The new implementation. In user-space, without syscall in the common case when a
mutex is free when locking it, and was not claimed when unlocking it.
Note that this change entails a change in behaviour of the mutexes: before this
change locking a mutex caused the calling thread to switch to primary mode. Now,
the thread locking a mutex without syscall remains in the same mode.
---
Makefile.am | 2
cond.c | 21 ++++
mutex.c | 262 ++++++++++++++++++++++++++++++++++++++++++++++++++++++------
3 files changed, 260 insertions(+), 25 deletions(-)
Index: src/skins/posix/mutex.c
===================================================================
--- src/skins/posix/mutex.c (revision 3718)
+++ src/skins/posix/mutex.c (working copy)
@@ -18,9 +18,14 @@
#include <errno.h>
#include <posix/syscall.h>
+#include <posix/cb_lock.h>
#include <pthread.h>
+#define PSE51_MUTEX_MAGIC (0x86860303)
+
extern int __pse51_muxid;
+extern pthread_key_t pse51_cur_key;
+extern unsigned long pse51_shared_map[2];
int __wrap_pthread_mutexattr_init(pthread_mutexattr_t *attr)
{
@@ -73,66 +78,279 @@ int __wrap_pthread_mutexattr_setpshared(
__pse51_mutexattr_setpshared, attr, pshared);
}
-int __wrap_pthread_mutex_init(pthread_mutex_t * mutex,
- const pthread_mutexattr_t * attr)
+static atomic_ptr_t *get_ownerp(struct __shadow_mutex *shadow)
+{
+ if (likely(!shadow->attr.pshared))
+ return shadow->owner;
+
+ return (atomic_ptr_t *) (pse51_shared_map[1] + shadow->owner_offset);
+}
+
+int __wrap_pthread_mutex_init(pthread_mutex_t *mutex,
+ const pthread_mutexattr_t *attr)
{
union __xeno_mutex *_mutex = (union __xeno_mutex *)mutex;
+ struct __shadow_mutex *shadow = &_mutex->shadow_mutex;
int err;
- err = -XENOMAI_SKINCALL2(__pse51_muxid,
- __pse51_mutex_init,&_mutex->shadow_mutex,attr);
+#ifdef XNARCH_HAVE_US_ATOMIC_CMPXCHG
+ if (unlikely(cb_try_read_lock(&shadow->lock, s)))
+ goto checked;
+
+ err = -XENOMAI_SKINCALL2(__pse51_muxid,__pse51_check_init,shadow,attr);
+
+ if (err) {
+ cb_read_unlock(&shadow->lock, s);
+ return err;
+ }
+
+ checked:
+ cb_force_write_lock(&shadow->lock, s);
+#endif /* XNARCH_HAVE_US_ATOMIC_CMPXCHG */
+
+ err = -XENOMAI_SKINCALL2(__pse51_muxid,__pse51_mutex_init,shadow,attr);
+
+ if (!shadow->attr.pshared)
+ shadow->owner = (atomic_ptr_t *)
+ (pse51_shared_map[0] + shadow->owner_offset);
+
+ cb_write_unlock(&shadow->lock, s);
+
return err;
}
-int __wrap_pthread_mutex_destroy(pthread_mutex_t * mutex)
+int __wrap_pthread_mutex_destroy(pthread_mutex_t *mutex)
{
union __xeno_mutex *_mutex = (union __xeno_mutex *)mutex;
+ struct __shadow_mutex *shadow = &_mutex->shadow_mutex;
+ int err;
- return -XENOMAI_SKINCALL1(__pse51_muxid,
- __pse51_mutex_destroy, &_mutex->shadow_mutex);
+ if (unlikely(cb_try_write_lock(&shadow->lock, s)))
+ return EINVAL;
+
+ err = -XENOMAI_SKINCALL1(__pse51_muxid, __pse51_mutex_destroy, shadow);
+
+ cb_write_unlock(&shadow->lock, s);
+
+ return err;
}
-int __wrap_pthread_mutex_lock(pthread_mutex_t * mutex)
+int __wrap_pthread_mutex_lock(pthread_mutex_t *mutex)
{
union __xeno_mutex *_mutex = (union __xeno_mutex *)mutex;
- int err;
+ struct __shadow_mutex *shadow = &_mutex->shadow_mutex;
+ xnthread_t *cur, *owner;
+ int err = 0;
+
+#ifdef XNARCH_HAVE_US_ATOMIC_CMPXCHG
+ cur = pthread_getspecific(pse51_cur_key);
+ if (!cur)
+ return EPERM;
+
+ if (unlikely(cb_try_read_lock(&shadow->lock, s)))
+ return EINVAL;
+
+ if (unlikely(shadow->magic != PSE51_MUTEX_MAGIC)) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ owner = atomic_ptr_cmpxchg(get_ownerp(shadow), NULL, cur);
