path: root/include/pthread.h
diff options
authorKonstantin Belousov <kib@FreeBSD.org>2016-05-17 09:56:22 +0000
committerKonstantin Belousov <kib@FreeBSD.org>2016-05-17 09:56:22 +0000
commit2a339d9e3dc129f0b0b79c2cb8d2bb0386fb0f5f (patch)
treed626a38beb7329b5a3aa09877b11a5ec03a6eb38 /include/pthread.h
parent5105a92c4945e74f7d7c5eb97969d3e7da8fea9b (diff)
Add implementation of robust mutexes, hopefully close enough to the
intention of the POSIX IEEE Std 1003.1TM-2008/Cor 1-2013. A robust mutex is guaranteed to be cleared by the system upon either thread or process owner termination while the mutex is held. The next mutex locker is then notified about inconsistent mutex state and can execute (or abandon) corrective actions. The patch mostly consists of small changes here and there, adding neccessary checks for the inconsistent and abandoned conditions into existing paths. Additionally, the thread exit handler was extended to iterate over the userspace-maintained list of owned robust mutexes, unlocking and marking as terminated each of them. The list of owned robust mutexes cannot be maintained atomically synchronous with the mutex lock state (it is possible in kernel, but is too expensive). Instead, for the duration of lock or unlock operation, the current mutex is remembered in a special slot that is also checked by the kernel at thread termination. Kernel must be aware about the per-thread location of the heads of robust mutex lists and the current active mutex slot. When a thread touches a robust mutex for the first time, a new umtx op syscall is issued which informs about location of lists heads. The umtx sleep queues for PP and PI mutexes are split between non-robust and robust. Somewhat unrelated changes in the patch: 1. Style. 2. The fix for proper tdfind() call use in umtxq_sleep_pi() for shared pi mutexes. 3. Removal of the userspace struct pthread_mutex m_owner field. 4. The sysctl kern.ipc.umtx_vnode_persistent is added, which controls the lifetime of the shared mutex associated with a vnode' page. Reviewed by: jilles (previous version, supposedly the objection was fixed) Discussed with: brooks, Martin Simmons <martin@lispworks.com> (some aspects) Tested by: pho Sponsored by: The FreeBSD Foundation
Notes: svn path=/head/; revision=300043
Diffstat (limited to 'include/pthread.h')
1 files changed, 10 insertions, 0 deletions
diff --git a/include/pthread.h b/include/pthread.h
index 8078bcb69828..40dca7a4907a 100644
--- a/include/pthread.h
+++ b/include/pthread.h
@@ -135,6 +135,9 @@ enum pthread_mutextype {
struct _pthread_cleanup_info {
__uintptr_t pthread_cleanup_pad[8];
@@ -229,6 +232,8 @@ int pthread_mutexattr_settype(pthread_mutexattr_t *, int)
int pthread_mutexattr_setpshared(pthread_mutexattr_t *, int)
+int pthread_mutex_consistent(pthread_mutex_t *__mutex)
+ __nonnull(1) __requires_exclusive(*__mutex);
int pthread_mutex_destroy(pthread_mutex_t *__mutex)
__nonnull(1) __requires_unlocked(*__mutex);
int pthread_mutex_init(pthread_mutex_t *__mutex,
@@ -310,6 +315,11 @@ int pthread_mutex_setprioceiling(pthread_mutex_t *, int, int *);
int pthread_mutexattr_getprotocol(pthread_mutexattr_t *, int *);
int pthread_mutexattr_setprotocol(pthread_mutexattr_t *, int);
+int pthread_mutexattr_getrobust(pthread_mutexattr_t *__restrict,
+ int *__restrict) __nonnull_all;
+int pthread_mutexattr_setrobust(pthread_mutexattr_t *, int)
+ __nonnull(1);
int pthread_attr_getinheritsched(const pthread_attr_t *, int *);
int pthread_attr_getschedparam(const pthread_attr_t *,
struct sched_param *) __nonnull_all;