Bug 1297067 - Remove unused decommit threshold r=jonco

--HG--
extra : rebase_source : 83c4d2b86bdda4912c8213d60a8a3789c87e0c61

dom/base/nsJSEnvironment.cpp

@@ -2534,10 +2534,6 @@ nsJSContext::EnsureStatics()
                                        "javascript.options.mem.gc_allocation_threshold_mb",
                                        (void *)JSGC_ALLOCATION_THRESHOLD);
 
-  Preferences::RegisterCallbackAndCall(SetMemoryGCPrefChangedCallback,
-                                       "javascript.options.mem.gc_decommit_threshold_mb",
-                                       (void *)JSGC_DECOMMIT_THRESHOLD);
-
   Preferences::RegisterCallbackAndCall(SetIncrementalCCPrefChangedCallback,
                                        "dom.cycle_collector.incremental");
 

js/src/builtin/TestingFunctions.cpp

@@ -360,7 +360,6 @@ MinorGC(JSContext* cx, unsigned argc, Value* vp)
     _("dynamicHeapGrowth",          JSGC_DYNAMIC_HEAP_GROWTH,            true)  \
     _("dynamicMarkSlice",           JSGC_DYNAMIC_MARK_SLICE,             true)  \
     _("allocationThreshold",        JSGC_ALLOCATION_THRESHOLD,           true)  \
-    _("decommitThreshold",          JSGC_DECOMMIT_THRESHOLD,             true)  \
     _("minEmptyChunkCount",         JSGC_MIN_EMPTY_CHUNK_COUNT,          true)  \
     _("maxEmptyChunkCount",         JSGC_MAX_EMPTY_CHUNK_COUNT,          true)  \
     _("compactingEnabled",          JSGC_COMPACTING_ENABLED,             true)  \

js/src/gc/GCRuntime.h

@@ -1069,8 +1069,6 @@ class GCRuntime
 
     mozilla::Atomic<size_t, mozilla::ReleaseAcquire> numActiveZoneIters;
 
-    uint64_t decommitThreshold;
-
     /* During shutdown, the GC needs to clean up every possible object. */
     bool cleanUpEverything;
 

js/src/jit-test/tests/gc/gcparam.js

@@ -37,11 +37,9 @@ testChangeParam("lowFrequencyHeapGrowth");
 testChangeParam("dynamicHeapGrowth");
 testChangeParam("dynamicMarkSlice");
 testChangeParam("allocationThreshold");
-testChangeParam("decommitThreshold");
 testChangeParam("minEmptyChunkCount");
 testChangeParam("maxEmptyChunkCount");
 testChangeParam("compactingEnabled");
 
 testLargeParamValue("highFrequencyLowLimit");
 testLargeParamValue("highFrequencyHighLimit");
-testLargeParamValue("decommitThreshold");

js/src/jsapi.cpp

@@ -1448,7 +1448,6 @@ JS_SetGCParametersBasedOnAvailableMemory(JSContext* cx, uint32_t availMem)
         {JSGC_HIGH_FREQUENCY_TIME_LIMIT, 1500},
         {JSGC_HIGH_FREQUENCY_TIME_LIMIT, 1500},
         {JSGC_ALLOCATION_THRESHOLD, 1},
-        {JSGC_DECOMMIT_THRESHOLD, 1},
         {JSGC_MODE, JSGC_MODE_INCREMENTAL}
     };
 
@@ -1467,7 +1466,6 @@ JS_SetGCParametersBasedOnAvailableMemory(JSContext* cx, uint32_t availMem)
             {JSGC_HIGH_FREQUENCY_TIME_LIMIT, 1500},
             {JSGC_HIGH_FREQUENCY_TIME_LIMIT, 1500},
             {JSGC_ALLOCATION_THRESHOLD, 30},
-            {JSGC_DECOMMIT_THRESHOLD, 32},
             {JSGC_MODE, JSGC_MODE_COMPARTMENT}
         };
 

js/src/jsapi.h

@@ -1733,13 +1733,6 @@ typedef enum JSGCParamKey {
     /** Lower limit after which we limit the heap growth. */
     JSGC_ALLOCATION_THRESHOLD = 19,
 
-    /**
-     * We decommit memory lazily. If more than this number of megabytes is
-     * available to be decommitted, then JS_MaybeGC will trigger a shrinking GC
-     * to decommit it.
-     */
-    JSGC_DECOMMIT_THRESHOLD = 20,
-
     /**
      * We try to keep at least this many unused chunks in the free chunk pool at
      * all times, even after a shrinking GC.

js/src/jsgc.cpp

@@ -807,7 +807,6 @@ GCRuntime::GCRuntime(JSRuntime* rt) :
     lastGCTime(PRMJ_Now()),
     mode(JSGC_MODE_INCREMENTAL),
     numActiveZoneIters(0),
-    decommitThreshold(32 * 1024 * 1024),
     cleanUpEverything(false),
     grayBufferState(GCRuntime::GrayBufferState::Unused),
     grayBitsValid(false),
@@ -1131,9 +1130,6 @@ GCRuntime::setParameter(JSGCParamKey key, uint32_t value, AutoLockGC& lock)
             return false;
         setMarkStackLimit(value, lock);
         break;
-      case JSGC_DECOMMIT_THRESHOLD:
-        decommitThreshold = (uint64_t)value * 1024 * 1024;
-        break;
       case JSGC_MODE:
         if (mode != JSGC_MODE_GLOBAL &&
             mode != JSGC_MODE_COMPARTMENT &&
@@ -1292,8 +1288,6 @@ GCRuntime::getParameter(JSGCParamKey key, const AutoLockGC& lock)
         return tunables.isDynamicMarkSliceEnabled();
       case JSGC_ALLOCATION_THRESHOLD:
         return tunables.gcZoneAllocThresholdBase() / 1024 / 1024;
-      case JSGC_DECOMMIT_THRESHOLD:
-        return decommitThreshold / 1024 / 1024;
       case JSGC_MIN_EMPTY_CHUNK_COUNT:
         return tunables.minEmptyChunkCount(lock);
       case JSGC_MAX_EMPTY_CHUNK_COUNT: