gecko-dev/netwerk/cache2/CacheIOThread.cpp

357 lines
8.7 KiB
C++

/* 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 "CacheIOThread.h"
#include "CacheFileIOManager.h"
#include "nsIRunnable.h"
#include "nsISupportsImpl.h"
#include "nsPrintfCString.h"
#include "nsThreadUtils.h"
#include "mozilla/IOInterposer.h"
#include "mozilla/VisualEventTracer.h"
namespace mozilla {
namespace net {
CacheIOThread* CacheIOThread::sSelf = nullptr;
NS_IMPL_ISUPPORTS(CacheIOThread, nsIThreadObserver)
CacheIOThread::CacheIOThread()
: mMonitor("CacheIOThread")
, mThread(nullptr)
, mLowestLevelWaiting(LAST_LEVEL)
, mCurrentlyExecutingLevel(0)
, mHasXPCOMEvents(false)
, mRerunCurrentEvent(false)
, mShutdown(false)
{
sSelf = this;
}
CacheIOThread::~CacheIOThread()
{
sSelf = nullptr;
#ifdef DEBUG
for (uint32_t level = 0; level < LAST_LEVEL; ++level) {
MOZ_ASSERT(!mEventQueue[level].Length());
}
#endif
}
nsresult CacheIOThread::Init()
{
mThread = PR_CreateThread(PR_USER_THREAD, ThreadFunc, this,
PR_PRIORITY_NORMAL, PR_GLOBAL_THREAD,
PR_JOINABLE_THREAD, 128 * 1024);
if (!mThread)
return NS_ERROR_FAILURE;
return NS_OK;
}
nsresult CacheIOThread::Dispatch(nsIRunnable* aRunnable, uint32_t aLevel)
{
NS_ENSURE_ARG(aLevel < LAST_LEVEL);
// Runnable is always expected to be non-null, hard null-check bellow.
MOZ_ASSERT(aRunnable);
MonitorAutoLock lock(mMonitor);
if (mShutdown && (PR_GetCurrentThread() != mThread))
return NS_ERROR_UNEXPECTED;
return DispatchInternal(aRunnable, aLevel);
}
nsresult CacheIOThread::DispatchAfterPendingOpens(nsIRunnable* aRunnable)
{
// Runnable is always expected to be non-null, hard null-check bellow.
MOZ_ASSERT(aRunnable);
MonitorAutoLock lock(mMonitor);
if (mShutdown && (PR_GetCurrentThread() != mThread))
return NS_ERROR_UNEXPECTED;
// Move everything from later executed OPEN level to the OPEN_PRIORITY level
// where we post the (eviction) runnable.
mEventQueue[OPEN_PRIORITY].AppendElements(mEventQueue[OPEN]);
mEventQueue[OPEN].Clear();
return DispatchInternal(aRunnable, OPEN_PRIORITY);
}
nsresult CacheIOThread::DispatchInternal(nsIRunnable* aRunnable, uint32_t aLevel)
{
if (NS_WARN_IF(!aRunnable))
return NS_ERROR_NULL_POINTER;
mMonitor.AssertCurrentThreadOwns();
mEventQueue[aLevel].AppendElement(aRunnable);
if (mLowestLevelWaiting > aLevel)
mLowestLevelWaiting = aLevel;
mMonitor.NotifyAll();
return NS_OK;
}
bool CacheIOThread::IsCurrentThread()
{
return mThread == PR_GetCurrentThread();
}
bool CacheIOThread::YieldInternal()
{
if (!IsCurrentThread()) {
NS_WARNING("Trying to yield to priority events on non-cache2 I/O thread? "
"You probably do something wrong.");
return false;
}
if (mCurrentlyExecutingLevel == XPCOM_LEVEL) {
// Doesn't make any sense, since this handler is the one
// that would be executed as the next one.
return false;
}
if (!EventsPending(mCurrentlyExecutingLevel))
return false;
mRerunCurrentEvent = true;
return true;
}
nsresult CacheIOThread::Shutdown()
{
{
MonitorAutoLock lock(mMonitor);
mShutdown = true;
mMonitor.NotifyAll();
}
PR_JoinThread(mThread);
mThread = nullptr;
return NS_OK;
}
already_AddRefed<nsIEventTarget> CacheIOThread::Target()
{
nsCOMPtr<nsIEventTarget> target;
target = mXPCOMThread;
if (!target && mThread)
{
MonitorAutoLock lock(mMonitor);
if (!mXPCOMThread)
lock.Wait();
target = mXPCOMThread;
}
return target.forget();
}
// static
void CacheIOThread::ThreadFunc(void* aClosure)
{
PR_SetCurrentThreadName("Cache2 I/O");
mozilla::IOInterposer::RegisterCurrentThread();
CacheIOThread* thread = static_cast<CacheIOThread*>(aClosure);
thread->ThreadFunc();
mozilla::IOInterposer::UnregisterCurrentThread();
}
void CacheIOThread::ThreadFunc()
{
nsCOMPtr<nsIThreadInternal> threadInternal;
{
MonitorAutoLock lock(mMonitor);
// This creates nsThread for this PRThread
nsCOMPtr<nsIThread> xpcomThread = NS_GetCurrentThread();
threadInternal = do_QueryInterface(xpcomThread);
if (threadInternal)
threadInternal->SetObserver(this);
mXPCOMThread.swap(xpcomThread);
lock.NotifyAll();
do {
loopStart:
// Reset the lowest level now, so that we can detect a new event on
// a lower level (i.e. higher priority) has been scheduled while
// executing any previously scheduled event.
