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authorchristos <christos@NetBSD.org>2016-07-03 14:24:58 +0000
committerchristos <christos@NetBSD.org>2016-07-03 14:24:58 +0000
commit774674fd4710ea607eef47c793bd0cf3d4eb5184 (patch)
tree05cc5703bc1498308ea98c1fe07c25fdaee74f76 /lib/libpthread/pthread_mutex.c
parent3abdd8b82ad97d2929a64342f1bbc596ee3b1efa (diff)
GSoC 2016 Charles Cui: Implement thread priority protection based on work
by Andy Doran. Also document the get/set pshared thread calls as not implemented, and add a skeleton implementation that is disabled. XXX: document _sched_protect(2).
Diffstat (limited to 'lib/libpthread/pthread_mutex.c')
-rw-r--r--lib/libpthread/pthread_mutex.c197
1 files changed, 184 insertions, 13 deletions
diff --git a/lib/libpthread/pthread_mutex.c b/lib/libpthread/pthread_mutex.c
index 2d8eed5f144..d8879eea523 100644
--- a/lib/libpthread/pthread_mutex.c
+++ b/lib/libpthread/pthread_mutex.c
@@ -1,4 +1,4 @@
-/* $NetBSD: pthread_mutex.c,v 1.59 2014/02/03 15:51:01 rmind Exp $ */
+/* $NetBSD: pthread_mutex.c,v 1.60 2016/07/03 14:24:58 christos Exp $ */
/*-
* Copyright (c) 2001, 2003, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -47,10 +47,11 @@
*/
#include <sys/cdefs.h>
-__RCSID("$NetBSD: pthread_mutex.c,v 1.59 2014/02/03 15:51:01 rmind Exp $");
+__RCSID("$NetBSD: pthread_mutex.c,v 1.60 2016/07/03 14:24:58 christos Exp $");
#include <sys/types.h>
#include <sys/lwpctl.h>
+#include <sys/sched.h>
#include <sys/lock.h>
#include <errno.h>
@@ -67,12 +68,27 @@ __RCSID("$NetBSD: pthread_mutex.c,v 1.59 2014/02/03 15:51:01 rmind Exp $");
#define MUTEX_WAITERS_BIT ((uintptr_t)0x01)
#define MUTEX_RECURSIVE_BIT ((uintptr_t)0x02)
#define MUTEX_DEFERRED_BIT ((uintptr_t)0x04)
-#define MUTEX_THREAD ((uintptr_t)-16L)
+#define MUTEX_PROTECT_BIT ((uintptr_t)0x08)
+#define MUTEX_THREAD ((uintptr_t)~0x0f)
#define MUTEX_HAS_WAITERS(x) ((uintptr_t)(x) & MUTEX_WAITERS_BIT)
#define MUTEX_RECURSIVE(x) ((uintptr_t)(x) & MUTEX_RECURSIVE_BIT)
+#define MUTEX_PROTECT(x) ((uintptr_t)(x) & MUTEX_PROTECT_BIT)
#define MUTEX_OWNER(x) ((uintptr_t)(x) & MUTEX_THREAD)
+#define MUTEX_GET_TYPE(x) \
+ ((int)(((uintptr_t)(x) & 0x000000ff) >> 0))
+#define MUTEX_SET_TYPE(x, t) \
+ (x) = (void *)(((uintptr_t)(x) & ~0x000000ff) | ((t) << 0))
+#define MUTEX_GET_PROTOCOL(x) \
+ ((int)(((uintptr_t)(x) & 0x0000ff00) >> 8))
+#define MUTEX_SET_PROTOCOL(x, p) \
+ (x) = (void *)(((uintptr_t)(x) & ~0x0000ff00) | ((p) << 8))
+#define MUTEX_GET_CEILING(x) \
+ ((int)(((uintptr_t)(x) & 0x00ff0000) >> 16))
+#define MUTEX_SET_CEILING(x, c) \
+ (x) = (void *)(((uintptr_t)(x) & ~0x00ff0000) | ((c) << 16))
+
#if __GNUC_PREREQ__(3, 0)
#define NOINLINE __attribute ((noinline))
#else
@@ -80,7 +96,8 @@ __RCSID("$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 *);
static int pthread__mutex_unlock_slow(pthread_mutex_t *);
static void pthread__mutex_pause(void);
@@ -103,16 +120,22 @@ __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 = MUTEX_GET_TYPE(val);
+ proto = MUTEX_GET_PROTOCOL(val);
