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Fix socket timeout logic.

master
Fedor 2020-12-23 03:02:42 +02:00
parent 1ae9412488
commit 21483a0ace
2 changed files with 121 additions and 67 deletions
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155
netwerk/base/nsSocketTransportService2.cpp
View File

@ -1,4 +1,3 @@
// vim:set sw=4 sts=4 et cin:
/* 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/. */
@ -52,6 +51,51 @@ Atomic<PRThread*, Relaxed> gSocketThread;
uint32_t nsSocketTransportService::gMaxCount;
PRCallOnceType nsSocketTransportService::gMaxCountInitOnce;
//-----------------------------------------------------------------------------
bool
nsSocketTransportService::SocketContext::IsTimedOut(PRIntervalTime now) const
{
return TimeoutIn(now) == 0;
}
void
nsSocketTransportService::SocketContext::StartTimeout(PRIntervalTime now)
{
if (!mPollStartEpoch) {
mPollStartEpoch = now;
}
}
void
nsSocketTransportService::SocketContext::StopTimeout()
{
mPollStartEpoch = 0;
}
void
nsSocketTransportService::SocketContext::ResetTimeout()
{
if (mPollStartEpoch && mHandler->mPollTimeout == UINT16_MAX) {
mPollStartEpoch = 0;
}
}
PRIntervalTime
nsSocketTransportService::SocketContext::TimeoutIn(PRIntervalTime now) const
{
if (mHandler->mPollTimeout == UINT16_MAX || !mPollStartEpoch) {
return NS_SOCKET_POLL_TIMEOUT;
}
PRIntervalTime elapsed = (now - mPollStartEpoch);
PRIntervalTime timeout = PR_SecondsToInterval(mHandler->mPollTimeout);
if (elapsed >= timeout) {
return 0;
}
return timeout - elapsed;
}
//-----------------------------------------------------------------------------
// ctor/dtor (called on the main/UI thread by the service manager)
@ -189,7 +233,7 @@ nsSocketTransportService::AttachSocket(PRFileDesc *fd, nsASocketHandler *handler
SocketContext sock;
sock.mFD = fd;
sock.mHandler = handler;
sock.mElapsedTime = 0;
sock.mPollStartEpoch = 0;
nsresult rv = AddToIdleList(&sock);
if (NS_SUCCEEDED(rv))
@ -275,6 +319,8 @@ nsSocketTransportService::AddToPollList(SocketContext *sock)
PodMove(mPollList + newSocketIndex + 2, mPollList + newSocketIndex + 1,
mActiveCount - newSocketIndex);
}
sock->StartTimeout(PR_IntervalNow());
mActiveList[newSocketIndex] = *sock;
mActiveCount++;
@ -399,34 +445,32 @@ nsSocketTransportService::GrowIdleList()
}
PRIntervalTime
nsSocketTransportService::PollTimeout()
nsSocketTransportService::PollTimeout(PRIntervalTime now)
{
if (mActiveCount == 0)
if (mActiveCount == 0) {
return NS_SOCKET_POLL_TIMEOUT;
}
// compute minimum time before any socket timeout expires.
uint32_t minR = UINT16_MAX;
PRIntervalTime minR = NS_SOCKET_POLL_TIMEOUT;
for (uint32_t i=0; i<mActiveCount; ++i) {
const SocketContext &s = mActiveList[i];
// mPollTimeout could be less than mElapsedTime if setTimeout
// was called with a value smaller than mElapsedTime.
