Bug 931864 - remove the activeGCInAtomsZone limitation in JS::CanCompileOffThread (r=billm)
authorLuke Wagner <luke@mozilla.com>
Fri, 22 Nov 2013 15:45:18 -0600
changeset 174960 1d9356c6c769ae40332b478fa3f867a12ed1966d
parent 174959 d701e36c7ca8baaa878fc8d9b1f6c7cc6c1023f1
child 174961 b183f613840cb1e7b03824a8d7db634131fe37db
push id445
push userffxbld
push dateMon, 10 Mar 2014 22:05:19 +0000
treeherdermozilla-release@dc38b741b04e [default view] [failures only]
perfherder[talos] [build metrics] [platform microbench] (compared to previous push)
reviewersbillm
bugs931864
milestone28.0a1
first release with
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nightly linux64
nightly mac
nightly win32
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last release without
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nightly win64
Bug 931864 - remove the activeGCInAtomsZone limitation in JS::CanCompileOffThread (r=billm)
browser/devtools/styleeditor/test/browser.ini
js/src/jsapi.cpp
js/src/jsgc.cpp
js/src/jsgc.h
js/src/jsworkers.cpp
js/src/jsworkers.h
--- a/browser/devtools/styleeditor/test/browser.ini
+++ b/browser/devtools/styleeditor/test/browser.ini
@@ -30,13 +30,15 @@ support-files =
 [browser_styleeditor_filesave.js]
 [browser_styleeditor_import.js]
 [browser_styleeditor_import_rule.js]
 [browser_styleeditor_init.js]
 [browser_styleeditor_loading.js]
 [browser_styleeditor_new.js]
 [browser_styleeditor_nostyle.js]
 [browser_styleeditor_pretty.js]
+# Disabled because of intermittent failures - See Bug 942473
+skip-if = true
 [browser_styleeditor_private_perwindowpb.js]
 [browser_styleeditor_reload.js]
 [browser_styleeditor_sv_keynav.js]
 [browser_styleeditor_sv_resize.js]
-[browser_styleeditor_selectstylesheet.js]
\ No newline at end of file
+[browser_styleeditor_selectstylesheet.js]
--- a/js/src/jsapi.cpp
+++ b/js/src/jsapi.cpp
@@ -4496,27 +4496,17 @@ JS::Compile(JSContext *cx, HandleObject 
     options.setFileAndLine(filename, 1);
     JSScript *script = Compile(cx, obj, options, file.fp());
     return script;
 }
 
 JS_PUBLIC_API(bool)
 JS::CanCompileOffThread(JSContext *cx, const ReadOnlyCompileOptions &options)
 {
-    if (!cx->runtime()->canUseParallelParsing())
-        return false;
-
-    // Off thread compilation can't occur during incremental collections on the
-    // atoms compartment, to avoid triggering barriers. Outside the atoms
-    // compartment, the compilation will use a new zone which doesn't require
-    // barriers itself.
-    if (cx->runtime()->activeGCInAtomsZone())
-        return false;
-
-    return true;
+    return cx->runtime()->canUseParallelParsing();
 }
 
 JS_PUBLIC_API(bool)
 JS::CompileOffThread(JSContext *cx, Handle<JSObject*> obj, const ReadOnlyCompileOptions &options,
                      const jschar *chars, size_t length,
                      OffThreadCompileCallback callback, void *callbackData)
 {
     JS_ASSERT(CanCompileOffThread(cx, options));
--- a/js/src/jsgc.cpp
+++ b/js/src/jsgc.cpp
@@ -4941,16 +4941,22 @@ Collect(JSRuntime *rt, bool incremental,
         /*
          * If we reset an existing GC, we need to start a new one. Also, we
          * repeat GCs that happen during shutdown (the gcShouldCleanUpEverything
          * case) until we can be sure that no additional garbage is created
          * (which typically happens if roots are dropped during finalizers).
          */
         repeat = (rt->gcPoke && rt->gcShouldCleanUpEverything) || wasReset;
     } while (repeat);
+
+    if (rt->gcIncrementalState == NO_INCREMENTAL) {
+#ifdef JS_WORKER_THREADS
+        EnqueuePendingParseTasksAfterGC(rt);
+#endif
+    }
 }
 
 void
 js::GC(JSRuntime *rt, JSGCInvocationKind gckind, JS::gcreason::Reason reason)
 {
     Collect(rt, false, SliceBudget::Unlimited, gckind, reason);
 }
 
