Merging upstream version 1:10.11.8.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 19 insertions, 6 deletions

diff --git a/tpool/tpool_generic.cc b/tpool/tpool_generic.cc
index fd97b446..a4d6c405 100644
--- a/tpool/tpool_generic.cc
+++ b/tpool/tpool_generic.cc
@@ -628,7 +628,7 @@ void thread_pool_generic::check_idle(std::chrono::system_clock::time_point now)
   }
 
   /* Switch timer off after 1 minute of idle time */
-  if (now - idle_since > max_idle_time)
+  if (now - idle_since > max_idle_time && m_active_threads.empty())
   {
     idle_since= invalid_timestamp;
     switch_timer(timer_state_t::OFF);
@@ -722,13 +722,17 @@ static int  throttling_interval_ms(size_t n_threads,size_t concurrency)
 /* Create a new worker.*/
 bool thread_pool_generic::add_thread()
 {
-  if (m_thread_creation_pending.test_and_set())
-    return false;
-
   size_t n_threads = thread_count();
 
   if (n_threads >= m_max_threads)
     return false;
+
+  /*
+    Deadlock danger exists, so monitor pool health
+    with maintenance timer.
+  */
+  switch_timer(timer_state_t::ON);
+
   if (n_threads >= m_min_threads)
   {
     auto now = std::chrono::system_clock::now();
@@ -739,12 +743,18 @@ bool thread_pool_generic::add_thread()
         Throttle thread creation and wakeup deadlock detection timer,
         if is it off.
       */
-      switch_timer(timer_state_t::ON);
-
       return false;
     }
   }
 
+  /* Check and set "thread creation pending" flag before creating the thread. We
+  reset the flag in thread_pool_generic::worker_main in new thread created. The
+  flag must be reset back in case we fail to create the thread. If this flag is
+  not reset all future attempt to create thread for this pool would not work as
+  we would return from here. */
+  if (m_thread_creation_pending.test_and_set())
+    return false;
+
   worker_data *thread_data = m_thread_data_cache.get();
   m_active_threads.push_back(thread_data);
   try
@@ -764,6 +774,7 @@ bool thread_pool_generic::add_thread()
         "current number of threads in pool %zu\n", e.what(), thread_count());
       warning_written = true;
     }
+    m_thread_creation_pending.clear();
     return false;
   }
   return true;
@@ -801,6 +812,7 @@ thread_pool_generic::thread_pool_generic(int min_threads, int max_threads) :
   m_tasks_dequeued(),
   m_wakeups(),
   m_spurious_wakeups(),
+  m_timer_state(timer_state_t::ON),
   m_in_shutdown(),
   m_timestamp(),
   m_long_tasks_count(),
@@ -813,6 +825,7 @@ thread_pool_generic::thread_pool_generic(int min_threads, int max_threads) :
   m_maintenance_timer(thread_pool_generic::maintenance_func, this, nullptr)
 {
   set_concurrency();
+
   // start the timer
   m_maintenance_timer.set_time(0, (int)m_timer_interval.count());
 }