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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
#include "CanvasRenderThread.h"
#include "mozilla/BackgroundHangMonitor.h"
#include "mozilla/SharedThreadPool.h"
#include "mozilla/StaticPrefs_gfx.h"
#include "mozilla/TaskQueue.h"
#include "mozilla/gfx/CanvasManagerParent.h"
#include "mozilla/gfx/gfxVars.h"
#include "mozilla/layers/CanvasTranslator.h"
#include "mozilla/layers/CompositorThread.h"
#include "mozilla/webrender/RenderThread.h"
#include "nsThread.h"
#include "prsystem.h"
#include "transport/runnable_utils.h"
bool NS_IsInCanvasThreadOrWorker() {
return mozilla::gfx::CanvasRenderThread::IsInCanvasRenderOrWorkerThread();
}
namespace mozilla::gfx {
static StaticRefPtr<CanvasRenderThread> sCanvasRenderThread;
static mozilla::BackgroundHangMonitor* sBackgroundHangMonitor;
#ifdef DEBUG
static bool sCanvasRenderThreadEverStarted = false;
#endif
CanvasRenderThread::CanvasRenderThread(nsCOMPtr<nsIThread>&& aThread,
nsCOMPtr<nsIThreadPool>&& aWorkers,
bool aCreatedThread)
: mMutex("CanvasRenderThread::mMutex"),
mThread(std::move(aThread)),
mWorkers(std::move(aWorkers)),
mCreatedThread(aCreatedThread) {}
CanvasRenderThread::~CanvasRenderThread() = default;
// static
void CanvasRenderThread::Start() {
MOZ_ASSERT(NS_IsMainThread());
MOZ_ASSERT(!sCanvasRenderThread);
#ifdef DEBUG
// Check to ensure nobody will try to ever start us more than once during
// the process' lifetime (in particular after Stop).
MOZ_ASSERT(!sCanvasRenderThreadEverStarted);
sCanvasRenderThreadEverStarted = true;
#endif
int32_t threadPref =
StaticPrefs::gfx_canvas_remote_worker_threads_AtStartup();
uint32_t threadLimit;
if (threadPref < 0) {
// Given that the canvas workers are receiving instructions from
// content processes, it probably doesn't make sense to have more than
// half the number of processors doing canvas drawing. We set the
// lower limit to 2, so that even on single processor systems, if
// there is more than one window with canvas drawing, the OS can
// manage the load between them.
threadLimit = std::max(2, PR_GetNumberOfProcessors() / 2);
} else {
threadLimit = uint32_t(threadPref);
}
// We don't spawn any workers if the user set the limit to 0. Instead we will
// use the CanvasRenderThread virtual thread.
nsCOMPtr<nsIThreadPool> workers;
if (threadLimit > 0) {
workers = SharedThreadPool::Get("CanvasWorkers"_ns, threadLimit);
if (NS_WARN_IF(!workers)) {
return;
}
}
nsCOMPtr<nsIThread> thread;
if (!gfxVars::SupportsThreadsafeGL()) {
thread = wr::RenderThread::GetRenderThread();
MOZ_ASSERT(thread);
} else if (!gfxVars::UseCanvasRenderThread()) {
thread = layers::CompositorThread();
MOZ_ASSERT(thread);
}
if (thread) {
sCanvasRenderThread = new CanvasRenderThread(
std::move(thread), std::move(workers), /* aCreatedThread */ false);
return;
}
// This is 4M, which is higher than the default 256K.
// ANGLE, which has large peak stack usage for some pathological shader
// compilations.
//
//
// Previously increased to 320K to avoid a stack overflow in the
//
// Note: we only override it if it's limited already.
const uint32_t stackSize =
nsIThreadManager::DEFAULT_STACK_SIZE ? 4096 << 10 : 0;
nsresult rv = NS_NewNamedThread(
"CanvasRenderer", getter_AddRefs(thread),
NS_NewRunnableFunction(
"CanvasRender::BackgroundHangSetup",
[]() {
sBackgroundHangMonitor = new mozilla::BackgroundHangMonitor(
"CanvasRendererBHM",
/* Timeout values are powers-of-two to enable us get better
data. 128ms is chosen for transient hangs because 8Hz should
be the minimally acceptable goal for Compositor
responsiveness (normal goal is 60Hz). */
128,
/* 2048ms is chosen for permanent hangs because it's longer than
* most Compositor hangs seen in the wild, but is short enough
* to not miss getting native hang stacks. */
2048);
nsCOMPtr<nsIThread> thread = NS_GetCurrentThread();
nsThread* nsthread = static_cast<nsThread*>(thread.get());
nsthread->SetUseHangMonitor(true);
nsthread->SetPriority(nsISupportsPriority::PRIORITY_HIGH);
}),
{.stackSize = stackSize});
if (NS_WARN_IF(NS_FAILED(rv))) {
return;
}
sCanvasRenderThread = new CanvasRenderThread(
std::move(thread), std::move(workers), /* aCreatedThread */ true);
}
// static
void CanvasRenderThread::Shutdown() {
MOZ_ASSERT(NS_IsMainThread());
// It is possible we never initialized this thread in the parent process,
// because we used the GPU process instead.
if (!sCanvasRenderThread) {
MOZ_ASSERT(XRE_IsParentProcess());
return;
}
// This closes all of the IPDL actors with possibly active task queues.
