Use a lock in pages to synchronize sweeper threads to allow others to wait on concurrently swept pa…

src/heap/store-buffer.cc

Index: src/heap/store-buffer.cc
diff --git a/src/heap/store-buffer.cc b/src/heap/store-buffer.cc
index 03f587f2154e14bc3093a920cc5be7c4ba200154..a5191dc748e34e944b015b52c67207c6ba537553 100644
--- a/src/heap/store-buffer.cc
+++ b/src/heap/store-buffer.cc
@@ -472,10 +472,9 @@ void StoreBuffer::IteratePointersToNewSpace(ObjectSlotCallback slot_callback) {
               heap_->mark_compact_collector()->SweepInParallel(page, owner);
               if (!page->SweepingCompleted()) {
                 // We were not able to sweep that page, i.e., a concurrent
-                // sweeper thread currently owns this page.
-                // TODO(hpayer): This may introduce a huge pause here. We
-                // just care about finish sweeping of the scan on scavenge page.
-                heap_->mark_compact_collector()->EnsureSweepingCompleted();
+                // sweeper thread currently owns this page. Wait for the sweeper
+                // thread to be done with this page.
+                page->WaitUntilSweepingCompleted();
               }
             }
             CHECK(page->owner() == heap_->old_space());