Module: xenomai-3
Branch: prioceil
Commit: 7bfb52399564c5853bd9cbf3cbb749282575d5f9
URL:
http://git.xenomai.org/?p=xenomai-3.git;a=commit;h=7bfb52399564c5853bd9cbf3cbb749282575d5f9
Author: Philippe Gerum <r...@xenomai.org>
Date: Tue Feb 16 10:13:03 2016 +0100
lib/cobalt/mutex: add support for priority ceiling protocol
---
configure.ac | 2 +
include/boilerplate/libc.h | 19 +++++
lib/cobalt/mutex.c | 172 ++++++++++++++++++++++++++++++--------------
3 files changed, 141 insertions(+), 52 deletions(-)
diff --git a/configure.ac b/configure.ac
index 20fa0ec..7aaedc2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -504,6 +504,8 @@ save_LIBS="$LIBS"
LIBS="$LIBS -lrt -lpthread"
AC_CHECK_FUNCS([pthread_mutexattr_setprotocol \
pthread_mutexattr_getprotocol \
+ pthread_mutexattr_getprioceiling \
+ pthread_mutexattr_setprioceiling \
pthread_mutexattr_setrobust_np \
pthread_condattr_getclock \
pthread_condattr_setclock \
diff --git a/include/boilerplate/libc.h b/include/boilerplate/libc.h
index 0e51b86..3a5af8c 100644
--- a/include/boilerplate/libc.h
+++ b/include/boilerplate/libc.h
@@ -108,6 +108,25 @@ int pthread_mutexattr_getprotocol(const
pthread_mutexattr_t *
}
#endif /* !HAVE_PTHREAD_MUTEXATTR_GETPROTOCOL */
+#ifndef HAVE_PTHREAD_MUTEXATTR_SETPRIOCEILING
+static inline
+int pthread_mutexattr_setprioceiling(pthread_mutexattr_t *attr,
+ int prioceiling)
+{
+ return ENOSYS;
+}
+#endif /* !HAVE_PTHREAD_MUTEXATTR_SETPRIOCEILING */
+
+#ifndef HAVE_PTHREAD_MUTEXATTR_GETPRIOCEILING
+static inline
+int pthread_mutexattr_getprioceiling(const pthread_mutexattr_t *
+ __restrict attr,
+ int *__restrict prioceiling)
+{
+ return ENOSYS;
+}
+#endif /* !HAVE_PTHREAD_MUTEXATTR_GETPRIOCEILING */
+
#ifndef HAVE_PTHREAD_ATTR_SETAFFINITY_NP
#include <sched.h>
static inline
diff --git a/lib/cobalt/mutex.c b/lib/cobalt/mutex.c
index 9d8a914..d0e61f2 100644
--- a/lib/cobalt/mutex.c
+++ b/lib/cobalt/mutex.c
@@ -99,6 +99,9 @@ void cobalt_mutex_init(void)
* mutex, increase CONFIG_XENO_OPT_SHARED_HEAPSZ for a process-shared
* mutex, or CONFIG_XENO_OPT_PRIVATE_HEAPSZ for a process-private mutex.
* - EAGAIN, no registry slot available, check/raise
CONFIG_XENO_OPT_REGISTRY_NRSLOTS.
+ * - ENOSYS, @a attr mentions priority protection
+ * (PTHREAD_PRIO_PROTECT), but the C library does not provide
+ * pthread_mutexattr_get/setprioceiling().