@@ -5401,47 +5407,52 @@ js::PurgeJITCaches(Zone *zone)
         JSScript *script = i.get<JSScript>();
 
         /* Discard Ion caches. */
         jit::PurgeCaches(script, zone);
     }
 #endif
 }
 
+void
+ArenaLists::normalizeBackgroundFinalizeState(AllocKind thingKind)
+{
+    volatile uintptr_t *bfs = &backgroundFinalizeState[thingKind];
+    switch (*bfs) {
+      case BFS_DONE:
+        break;
+      case BFS_JUST_FINISHED:
+        // No allocations between end of last sweep and now.
+        // Transfering over arenas is a kind of allocation.
+        *bfs = BFS_DONE;
+        break;
+      default:
+        JS_ASSERT(!"Background finalization in progress, but it should not be.");
+        break;
+    }
+}
 
 void
 ArenaLists::adoptArenas(JSRuntime *rt, ArenaLists *fromArenaLists)
 {
     // The other parallel threads have all completed now, and GC
     // should be inactive, but still take the lock as a kind of read
     // fence.
     AutoLockGC lock(rt);
 
     fromArenaLists->purge();
 
     for (size_t thingKind = 0; thingKind != FINALIZE_LIMIT; thingKind++) {
 #ifdef JS_THREADSAFE
         // When we enter a parallel section, we join the background
         // thread, and we do not run GC while in the parallel section,
         // so no finalizer should be active!
-        volatile uintptr_t *bfs = &backgroundFinalizeState[thingKind];
-        switch (*bfs) {
-          case BFS_DONE:
-            break;
-          case BFS_JUST_FINISHED:
-            // No allocations between end of last sweep and now.
-            // Transfering over arenas is a kind of allocation.
-            *bfs = BFS_DONE;
-            break;
-          default:
-            JS_ASSERT(!"Background finalization in progress, but it should not be.");
-            break;
-        }
-#endif /* JS_THREADSAFE */
-
+        normalizeBackgroundFinalizeState(AllocKind(thingKind));
+        fromArenaLists->normalizeBackgroundFinalizeState(AllocKind(thingKind));
+#endif
         ArenaList *fromList = &fromArenaLists->arenaLists[thingKind];
         ArenaList *toList = &arenaLists[thingKind];
         while (fromList->head != nullptr) {
             ArenaHeader *fromHeader = fromList->head;
             fromList->head = fromHeader->next;
             fromHeader->next = nullptr;
 
             toList->insert(fromHeader);
--- a/js/src/jsgc.h
+++ b/js/src/jsgc.h
@@ -611,16 +611,18 @@ class ArenaLists
   private:
     inline void finalizeNow(FreeOp *fop, AllocKind thingKind);
     inline void queueForForegroundSweep(FreeOp *fop, AllocKind thingKind);
     inline void queueForBackgroundSweep(FreeOp *fop, AllocKind thingKind);
 
     void *allocateFromArena(JS::Zone *zone, AllocKind thingKind);
     inline void *allocateFromArenaInline(JS::Zone *zone, AllocKind thingKind);
 
+    inline void normalizeBackgroundFinalizeState(AllocKind thingKind);
+
     friend class js::Nursery;
 };
 
 /*
  * Initial allocation size for data structures holding chunks is set to hold
  * chunks with total capacity of 16MB to avoid buffer resizes during browser
  * startup.
  */
--- a/js/src/jsworkers.cpp
+++ b/js/src/jsworkers.cpp
@@ -171,41 +171,51 @@ js::CancelOffThreadIonCompile(JSCompartm
 static const JSClass workerGlobalClass = {
     "internal-worker-global", JSCLASS_GLOBAL_FLAGS,
     JS_PropertyStub,  JS_DeletePropertyStub,
     JS_PropertyStub,  JS_StrictPropertyStub,
     JS_EnumerateStub, JS_ResolveStub,
     JS_ConvertStub,   nullptr
 };
 
