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Backed out changeset 806a941c8580 (bug 1379814) for asserting at HelperThreads.cpp:997, e.g. in chrome tests on OS X. r=backout on a CLOSED TREE

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This commit is contained in:
Sebastian Hengst 2017-08-11 10:34:36 +02:00
parent a3bc704783
commit b18e1ac009
2 changed files with 39 additions and 90 deletions
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119
js/src/vm/HelperThreads.cpp
View File

@ -963,42 +963,21 @@ GlobalHelperThreadState::waitForAllThreads()
wait(lock, CONSUMER);
}
// A task can be a "master" task, ie, it will block waiting for other worker
// threads that perform work on its behalf. If so it must not take the last
// available thread; there must always be at least one worker thread able to do
// the actual work. (Or the system may deadlock.)
//
// If a task is a master task it *must* pass isMaster=true here, or perform a
// similar calculation to avoid deadlock from starvation.
template <typename T>
bool
GlobalHelperThreadState::checkTaskThreadLimit(size_t maxThreads, bool isMaster) const
GlobalHelperThreadState::checkTaskThreadLimit(size_t maxThreads) const
{
MOZ_ASSERT(maxThreads > 0);
if (!isMaster && maxThreads >= threadCount)
if (maxThreads >= threadCount)
return true;
size_t count = 0;
size_t idle = 0;
for (auto& thread : *threads) {
if (thread.currentTask.isSome()) {
if (thread.currentTask->is<T>())
count++;
} else {
idle++;
}
if (thread.currentTask.isSome() && thread.currentTask->is<T>())
count++;
if (count >= maxThreads)
return false;
}
// At least the current thread is idle.
MOZ_ASSERT(idle > 0);
if (isMaster && idle <= 1)
return false;
return true;
}
@ -1234,12 +1213,7 @@ GlobalHelperThreadState::pendingIonCompileHasSufficientPriority(
bool
GlobalHelperThreadState::canStartParseTask(const AutoLockHelperThreadState& lock)
{
// Parse tasks that end up compiling asm.js in turn may use Wasm compilation
// threads to generate machine code. We have no way (at present) to know
// ahead of time whether a parse task is going to parse asm.js content or
// not, so we just assume that all parse tasks are master tasks.
return !parseWorklist(lock).empty() &&
checkTaskThreadLimit<ParseTask*>(maxParseThreads(), /*isMaster=*/true);
return !parseWorklist(lock).empty() && checkTaskThreadLimit<ParseTask*>(maxParseThreads());
}
bool
@ -2168,74 +2142,53 @@ HelperThread::threadLoop()
while (true) {
MOZ_ASSERT(idle());
js::oom::ThreadType task;
// Block until a task is available. Save the value of whether we are
// going to do an Ion compile, in case the value returned by the method
// changes.
bool ionCompile = false;
while (true) {
if (terminate)
return;
// Select the task type to run. Task priority is determined
// exclusively here.
//
// The selectors may depend on the HelperThreadState not changing
// between task selection and task execution, in particular, on new
// tasks not being added (because of the lifo structure of the work
// lists). Unlocking the HelperThreadState between task selection
// and execution is not well-defined.
if (HelperThreadState().canStartGCParallelTask(lock))
task = js::oom::THREAD_TYPE_GCPARALLEL;
else if (HelperThreadState().canStartGCHelperTask(lock))
task = js::oom::THREAD_TYPE_GCHELPER;
else if (HelperThreadState().pendingIonCompileHasSufficientPriority(lock))
task = js::oom::THREAD_TYPE_ION;
else if (HelperThreadState().canStartWasmCompile(lock))
task = js::oom::THREAD_TYPE_WASM;
else if (HelperThreadState().canStartPromiseTask(lock))