*
* @see
* <a
href="http://www.opengroup.org/onlinepubs/000095399/functions/pthread_mutex_init.html";>
@@ -117,7 +120,6 @@ COBALT_IMPL(int, pthread_mutex_init, (pthread_mutex_t
*mutex,
if (_mutex->magic == COBALT_MUTEX_MAGIC) {
err = -XENOMAI_SYSCALL1(sc_cobalt_mutex_check_init, _mutex);
-
if (err)
return err;
}
@@ -138,12 +140,15 @@ COBALT_IMPL(int, pthread_mutex_init, (pthread_mutex_t
*mutex,
err = pthread_mutexattr_getprotocol(attr, &tmp);
if (err)
return err;
- if (tmp == PTHREAD_PRIO_PROTECT) { /* Prio ceiling unsupported */
- err = EINVAL;
- return err;
- }
kmattr.protocol = tmp;
+ if (kmattr.protocol == PTHREAD_PRIO_PROTECT) {
+ err = pthread_mutexattr_getprioceiling(attr, &tmp);
+ if (err)
+ return err;
+ kmattr.ceiling = tmp;
+ }
+
err = -XENOMAI_SYSCALL2(sc_cobalt_mutex_init, _mutex, &kmattr);
if (err)
return err;
@@ -270,7 +275,8 @@ COBALT_IMPL(int, pthread_mutex_lock, (pthread_mutex_t
*mutex))
{
struct cobalt_mutex_shadow *_mutex =
&((union cobalt_mutex_union *)mutex)->shadow_mutex;
- int status, ret;
+ struct xnthread_user_window *u_window;
+ int status, ret, lazy_protect = 0;
xnhandle_t cur;
cur = cobalt_get_current();
@@ -285,21 +291,28 @@ COBALT_IMPL(int, pthread_mutex_lock, (pthread_mutex_t
*mutex))
* shadows and some debug features, so we must always obtain
* them via a syscall.
*/
- cont:
+start:
status = cobalt_get_current_mode();
if ((status & (XNRELAX|XNWEAK|XNDEBUG)) == 0) {
+ if (_mutex->attr.protocol == PTHREAD_PRIO_PROTECT)
+ goto protect;
+fast_path:
ret = xnsynch_fast_acquire(mutex_get_ownerp(_mutex), cur);
if (ret == 0) {
_mutex->lockcnt = 1;
return 0;
}
} else {
+slow_path:
ret = xnsynch_fast_owner_check(mutex_get_ownerp(_mutex), cur);
if (ret == 0)
ret = -EBUSY;
}
- if (ret == -EBUSY)
+ if (ret == -EBUSY) {
+ if (lazy_protect)
+ u_window->pp_pending = XN_NO_HANDLE;
+
switch(_mutex->attr.type) {
case PTHREAD_MUTEX_NORMAL:
break;
@@ -313,6 +326,7 @@ COBALT_IMPL(int, pthread_mutex_lock, (pthread_mutex_t
*mutex))
++_mutex->lockcnt;
return 0;
}
+ }
do
ret = XENOMAI_SYSCALL1(sc_cobalt_mutex_lock, _mutex);
@@ -322,12 +336,22 @@ COBALT_IMPL(int, pthread_mutex_lock, (pthread_mutex_t
*mutex))
_mutex->lockcnt = 1;
return -ret;
-
- autoinit:
+protect:
+ u_window = cobalt_get_current_window();
+ /*
+ * Can't nest lazy ceiling requests, have to take the slow
+ * path when this happens.
+ */
+ if (u_window->pp_pending != XN_NO_HANDLE)
+ goto slow_path;
+ u_window->pp_pending = _mutex->handle;
+ lazy_protect = 1;
+ goto fast_path;
+autoinit:
ret = cobalt_mutex_autoinit(mutex);
if (ret)
return ret;
- goto cont;
+ goto start;
}
/**
@@ -366,7 +390,8 @@ COBALT_IMPL(int, pthread_mutex_timedlock, (pthread_mutex_t
*mutex,
{
struct cobalt_mutex_shadow *_mutex =
&((union cobalt_mutex_union *)mutex)->shadow_mutex;
- int status, ret;
+ struct xnthread_user_window *u_window;
+ int status, ret, lazy_protect = 0;
xnhandle_t cur;
cur = cobalt_get_current();
@@ -377,21 +402,28 @@ COBALT_IMPL(int, pthread_mutex_timedlock,
(pthread_mutex_t *mutex,
goto autoinit;
/* See __cobalt_pthread_mutex_lock() */
- cont:
+start:
status = cobalt_get_current_mode();
if ((status & (XNRELAX|XNWEAK|XNDEBUG)) == 0) {
+ if (_mutex->attr.protocol == PTHREAD_PRIO_PROTECT)