-ParseTask::ParseTask(ExclusiveContext *cx, JSContext *initCx,
+ParseTask::ParseTask(ExclusiveContext *cx, JSObject *exclusiveContextGlobal, JSContext *initCx,
                      const jschar *chars, size_t length, JSObject *scopeChain,
                      JS::OffThreadCompileCallback callback, void *callbackData)
   : cx(cx), options(initCx), chars(chars), length(length),
     alloc(JSRuntime::TEMP_LIFO_ALLOC_PRIMARY_CHUNK_SIZE), scopeChain(scopeChain),
-    callback(callback), callbackData(callbackData), script(nullptr),
-    errors(cx), overRecursed(false)
+    exclusiveContextGlobal(exclusiveContextGlobal), callback(callback),
+    callbackData(callbackData), script(nullptr), errors(cx), overRecursed(false)
 {
     JSRuntime *rt = scopeChain->runtimeFromMainThread();
 
     if (!AddObjectRoot(rt, &this->scopeChain, "ParseTask::scopeChain"))
         MOZ_CRASH();
+    if (!AddObjectRoot(rt, &this->exclusiveContextGlobal, "ParseTask::exclusiveContextGlobal"))
+        MOZ_CRASH();
 }
 
 bool
 ParseTask::init(JSContext *cx, const ReadOnlyCompileOptions &options)
 {
     return this->options.copy(cx, options);
 }
 
+void
+ParseTask::activate(JSRuntime *rt)
+{
+    rt->setUsedByExclusiveThread(exclusiveContextGlobal->zone());
+    cx->enterCompartment(exclusiveContextGlobal->compartment());
+}
+
 ParseTask::~ParseTask()
 {
     JSRuntime *rt = scopeChain->runtimeFromMainThread();
 
     JS_RemoveObjectRootRT(rt, &scopeChain);
+    JS_RemoveObjectRootRT(rt, &exclusiveContextGlobal);
 
     // ParseTask takes over ownership of its input exclusive context.
     js_delete(cx);
 
     for (size_t i = 0; i < errors.length(); i++)
         js_delete(errors[i]);
 }
 
@@ -252,46 +262,83 @@ js::StartOffThreadParseScript(JSContext 
             !js_GetClassObject(cx, global, JSProto_Array, &obj) ||
             !js_GetClassObject(cx, global, JSProto_RegExp, &obj) ||
             !js_GetClassObject(cx, global, JSProto_GeneratorFunction, &obj))
         {
             return false;
         }
     }
 
-    cx->runtime()->setUsedByExclusiveThread(global->zone());
-
     ScopedJSDeletePtr<ExclusiveContext> workercx(
         cx->new_<ExclusiveContext>(cx->runtime(), (PerThreadData *) nullptr,
                                    ThreadSafeContext::Context_Exclusive));
     if (!workercx)
         return false;
 
-    workercx->enterCompartment(global->compartment());
-
     ScopedJSDeletePtr<ParseTask> task(
-        cx->new_<ParseTask>(workercx.get(), cx, chars, length,
+        cx->new_<ParseTask>(workercx.get(), global, cx, chars, length,
                             scopeChain, callback, callbackData));
-    if (!task || !task->init(cx, options))
+    if (!task)
         return false;
 
     workercx.forget();
 
+    if (!task->init(cx, options))
+        return false;
+
     WorkerThreadState &state = *cx->runtime()->workerThreadState;
     JS_ASSERT(state.numThreads);
 
+    // Off thread parsing can't occur during incremental collections on the
+    // atoms compartment, to avoid triggering barriers. (Outside the atoms
+    // compartment, the compilation will use a new zone which doesn't require
+    // barriers itself.) If an atoms-zone GC is in progress, hold off on
+    // executing the parse task until the atoms-zone GC completes (see
+    // EnqueuePendingParseTasksAfterGC).
+    if (cx->runtime()->activeGCInAtomsZone()) {
+        if (!state.parseWaitingOnGC.append(task.get()))
+            return false;
+    } else {
+        task->activate(cx->runtime());
+
+        AutoLockWorkerThreadState lock(state);
+
+        if (!state.parseWorklist.append(task.get()))
+            return false;
+
+        state.notifyAll(WorkerThreadState::PRODUCER);
+    }
+
+    task.forget();
+
+    return true;
+}
+
+void
+js::EnqueuePendingParseTasksAfterGC(JSRuntime *rt)
+{
+    JS_ASSERT(!rt->activeGCInAtomsZone());
+
+    if (!rt->workerThreadState || rt->workerThreadState->parseWaitingOnGC.empty())
+        return;
+
+    // This logic should mirror the contents of the !activeGCInAtomsZone()
+    // branch in StartOffThreadParseScript:
+
+    WorkerThreadState &state = *rt->workerThreadState;
+
+    for (size_t i = 0; i < state.parseWaitingOnGC.length(); i++)
+        state.parseWaitingOnGC[i]->activate(rt);
+
     AutoLockWorkerThreadState lock(state);
 
