[OpenMP] Add omp_pause_resource* API

Add omp_pause_resource and omp_pause_resource_all API and enum, plus stub for
internal implementation. Implemented callable helper function to do local pause,
and added basic functionality for hard and soft pause.

Patch by Terry Wilmarth

Differential Revision: https://reviews.llvm.org/D55078

llvm-svn: 351372

1 files changed, 24 insertions, 1 deletions

diff --git a/openmp/runtime/src/z_Linux_util.cpp b/openmp/runtime/src/z_Linux_util.cpp
index aa0302c0fc3..eb6c3c0b4ce 100644
--- a/openmp/runtime/src/z_Linux_util.cpp
+++ b/openmp/runtime/src/z_Linux_util.cpp
@@ -1414,6 +1414,21 @@ void __kmp_suspend_uninitialize_thread(kmp_info_t *th) {
   }
 }
 
+// return true if lock obtained, false otherwise
+int __kmp_try_suspend_mx(kmp_info_t *th) {
+  return (pthread_mutex_trylock(&th->th.th_suspend_mx.m_mutex) == 0);
+}
+
+void __kmp_lock_suspend_mx(kmp_info_t *th) {
+  int status = pthread_mutex_lock(&th->th.th_suspend_mx.m_mutex);
+  KMP_CHECK_SYSFAIL("pthread_mutex_lock", status);
+}
+
+void __kmp_unlock_suspend_mx(kmp_info_t *th) {
+  int status = pthread_mutex_unlock(&th->th.th_suspend_mx.m_mutex);
+  KMP_CHECK_SYSFAIL("pthread_mutex_unlock", status);
+}
+
 /* This routine puts the calling thread to sleep after setting the
    sleep bit for the indicated flag variable to true. */
 template <class C>
@@ -1437,7 +1452,15 @@ static inline void __kmp_suspend_template(int th_gtid, C *flag) {
   /* TODO: shouldn't this use release semantics to ensure that
      __kmp_suspend_initialize_thread gets called first? */
   old_spin = flag->set_sleeping();
-
+#if OMP_50_ENABLED
+  if (__kmp_dflt_blocktime == KMP_MAX_BLOCKTIME &&
+      __kmp_pause_status != kmp_soft_paused) {
+    flag->unset_sleeping();
+    status = pthread_mutex_unlock(&th->th.th_suspend_mx.m_mutex);
+    KMP_CHECK_SYSFAIL("pthread_mutex_unlock", status);
+    return;
+  }
+#endif
   KF_TRACE(5, ("__kmp_suspend_template: T#%d set sleep bit for spin(%p)==%x,"
                " was %x\n",
                th_gtid, flag->get(), flag->load(), old_spin));