Backed out changeset 41da9bcec12e (bug 1029648) for possible Sunspider regression on FxOS Flame

js/src/gc/GCRuntime.h

@@ -321,9 +321,8 @@ class GCRuntime
 
     bool isGcNeeded() { return isNeeded; }
 
-    double computeHeapGrowthFactor(size_t lastBytes) const;
-    size_t computeTriggerBytes(double growthFactor, size_t lastBytes,
-                               JSGCInvocationKind gckind) const;
+    double computeHeapGrowthFactor(size_t lastBytes);
+    size_t computeTriggerBytes(double growthFactor, size_t lastBytes, JSGCInvocationKind gckind);
     size_t allocationThreshold() { return allocThreshold; }
 
     JSGCMode gcMode() const { return mode; }
@@ -394,7 +393,7 @@ class GCRuntime
     bool releaseObservedTypes();
     void endSweepingZoneGroup();
     bool sweepPhase(SliceBudget &sliceBudget);
-    void endSweepPhase(bool lastGC);
+    void endSweepPhase(JSGCInvocationKind gckind, bool lastGC);
     void sweepZones(FreeOp *fop, bool lastGC);
     void decommitArenasFromAvailableList(Chunk **availableListHeadp);
     void decommitArenas();
@@ -514,9 +513,6 @@ class GCRuntime
     /* Whether all compartments are being collected in first GC slice. */
     bool                  isFull;
 
-    /* The kind of the last collection. */
-    JSGCInvocationKind    lastKind;
-
     /* The reason that an interrupt-triggered GC should be called. */
     JS::gcreason::Reason  triggerReason;
 

js/src/gc/Zone.cpp

@@ -31,7 +31,6 @@ JS::Zone::Zone(JSRuntime *rt)
     gcMallocBytes(0),
     gcMallocGCTriggered(false),
     gcBytes(0),
-    gcBytesAfterGC(0),
     gcTriggerBytes(0),
     data(nullptr),
     isSystem(false),

js/src/gc/Zone.h

@@ -106,6 +106,7 @@ struct Zone : public JS::shadow::Zone,
                                 size_t *baselineStubsOptimized);
 
     void setGCLastBytes(size_t lastBytes, js::JSGCInvocationKind gckind);
+    void reduceGCTriggerBytes(size_t amount);
 
     void resetGCMallocBytes();
     void setGCMaxMallocBytes(size_t value);
@@ -247,12 +248,8 @@ struct Zone : public JS::shadow::Zone,
     // updated by both the main and GC helper threads.
     mozilla::Atomic<size_t, mozilla::ReleaseAcquire> gcBytes;
 
-    // The number of bytes allocated in the GC heap for this zone after the last GC.
-    size_t gcBytesAfterGC;
-
-    // GC trigger threshold for allocations on the GC heap. It is updated by
-    // both the main and GC helper threads.
-    mozilla::Atomic<size_t, mozilla::ReleaseAcquire> gcTriggerBytes;
+    // GC trigger threshold for allocations on the GC heap.
+    size_t gcTriggerBytes;
 
     // Per-zone data for use by an embedder.
     void *data;

js/src/jsgc.cpp

@@ -985,7 +985,7 @@ Chunk::releaseArena(ArenaHeader *aheader)
     JS_ASSERT(rt->gc.bytesAllocated() >= ArenaSize);
     JS_ASSERT(zone->gcBytes >= ArenaSize);
     if (rt->gc.isBackgroundSweeping())
-        zone->gcBytesAfterGC -= ArenaSize;
+        zone->reduceGCTriggerBytes(zone->gcHeapGrowthFactor * ArenaSize);
     rt->gc.updateBytesAllocated(-ArenaSize);
     zone->gcBytes -= ArenaSize;
 