mLowestLevelWaiting = LAST_LEVEL;
// Process xpcom events first
while (mHasXPCOMEvents) {
eventtracer::AutoEventTracer tracer(this, eventtracer::eExec, eventtracer::eDone,
"net::cache::io::level(xpcom)");
mHasXPCOMEvents = false;
mCurrentlyExecutingLevel = XPCOM_LEVEL;
MonitorAutoUnlock unlock(mMonitor);
bool processedEvent;
nsresult rv;
do {
rv = mXPCOMThread->ProcessNextEvent(false, &processedEvent);
} while (NS_SUCCEEDED(rv) && processedEvent);
}
uint32_t level;
for (level = 0; level < LAST_LEVEL; ++level) {
if (!mEventQueue[level].Length()) {
// no events on this level, go to the next level
continue;
}
LoopOneLevel(level);
// Go to the first (lowest) level again
goto loopStart;
}
if (EventsPending())
continue;
if (mShutdown)
break;
lock.Wait(PR_INTERVAL_NO_TIMEOUT);
if (EventsPending())
continue;
} while (true);
MOZ_ASSERT(!EventsPending());
} // lock
if (threadInternal)
threadInternal->SetObserver(nullptr);
}
static const char* const sLevelTraceName[] = {
"net::cache::io::level(0)",
"net::cache::io::level(1)",
"net::cache::io::level(2)",
"net::cache::io::level(3)",
"net::cache::io::level(4)",
"net::cache::io::level(5)",
"net::cache::io::level(6)",
"net::cache::io::level(7)",
"net::cache::io::level(8)",
"net::cache::io::level(9)",
"net::cache::io::level(10)",
"net::cache::io::level(11)",
"net::cache::io::level(12)"
};
void CacheIOThread::LoopOneLevel(uint32_t aLevel)
{
eventtracer::AutoEventTracer tracer(this, eventtracer::eExec, eventtracer::eDone,
sLevelTraceName[aLevel]);
nsTArray<nsRefPtr<nsIRunnable> > events;
events.SwapElements(mEventQueue[aLevel]);
uint32_t length = events.Length();
mCurrentlyExecutingLevel = aLevel;
bool returnEvents = false;
uint32_t index;
{
MonitorAutoUnlock unlock(mMonitor);
for (index = 0; index < length; ++index) {
if (EventsPending(aLevel)) {
// Somebody scheduled a new event on a lower level, break and harry
// to execute it! Don't forget to return what we haven't exec.
returnEvents = true;
break;
}
// Drop any previous flagging, only an event on the current level may set
// this flag.
mRerunCurrentEvent = false;
events[index]->Run();
if (mRerunCurrentEvent) {
// The event handler yields to higher priority events and wants to rerun.
returnEvents = true;
break;
}
// Release outside the lock.
events[index] = nullptr;
}
}
if (returnEvents)
mEventQueue[aLevel].InsertElementsAt(0, events.Elements() + index, length - index);
}
bool CacheIOThread::EventsPending(uint32_t aLastLevel)
{
return mLowestLevelWaiting < aLastLevel || mHasXPCOMEvents;
}
NS_IMETHODIMP CacheIOThread::OnDispatchedEvent(nsIThreadInternal *thread)
{
MonitorAutoLock lock(mMonitor);
mHasXPCOMEvents = true;
MOZ_ASSERT(!mShutdown || (PR_GetCurrentThread() == mThread));
lock.Notify();
return NS_OK;
}
NS_IMETHODIMP CacheIOThread::OnProcessNextEvent(nsIThreadInternal *thread, bool mayWait, uint32_t recursionDepth)
{
return NS_OK;
}
NS_IMETHODIMP CacheIOThread::AfterProcessNextEvent(nsIThreadInternal *thread, uint32_t recursionDepth,
bool eventWasProcessed)
{
return NS_OK;
}
// Memory reporting
size_t CacheIOThread::SizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const
{
MonitorAutoLock lock(const_cast<CacheIOThread*>(this)->mMonitor);
size_t n = 0;
n += mallocSizeOf(mThread);
for (uint32_t level = 0; level < LAST_LEVEL; ++level) {
n += mEventQueue[level].SizeOfExcludingThis(mallocSizeOf);
// Events referenced by the queues are arbitrary objects we cannot be sure
// are reported elsewhere as well as probably not implementing nsISizeOf
// interface. Deliberatly omitting them from reporting here.
}
return n;
}
size_t CacheIOThread::SizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const
{
return mallocSizeOf(this) + SizeOfExcludingThis(mallocSizeOf);
}
} // net
} // mozilla