[heap] Introduce enum of garbage collection reasons.

src/heap/heap.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/heap.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/ast/context-slot-cache.h"
 #include "src/base/bits.h"
@@ skipping 772 matching lines @@
 };
 
 
 void Heap::HandleGCRequest() {
   if (HighMemoryPressure()) {
     incremental_marking()->reset_request_type();
     CheckMemoryPressure();
   } else if (incremental_marking()->request_type() ==
              IncrementalMarking::COMPLETE_MARKING) {
     incremental_marking()->reset_request_type();
-    CollectAllGarbage(current_gc_flags_, "GC interrupt",
+    CollectAllGarbage(current_gc_flags_,
+                      GarbageCollectionReason::kFinalizeMarkingViaStackGuard,
                       current_gc_callback_flags_);
   } else if (incremental_marking()->request_type() ==
                  IncrementalMarking::FINALIZATION &&
              incremental_marking()->IsMarking() &&
              !incremental_marking()->finalize_marking_completed()) {
     incremental_marking()->reset_request_type();
-    FinalizeIncrementalMarking("GC interrupt: finalize incremental marking");
+    FinalizeIncrementalMarking(
+        GarbageCollectionReason::kFinalizeMarkingViaStackGuard);
   }
 }
 
 
 void Heap::ScheduleIdleScavengeIfNeeded(int bytes_allocated) {
   scavenge_job_->ScheduleIdleTaskIfNeeded(this, bytes_allocated);
 }
 
-
-void Heap::FinalizeIncrementalMarking(const char* gc_reason) {
+void Heap::FinalizeIncrementalMarking(GarbageCollectionReason gc_reason) {
   if (FLAG_trace_incremental_marking) {
     isolate()->PrintWithTimestamp("[IncrementalMarking] (%s).\n", gc_reason);
   }
 
   HistogramTimerScope incremental_marking_scope(
       isolate()->counters()->gc_incremental_marking_finalize());
   TRACE_EVENT0("v8", "V8.GCIncrementalMarkingFinalize");
   TRACE_GC(tracer(), GCTracer::Scope::MC_INCREMENTAL_FINALIZE);
 
   {
@@ skipping 29 matching lines @@
         return isolate_->counters()->gc_finalize_reduce_memory();
       } else {
         return isolate_->counters()->gc_finalize();
       }
     } else {
       return isolate_->counters()->gc_compactor();
     }
   }
 }
 
-void Heap::CollectAllGarbage(int flags, const char* gc_reason,
+void Heap::CollectAllGarbage(int flags, GarbageCollectionReason gc_reason,
                              const v8::GCCallbackFlags gc_callback_flags) {
   // Since we are ignoring the return value, the exact choice of space does
   // not matter, so long as we do not specify NEW_SPACE, which would not
   // cause a full GC.
   set_current_gc_flags(flags);
   CollectGarbage(OLD_SPACE, gc_reason, gc_callback_flags);
   set_current_gc_flags(kNoGCFlags);
 }
 
-
-void Heap::CollectAllAvailableGarbage(const char* gc_reason) {
+void Heap::CollectAllAvailableGarbage(GarbageCollectionReason gc_reason) {
   // Since we are ignoring the return value, the exact choice of space does
   // not matter, so long as we do not specify NEW_SPACE, which would not
   // cause a full GC.
   // Major GC would invoke weak handle callbacks on weakly reachable
   // handles, but won't collect weakly reachable objects until next
   // major GC.  Therefore if we collect aggressively and weak handle callback
   // has been invoked, we rerun major GC to release objects which become
   // garbage.
   // Note: as weak callbacks can execute arbitrary code, we cannot
   // hope that eventually there will be no weak callbacks invocations.
@@ skipping 13 matching lines @@
                         v8::kGCCallbackFlagCollectAllAvailableGarbage) &&
         attempt + 1 >= kMinNumberOfAttempts) {
       break;
     }
   }
   set_current_gc_flags(kNoGCFlags);
   new_space_->Shrink();
   UncommitFromSpace();
 }
 