+ goto protect;
+fast_path:
ret = xnsynch_fast_acquire(mutex_get_ownerp(_mutex), cur);
if (ret == 0) {
_mutex->lockcnt = 1;
return 0;
}
} else {
+slow_path:
ret = xnsynch_fast_owner_check(mutex_get_ownerp(_mutex), cur);
if (ret == 0)
ret = -EBUSY;
}
- if (ret == -EBUSY)
+ if (ret == -EBUSY) {
+ if (lazy_protect)
+ u_window->pp_pending = XN_NO_HANDLE;
+
switch(_mutex->attr.type) {
case PTHREAD_MUTEX_NORMAL:
break;
@@ -406,6 +438,7 @@ COBALT_IMPL(int, pthread_mutex_timedlock, (pthread_mutex_t
*mutex,
++_mutex->lockcnt;
return 0;
}
+ }
do {
ret = XENOMAI_SYSCALL2(sc_cobalt_mutex_timedlock, _mutex, to);
@@ -414,12 +447,22 @@ COBALT_IMPL(int, pthread_mutex_timedlock,
(pthread_mutex_t *mutex,
if (ret == 0)
_mutex->lockcnt = 1;
return -ret;
-
- autoinit:
+protect:
+ u_window = cobalt_get_current_window();
+ /*
+ * Can't nest lazy ceiling requests, have to take the slow
+ * path when this happens.
+ */
+ if (u_window->pp_pending != XN_NO_HANDLE)
+ goto slow_path;
+ u_window->pp_pending = _mutex->handle;
+ lazy_protect = 1;
+ goto fast_path;
+autoinit:
ret = cobalt_mutex_autoinit(mutex);
if (ret)
return ret;
- goto cont;
+ goto start;
}
/**
@@ -451,7 +494,8 @@ COBALT_IMPL(int, pthread_mutex_trylock, (pthread_mutex_t
*mutex))
{
struct cobalt_mutex_shadow *_mutex =
&((union cobalt_mutex_union *)mutex)->shadow_mutex;
- int status, err;
+ struct xnthread_user_window *u_window;
+ int status, ret, lazy_protect = 0;
xnhandle_t cur;
cur = cobalt_get_current();
@@ -460,49 +504,66 @@ COBALT_IMPL(int, pthread_mutex_trylock, (pthread_mutex_t
*mutex))
if (_mutex->magic != COBALT_MUTEX_MAGIC)
goto autoinit;
-
- cont:
+start:
status = cobalt_get_current_mode();
if ((status & (XNRELAX|XNWEAK|XNDEBUG)) == 0) {
- err = xnsynch_fast_acquire(mutex_get_ownerp(_mutex), cur);
- if (err == 0) {
+ if (_mutex->attr.protocol == PTHREAD_PRIO_PROTECT)
+ goto protect;
+fast_path:
+ ret = xnsynch_fast_acquire(mutex_get_ownerp(_mutex), cur);
+ if (ret == 0) {
_mutex->lockcnt = 1;
return 0;
}
} else {
- err = xnsynch_fast_owner_check(mutex_get_ownerp(_mutex), cur);
- if (err < 0)
+slow_path:
+ ret = xnsynch_fast_owner_check(mutex_get_ownerp(_mutex), cur);
+ if (ret < 0)
goto do_syscall;
- err = -EBUSY;
+ ret = -EBUSY;
}
- if (err == -EBUSY && _mutex->attr.type == PTHREAD_MUTEX_RECURSIVE) {
- if (_mutex->lockcnt == UINT32_MAX)
- return EAGAIN;
+ if (ret == -EBUSY) {
+ if (lazy_protect)
+ u_window->pp_pending = XN_NO_HANDLE;
- ++_mutex->lockcnt;
- return 0;
+ if (_mutex->attr.type == PTHREAD_MUTEX_RECURSIVE) {
+ if (_mutex->lockcnt == UINT32_MAX)
+ return EAGAIN;
+
+ ++_mutex->lockcnt;
+ return 0;
+ }
}
return EBUSY;
do_syscall:
-
do {
- err = XENOMAI_SYSCALL1(sc_cobalt_mutex_trylock, _mutex);
- } while (err == -EINTR);
+ ret = XENOMAI_SYSCALL1(sc_cobalt_mutex_trylock, _mutex);
+ } while (ret == -EINTR);
- if (!err)
+ if (ret == 0)
_mutex->lockcnt = 1;
- return -err;
-
- autoinit:
- err = cobalt_mutex_autoinit(mutex);
- if (err)
- return err;
- goto cont;
+ return -ret;
+autoinit:
+ ret = cobalt_mutex_autoinit(mutex);
+ if (ret)
+ return ret;
+ goto start;
+protect:
+ u_window = cobalt_get_current_window();
+ /*
+ * Can't nest lazy ceiling requests, have to take the slow
+ * path when this happens.
