Commit 338e8c0c authored by Jon Coppeard's avatar Jon Coppeard
Browse files

Bug 1672760 - Add an API to wait for parse tasks to complete without cancelling them r=sfink 

The problem here was cancelling parse tasks without the browser's knowledge (I
didn't realise that the cancel method did anything beyond waiting).

Differential Revision: https://phabricator.services.mozilla.com/D94819
parent 891cb2a2

js/src/vm/HelperThreads.cpp

+23 −17
Original line number Diff line number Diff line
@@ -879,24 +879,12 @@ void MultiScriptsDecodeTask::parse(JSContext* cx) { 
  }

}



void js::CancelOffThreadParses(JSRuntime* rt) {

  AutoLockHelperThreadState lock;



static void WaitForOffThreadParses(JSRuntime* rt,

                                   AutoLockHelperThreadState& lock) {

  if (HelperThreadState().threads(lock).empty()) {

    return;

  }



#ifdef DEBUG

  GlobalHelperThreadState::ParseTaskVector& waitingOnGC =

      HelperThreadState().parseWaitingOnGC(lock);

  for (size_t i = 0; i < waitingOnGC.length(); i++) {

    MOZ_ASSERT(!waitingOnGC[i]->runtimeMatches(rt));

  }

#endif



  // Instead of forcibly canceling pending parse tasks, just wait for all

  // scheduled and in progress ones to complete. Otherwise the final GC may not

  // collect everything due to zones being used off thread.

  while (true) {

    bool pending = false;

    GlobalHelperThreadState::ParseTaskVector& worklist =
@@ -923,6 +911,26 @@ void js::CancelOffThreadParses(JSRuntime* rt) { 
    }

    HelperThreadState().wait(lock, GlobalHelperThreadState::CONSUMER);

  }

}



void js::WaitForOffThreadParses(JSRuntime* rt) {

  AutoLockHelperThreadState lock;

  WaitForOffThreadParses(rt, lock);

}



void js::CancelOffThreadParses(JSRuntime* rt) {

  AutoLockHelperThreadState lock;



#ifdef DEBUG

  for (const auto& task : HelperThreadState().parseWaitingOnGC(lock)) {

    MOZ_ASSERT(!task->runtimeMatches(rt));

  }

#endif



  // Instead of forcibly canceling pending parse tasks, just wait for all

  // scheduled and in progress ones to complete. Otherwise the final GC may not

  // collect everything due to zones being used off thread.

  WaitForOffThreadParses(rt, lock);



  // Clean up any parse tasks which haven't been finished by the main thread.

  auto& finished = HelperThreadState().parseFinishedList(lock);
@@ -945,9 +953,7 @@ void js::CancelOffThreadParses(JSRuntime* rt) { 
  }



#ifdef DEBUG

  GlobalHelperThreadState::ParseTaskVector& worklist =

      HelperThreadState().parseWorklist(lock);

  for (const auto& task : worklist) {

  for (const auto& task : HelperThreadState().parseWorklist(lock)) {

    MOZ_ASSERT(!task->runtimeMatches(rt));

  }

#endif

js/src/vm/HelperThreads.h

+6 −0
Original line number Diff line number Diff line
@@ -177,6 +177,12 @@ inline void CancelOffThreadIonCompilesUsingNurseryPointers(JSRuntime* runtime) { 
bool HasOffThreadIonCompile(JS::Realm* realm);

#endif



/*

 * Wait for all scheduled, in progress or finished parse tasks for the runtime

 * to complete.

 */

void WaitForOffThreadParses(JSRuntime* runtime);



/* Cancel all scheduled, in progress or finished parses for runtime. */

void CancelOffThreadParses(JSRuntime* runtime);

js/src/vm/MemoryMetrics.cpp

+1 −1
Original line number Diff line number Diff line
@@ -625,7 +625,7 @@ static bool CollectRuntimeStatsHelper(JSContext* cx, RuntimeStats* rtStats, 
  // Wait for any off-thread parsing to finish, as that currently allocates GC

  // things.

  JSRuntime* rt = cx->runtime();

  CancelOffThreadParses(rt);

  WaitForOffThreadParses(rt);



  // Finish any ongoing incremental GC that may change the data we're gathering

  // and ensure that we don't do anything that could start another one.