-
-void Heap::ReportExternalMemoryPressure(const char* gc_reason) {
+void Heap::ReportExternalMemoryPressure() {
   if (external_memory_ >
       (external_memory_at_last_mark_compact_ + external_memory_hard_limit())) {
     CollectAllGarbage(
-        kReduceMemoryFootprintMask | kFinalizeIncrementalMarkingMask, gc_reason,
+        kReduceMemoryFootprintMask | kFinalizeIncrementalMarkingMask,
+        GarbageCollectionReason::kExternalMemoryPressure,
         static_cast<GCCallbackFlags>(kGCCallbackFlagCollectAllAvailableGarbage |
                                      kGCCallbackFlagCollectAllExternalMemory));
     return;
   }
   if (incremental_marking()->IsStopped()) {
     if (incremental_marking()->CanBeActivated()) {
       StartIncrementalMarking(
-          i::Heap::kNoGCFlags,
+          i::Heap::kNoGCFlags, GarbageCollectionReason::kExternalMemoryPressure,
           static_cast<GCCallbackFlags>(
               kGCCallbackFlagSynchronousPhantomCallbackProcessing |
-              kGCCallbackFlagCollectAllExternalMemory),
-          gc_reason);
+              kGCCallbackFlagCollectAllExternalMemory));
     } else {
-      CollectAllGarbage(i::Heap::kNoGCFlags, gc_reason,
+      CollectAllGarbage(i::Heap::kNoGCFlags,
+                        GarbageCollectionReason::kExternalMemoryPressure,
                         kGCCallbackFlagSynchronousPhantomCallbackProcessing);
     }
   } else {
     // Incremental marking is turned on an has already been started.
     const double pressure =
         static_cast<double>(external_memory_ -
                             external_memory_at_last_mark_compact_ -
                             kExternalAllocationSoftLimit) /
         external_memory_hard_limit();
     DCHECK_GE(1, pressure);
@@ skipping 13 matching lines @@
   // may be uninitialized memory behind top. We fill the remainder of the page
   // with a filler.
   Address to_top = new_space_->top();
   Page* page = Page::FromAddress(to_top - kPointerSize);
   if (page->Contains(to_top)) {
     int remaining_in_page = static_cast<int>(page->area_end() - to_top);
     CreateFillerObjectAt(to_top, remaining_in_page, ClearRecordedSlots::kNo);
   }
 }
 
-
-bool Heap::CollectGarbage(GarbageCollector collector, const char* gc_reason,
+bool Heap::CollectGarbage(GarbageCollector collector,
+                          GarbageCollectionReason gc_reason,
                           const char* collector_reason,
                           const v8::GCCallbackFlags gc_callback_flags) {
   // The VM is in the GC state until exiting this function.
   VMState<GC> state(isolate_);
 
 #ifdef DEBUG
   // Reset the allocation timeout to the GC interval, but make sure to
   // allow at least a few allocations after a collection. The reason
   // for this is that we have a lot of allocation sequences and we
   // assume that a garbage collection will allow the subsequent
@@ skipping 78 matching lines @@
 
   if (collector == MARK_COMPACTOR &&
       (gc_callback_flags & (kGCCallbackFlagForced |
                             kGCCallbackFlagCollectAllAvailableGarbage)) != 0) {
     isolate()->CountUsage(v8::Isolate::kForcedGC);
   }
 
   // Start incremental marking for the next cycle. The heap snapshot
   // generator needs incremental marking to stay off after it aborted.
   if (!ShouldAbortIncrementalMarking()) {
-    StartIncrementalMarkingIfNeeded(kNoGCFlags, kNoGCCallbackFlags,
-                                    "GC epilogue");
+    StartIncrementalMarkingIfAllocationLimitIsReached(kNoGCFlags,
+                                                      kNoGCCallbackFlags);
   }
 
   return next_gc_likely_to_collect_more;
 }
 
 
 int Heap::NotifyContextDisposed(bool dependant_context) {
   if (!dependant_context) {
     tracer()->ResetSurvivalEvents();
     old_generation_size_configured_ = false;
     MemoryReducer::Event event;
     event.type = MemoryReducer::kPossibleGarbage;
     event.time_ms = MonotonicallyIncreasingTimeInMs();
     memory_reducer_->NotifyPossibleGarbage(event);
   }
   if (isolate()->concurrent_recompilation_enabled()) {
     // Flush the queued recompilation tasks.
     isolate()->optimizing_compile_dispatcher()->Flush();
   }
   AgeInlineCaches();
   number_of_disposed_maps_ = retained_maps()->Length();
   tracer()->AddContextDisposalTime(MonotonicallyIncreasingTimeInMs());
   return ++contexts_disposed_;
 }
 
