				    __SIMPLELOCK_UNLOCKED,		\
+		                    __SIMPLELOCK_UNLOCKED,		\
+                                    __SIMPLELOCK_UNLOCKED,		\
 				    NULL, NULL, 0, NULL			\
 				  }
These were not changed, why are there whitespace diffs?

christos