Bug 1254108 - Remove incorrect assertion about heap size r=terrence

js/src/jit-test/tests/gc/bug-1254108.js

@@ -0,0 +1,4 @@
+function testChangeParam(key) {
+    gcparam(key, 0x22222222);
+}
+testChangeParam("lowFrequencyHeapGrowth");

js/src/jsapi.cpp

@@ -1475,6 +1475,7 @@ JS_UpdateWeakPointerAfterGCUnbarriered(JSObject** objp)
 JS_PUBLIC_API(void)
 JS_SetGCParameter(JSRuntime* rt, JSGCParamKey key, uint32_t value)
 {
+    rt->gc.waitBackgroundSweepEnd();
     AutoLockGC lock(rt);
     MOZ_ALWAYS_TRUE(rt->gc.setParameter(key, value, lock));
 }

js/src/jsgc.cpp

@@ -1919,12 +1919,13 @@ void
 ZoneHeapThreshold::updateForRemovedArena(const GCSchedulingTunables& tunables)
 {
     size_t amount = ArenaSize * gcHeapGrowthFactor_;
-
     MOZ_ASSERT(amount > 0);
-    MOZ_ASSERT(gcTriggerBytes_ >= amount);
 
-    if (gcTriggerBytes_ - amount < tunables.gcZoneAllocThresholdBase() * gcHeapGrowthFactor_)
+    if ((gcTriggerBytes_ < amount) ||
+        (gcTriggerBytes_ - amount < tunables.gcZoneAllocThresholdBase() * gcHeapGrowthFactor_))
+    {
         return;
+    }
 
     gcTriggerBytes_ -= amount;
 }