-
 void Heap::StartIncrementalMarking(int gc_flags,
-                                   const GCCallbackFlags gc_callback_flags,
-                                   const char* reason) {
+                                   GarbageCollectionReason gc_reason,
+                                   GCCallbackFlags gc_callback_flags) {
   DCHECK(incremental_marking()->IsStopped());
   set_current_gc_flags(gc_flags);
   current_gc_callback_flags_ = gc_callback_flags;
-  incremental_marking()->Start(reason);
+  incremental_marking()->Start(gc_reason);
 }
 
-void Heap::StartIncrementalMarkingIfNeeded(
-    int gc_flags, const GCCallbackFlags gc_callback_flags, const char* reason) {
+void Heap::StartIncrementalMarkingIfAllocationLimitIsReached(
+    int gc_flags, const GCCallbackFlags gc_callback_flags) {
   if (incremental_marking()->IsStopped() &&
       incremental_marking()->ShouldActivateEvenWithoutIdleNotification()) {
-    StartIncrementalMarking(gc_flags, gc_callback_flags, reason);
+    StartIncrementalMarking(gc_flags, GarbageCollectionReason::kAllocationLimit,
+                            gc_callback_flags);
   }
 }
 
-void Heap::StartIdleIncrementalMarking() {
+void Heap::StartIdleIncrementalMarking(GarbageCollectionReason gc_reason) {
   gc_idle_time_handler_->ResetNoProgressCounter();
-  StartIncrementalMarking(kReduceMemoryFootprintMask, kNoGCCallbackFlags,
-                          "idle");
+  StartIncrementalMarking(kReduceMemoryFootprintMask, gc_reason,
+                          kNoGCCallbackFlags);
 }
 
 
 void Heap::MoveElements(FixedArray* array, int dst_index, int src_index,
                         int len) {
   if (len == 0) return;
 
   DCHECK(array->map() != fixed_cow_array_map());
   Object** dst_objects = array->data_start() + dst_index;
   MemMove(dst_objects, array->data_start() + src_index, len * kPointerSize);
@@ skipping 88 matching lines @@
             chunk.start = free_space_address;
             chunk.end = free_space_address + size;
           } else {
             perform_gc = true;
             break;
           }
         }
       }
       if (perform_gc) {
         if (space == NEW_SPACE) {
-          CollectGarbage(NEW_SPACE, "failed to reserve space in the new space");
+          CollectGarbage(NEW_SPACE, GarbageCollectionReason::kDeserializer);
         } else {
           if (counter > 1) {
             CollectAllGarbage(
                 kReduceMemoryFootprintMask | kAbortIncrementalMarkingMask,
-                "failed to reserve space in paged or large "
-                "object space, trying to reduce memory footprint");
+                GarbageCollectionReason::kDeserializer);
           } else {
-            CollectAllGarbage(
-                kAbortIncrementalMarkingMask,
-                "failed to reserve space in paged or large object space");
+            CollectAllGarbage(kAbortIncrementalMarkingMask,
+                              GarbageCollectionReason::kDeserializer);
           }
         }
         gc_performed = true;
         break;  // Abort for-loop over spaces and retry.
       }
     }
   }
 
   return !gc_performed;
 }
@@ skipping 2833 matching lines @@
 bool Heap::IsHeapIterable() {
   // TODO(hpayer): This function is not correct. Allocation folding in old
   // space breaks the iterability.
   return new_space_top_after_last_gc_ == new_space()->top();
 }
 