uint32_t r = (s.mElapsedTime < s.mHandler->mPollTimeout)
? s.mHandler->mPollTimeout - s.mElapsedTime
: 0;
if (r < minR)
PRIntervalTime r = s.TimeoutIn(now);
if (r < minR) {
minR = r;
}
}
// nsASocketHandler defines UINT16_MAX as do not timeout
if (minR == UINT16_MAX) {
if (minR == NS_SOCKET_POLL_TIMEOUT) {
SOCKET_LOG(("poll timeout: none\n"));
return NS_SOCKET_POLL_TIMEOUT;
}
SOCKET_LOG(("poll timeout: %lu\n", minR));
return PR_SecondsToInterval(minR);
SOCKET_LOG(("poll timeout: %lu seconds\n", PR_IntervalToSeconds(minR)));
return minR;
}
int32_t
nsSocketTransportService::Poll(uint32_t *interval)
nsSocketTransportService::Poll(PRIntervalTime ts)
{
PRPollDesc *pollList;
uint32_t pollCount;
@ -436,12 +480,12 @@ nsSocketTransportService::Poll(uint32_t *interval)
// DoPollIteration() should service the network without blocking.
bool pendingEvents = false;
mRawThread->HasPendingEvents(&pendingEvents);
if (mPollList[0].fd) {
mPollList[0].out_flags = 0;
pollList = mPollList;
pollCount = mActiveCount + 1;
pollTimeout = pendingEvents ? PR_INTERVAL_NO_WAIT : PollTimeout();
pollTimeout = pendingEvents ? PR_INTERVAL_NO_WAIT : PollTimeout(ts);
}
else {
// no pollable event, so busy wait...
@ -454,18 +498,14 @@ nsSocketTransportService::Poll(uint32_t *interval)
pendingEvents ? PR_INTERVAL_NO_WAIT : PR_MillisecondsToInterval(25);
}
PRIntervalTime ts = PR_IntervalNow();
SOCKET_LOG((" timeout = %i milliseconds\n",
PR_IntervalToMilliseconds(pollTimeout)));
int32_t rv = PR_Poll(pollList, pollCount, pollTimeout);
PRIntervalTime passedInterval = PR_IntervalNow() - ts;
SOCKET_LOG((" ...returned after %i milliseconds\n",
PR_IntervalToMilliseconds(passedInterval)));
PR_IntervalToMilliseconds(PR_IntervalNow() - ts)));
*interval = PR_IntervalToSeconds(passedInterval);
return rv;
}
@ -811,13 +851,8 @@ nsSocketTransportService::Run()
// make sure the pseudo random number generator is seeded on this thread
srand(static_cast<unsigned>(PR_Now()));
int numberOfPendingEvents;
// If there is too many pending events queued, we will run some poll()
// between them.
for (;;) {
bool pendingEvents = false;
numberOfPendingEvents = 0;
do {
DoPollIteration();
@ -838,7 +873,6 @@ nsSocketTransportService::Run()
TimeStamp eventQueueStart = TimeStamp::NowLoRes();
do {
NS_ProcessNextEvent(mRawThread);
numberOfPendingEvents++;
pendingEvents = false;
mRawThread->HasPendingEvents(&pendingEvents);
} while (pendingEvents && mServingPendingQueue &&
@ -915,6 +949,9 @@ nsSocketTransportService::DoPollIteration()
{
SOCKET_LOG(("STS poll iter\n"));
// Freeze "now" for list updates and polling.
PRIntervalTime now = PR_IntervalNow();
int32_t i, count;
//
// poll loop
@ -932,16 +969,18 @@ nsSocketTransportService::DoPollIteration()
mActiveList[i].mHandler->mCondition,
mActiveList[i].mHandler->mPollFlags));
//---
if (NS_FAILED(mActiveList[i].mHandler->mCondition))
if (NS_FAILED(mActiveList[i].mHandler->mCondition)) {
DetachSocket(mActiveList, &mActiveList[i]);
else {
} else {
uint16_t in_flags = mActiveList[i].mHandler->mPollFlags;
if (in_flags == 0)
if (in_flags == 0) {
MoveToIdleList(&mActiveList[i]);
else {
} else {
// update poll flags
mPollList[i+1].in_flags = in_flags;
mPollList[i+1].out_flags = 0;
// Active polling entry; start timeout.