-    if (!state.parseWorklist.append(task.get()))
-        return false;
-
-    task.forget();
+    JS_ASSERT(state.parseWorklist.empty());
+    state.parseWorklist.swap(state.parseWaitingOnGC);
 
     state.notifyAll(WorkerThreadState::PRODUCER);
-    return true;
 }
 
 void
 js::WaitForOffThreadParsingToFinish(JSRuntime *rt)
 {
     if (!rt->workerThreadState)
         return;
 
--- a/js/src/jsworkers.h
+++ b/js/src/jsworkers.h
@@ -66,16 +66,19 @@ class WorkerThreadState
      * For now, only allow a single parallel asm.js compilation to happen at a
      * time. This avoids race conditions on asmJSWorklist/asmJSFinishedList/etc.
      */
     mozilla::Atomic<uint32_t> asmJSCompilationInProgress;
 
     /* Shared worklist for parsing/emitting scripts on worker threads. */
     Vector<ParseTask*, 0, SystemAllocPolicy> parseWorklist, parseFinishedList;
 
+    /* Main-thread-only list of parse tasks waiting for an atoms-zone GC to complete. */
+    Vector<ParseTask*, 0, SystemAllocPolicy> parseWaitingOnGC;
+
     /* Worklist for source compression worker threads. */
     Vector<SourceCompressionTask *, 0, SystemAllocPolicy> compressionWorklist;
 
     WorkerThreadState(JSRuntime *rt) {
         mozilla::PodZero(this);
         runtime = rt;
     }
     ~WorkerThreadState();
@@ -225,16 +228,23 @@ CancelOffThreadIonCompile(JSCompartment 
  * Start a parse/emit cycle for a stream of source. The characters must stay
  * alive until the compilation finishes.
  */
 bool
 StartOffThreadParseScript(JSContext *cx, const ReadOnlyCompileOptions &options,
                           const jschar *chars, size_t length, HandleObject scopeChain,
                           JS::OffThreadCompileCallback callback, void *callbackData);
 
+/*
+ * Called at the end of GC to enqueue any Parse tasks that were waiting on an
+ * atoms-zone GC to finish.
+ */
+void
+EnqueuePendingParseTasksAfterGC(JSRuntime *rt);
+
 /* Block until in progress and pending off thread parse jobs have finished. */
 void
 WaitForOffThreadParsingToFinish(JSRuntime *rt);
 
 /* Start a compression job for the specified token. */
 bool
 StartOffThreadCompression(ExclusiveContext *cx, SourceCompressionTask *task);
 
@@ -324,35 +334,40 @@ struct ParseTask
     size_t length;
     LifoAlloc alloc;
 
     // Rooted pointer to the scope in the target compartment which the
     // resulting script will be merged into. This is not safe to use off the
     // main thread.
     JSObject *scopeChain;
 
+    // Rooted pointer to the global object used by 'cx'.
+    JSObject *exclusiveContextGlobal;
+
     // Callback invoked off the main thread when the parse finishes.
     JS::OffThreadCompileCallback callback;
     void *callbackData;
 
     // Holds the final script between the invocation of the callback and the
     // point where FinishOffThreadScript is called, which will destroy the
     // ParseTask.
     JSScript *script;
 
     // Any errors or warnings produced during compilation. These are reported
     // when finishing the script.
     Vector<frontend::CompileError *> errors;
     bool overRecursed;
 
-    ParseTask(ExclusiveContext *cx, JSContext *initCx,
+    ParseTask(ExclusiveContext *cx, JSObject *exclusiveContextGlobal, JSContext *initCx,
               const jschar *chars, size_t length, JSObject *scopeChain,
               JS::OffThreadCompileCallback callback, void *callbackData);
     bool init(JSContext *cx, const ReadOnlyCompileOptions &options);
 
+    void activate(JSRuntime *rt);
+
     ~ParseTask();
 };
 
 // Compression tasks are allocated on the stack by their triggering thread,
 // which will block on the compression completing as the task goes out of scope
 // to ensure it completes at the required time.
 struct SourceCompressionTask
 {