From 5676443139b4153b33eec51af04e083cc01fe1f7 Mon Sep 17 00:00:00 2001
From: Kamil Rakoczy <krakoczy@antmicro.com>
Date: Mon, 11 Sep 2023 19:43:26 +0200
Subject: [PATCH] Internals: Rename and slightly change other threads
 stopping/resuming methods. (#4478)

Co-authored-by: Mariusz Glebocki <mglebocki@antmicro.com>
---
 src/V3ThreadPool.cpp |  7 ++++---
 src/V3ThreadPool.h   | 22 +++++++++++++---------
 2 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/src/V3ThreadPool.cpp b/src/V3ThreadPool.cpp
index 8eadc7b61..36a6d6c50 100644
--- a/src/V3ThreadPool.cpp
+++ b/src/V3ThreadPool.cpp
@@ -84,11 +84,11 @@ void V3ThreadPool::workerJobLoop(int id) VL_MT_SAFE {
 bool V3ThreadPool::waitIfStopRequested() VL_MT_SAFE VL_EXCLUDES(m_stoppedJobsMutex) {
     if (!stopRequested()) return false;
     V3LockGuard stoppedJobLock(m_stoppedJobsMutex);
-    waitStopRequested();
+    waitForResumeRequest();
     return true;
 }
 
-void V3ThreadPool::waitStopRequested() VL_REQUIRES(m_stoppedJobsMutex) {
+void V3ThreadPool::waitForResumeRequest() VL_REQUIRES(m_stoppedJobsMutex) {
     ++m_stoppedJobs;
     m_stoppedJobsCV.notify_all();
     m_stoppedJobsCV.wait(m_stoppedJobsMutex, [&]() VL_REQUIRES(m_stoppedJobsMutex) {
@@ -98,8 +98,9 @@ void V3ThreadPool::waitStopRequested() VL_REQUIRES(m_stoppedJobsMutex) {
     m_stoppedJobsCV.notify_all();
 }
 
-void V3ThreadPool::waitOtherThreads() VL_MT_SAFE_EXCLUDES(m_mutex)
+void V3ThreadPool::stopOtherThreads() VL_MT_SAFE_EXCLUDES(m_mutex)
     VL_REQUIRES(m_stoppedJobsMutex) {
+    m_stopRequested = true;
     ++m_stoppedJobs;
     m_stoppedJobsCV.notify_all();
     m_cv.notify_all();
diff --git a/src/V3ThreadPool.h b/src/V3ThreadPool.h
index 7d21d157a..ad47ec093 100644
--- a/src/V3ThreadPool.h
+++ b/src/V3ThreadPool.h
@@ -192,11 +192,17 @@ private:
         return m_stopRequested;
     }
 
-    // Waits until exclusive access job completes its job
-    void waitStopRequested() VL_REQUIRES(m_stoppedJobsMutex);
+    // Waits until `resumeOtherThreads()` is called or exclusive access scope end.
+    void waitForResumeRequest() VL_REQUIRES(m_stoppedJobsMutex);
 
-    // Waits until all other jobs are stopped
-    void waitOtherThreads() VL_MT_SAFE_EXCLUDES(m_mutex) VL_REQUIRES(m_stoppedJobsMutex);
+    // Sends stop request to other threads and waits until they stop.
+    void stopOtherThreads() VL_MT_SAFE_EXCLUDES(m_mutex) VL_REQUIRES(m_stoppedJobsMutex);
+
+    // Resumes threads stopped through previous call to `stopOtherThreads()`.
+    void resumeOtherThreads() VL_MT_SAFE_EXCLUDES(m_mutex) VL_REQUIRES(m_stoppedJobsMutex) {
+        m_stopRequested = false;
+        m_stoppedJobsCV.notify_all();
+    }
 
     void workerJobLoop(int id) VL_MT_SAFE;
 
@@ -209,9 +215,8 @@ public:
         if (!V3ThreadPool::s().willExecuteSynchronously()) {
             V3ThreadPool::s().m_stoppedJobsMutex.lock();
 
-            if (V3ThreadPool::s().stopRequested()) { V3ThreadPool::s().waitStopRequested(); }
-            V3ThreadPool::s().m_stopRequested = true;
-            V3ThreadPool::s().waitOtherThreads();
+            if (V3ThreadPool::s().stopRequested()) { V3ThreadPool::s().waitForResumeRequest(); }
+            V3ThreadPool::s().stopOtherThreads();
             V3ThreadPool::s().m_exclusiveAccess = true;
         } else {
             V3ThreadPool::s().m_stoppedJobsMutex.assumeLocked();
@@ -221,8 +226,7 @@ public:
         // Can't use `willExecuteSynchronously`, we're still in exclusive execution state.
         if (V3ThreadPool::s().m_exclusiveAccess) {
             V3ThreadPool::s().m_exclusiveAccess = false;
-            V3ThreadPool::s().m_stopRequested = false;
-            V3ThreadPool::s().m_stoppedJobsCV.notify_all();
+            V3ThreadPool::s().resumeOtherThreads();
 
             V3ThreadPool::s().m_stoppedJobsMutex.unlock();
         } else {