task = js::oom::THREAD_TYPE_PROMISE_TASK;
else if (HelperThreadState().canStartParseTask(lock))
task = js::oom::THREAD_TYPE_PARSE;
else if (HelperThreadState().canStartCompressionTask(lock))
task = js::oom::THREAD_TYPE_COMPRESS;
else if (HelperThreadState().canStartIonFreeTask(lock))
task = js::oom::THREAD_TYPE_ION_FREE;
else
task = js::oom::THREAD_TYPE_NONE;
if (task != js::oom::THREAD_TYPE_NONE)
if ((ionCompile = HelperThreadState().pendingIonCompileHasSufficientPriority(lock)) ||
HelperThreadState().canStartWasmCompile(lock) ||
HelperThreadState().canStartPromiseTask(lock) ||
HelperThreadState().canStartParseTask(lock) ||
HelperThreadState().canStartCompressionTask(lock) ||
HelperThreadState().canStartGCHelperTask(lock) ||
HelperThreadState().canStartGCParallelTask(lock) ||
HelperThreadState().canStartIonFreeTask(lock))
{
break;
}
HelperThreadState().wait(lock, GlobalHelperThreadState::PRODUCER);
}
js::oom::SetThreadType(task);
switch (task) {
case js::oom::THREAD_TYPE_GCPARALLEL:
if (HelperThreadState().canStartGCParallelTask(lock)) {
js::oom::SetThreadType(js::oom::THREAD_TYPE_GCPARALLEL);
handleGCParallelWorkload(lock);
break;
case js::oom::THREAD_TYPE_GCHELPER:
} else if (HelperThreadState().canStartGCHelperTask(lock)) {
js::oom::SetThreadType(js::oom::THREAD_TYPE_GCHELPER);
handleGCHelperWorkload(lock);
break;
case js::oom::THREAD_TYPE_ION:
} else if (ionCompile) {
js::oom::SetThreadType(js::oom::THREAD_TYPE_ION);
handleIonWorkload(lock);
break;
case js::oom::THREAD_TYPE_WASM:
} else if (HelperThreadState().canStartWasmCompile(lock)) {
js::oom::SetThreadType(js::oom::THREAD_TYPE_WASM);
handleWasmWorkload(lock);
break;
case js::oom::THREAD_TYPE_PROMISE_TASK:
} else if (HelperThreadState().canStartPromiseTask(lock)) {
js::oom::SetThreadType(js::oom::THREAD_TYPE_PROMISE_TASK);
handlePromiseTaskWorkload(lock);
break;
case js::oom::THREAD_TYPE_PARSE:
} else if (HelperThreadState().canStartParseTask(lock)) {
js::oom::SetThreadType(js::oom::THREAD_TYPE_PARSE);
handleParseWorkload(lock);
break;
case js::oom::THREAD_TYPE_COMPRESS:
} else if (HelperThreadState().canStartCompressionTask(lock)) {
js::oom::SetThreadType(js::oom::THREAD_TYPE_COMPRESS);
handleCompressionWorkload(lock);
break;
case js::oom::THREAD_TYPE_ION_FREE:
} else if (HelperThreadState().canStartIonFreeTask(lock)) {
js::oom::SetThreadType(js::oom::THREAD_TYPE_ION_FREE);
handleIonFreeWorkload(lock);
break;
default:
} else {
MOZ_CRASH("No task to perform");
}
js::oom::SetThreadType(js::oom::THREAD_TYPE_NONE);
}
}

10
js/src/vm/HelperThreads.h
View File

@ -146,14 +146,10 @@ class GlobalHelperThreadState
#endif
enum CondVar {
// For notifying threads waiting for work that they may be able to make
// progress, ie, a work item has been completed by a helper thread and
// the thread that created the work item can now consume it.
// For notifying threads waiting for work that they may be able to make progress.
CONSUMER,
// For notifying helper threads doing the work that they may be able to
// make progress, ie, a work item has been enqueued and an idle helper
// thread may pick up up the work item and perform it.
// For notifying threads doing work that they may be able to make progress.
PRODUCER,
// For notifying threads doing work which are paused that they may be
@ -314,7 +310,7 @@ class GlobalHelperThreadState
void waitForAllThreads();
template <typename T>
bool checkTaskThreadLimit(size_t maxThreads, bool isMaster = false) const;
bool checkTaskThreadLimit(size_t maxThreads) const;
private: