// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/threading/platform_thread_win.h"
#include <windows.h>
#include <stddef.h>
#include <string>
#include "base/debug/alias.h"
#include "base/debug/crash_logging.h"
#include "base/debug/profiler.h"
#include "base/feature_list.h"
#include "base/logging.h"
#include "base/memory/raw_ptr.h"
#include "base/metrics/histogram_macros.h"
#include "base/process/memory.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/utf_string_conversions.h"
#include "base/threading/scoped_blocking_call.h"
#include "base/threading/scoped_thread_priority.h"
#include "base/threading/thread_id_name_manager.h"
#include "base/threading/thread_restrictions.h"
#include "base/threading/threading_features.h"
#include "base/time/time_override.h"
#include "base/win/scoped_handle.h"
#include "base/win/windows_version.h"
#include "build/build_config.h"
#include "partition_alloc/buildflags.h"
#if PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)
#include "partition_alloc/stack/stack.h"
#endif
namespace base {
BASE_FEATURE(kUseThreadPriorityLowest,
"UseThreadPriorityLowest",
base::FEATURE_DISABLED_BY_DEFAULT);
BASE_FEATURE(kAboveNormalCompositingBrowserWin,
"AboveNormalCompositingBrowserWin",
base::FEATURE_ENABLED_BY_DEFAULT);
namespace {
// Flag used to set thread priority to |THREAD_PRIORITY_LOWEST| for
// |kUseThreadPriorityLowest| Feature.
std::atomic<bool> g_use_thread_priority_lowest{false};
// Flag used to map Compositing ThreadType |THREAD_PRIORITY_ABOVE_NORMAL| on the
// UI thread for |kAboveNormalCompositingBrowserWin| Feature.
std::atomic<bool> g_above_normal_compositing_browser{true};
// These values are sometimes returned by ::GetThreadPriority().
constexpr int kWinDisplayPriority1 = 5;
constexpr int kWinDisplayPriority2 = 6;
// The information on how to set the thread name comes from
// a MSDN article: http://msdn2.microsoft.com/en-us/library/xcb2z8hs.aspx
const DWORD kVCThreadNameException = 0x406D1388;
typedef struct tagTHREADNAME_INFO {
DWORD dwType; // Must be 0x1000.
LPCSTR szName; // Pointer to name (in user addr space).
DWORD dwThreadID; // Thread ID (-1=caller thread).
DWORD dwFlags; // Reserved for future use, must be zero.
} THREADNAME_INFO;
// The SetThreadDescription API was brought in version 1607 of Windows 10.
typedef HRESULT(WINAPI* SetThreadDescription)(HANDLE hThread,
PCWSTR lpThreadDescription);
// This function has try handling, so it is separated out of its caller.
void SetNameInternal(PlatformThreadId thread_id, const char* name) {
THREADNAME_INFO info;
info.dwType = 0x1000;
info.szName = name;
info.dwThreadID = thread_id;
info.dwFlags = 0;
__try {
RaiseException(kVCThreadNameException, 0, sizeof(info) / sizeof(ULONG_PTR),
reinterpret_cast<ULONG_PTR*>(&info));
} __except (EXCEPTION_EXECUTE_HANDLER) {
}
}
struct ThreadParams {
raw_ptr<PlatformThread::Delegate> delegate;
bool joinable;
ThreadType thread_type;
MessagePumpType message_pump_type;
};
DWORD __stdcall ThreadFunc(void* params) {
ThreadParams* thread_params = static_cast<ThreadParams*>(params);
PlatformThread::Delegate* delegate = thread_params->delegate;
if (!thread_params->joinable)
base::DisallowSingleton();
if (thread_params->thread_type != ThreadType::kDefault)
internal::SetCurrentThreadType(thread_params->thread_type,
thread_params->message_pump_type);
// Retrieve a copy of the thread handle to use as the key in the
// thread name mapping.