 
 void Heap::MakeHeapIterable() {
   DCHECK(AllowHeapAllocation::IsAllowed());
   if (!IsHeapIterable()) {
-    CollectAllGarbage(kMakeHeapIterableMask, "Heap::MakeHeapIterable");
+    CollectAllGarbage(kMakeHeapIterableMask,
+                      GarbageCollectionReason::kMakeHeapIterable);
   }
   if (mark_compact_collector()->sweeping_in_progress()) {
     mark_compact_collector()->EnsureSweepingCompleted();
   }
   DCHECK(IsHeapIterable());
 }
 
 
 static double ComputeMutatorUtilization(double mutator_speed, double gc_speed) {
   const double kMinMutatorUtilization = 0.0;
@@ skipping 114 matching lines @@
 
 bool Heap::MarkingDequesAreEmpty() {
   return mark_compact_collector()->marking_deque()->IsEmpty() &&
          (!UsingEmbedderHeapTracer() ||
           (mark_compact_collector()->wrappers_to_trace() == 0 &&
            mark_compact_collector()
                    ->embedder_heap_tracer()
                    ->NumberOfWrappersToTrace() == 0));
 }
 
-void Heap::FinalizeIncrementalMarkingIfComplete(const char* comment) {
+void Heap::FinalizeIncrementalMarkingIfComplete(
+    GarbageCollectionReason gc_reason) {
   if (incremental_marking()->IsMarking() &&
       (incremental_marking()->IsReadyToOverApproximateWeakClosure() ||
        (!incremental_marking()->finalize_marking_completed() &&
         MarkingDequesAreEmpty()))) {
-    FinalizeIncrementalMarking(comment);
+    FinalizeIncrementalMarking(gc_reason);
   } else if (incremental_marking()->IsComplete() ||
              (mark_compact_collector()->marking_deque()->IsEmpty())) {
-    CollectAllGarbage(current_gc_flags_, comment);
+    CollectAllGarbage(current_gc_flags_, gc_reason);
   }
 }
 
-
-bool Heap::TryFinalizeIdleIncrementalMarking(double idle_time_in_ms) {
+bool Heap::TryFinalizeIdleIncrementalMarking(
+    double idle_time_in_ms, GarbageCollectionReason gc_reason) {
   size_t size_of_objects = static_cast<size_t>(SizeOfObjects());
   double final_incremental_mark_compact_speed_in_bytes_per_ms =
       tracer()->FinalIncrementalMarkCompactSpeedInBytesPerMillisecond();
   if (incremental_marking()->IsReadyToOverApproximateWeakClosure() ||
       (!incremental_marking()->finalize_marking_completed() &&
        MarkingDequesAreEmpty() &&
        gc_idle_time_handler_->ShouldDoOverApproximateWeakClosure(
            idle_time_in_ms))) {
-    FinalizeIncrementalMarking(
-        "Idle notification: finalize incremental marking");
+    FinalizeIncrementalMarking(gc_reason);
     return true;
   } else if (incremental_marking()->IsComplete() ||
              (MarkingDequesAreEmpty() &&
               gc_idle_time_handler_->ShouldDoFinalIncrementalMarkCompact(
                   idle_time_in_ms, size_of_objects,
                   final_incremental_mark_compact_speed_in_bytes_per_ms))) {
-    CollectAllGarbage(current_gc_flags_,
-                      "idle notification: finalize incremental marking");
+    CollectAllGarbage(current_gc_flags_, gc_reason);
     return true;
   }
   return false;
 }
 
 void Heap::RegisterReservationsForBlackAllocation(Reservation* reservations) {
   // TODO(hpayer): We do not have to iterate reservations on black objects
   // for marking. We just have to execute the special visiting side effect
   // code that adds objects to global data structures, e.g. for array buffers.
 
