--- a/js/src/gc/GC.cpp
+++ b/js/src/gc/GC.cpp
@@ -2048,41 +2048,34 @@ MemoryCounter::updateOnGCEnd(const GCSch
     bytes_ -= bytesAtStartOfGC_;
     triggered_ = NoTrigger;
 }
 
 void
 MemoryCounter::setMax(size_t newMax, const AutoLockGC& lock)
 {
     maxBytes_ = newMax;
-    reset();
 }
 
 void
 MemoryCounter::adopt(MemoryCounter& other)
 {
     update(other.bytes());
-    other.reset();
+    other.bytes_ = 0;
+    other.triggered_ = NoTrigger;
 }
 
 void
 MemoryCounter::recordTrigger(TriggerKind trigger)
 {
     MOZ_ASSERT(trigger > triggered_);
     triggered_ = trigger;
 }
 
 void
-MemoryCounter::reset()
-{
-    bytes_ = 0;
-    triggered_ = NoTrigger;
-}
-
-void
 GCMarker::delayMarkingArena(Arena* arena)
 {
     if (arena->hasDelayedMarking) {
         /* Arena already scheduled to be marked later */
         return;
     }
     arena->setNextDelayedMarking(unmarkedArenaStackTop);
     unmarkedArenaStackTop = arena;

--- a/js/src/gc/Scheduling.h
+++ b/js/src/gc/Scheduling.h
@@ -533,19 +533,16 @@ class MemoryCounter
     bool shouldResetIncrementalGC(const GCSchedulingTunables& tunables) const {
         return bytes_ > maxBytes_ * tunables.allocThresholdFactorAvoidInterrupt();
     }
 
     void recordTrigger(TriggerKind trigger);
 
     void updateOnGCStart();
     void updateOnGCEnd(const GCSchedulingTunables& tunables, const AutoLockGC& lock);
-
-  private:
-    void reset();
 };
 
 // This class encapsulates the data that determines when we need to do a zone GC.
 class ZoneHeapThreshold
 {
     // The "growth factor" for computing our next thresholds after a GC.
     GCLockData<double> gcHeapGrowthFactor_;
 

new file mode 100644
--- /dev/null
+++ b/js/src/jit-test/tests/gc/bug-1455709.js
@@ -0,0 +1,6 @@
+gcslice(0);
+function testChangeParam(key) {
+    let prev = gcparam(key);
+    gcparam(key, prev);
+}
+testChangeParam("maxMallocBytes");