When context disposal rate is high and we cannot perform a full GC, we do nothing until the context…

src/heap/gc-idle-time-handler.cc

 // Copyright 2014 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/gc-idle-time-handler.h"
 #include "src/heap/gc-tracer.h"
 #include "src/utils.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 225 matching lines @@
   } else {
     return Action(idle_time_in_ms, heap_state, mode_ == kReduceMemory);
   }
 }
 
 
 // The following logic is implemented by the controller:
 // (1) If we don't have any idle time, do nothing, unless a context was
 // disposed, incremental marking is stopped, and the heap is small. Then do
 // a full GC.
-// (2) If the new space is almost full and we can afford a Scavenge or if the
+// (2) If the context disposal rate is high and we cannot perform a full GC,
+// we do nothing until the context disposal rate becomes lower.
+// (3) If the new space is almost full and we can affort a Scavenge or if the
 // next Scavenge will very likely take long, then a Scavenge is performed.
-// (3) If incremental marking is done, we perform a full garbage collection
+// (4) If there is currently no MarkCompact idle round going on, we start a
+// new idle round if enough garbage was created. Otherwise we do not perform
+// garbage collection to keep system utilization low.
+// (5) If incremental marking is done, we perform a full garbage collection
 // if  we are allowed to still do full garbage collections during this idle
 // round or if we are not allowed to start incremental marking. Otherwise we
 // do not perform garbage collection to keep system utilization low.
-// (4) If sweeping is in progress and we received a large enough idle time
+// (6) If sweeping is in progress and we received a large enough idle time
 // request, we finalize sweeping here.
-// (5) If incremental marking is in progress, we perform a marking step. Note,
+// (7) If incremental marking is in progress, we perform a marking step. Note,
 // that this currently may trigger a full garbage collection.
 GCIdleTimeAction GCIdleTimeHandler::Action(double idle_time_in_ms,
                                            const HeapState& heap_state,
                                            bool reduce_memory) {
   if (static_cast<int>(idle_time_in_ms) <= 0) {
     if (heap_state.incremental_marking_stopped) {
       if (ShouldDoContextDisposalMarkCompact(
               heap_state.contexts_disposed,
               heap_state.contexts_disposal_rate)) {
         return GCIdleTimeAction::FullGC(false);
       }
     }
     return GCIdleTimeAction::Nothing();
   }
 
+  // We are in a context disposal GC scenario. Don't do anything if we do not
+  // get the right idle signal.
+  if (ShouldDoContextDisposalMarkCompact(heap_state.contexts_disposed,
+                                         heap_state.contexts_disposal_rate)) {
+    return GCIdleTimeAction::Nothing();
+  }
+
   if (ShouldDoScavenge(
           static_cast<size_t>(idle_time_in_ms), heap_state.new_space_capacity,
           heap_state.used_new_space_size,
           heap_state.scavenge_speed_in_bytes_per_ms,
           heap_state.new_space_allocation_throughput_in_bytes_per_ms)) {
     return GCIdleTimeAction::Scavenge();
   }
 
   if (heap_state.incremental_marking_stopped && reduce_memory) {
     if (ShouldDoMarkCompact(static_cast<size_t>(idle_time_in_ms),
@@ skipping 84 matching lines @@
       }
       if (mutator_gcs > idle_mark_compacts_) {
         return kReduceLatency;
       }
       break;
   }
   return mode_;
 }
 }
 }