@@ skipping 54 matching lines @@
             ->NotifyIdleTaskProgress();
         result = IncrementalMarkingJob::IdleTask::Step(this, deadline_in_ms) ==
                  IncrementalMarkingJob::IdleTask::kDone;
       }
       break;
     }
     case DO_FULL_GC: {
       DCHECK(contexts_disposed_ > 0);
       HistogramTimerScope scope(isolate_->counters()->gc_context());
       TRACE_EVENT0("v8", "V8.GCContext");
-      CollectAllGarbage(kNoGCFlags, "idle notification: contexts disposed");
+      CollectAllGarbage(kNoGCFlags, GarbageCollectionReason::kContextDisposal);
       break;
     }
     case DO_NOTHING:
       break;
   }
 
   return result;
 }
 
 
@@ skipping 112 matching lines @@
 
 void Heap::CheckMemoryPressure() {
   if (HighMemoryPressure()) {
     if (isolate()->concurrent_recompilation_enabled()) {
       // The optimizing compiler may be unnecessarily holding on to memory.
       DisallowHeapAllocation no_recursive_gc;
       isolate()->optimizing_compile_dispatcher()->Flush();
     }
   }
   if (memory_pressure_level_.Value() == MemoryPressureLevel::kCritical) {
-    CollectGarbageOnMemoryPressure("memory pressure");
+    CollectGarbageOnMemoryPressure();
   } else if (memory_pressure_level_.Value() == MemoryPressureLevel::kModerate) {
     if (FLAG_incremental_marking && incremental_marking()->IsStopped()) {
-      StartIdleIncrementalMarking();
+      StartIncrementalMarking(kReduceMemoryFootprintMask,
+                              GarbageCollectionReason::kMemoryPressure);
     }
   }
   MemoryReducer::Event event;
   event.type = MemoryReducer::kPossibleGarbage;
   event.time_ms = MonotonicallyIncreasingTimeInMs();
   memory_reducer_->NotifyPossibleGarbage(event);
 }
 
-void Heap::CollectGarbageOnMemoryPressure(const char* source) {
+void Heap::CollectGarbageOnMemoryPressure() {
   const int kGarbageThresholdInBytes = 8 * MB;
   const double kGarbageThresholdAsFractionOfTotalMemory = 0.1;
   // This constant is the maximum response time in RAIL performance model.
   const double kMaxMemoryPressurePauseMs = 100;
 
   double start = MonotonicallyIncreasingTimeInMs();
   CollectAllGarbage(kReduceMemoryFootprintMask | kAbortIncrementalMarkingMask,
-                    source, kGCCallbackFlagCollectAllAvailableGarbage);
+                    GarbageCollectionReason::kMemoryPressure,
+                    kGCCallbackFlagCollectAllAvailableGarbage);
   double end = MonotonicallyIncreasingTimeInMs();
 
   // Estimate how much memory we can free.
   int64_t potential_garbage =
       (CommittedMemory() - SizeOfObjects()) + external_memory_;
   // If we can potentially free large amount of memory, then start GC right
   // away instead of waiting for memory reducer.
   if (potential_garbage >= kGarbageThresholdInBytes &&
       potential_garbage >=
           CommittedMemory() * kGarbageThresholdAsFractionOfTotalMemory) {
     // If we spent less than half of the time budget, then perform full GC
     // Otherwise, start incremental marking.
     if (end - start < kMaxMemoryPressurePauseMs / 2) {
       CollectAllGarbage(
-          kReduceMemoryFootprintMask | kAbortIncrementalMarkingMask, source,
+          kReduceMemoryFootprintMask | kAbortIncrementalMarkingMask,
+          GarbageCollectionReason::kMemoryPressure,
           kGCCallbackFlagCollectAllAvailableGarbage);
     } else {
       if (FLAG_incremental_marking && incremental_marking()->IsStopped()) {
-        StartIdleIncrementalMarking();
+        StartIncrementalMarking(kReduceMemoryFootprintMask,
+                                GarbageCollectionReason::kMemoryPressure);
       }
     }
   }
 }
 
 void Heap::MemoryPressureNotification(MemoryPressureLevel level,
                                       bool is_isolate_locked) {
   MemoryPressureLevel previous = memory_pressure_level_.Value();
   memory_pressure_level_.SetValue(level);
   if ((previous != MemoryPressureLevel::kCritical &&
@@ skipping 1972 matching lines @@
 }
 
 
 // static
 int Heap::GetStaticVisitorIdForMap(Map* map) {
   return StaticVisitorBase::GetVisitorId(map);
 }
 
 }  // namespace internal
 }  // namespace v8