PlatformThreadHandle::Handle platform_handle;
BOOL did_dup = DuplicateHandle(GetCurrentProcess(),
GetCurrentThread(),
GetCurrentProcess(),
&platform_handle,
0,
FALSE,
DUPLICATE_SAME_ACCESS);
#if PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)
partition_alloc::internal::StackTopRegistry::Get().NotifyThreadCreated();
#endif
win::ScopedHandle scoped_platform_handle;
if (did_dup) {
scoped_platform_handle.Set(platform_handle);
ThreadIdNameManager::GetInstance()->RegisterThread(
scoped_platform_handle.get(), PlatformThread::CurrentId());
}
delete thread_params;
delegate->ThreadMain();
if (did_dup) {
ThreadIdNameManager::GetInstance()->RemoveName(scoped_platform_handle.get(),
PlatformThread::CurrentId());
}
#if PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)
partition_alloc::internal::StackTopRegistry::Get().NotifyThreadDestroyed();
#endif
// Ensure thread priority is at least NORMAL before initiating thread
// destruction. Thread destruction on Windows holds the LdrLock while
// performing TLS destruction which causes hangs if performed at background
// priority (priority inversion) (see: http://crbug.com/1096203).
if (::GetThreadPriority(::GetCurrentThread()) < THREAD_PRIORITY_NORMAL)
PlatformThread::SetCurrentThreadType(ThreadType::kDefault);
return 0;
}
// CreateThreadInternal() matches PlatformThread::CreateWithType(), except
// that |out_thread_handle| may be nullptr, in which case a non-joinable thread
// is created.
bool CreateThreadInternal(size_t stack_size,
PlatformThread::Delegate* delegate,
PlatformThreadHandle* out_thread_handle,
ThreadType thread_type,
MessagePumpType message_pump_type) {
unsigned int flags = 0;
if (stack_size > 0) {
flags = STACK_SIZE_PARAM_IS_A_RESERVATION;
#if defined(ARCH_CPU_32_BITS)
} else {
// The process stack size is increased to give spaces to |RendererMain| in
// |chrome/BUILD.gn|, but keep the default stack size of other threads to
// 1MB for the address space pressure.
flags = STACK_SIZE_PARAM_IS_A_RESERVATION;
static BOOL is_wow64 = -1;
if (is_wow64 == -1 && !IsWow64Process(GetCurrentProcess(), &is_wow64))
is_wow64 = FALSE;
// When is_wow64 is set that means we are running on 64-bit Windows and we
// get 4 GiB of address space. In that situation we can afford to use 1 MiB
// of address space for stacks. When running on 32-bit Windows we only get
// 2 GiB of address space so we need to conserve. Typically stack usage on
// these threads is only about 100 KiB.
if (is_wow64)
stack_size = 1024 * 1024;
else
stack_size = 512 * 1024;
#endif
}
ThreadParams* params = new ThreadParams;
params->delegate = delegate;
params->joinable = out_thread_handle != nullptr;
params->thread_type = thread_type;
params->message_pump_type = message_pump_type;
// Using CreateThread here vs _beginthreadex makes thread creation a bit
// faster and doesn't require the loader lock to be available. Our code will
// have to work running on CreateThread() threads anyway, since we run code on
// the Windows thread pool, etc. For some background on the difference:
// http://www.microsoft.com/msj/1099/win32/win321099.aspx
void* thread_handle =
::CreateThread(nullptr, stack_size, ThreadFunc, params, flags, nullptr);
if (!thread_handle) {
DWORD last_error = ::GetLastError();
switch (last_error) {
case ERROR_NOT_ENOUGH_MEMORY:
case ERROR_OUTOFMEMORY:
case ERROR_COMMITMENT_LIMIT:
case ERROR_COMMITMENT_MINIMUM:
TerminateBecauseOutOfMemory(stack_size);
break;
default:
static auto* last_error_crash_key = debug::AllocateCrashKeyString(
"create_thread_last_error", debug::CrashKeySize::Size32);
debug::SetCrashKeyString(last_error_crash_key,
base::NumberToString(last_error));
break;
}
delete params;
return false;
}
if (out_thread_handle)
*out_thread_handle = PlatformThreadHandle(thread_handle);
else
CloseHandle(thread_handle);
return true;
}
} // namespace
namespace internal {
void AssertMemoryPriority(HANDLE thread, int memory_priority) {
#if DCHECK_IS_ON()
static const auto get_thread_information_fn =
reinterpret_cast<decltype(&::GetThreadInformation)>(::GetProcAddress(
::GetModuleHandle(L"Kernel32.dll"), "GetThreadInformation"));
DCHECK(get_thread_information_fn);
MEMORY_PRIORITY_INFORMATION memory_priority_information = {};
DCHECK(get_thread_information_fn(thread, ::ThreadMemoryPriority,
&memory_priority_information,
sizeof(memory_priority_information)));
DCHECK_EQ(memory_priority,
static_cast<int>(memory_priority_information.MemoryPriority));
#endif
}
} // namespace internal
// static
PlatformThreadId PlatformThread::CurrentId() {
return ::GetCurrentThreadId();
}
// static
PlatformThreadRef PlatformThread::CurrentRef() {
return PlatformThreadRef(::GetCurrentThreadId());
}
// static
PlatformThreadHandle PlatformThread::CurrentHandle() {
return PlatformThreadHandle(::GetCurrentThread());
}
// static
void PlatformThread::YieldCurrentThread() {
::Sleep(0);
}
// static
void PlatformThread::Sleep(TimeDelta duration) {
// When measured with a high resolution clock, Sleep() sometimes returns much
// too early. We may need to call it repeatedly to get the desired duration.
