Bug 1380967 - Add a separate reason code for minor GC performed at the start of major GC r=sfink

js/src/gc/GenerateStatsPhases.py

@@ -74,6 +74,9 @@ JoinParallelTasksPhaseKind = PhaseKind("JOIN_PARALLEL_TASKS", "Join Parallel Tas
 PhaseKindGraphRoots = [
     PhaseKind("MUTATOR", "Mutator Running", 0),
     PhaseKind("GC_BEGIN", "Begin Callback", 1),
+    PhaseKind("EVICT_NURSERY_FOR_MAJOR_GC", "Evict Nursery For Major GC", 70, [
+        MarkRootsPhaseKind,
+    ]),
     PhaseKind("WAIT_BACKGROUND_THREAD", "Wait Background Thread", 2),
     PhaseKind("PREPARE", "Prepare For Collection", 69, [
         PhaseKind("UNMARK", "Unmark", 7),

js/src/gc/Statistics.cpp

@@ -45,12 +45,21 @@ using mozilla::TimeDuration;
  */
 JS_STATIC_ASSERT(JS::gcreason::NUM_TELEMETRY_REASONS >= JS::gcreason::NUM_REASONS);
 
-static inline decltype(mozilla::MakeEnumeratedRange(PhaseKind::FIRST, PhaseKind::LIMIT))
+using PhaseKindRange = decltype(mozilla::MakeEnumeratedRange(PhaseKind::FIRST, PhaseKind::LIMIT));
+
+static inline PhaseKindRange
 AllPhaseKinds()
 {
     return mozilla::MakeEnumeratedRange(PhaseKind::FIRST, PhaseKind::LIMIT);
 }
 
+static inline PhaseKindRange
+MajorGCPhaseKinds()
+{
+    return mozilla::MakeEnumeratedRange(PhaseKind::GC_BEGIN,
+                                        PhaseKind(size_t(PhaseKind::GC_END) + 1));
+}
+
 const char*
 js::gcstats::ExplainInvocationKind(JSGCInvocationKind gckind)
 {
@@ -796,7 +805,7 @@ CheckSelfTime(Phase parent,
 }
 
 static PhaseKind
-LongestPhaseSelfTime(const Statistics::PhaseTimeTable& times)
+LongestPhaseSelfTimeInMajorGC(const Statistics::PhaseTimeTable& times)
 {
     // Start with total times per expanded phase, including children's times.
     Statistics::PhaseTimeTable selfTimes(times);
@@ -820,7 +829,7 @@ LongestPhaseSelfTime(const Statistics::PhaseTimeTable& times)
     // Loop over this table to find the longest phase.
     TimeDuration longestTime = 0;
     PhaseKind longestPhase = PhaseKind::NONE;
-    for (auto i : AllPhaseKinds()) {
+    for (auto i : MajorGCPhaseKinds()) {
         if (phaseTimes[i] > longestTime) {
             longestTime = phaseTimes[i];
             longestPhase = i;
@@ -973,12 +982,12 @@ Statistics::endSlice()
 
             // Record any phase that goes more than 2x over its budget.
             if (sliceTime.ToMilliseconds() > 2 * budget_ms) {
-                reportLongestPhase(slice.phaseTimes, JS_TELEMETRY_GC_SLOW_PHASE);
+                reportLongestPhaseInMajorGC(slice.phaseTimes, JS_TELEMETRY_GC_SLOW_PHASE);
                 // If we spend a significant length of time waiting for parallel
                 // tasks then report the longest task.
                 TimeDuration joinTime = SumPhase(PhaseKind::JOIN_PARALLEL_TASKS, slice.phaseTimes);
                 if (joinTime.ToMilliseconds() > budget_ms)
-                    reportLongestPhase(slice.parallelTimes, JS_TELEMETRY_GC_SLOW_TASK);
+                    reportLongestPhaseInMajorGC(slice.parallelTimes, JS_TELEMETRY_GC_SLOW_TASK);
             }
         }
 
@@ -1027,9 +1036,9 @@ Statistics::endSlice()
 }
 
 void
-Statistics::reportLongestPhase(const PhaseTimeTable& times, int telemetryId)
+Statistics::reportLongestPhaseInMajorGC(const PhaseTimeTable& times, int telemetryId)
 {
-    PhaseKind longest = LongestPhaseSelfTime(times);
+    PhaseKind longest = LongestPhaseSelfTimeInMajorGC(times);
     if (longest == PhaseKind::NONE)
         return;
 

js/src/gc/Statistics.h

@@ -371,7 +371,7 @@ FOR_EACH_GC_PROFILE_TIME(DEFINE_TIME_KEY)
     void sccDurations(TimeDuration* total, TimeDuration* maxPause) const;
     void printStats();
 
-    void reportLongestPhase(const PhaseTimeTable& times, int telemetryId);
+    void reportLongestPhaseInMajorGC(const PhaseTimeTable& times, int telemetryId);
 
     UniqueChars formatCompactSlicePhaseTimes(const PhaseTimeTable& phaseTimes) const;
 

js/src/jsgc.cpp

@@ -6779,7 +6779,7 @@ GCRuntime::gcCycle(bool nonincrementalByAPI, SliceBudget& budget, JS::gcreason::
 
     AutoExposeLiveCrossZoneEdges aelcze(&foundBlackGrayEdges.ref());
 
-    EvictAllNurseries(rt, reason);
+    minorGC(reason, gcstats::PhaseKind::EVICT_NURSERY_FOR_MAJOR_GC);
 
     AutoTraceSession session(rt, JS::HeapState::MajorCollecting);