1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
|
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "mozilla/mscom/MainThreadInvoker.h"
#include "GeckoProfiler.h"
#include "MainThreadUtils.h"
#include "mozilla/Assertions.h"
#include "mozilla/Atomics.h"
#include "mozilla/ClearOnShutdown.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/HangMonitor.h"
#include "mozilla/RefPtr.h"
#include "nsServiceManagerUtils.h"
#include "nsSystemInfo.h"
#include "private/prpriv.h" // For PR_GetThreadID
#include "WinUtils.h"
// This gives us compiler intrinsics for the x86 PAUSE instruction
#if defined(_MSC_VER)
#include <intrin.h>
#pragma intrinsic(_mm_pause)
#define CPU_PAUSE() _mm_pause()
#elif defined(__GNUC__) || defined(__clang__)
#define CPU_PAUSE() __builtin_ia32_pause()
#endif
static bool sIsMulticore;
namespace {
/**
* SyncRunnable implements different code paths depending on whether or not
* we are running on a multiprocessor system. In the multiprocessor case, we
* leave the thread in a spin loop while waiting for the main thread to execute
* our runnable. Since spinning is pointless in the uniprocessor case, we block
* on an event that is set by the main thread once it has finished the runnable.
*/
class MOZ_RAII SyncRunnable
{
public:
explicit SyncRunnable(already_AddRefed<nsIRunnable>&& aRunnable)
: mDoneEvent(sIsMulticore ? nullptr :
::CreateEventW(nullptr, FALSE, FALSE, nullptr))
, mDone(false)
, mRunnable(aRunnable)
{
MOZ_ASSERT(sIsMulticore || mDoneEvent);
MOZ_ASSERT(mRunnable);
}
~SyncRunnable()
{
if (mDoneEvent) {
::CloseHandle(mDoneEvent);
}
}
void Run()
{
mRunnable->Run();
if (mDoneEvent) {
::SetEvent(mDoneEvent);
} else {
mDone = true;
}
}
bool WaitUntilComplete()
{
if (mDoneEvent) {
HANDLE handles[] = {mDoneEvent,
mozilla::mscom::MainThreadInvoker::GetTargetThread()};
DWORD waitResult = ::WaitForMultipleObjects(mozilla::ArrayLength(handles),
handles, FALSE, INFINITE);
return waitResult == WAIT_OBJECT_0;
}
while (!mDone) {
// The PAUSE instruction is a hint to the CPU that we're doing a spin
// loop. It is a no-op on older processors that don't support it, so
// it is safe to use here without any CPUID checks.
CPU_PAUSE();
}
return true;
}
private:
HANDLE mDoneEvent;
mozilla::Atomic<bool> mDone;
nsCOMPtr<nsIRunnable> mRunnable;
};
} // anonymous namespace
namespace mozilla {
namespace mscom {
HANDLE MainThreadInvoker::sMainThread = nullptr;
/* static */ bool
MainThreadInvoker::InitStatics()
{
nsCOMPtr<nsIThread> mainThread;
nsresult rv = ::NS_GetMainThread(getter_AddRefs(mainThread));
if (NS_FAILED(rv)) {
return false;
}
PRThread* mainPrThread = nullptr;
rv = mainThread->GetPRThread(&mainPrThread);
if (NS_FAILED(rv)) {
return false;
}
PRUint32 tid = ::PR_GetThreadID(mainPrThread);
sMainThread = ::OpenThread(SYNCHRONIZE | THREAD_SET_CONTEXT, FALSE, tid);
nsCOMPtr<nsIPropertyBag2> infoService = do_GetService(NS_SYSTEMINFO_CONTRACTID);
if (infoService) {
uint32_t cpuCount;
nsresult rv = infoService->GetPropertyAsUint32(NS_LITERAL_STRING("cpucount"),
&cpuCount);
sIsMulticore = NS_SUCCEEDED(rv) && cpuCount > 1;
}
return !!sMainThread;
}
MainThreadInvoker::MainThreadInvoker()
{
static const bool gotStatics = InitStatics();
MOZ_ASSERT(gotStatics);
}
bool
MainThreadInvoker::Invoke(already_AddRefed<nsIRunnable>&& aRunnable)
{
nsCOMPtr<nsIRunnable> runnable(Move(aRunnable));
if (!runnable) {
return false;
}
if (NS_IsMainThread()) {
runnable->Run();
return true;
}
SyncRunnable syncRunnable(runnable.forget());
if (!::QueueUserAPC(&MainThreadAPC, sMainThread,
reinterpret_cast<UINT_PTR>(&syncRunnable))) {
return false;
}
// We should ensure a call to NtTestAlert() is made on the main thread so
// that the main thread will check for APCs during event processing. If we
// omit this then the main thread will not check its APC queue until it is
// idle.
widget::WinUtils::SetAPCPending();
return syncRunnable.WaitUntilComplete();
}
/* static */ VOID CALLBACK
MainThreadInvoker::MainThreadAPC(ULONG_PTR aParam)
{
GeckoProfilerWakeRAII wakeProfiler;
mozilla::HangMonitor::NotifyActivity(mozilla::HangMonitor::kGeneralActivity);
MOZ_ASSERT(NS_IsMainThread());
auto runnable = reinterpret_cast<SyncRunnable*>(aParam);
runnable->Run();
}
} // namespace mscom
} // namespace mozilla
|