// PlatformThread::Sleep doesn't support mock-time, so this always uses
// real-time.
const TimeTicks end = subtle::TimeTicksNowIgnoringOverride() + duration;
for (TimeTicks now = subtle::TimeTicksNowIgnoringOverride(); now < end;
now = subtle::TimeTicksNowIgnoringOverride()) {
::Sleep(static_cast<DWORD>((end - now).InMillisecondsRoundedUp()));
}
}
// static
void PlatformThread::SetName(const std::string& name) {
SetNameCommon(name);
// The SetThreadDescription API works even if no debugger is attached.
static auto set_thread_description_func =
reinterpret_cast<SetThreadDescription>(::GetProcAddress(
::GetModuleHandle(L"Kernel32.dll"), "SetThreadDescription"));
if (set_thread_description_func) {
set_thread_description_func(::GetCurrentThread(),
base::UTF8ToWide(name).c_str());
}
// The debugger needs to be around to catch the name in the exception. If
// there isn't a debugger, we are just needlessly throwing an exception.
if (!::IsDebuggerPresent())
return;
SetNameInternal(CurrentId(), name.c_str());
}
// static
const char* PlatformThread::GetName() {
return ThreadIdNameManager::GetInstance()->GetName(CurrentId());
}
// static
bool PlatformThread::CreateWithType(size_t stack_size,
Delegate* delegate,
PlatformThreadHandle* thread_handle,
ThreadType thread_type,
MessagePumpType pump_type_hint) {
DCHECK(thread_handle);
return CreateThreadInternal(stack_size, delegate, thread_handle, thread_type,
pump_type_hint);
}
// static
bool PlatformThread::CreateNonJoinable(size_t stack_size, Delegate* delegate) {
return CreateNonJoinableWithType(stack_size, delegate, ThreadType::kDefault);
}
// static
bool PlatformThread::CreateNonJoinableWithType(size_t stack_size,
Delegate* delegate,
ThreadType thread_type,
MessagePumpType pump_type_hint) {
return CreateThreadInternal(stack_size, delegate, nullptr /* non-joinable */,
thread_type, pump_type_hint);
}
// static
void PlatformThread::Join(PlatformThreadHandle thread_handle) {
DCHECK(thread_handle.platform_handle());
DWORD thread_id = 0;
thread_id = ::GetThreadId(thread_handle.platform_handle());
DWORD last_error = 0;
if (!thread_id)
last_error = ::GetLastError();
// Record information about the exiting thread in case joining hangs.
base::debug::Alias(&thread_id);
base::debug::Alias(&last_error);
base::internal::ScopedBlockingCallWithBaseSyncPrimitives scoped_blocking_call(
FROM_HERE, base::BlockingType::MAY_BLOCK);
// Wait for the thread to exit. It should already have terminated but make
// sure this assumption is valid.
CHECK_EQ(WAIT_OBJECT_0,
WaitForSingleObject(thread_handle.platform_handle(), INFINITE));
CloseHandle(thread_handle.platform_handle());
}
// static
void PlatformThread::Detach(PlatformThreadHandle thread_handle) {
CloseHandle(thread_handle.platform_handle());
}
// static
bool PlatformThread::CanChangeThreadType(ThreadType from, ThreadType to) {
return true;
}
namespace {
void SetCurrentThreadPriority(ThreadType thread_type,
MessagePumpType pump_type_hint) {
if (thread_type == ThreadType::kDisplayCritical &&
pump_type_hint == MessagePumpType::UI &&
!g_above_normal_compositing_browser) {
// Ignore kDisplayCritical thread type for UI thread as Windows has a
// priority boost mechanism. See
// https://docs.microsoft.com/en-us/windows/win32/procthread/priority-boosts
return;
}
PlatformThreadHandle::Handle thread_handle =
PlatformThread::CurrentHandle().platform_handle();
if (!g_use_thread_priority_lowest && thread_type != ThreadType::kBackground) {
// Exit background mode if the new priority is not BACKGROUND. This is a
// no-op if not in background mode.