+ ceil = MUTEX_GET_CEILING(val);
+ }
switch (type) {
case PTHREAD_MUTEX_ERRORCHECK:
__cpu_simple_lock_set(&ptm->ptm_errorcheck);
@@ -127,10 +150,18 @@ 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;
+ 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 +199,24 @@ 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 +306,12 @@ 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 +331,10 @@ 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 +392,23 @@ 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 +524,10 @@ 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 +659,18 @@ pthread_mutexattr_destroy(pthread_mutexattr_t *attr)
int
pthread_mutexattr_gettype(const pthread_mutexattr_t *attr, int *typep)
{
+
pthread__error(EINVAL, "Invalid mutex attribute",
attr->ptma_magic == _PT_MUTEXATTR_MAGIC);
- *typep = (int)(intptr_t)attr->ptma_private;
+ *typep = MUTEX_GET_TYPE(attr->ptma_private);
return 0;
}
int
pthread_mutexattr_settype(pthread_mutexattr_t *attr, int type)
{
+
if (__predict_false(__uselibcstub))
return __libc_mutexattr_settype_stub(attr, type);
@@ -611,13 +681,92 @@ 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;
+ MUTEX_SET_TYPE(attr->ptma_private, type);
return 0;
default:
return EINVAL;
}
}
+int
+pthread_mutexattr_getprotocol(const pthread_mutexattr_t *attr, int*proto)
+{
+
+ pthread__error(EINVAL, "Invalid mutex attribute",
+ attr->ptma_magic == _PT_MUTEXATTR_MAGIC);
+
+ *proto = MUTEX_GET_PROTOCOL(attr->ptma_private);
+ return 0;
+}
+
+int
+pthread_mutexattr_setprotocol(pthread_mutexattr_t* attr, int proto)
+{
+
+ pthread__error(EINVAL, "Invalid mutex attribute",
+ attr->ptma_magic == _PT_MUTEXATTR_MAGIC);
+
+ switch (proto) {
+ case PTHREAD_PRIO_NONE:
+ case PTHREAD_PRIO_PROTECT:
+ MUTEX_SET_PROTOCOL(attr->ptma_private, proto);
+ return 0;
+ case PTHREAD_PRIO_INHERIT:
+ return ENOTSUP;
+ default:
+ return EINVAL;
+ }
+}
+
+int
+pthread_mutexattr_getprioceiling(const pthread_mutexattr_t *attr, int *ceil)
+{
+
+ pthread__error(EINVAL, "Invalid mutex attribute",
+ attr->ptma_magic == _PT_MUTEXATTR_MAGIC);
+
+ *ceil = MUTEX_GET_CEILING(attr->ptma_private);
+ return 0;
+}
+
+int
+pthread_mutexattr_setprioceiling(pthread_mutexattr_t *attr, int ceil)
+{
+
+ pthread__error(EINVAL, "Invalid mutex attribute",
+ attr->ptma_magic == _PT_MUTEXATTR_MAGIC);
+
+ if (ceil & ~0xff)
+ return EINVAL;
+
+ MUTEX_SET_CEILING(attr->ptma_private, ceil);
+ return 0;
+}
+
+#ifdef _PTHREAD_PSHARED
+int
+pthread_mutexattr_getpshared(const pthread_mutexattr_t * __restrict attr,
+ int * __restrict pshared)
+{
+
+ *pshared = PTHREAD_PROCESS_PRIVATE;
+ return 0;
+}
+
+int
+pthread_mutexattr_setpshared(pthread_mutexattr_t *attr, int pshared)
+{
+
+ switch(pshared) {
+ case PTHREAD_PROCESS_PRIVATE:
+ return 0;
+ case PTHREAD_PROCESS_SHARED:
+ return ENOSYS;
+ }
+ return EINVAL;
+}
+#endif
+
/*
* pthread__mutex_deferwake: try to defer unparking threads in self->pt_waiters
*
@@ -645,6 +794,28 @@ 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)
{