CanvasManagerParent::Shutdown();
// Queue any remaining global cleanup for CanvasTranslator
layers::CanvasTranslator::Shutdown();
// Any task queues that are in the process of shutting down are tracked in
// mPendingShutdownTaskQueues. We need to block on each one until all events
// are flushed so that we can safely teardown RemoteTextureMap afterwards.
while (true) {
RefPtr<TaskQueue> taskQueue;
{
MutexAutoLock lock(sCanvasRenderThread->mMutex);
auto& pendingQueues = sCanvasRenderThread->mPendingShutdownTaskQueues;
if (pendingQueues.IsEmpty()) {
break;
}
taskQueue = pendingQueues.PopLastElement();
}
taskQueue->AwaitShutdownAndIdle();
}
bool createdThread = sCanvasRenderThread->mCreatedThread;
nsCOMPtr<nsIThread> oldThread = sCanvasRenderThread->GetCanvasRenderThread();
nsCOMPtr<nsIThreadPool> oldWorkers = sCanvasRenderThread->mWorkers;
// Ensure that we flush the CanvasRenderThread event queue before clearing our
// singleton.
NS_DispatchAndSpinEventLoopUntilComplete(
"CanvasRenderThread::Shutdown"_ns, oldThread,
NS_NewRunnableFunction("CanvasRenderThread::Shutdown", []() -> void {}));
// Null out sCanvasRenderThread before we enter synchronous Shutdown,
// from here on we are to be considered shut down for our consumers.
sCanvasRenderThread = nullptr;
if (oldWorkers) {
oldWorkers->Shutdown();
}
// We do a synchronous shutdown here while spinning the MT event loop, but
// only if we created a dedicated CanvasRender thread.
if (createdThread) {
oldThread->Shutdown();
}
}
// static
bool CanvasRenderThread::IsInCanvasRenderThread() {
return sCanvasRenderThread &&
sCanvasRenderThread->mThread == NS_GetCurrentThread();
}
/* static */ bool CanvasRenderThread::IsInCanvasWorkerThread() {
// It is possible there are no worker threads, and the worker is the same as
// the CanvasRenderThread itself.
return sCanvasRenderThread &&
((sCanvasRenderThread->mWorkers &&
sCanvasRenderThread->mWorkers->IsOnCurrentThread()) ||
(!sCanvasRenderThread->mWorkers &&
sCanvasRenderThread->mThread == NS_GetCurrentThread()));
}
/* static */ bool CanvasRenderThread::IsInCanvasRenderOrWorkerThread() {
// It is possible there are no worker threads, and the worker is the same as
// the CanvasRenderThread itself.
return sCanvasRenderThread &&
(sCanvasRenderThread->mThread == NS_GetCurrentThread() ||
(sCanvasRenderThread->mWorkers &&
sCanvasRenderThread->mWorkers->IsOnCurrentThread()));
}
// static
already_AddRefed<nsIThread> CanvasRenderThread::GetCanvasRenderThread() {
nsCOMPtr<nsIThread> thread;
if (sCanvasRenderThread) {
thread = sCanvasRenderThread->mThread;
}
return thread.forget();
}
/* static */ already_AddRefed<TaskQueue>
CanvasRenderThread::CreateWorkerTaskQueue() {
if (!sCanvasRenderThread || !sCanvasRenderThread->mWorkers) {
return nullptr;
}
return TaskQueue::Create(do_AddRef(sCanvasRenderThread->mWorkers),
"CanvasWorker")
.forget();
}
/* static */ void CanvasRenderThread::ShutdownWorkerTaskQueue(
TaskQueue* aTaskQueue) {
MOZ_ASSERT(aTaskQueue);
aTaskQueue->BeginShutdown();
if (!sCanvasRenderThread) {
MOZ_ASSERT_UNREACHABLE("No CanvasRenderThread!");
return;
}
MutexAutoLock lock(sCanvasRenderThread->mMutex);
auto& pendingQueues = sCanvasRenderThread->mPendingShutdownTaskQueues;
pendingQueues.AppendElement(aTaskQueue);
}
/* static */ void CanvasRenderThread::FinishShutdownWorkerTaskQueue(
TaskQueue* aTaskQueue) {
if (!sCanvasRenderThread) {
return;
}
MutexAutoLock lock(sCanvasRenderThread->mMutex);
sCanvasRenderThread->mPendingShutdownTaskQueues.RemoveElement(aTaskQueue);
}
/* static */ void CanvasRenderThread::Dispatch(
already_AddRefed<nsIRunnable> aRunnable) {
if (!sCanvasRenderThread) {
MOZ_DIAGNOSTIC_ASSERT(false,
"Dispatching after CanvasRenderThread shutdown!");
return;
}
sCanvasRenderThread->mThread->Dispatch(std::move(aRunnable));
}
} // namespace mozilla::gfx