::SetThreadPriority(thread_handle, THREAD_MODE_BACKGROUND_END);
// We used to DCHECK that memory priority is MEMORY_PRIORITY_NORMAL here,
// but found that it is not always the case (e.g. in the installer).
// crbug.com/1340578#c2
}
int desired_priority = THREAD_PRIORITY_ERROR_RETURN;
switch (thread_type) {
case ThreadType::kBackground:
// Using THREAD_MODE_BACKGROUND_BEGIN instead of THREAD_PRIORITY_LOWEST
// improves input latency and navigation time. See
// https://docs.google.com/document/d/16XrOwuwTwKWdgPbcKKajTmNqtB4Am8TgS9GjbzBYLc0
//
// MSDN recommends THREAD_MODE_BACKGROUND_BEGIN for threads that perform
// background work, as it reduces disk and memory priority in addition to
// CPU priority.
desired_priority =
g_use_thread_priority_lowest.load(std::memory_order_relaxed)
? THREAD_PRIORITY_LOWEST
: THREAD_MODE_BACKGROUND_BEGIN;
break;
case ThreadType::kUtility:
desired_priority = THREAD_PRIORITY_BELOW_NORMAL;
break;
case ThreadType::kResourceEfficient:
case ThreadType::kDefault:
desired_priority = THREAD_PRIORITY_NORMAL;
break;
case ThreadType::kDisplayCritical:
desired_priority = THREAD_PRIORITY_ABOVE_NORMAL;
break;
case ThreadType::kRealtimeAudio:
desired_priority = THREAD_PRIORITY_TIME_CRITICAL;
break;
}
DCHECK_NE(desired_priority, THREAD_PRIORITY_ERROR_RETURN);
[[maybe_unused]] const BOOL cpu_priority_success =
::SetThreadPriority(thread_handle, desired_priority);
DPLOG_IF(ERROR, !cpu_priority_success)
<< "Failed to set thread priority to " << desired_priority;
if (desired_priority == THREAD_MODE_BACKGROUND_BEGIN) {
// Override the memory priority.
MEMORY_PRIORITY_INFORMATION memory_priority{.MemoryPriority =
MEMORY_PRIORITY_NORMAL};
[[maybe_unused]] const BOOL memory_priority_success =
SetThreadInformation(thread_handle, ::ThreadMemoryPriority,
&memory_priority, sizeof(memory_priority));
DPLOG_IF(ERROR, !memory_priority_success)
<< "Set thread memory priority failed.";
}
if (!g_use_thread_priority_lowest && thread_type == ThreadType::kBackground) {
// In a background process, THREAD_MODE_BACKGROUND_BEGIN lowers the memory
// and I/O priorities but not the CPU priority (kernel bug?). Use
// THREAD_PRIORITY_LOWEST to also lower the CPU priority.
// https://crbug.com/901483
if (PlatformThread::GetCurrentThreadPriorityForTest() !=
ThreadPriorityForTest::kBackground) {
::SetThreadPriority(thread_handle, THREAD_PRIORITY_LOWEST);
// We used to DCHECK that memory priority is MEMORY_PRIORITY_VERY_LOW
// here, but found that it is not always the case (e.g. in the installer).
// crbug.com/1340578#c2
}
}
}
void SetCurrentThreadQualityOfService(ThreadType thread_type) {
// QoS and power throttling were introduced in Win10 1709.
bool desire_ecoqos = false;
switch (thread_type) {
case ThreadType::kBackground:
case ThreadType::kUtility:
case ThreadType::kResourceEfficient:
desire_ecoqos = true;
break;
case ThreadType::kDefault:
case ThreadType::kDisplayCritical:
case ThreadType::kRealtimeAudio:
desire_ecoqos = false;
break;
}
THREAD_POWER_THROTTLING_STATE thread_power_throttling_state{
.Version = THREAD_POWER_THROTTLING_CURRENT_VERSION,
.ControlMask =
desire_ecoqos ? THREAD_POWER_THROTTLING_EXECUTION_SPEED : 0ul,
.StateMask =
desire_ecoqos ? THREAD_POWER_THROTTLING_EXECUTION_SPEED : 0ul,
};
[[maybe_unused]] const BOOL success = ::SetThreadInformation(
::GetCurrentThread(), ::ThreadPowerThrottling,
&thread_power_throttling_state, sizeof(thread_power_throttling_state));
// Failure is expected on versions of Windows prior to RS3.