@@ -1695,8 +1695,7 @@ GCRuntime::onTooMuchMalloc()
 }
 
 size_t
-GCRuntime::computeTriggerBytes(double growthFactor, size_t lastBytes,
-                               JSGCInvocationKind gckind) const
+GCRuntime::computeTriggerBytes(double growthFactor, size_t lastBytes, JSGCInvocationKind gckind)
 {
     size_t base = gckind == GC_SHRINK ? lastBytes : Max(lastBytes, allocThreshold);
     double trigger = double(base) * growthFactor;
@@ -1704,7 +1703,7 @@ GCRuntime::computeTriggerBytes(double growthFactor, size_t lastBytes,
 }
 
 double
-GCRuntime::computeHeapGrowthFactor(size_t lastBytes) const
+GCRuntime::computeHeapGrowthFactor(size_t lastBytes)
 {
     /*
      * The heap growth factor depends on the heap size after a GC and the GC frequency.
@@ -1746,11 +1745,22 @@ GCRuntime::computeHeapGrowthFactor(size_t lastBytes) const
 void
 Zone::setGCLastBytes(size_t lastBytes, JSGCInvocationKind gckind)
 {
-    const GCRuntime &gc = runtimeFromAnyThread()->gc;
+    GCRuntime &gc = runtimeFromMainThread()->gc;
     gcHeapGrowthFactor = gc.computeHeapGrowthFactor(lastBytes);
     gcTriggerBytes = gc.computeTriggerBytes(gcHeapGrowthFactor, lastBytes, gckind);
 }
 
+void
+Zone::reduceGCTriggerBytes(size_t amount)
+{
+    JS_ASSERT(amount > 0);
+    JS_ASSERT(gcTriggerBytes >= amount);
+    GCRuntime &gc = runtimeFromAnyThread()->gc;
+    if (gcTriggerBytes - amount < gc.allocationThreshold() * gcHeapGrowthFactor)
+        return;
+    gcTriggerBytes -= amount;
+}
+
 Allocator::Allocator(Zone *zone)
   : zone_(zone)
 {}
@@ -2580,15 +2590,6 @@ GCRuntime::sweepBackgroundThings(bool onBackgroundThread)
         }
     }
 
-    if (onBackgroundThread) {
-        /*
-         * Update zone triggers a second time now we have completely finished
-         * sweeping these zones.
-         */
-        for (Zone *zone = sweepingZones; zone; zone = zone->gcNextGraphNode)
-            zone->setGCLastBytes(zone->gcBytesAfterGC, lastKind);
-    }
-
     sweepingZones = nullptr;
 }
 
@@ -4386,7 +4387,7 @@ GCRuntime::sweepPhase(SliceBudget &sliceBudget)
 }
 
 void
-GCRuntime::endSweepPhase(bool lastGC)
+GCRuntime::endSweepPhase(JSGCInvocationKind gckind, bool lastGC)
 {
     gcstats::AutoPhase ap(stats, gcstats::PHASE_SWEEP);
     FreeOp fop(rt, sweepOnBackgroundThread);
@@ -4459,7 +4460,7 @@ GCRuntime::endSweepPhase(bool lastGC)
              * Expire needs to unlock it for other callers.
              */
             AutoLockGC lock(rt);
-            expireChunksAndArenas(lastKind == GC_SHRINK);
+            expireChunksAndArenas(gckind == GC_SHRINK);
         }
     }
 
@@ -4502,10 +4503,9 @@ GCRuntime::endSweepPhase(bool lastGC)
         lastGCTime + highFrequencyTimeThreshold * PRMJ_USEC_PER_MSEC > currentTime;
 
     for (ZonesIter zone(rt, WithAtoms); !zone.done(); zone.next()) {
-        zone->setGCLastBytes(zone->gcBytes, lastKind);
+        zone->setGCLastBytes(zone->gcBytes, gckind);
         if (zone->isCollecting()) {
             JS_ASSERT(zone->isGCFinished());
-            zone->gcBytesAfterGC = zone->gcBytes;
             zone->setGCState(Zone::NoGC);
         }
 
@@ -4787,8 +4787,6 @@ GCRuntime::incrementalCollectSlice(int64_t budget,
     JS_ASSERT_IF(incrementalState != NO_INCREMENTAL, isIncremental);
     isIncremental = budget != SliceBudget::Unlimited;
 
-    lastKind = gckind;
-
     if (zeal == ZealIncrementalRootsThenFinish || zeal == ZealIncrementalMarkAllThenFinish) {
         /*
          * Yields between slices occurs at predetermined points in these modes;
@@ -4876,7 +4874,7 @@ GCRuntime::incrementalCollectSlice(int64_t budget,
         if (!finished)
             break;
 
-        endSweepPhase(lastGC);
+        endSweepPhase(gckind, lastGC);
 
         if (sweepOnBackgroundThread)
             helperState.startBackgroundSweep(gckind == GC_SHRINK);