[heap] Print more info in incremental marking tracing.

src/heap/incremental-marking.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/heap/incremental-marking.h"
 
 #include "src/code-stubs.h"
 #include "src/compilation-cache.h"
 #include "src/conversions.h"
 #include "src/heap/gc-idle-time-handler.h"
@@ skipping 469 matching lines @@
           RecordWriteStub::Patch(Code::cast(e), mode);
         }
       }
     }
   }
 }
 
 
 void IncrementalMarking::Start(const char* reason) {
   if (FLAG_trace_incremental_marking) {
+    int old_generation_size_mb =
+        static_cast<int>(heap()->PromotedSpaceSizeOfObjects() / MB);
+    int old_generation_limit_mb =
+        static_cast<int>(heap()->old_generation_allocation_limit() / MB);
     heap()->isolate()->PrintWithTimestamp(
-        "[IncrementalMarking] Start (%s)\n",
-        (reason == nullptr) ? "unknown reason" : reason);
+        "[IncrementalMarking] Start (%s): old generation %dMB, limit %dMB, "
+        "slack %dMB\n",
+        (reason == nullptr) ? "unknown reason" : reason, old_generation_size_mb,
+        old_generation_limit_mb,
+        Max(0, old_generation_limit_mb - old_generation_size_mb));
   }
   DCHECK(FLAG_incremental_marking);
   DCHECK(state_ == STOPPED);
   DCHECK(heap_->gc_state() == Heap::NOT_IN_GC);
   DCHECK(!heap_->isolate()->serializer_enabled());
 
   HistogramTimerScope incremental_marking_scope(
       heap_->isolate()->counters()->gc_incremental_marking_start());
   TRACE_EVENT0("v8", "V8.GCIncrementalMarkingStart");
   ResetStepCounters();
@@ skipping 449 matching lines @@
       }
     }
     context = Context::cast(context)->next_context_link();
   }
 }
 
 
 void IncrementalMarking::Stop() {
   if (IsStopped()) return;
   if (FLAG_trace_incremental_marking) {
-    heap()->isolate()->PrintWithTimestamp("[IncrementalMarking] Stopping.\n");
+    int old_generation_size_mb =
+        static_cast<int>(heap()->PromotedSpaceSizeOfObjects() / MB);
+    int old_generation_limit_mb =
+        static_cast<int>(heap()->old_generation_allocation_limit() / MB);
+    heap()->isolate()->PrintWithTimestamp(
+        "[IncrementalMarking] Stopping: old generation %dMB, limit %dMB, "
+        "overshoot %dMB\n",
+        old_generation_size_mb, old_generation_limit_mb,
+        Max(0, old_generation_size_mb - old_generation_limit_mb));
   }
 
   heap_->new_space()->RemoveAllocationObserver(&observer_);
   IncrementalMarking::set_should_hurry(false);
   ResetStepCounters();
   if (IsMarking()) {
     PatchIncrementalMarkingRecordWriteStubs(heap_,
                                             RecordWriteStub::STORE_BUFFER_ONLY);
     DeactivateIncrementalWriteBarrier();
   }
@@ skipping 224 matching lines @@
   idle_marking_delay_counter_++;
 }
 
 
 void IncrementalMarking::ClearIdleMarkingDelayCounter() {
   idle_marking_delay_counter_ = 0;
 }
 
 }  // namespace internal
 }  // namespace v8