+ if (likely(!owner)) {
+ shadow->lockcnt = 1;
+ cb_read_unlock(&shadow->lock, s);
+ return 0;
+ }
+
+ if (clear_claimed(owner) == cur)
+ switch(shadow->attr.type) {
+ case PTHREAD_MUTEX_NORMAL:
+ break;
+
+ case PTHREAD_MUTEX_ERRORCHECK:
+ err = -EDEADLK;
+ goto out;
+
+ case PTHREAD_MUTEX_RECURSIVE:
+ if (shadow->lockcnt == UINT_MAX) {
+ err = -EAGAIN;
+ goto out;
+ }
+
+ ++shadow->lockcnt;
+ goto out;
+ }
+#endif /* XNARCH_HAVE_US_ATOMIC_CMPXCHG */
do {
- err = XENOMAI_SKINCALL1(__pse51_muxid,
- __pse51_mutex_lock,
- &_mutex->shadow_mutex);
+ err =
XENOMAI_SKINCALL1(__pse51_muxid,__pse51_mutex_lock,shadow);
} while (err == -EINTR);
+#ifdef XNARCH_HAVE_US_ATOMIC_CMPXCHG
+ out:
+ cb_read_unlock(&shadow->lock, s);
+#endif /* XNARCH_HAVE_US_ATOMIC_CMPXCHG */
+
return -err;
}
-int __wrap_pthread_mutex_timedlock(pthread_mutex_t * mutex,
+int __wrap_pthread_mutex_timedlock(pthread_mutex_t *mutex,
const struct timespec *to)
{
union __xeno_mutex *_mutex = (union __xeno_mutex *)mutex;
- int err;
+ struct __shadow_mutex *shadow = &_mutex->shadow_mutex;
+ xnthread_t *cur, *owner;
+ int err = 0;
+
+#ifdef XNARCH_HAVE_US_ATOMIC_CMPXCHG
+ cur = pthread_getspecific(pse51_cur_key);
+ if (!cur)
+ return EPERM;
+
+ if (unlikely(cb_try_read_lock(&shadow->lock, s)))
+ return EINVAL;
+
+ if (shadow->magic != PSE51_MUTEX_MAGIC) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ owner = atomic_ptr_cmpxchg(get_ownerp(shadow), NULL, cur);
+ if (likely(!owner)) {
+ shadow->lockcnt = 1;
+ cb_read_unlock(&shadow->lock, s);
+ return 0;
+ }
+
+ if (clear_claimed(owner) == cur)
+ switch(shadow->attr.type) {
+ case PTHREAD_MUTEX_NORMAL:
+ break;
+
+ case PTHREAD_MUTEX_ERRORCHECK:
+ err = -EDEADLK;
+ goto out;
+
+ case PTHREAD_MUTEX_RECURSIVE:
+ if (shadow->lockcnt == UINT_MAX) {
+ err = -EAGAIN;
+ goto out;
+ }
+
+ ++shadow->lockcnt;
+ goto out;
+ }
+#endif /* XNARCH_HAVE_US_ATOMIC_CMPXCHG */
do {
err = XENOMAI_SKINCALL2(__pse51_muxid,
- __pse51_mutex_timedlock,
- &_mutex->shadow_mutex, to);
+ __pse51_mutex_timedlock, shadow, to);
} while (err == -EINTR);
+#ifdef XNARCH_HAVE_US_ATOMIC_CMPXCHG
+ out:
+ cb_read_unlock(&shadow->lock, s);
+#endif /* XNARCH_HAVE_US_ATOMIC_CMPXCHG */
+
return -err;
}
-int __wrap_pthread_mutex_trylock(pthread_mutex_t * mutex)
+int __wrap_pthread_mutex_trylock(pthread_mutex_t *mutex)
{
union __xeno_mutex *_mutex = (union __xeno_mutex *)mutex;
+ struct __shadow_mutex *shadow = &_mutex->shadow_mutex;
+ xnthread_t *cur, *owner;
+ int err = 0;
+
+#ifdef XNARCH_HAVE_US_ATOMIC_CMPXCHG
+ cur = pthread_getspecific(pse51_cur_key);
+ if (!cur)
+ return EPERM;
+
+ if (unlikely(cb_try_read_lock(&shadow->lock, s)))
+ return EINVAL;
+
+ if (unlikely(shadow->magic != PSE51_MUTEX_MAGIC)) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ owner = atomic_ptr_cmpxchg(get_ownerp(shadow), NULL, cur);
+ if (likely(!owner)) {
+ shadow->lockcnt = 1;
+ cb_read_unlock(&shadow->lock, s);
+ return 0;
+ }
+
+ err = -EBUSY;
+ if (clear_claimed(owner) == cur
+ && shadow->attr.type == PTHREAD_MUTEX_RECURSIVE)
+ if (shadow->lockcnt == UINT_MAX)
+ err = -EAGAIN;
+ else {
+ ++shadow->lockcnt;
+ err = 0;
+ }
+
+ out:
+ cb_read_unlock(&shadow->lock, s);
+
+ return -err;
+
+#else /* !XNARCH_HAVE_US_ATOMIC_CMPXCHG */
+
+ return -XENOMAI_SKINCALL1(__pse51_muxid, __pse51_mutex_trylock, shadow);
- return -XENOMAI_SKINCALL1(__pse51_muxid,
- __pse51_mutex_trylock, &_mutex->shadow_mutex);
+#endif /* !XNARCH_HAVE_US_ATOMIC_CMPXCHG */
}