+ */
+ if (u_window->pp_pending != XN_NO_HANDLE)
+ goto slow_path;
+ u_window->pp_pending = _mutex->handle;
+ lazy_protect = 1;
+ goto fast_path;
}
/**
@@ -535,14 +596,14 @@ COBALT_IMPL(int, pthread_mutex_unlock, (pthread_mutex_t
*mutex))
{
struct cobalt_mutex_shadow *_mutex =
&((union cobalt_mutex_union *)mutex)->shadow_mutex;
+ struct xnthread_user_window *u_window;
struct cobalt_mutex_state *state;
xnhandle_t cur;
int err;
if (_mutex->magic != COBALT_MUTEX_MAGIC)
goto autoinit;
-
- cont:
+start:
cur = cobalt_get_current();
if (cur == XN_NO_HANDLE)
return EPERM;
@@ -562,21 +623,28 @@ COBALT_IMPL(int, pthread_mutex_unlock, (pthread_mutex_t
*mutex))
if (cobalt_get_current_mode() & (XNWEAK|XNDEBUG))
goto do_syscall;
- if (xnsynch_fast_release(&state->owner, cur))
+ if (xnsynch_fast_release(&state->owner, cur)) {
+ if (_mutex->attr.protocol == PTHREAD_PRIO_PROTECT)
+ goto unprotect;
return 0;
+ }
do_syscall:
-
do {
err = XENOMAI_SYSCALL1(sc_cobalt_mutex_unlock, _mutex);
} while (err == -EINTR);
return -err;
- autoinit:
+autoinit:
err = cobalt_mutex_autoinit(mutex);
if (err)
return err;
- goto cont;
+ goto start;
+unprotect:
+ u_window = cobalt_get_current_window();
+ u_window->pp_pending = XN_NO_HANDLE;
+
+ return 0;
}
/**
@@ -692,9 +760,9 @@ int pthread_mutexattr_settype(pthread_mutexattr_t * attr,
int type);
* This service stores, at the address @a proto, the value of the @a protocol
* attribute in the mutex attributes object @a attr.
*
- * The @a protcol attribute may only be one of @a PTHREAD_PRIO_NONE or @a
- * PTHREAD_PRIO_INHERIT. See pthread_mutexattr_setprotocol() for the meaning of
- * these two constants.
+ * The @a protcol attribute may be one of @a PTHREAD_PRIO_NONE, @a
+ * PTHREAD_PRIO_INHERIT or @a PTHREAD_PRIO_PROTECT. See
+ * pthread_mutexattr_setprotocol() for the meaning of these constants.
*
* @param attr an initialized mutex attributes object;
*
@@ -727,8 +795,8 @@ int pthread_mutexattr_getprotocol(const pthread_mutexattr_t
* attr, int *proto);
* @a attr will not follow any priority protocol;
* - PTHREAD_PRIO_INHERIT, meaning that a mutex created with the attributes
* object @a attr, will follow the priority inheritance protocol.
- *
- * The value PTHREAD_PRIO_PROTECT (priority ceiling protocol) is unsupported.
+ * - PTHREAD_PRIO_PROTECT, meaning that a mutex created with the attributes
+ * object @a attr, will follow the priority protect protocol.
*
* @return 0 on success,
* @return an error number if:
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