[heap] Cancel concurrent workers in minor final pause

This CL cancels concurrent workers instead of joining them in
MarkLiveObjects. Joining could trigger another costly run.

Bug: v8:13012
Change-Id: I873db6e9d612e219060de0fa2447f6c7c0e9de3b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3885876Reviewed-by: Omer Katz <omerkatz@chromium.org>
Commit-Queue: Leon Bettscheider <bettscheider@google.com>
Cr-Commit-Position: refs/heads/main@{#83105}

src/heap/concurrent-marking.cc

@@ -954,6 +954,11 @@ bool ConcurrentMarking::Pause() {
   return true;
 }
 
+void ConcurrentMarking::Cancel() {
+  Pause();
+  garbage_collector_.reset();
+}
+
 bool ConcurrentMarking::IsStopped() {
   if (!v8_flags.concurrent_marking && !v8_flags.parallel_marking) return true;
 

src/heap/concurrent-marking.h

@@ -67,6 +67,7 @@ class V8_EXPORT_PRIVATE ConcurrentMarking {
   // Preempts ongoing job ASAP. Returns true if concurrent marking was in
   // progress, false otherwise.
   bool Pause();
+  void Cancel();
 
   // Schedules asynchronous job to perform concurrent marking at |priority| if
   // not already running, otherwise adjusts the number of workers running job

src/heap/mark-compact.cc

@@ -5809,7 +5809,7 @@ void MinorMarkCompactCollector::FinishConcurrentMarking() {
   if (v8_flags.concurrent_marking) {
     DCHECK_EQ(heap()->concurrent_marking()->garbage_collector(),
               GarbageCollector::MINOR_MARK_COMPACTOR);
-    heap()->concurrent_marking()->Join();
+    heap()->concurrent_marking()->Cancel();
     heap()->concurrent_marking()->FlushMemoryChunkData(
         non_atomic_marking_state());
   }