DPLOG_IF(ERROR, !success && win::GetVersion() >= win::Version::WIN10_RS3)
<< "Failed to set EcoQoS to " << std::boolalpha << desire_ecoqos;
}
} // namespace
namespace internal {
void SetCurrentThreadTypeImpl(ThreadType thread_type,
MessagePumpType pump_type_hint) {
SetCurrentThreadPriority(thread_type, pump_type_hint);
SetCurrentThreadQualityOfService(thread_type);
}
} // namespace internal
// static
ThreadPriorityForTest PlatformThread::GetCurrentThreadPriorityForTest() {
static_assert(
THREAD_PRIORITY_IDLE < 0,
"THREAD_PRIORITY_IDLE is >= 0 and will incorrectly cause errors.");
static_assert(
THREAD_PRIORITY_LOWEST < 0,
"THREAD_PRIORITY_LOWEST is >= 0 and will incorrectly cause errors.");
static_assert(THREAD_PRIORITY_BELOW_NORMAL < 0,
"THREAD_PRIORITY_BELOW_NORMAL is >= 0 and will incorrectly "
"cause errors.");
static_assert(
THREAD_PRIORITY_NORMAL == 0,
"The logic below assumes that THREAD_PRIORITY_NORMAL is zero. If it is "
"not, ThreadPriorityForTest::kBackground may be incorrectly detected.");
static_assert(THREAD_PRIORITY_ABOVE_NORMAL >= 0,
"THREAD_PRIORITY_ABOVE_NORMAL is < 0 and will incorrectly be "
"translated to ThreadPriorityForTest::kBackground.");
static_assert(THREAD_PRIORITY_HIGHEST >= 0,
"THREAD_PRIORITY_HIGHEST is < 0 and will incorrectly be "
"translated to ThreadPriorityForTest::kBackground.");
static_assert(THREAD_PRIORITY_TIME_CRITICAL >= 0,
"THREAD_PRIORITY_TIME_CRITICAL is < 0 and will incorrectly be "
"translated to ThreadPriorityForTest::kBackground.");
static_assert(THREAD_PRIORITY_ERROR_RETURN >= 0,
"THREAD_PRIORITY_ERROR_RETURN is < 0 and will incorrectly be "
"translated to ThreadPriorityForTest::kBackground.");
const int priority =
::GetThreadPriority(PlatformThread::CurrentHandle().platform_handle());
// Negative values represent a background priority. We have observed -3, -4,
// -6 when THREAD_MODE_BACKGROUND_* is used. THREAD_PRIORITY_IDLE,
// THREAD_PRIORITY_LOWEST and THREAD_PRIORITY_BELOW_NORMAL are other possible
// negative values.
if (priority < THREAD_PRIORITY_BELOW_NORMAL)
return ThreadPriorityForTest::kBackground;
switch (priority) {
case THREAD_PRIORITY_BELOW_NORMAL:
return ThreadPriorityForTest::kUtility;
case THREAD_PRIORITY_NORMAL:
return ThreadPriorityForTest::kNormal;
case kWinDisplayPriority1:
[[fallthrough]];
case kWinDisplayPriority2:
return ThreadPriorityForTest::kDisplay;
case THREAD_PRIORITY_ABOVE_NORMAL:
case THREAD_PRIORITY_HIGHEST:
return ThreadPriorityForTest::kDisplay;
case THREAD_PRIORITY_TIME_CRITICAL:
return ThreadPriorityForTest::kRealtimeAudio;
case THREAD_PRIORITY_ERROR_RETURN:
DPCHECK(false) << "::GetThreadPriority error";
}
NOTREACHED() << "::GetThreadPriority returned " << priority << ".";
}
void InitializePlatformThreadFeatures() {
g_use_thread_priority_lowest.store(
FeatureList::IsEnabled(kUseThreadPriorityLowest),
std::memory_order_relaxed);
g_above_normal_compositing_browser.store(
FeatureList::IsEnabled(kAboveNormalCompositingBrowserWin),
std::memory_order_relaxed);
}
// static
size_t PlatformThread::GetDefaultThreadStackSize() {
return 0;
}
} // namespace base
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