-int __wrap_pthread_mutex_unlock(pthread_mutex_t * mutex)
+int __wrap_pthread_mutex_unlock(pthread_mutex_t *mutex)
{
union __xeno_mutex *_mutex = (union __xeno_mutex *)mutex;
+ struct __shadow_mutex *shadow = &_mutex->shadow_mutex;
- return -XENOMAI_SKINCALL1(__pse51_muxid,
- __pse51_mutex_unlock, &_mutex->shadow_mutex);
+#ifdef XNARCH_HAVE_US_ATOMIC_CMPXCHG
+ atomic_ptr_t *ownerp;
+ xnthread_t *cur;
+ int err = 0;
+
+ cur = pthread_getspecific(pse51_cur_key);
+ if (!cur)
+ return EPERM;
+
+ if (unlikely(cb_try_read_lock(&shadow->lock, s)))
+ return EINVAL;
+
+ if (unlikely(shadow->magic != PSE51_MUTEX_MAGIC)) {
+ err = -EINVAL;
+ goto out_err;
+ }
+
+ ownerp = get_ownerp(shadow);
+ if (unlikely(clear_claimed(atomic_ptr_read(ownerp)) != cur)) {
+ err = -EPERM;
+ goto out_err;
+ }
+
+ err = 0;
+ if (shadow->lockcnt > 1) {
+ --shadow->lockcnt;
+ goto out;
+ }
+
+ if (likely(atomic_ptr_cmpxchg(ownerp, cur, NULL) == cur)) {
+ out:
+ cb_read_unlock(&shadow->lock, s);
+ return 0;
+ }
+#endif /* XNARCH_HAVE_US_ATOMIC_CMPXCHG */
+
+ err = XENOMAI_SKINCALL1(__pse51_muxid, __pse51_mutex_unlock, shadow);
+
+#ifdef XNARCH_HAVE_US_ATOMIC_CMPXCHG
+ out_err:
+ cb_read_unlock(&shadow->lock, s);
+#endif /* XNARCH_HAVE_US_ATOMIC_CMPXCHG */
+
+ return -err;
}
Index: src/skins/posix/cond.c
===================================================================
--- src/skins/posix/cond.c (revision 3718)
+++ src/skins/posix/cond.c (working copy)
@@ -19,6 +19,7 @@
#include <errno.h>
#include <posix/syscall.h>
#include <pthread.h>
+#include <posix/cb_lock.h>
extern int __pse51_muxid;
@@ -95,7 +96,7 @@ static void __pthread_cond_cleanup(void
c->count);
}
-int __wrap_pthread_cond_wait(pthread_cond_t * cond, pthread_mutex_t * mutex)
+int __wrap_pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
{
struct pse51_cond_cleanup_t c = {
.cond = (union __xeno_cond *)cond,
@@ -103,6 +104,9 @@ int __wrap_pthread_cond_wait(pthread_con
};
int err, oldtype;
+ if (cb_try_read_lock(&c.mutex->shadow_mutex.lock, s))
+ return EINVAL;
+
pthread_cleanup_push(&__pthread_cond_cleanup, &c);
pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, &oldtype);
@@ -118,11 +122,15 @@ int __wrap_pthread_cond_wait(pthread_con
pthread_cleanup_pop(0);
- if (err)
+ if (err) {
+ cb_read_unlock(&c.mutex->shadow_mutex.lock, s);
return err;
+ }
__pthread_cond_cleanup(&c);
+ cb_read_unlock(&c.mutex->shadow_mutex.lock, s);
+
pthread_testcancel();
return 0;
@@ -138,6 +146,9 @@ int __wrap_pthread_cond_timedwait(pthrea
};
int err, oldtype;
+ if (cb_try_read_lock(&c.mutex->shadow_mutex.lock, s))
+ return EINVAL;
+
pthread_cleanup_push(&__pthread_cond_cleanup, &c);
pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, &oldtype);
@@ -153,11 +164,15 @@ int __wrap_pthread_cond_timedwait(pthrea
pthread_cleanup_pop(0);
- if (err && err != ETIMEDOUT)
+ if (err && err != ETIMEDOUT) {
+ cb_read_unlock(&c.mutex->shadow_mutex.lock, s);
return err;
+ }
__pthread_cond_cleanup(&c);
+ cb_read_unlock(&c.mutex->shadow_mutex.lock, s);
+
pthread_testcancel();
return err;
Index: src/skins/posix/Makefile.am
===================================================================
--- src/skins/posix/Makefile.am (revision 3718)
+++ src/skins/posix/Makefile.am (working copy)
@@ -2,6 +2,8 @@ includedir = $(prefix)/include/posix
lib_LTLIBRARIES = libpthread_rt.la
+CPPFLAGS+=-I$(top_srcdir)/ksrc/skins
+
libpthread_rt_la_LDFLAGS = -version-info 1:0:0 -lpthread
libpthread_rt_la_SOURCES = \
--
Gilles.
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