mActiveList[i].StartTimeout(now);
}
}
}
@ -952,10 +991,11 @@ nsSocketTransportService::DoPollIteration()
mIdleList[i].mHandler->mCondition,
mIdleList[i].mHandler->mPollFlags));
//---
if (NS_FAILED(mIdleList[i].mHandler->mCondition))
if (NS_FAILED(mIdleList[i].mHandler->mCondition)) {
DetachSocket(mIdleList, &mIdleList[i]);
else if (mIdleList[i].mHandler->mPollFlags != 0)
} else if (mIdleList[i].mHandler->mPollFlags != 0) {
MoveToPollList(&mIdleList[i]);
}
}
SOCKET_LOG((" calling PR_Poll [active=%u idle=%u]\n", mActiveCount, mIdleCount));
@ -969,55 +1009,44 @@ nsSocketTransportService::DoPollIteration()
#endif
// Measures seconds spent while blocked on PR_Poll
uint32_t pollInterval = 0;
int32_t n = 0;
if (!gIOService->IsNetTearingDown()) {
// Let's not do polling during shutdown.
#if defined(XP_WIN)
StartPolling();
#endif
n = Poll(&pollInterval);
n = Poll(now);
#if defined(XP_WIN)
EndPolling();
#endif
}
// Refresh when "now" is for following checks.
now = PR_IntervalNow();
if (n < 0) {
SOCKET_LOG((" PR_Poll error [%d] os error [%d]\n", PR_GetError(),
PR_GetOSError()));
}
else {
} else {
//
// service "active" sockets...
//
uint32_t numberOfOnSocketReadyCalls = 0;
for (i=0; i<int32_t(mActiveCount); ++i) {
PRPollDesc &desc = mPollList[i+1];
SocketContext &s = mActiveList[i];
if (n > 0 && desc.out_flags != 0) {
s.mElapsedTime = 0;
s.StopTimeout();
s.mHandler->OnSocketReady(desc.fd, desc.out_flags);
numberOfOnSocketReadyCalls++;
}
// check for timeout errors unless disabled...
else if (s.mHandler->mPollTimeout != UINT16_MAX) {
// update elapsed time counter
// (NOTE: We explicitly cast UINT16_MAX to be an unsigned value
// here -- otherwise, some compilers will treat it as signed,
// which makes them fire signed/unsigned-comparison build
// warnings for the comparison against 'pollInterval'.)
if (MOZ_UNLIKELY(pollInterval >
static_cast<uint32_t>(UINT16_MAX) -
s.mElapsedTime))
s.mElapsedTime = UINT16_MAX;
else
s.mElapsedTime += uint16_t(pollInterval);
// check for timeout expiration
if (s.mElapsedTime >= s.mHandler->mPollTimeout) {
s.mElapsedTime = 0;
s.mHandler->OnSocketReady(desc.fd, -1);
numberOfOnSocketReadyCalls++;
}
} else if (s.IsTimedOut(now)) {
// Socket timed out; disengage.
s.StopTimeout();
s.mHandler->OnSocketReady(desc.fd, -1);
} else {
// We may have recorded a timeout start on a socket and subsequently
// set it to not time out. Check the socket and reset the timestamp
// in this case to keep our states predictable.
s.ResetTimeout();
}
}

33
netwerk/base/nsSocketTransportService2.h
View File

@ -19,7 +19,6 @@
#include "mozilla/Mutex.h"
#include "mozilla/net/DashboardTypes.h"
#include "mozilla/Atomics.h"
#include "mozilla/TimeStamp.h"
#include "nsITimer.h"
#include "mozilla/UniquePtr.h"
#include "PollableEvent.h"
@ -167,7 +166,33 @@ private:
{
PRFileDesc *mFD;
nsASocketHandler *mHandler;
uint16_t mElapsedTime; // time elapsed w/o activity
PRIntervalTime mPollStartEpoch; // Epoch timestamp when we started to poll this socket
public:
// Helper functions implementing a timeout mechanism.
// Returns true if the socket has not been signalled in more than the desired
// timeout for this socket (mHandler->mPollTimeout).
bool IsTimedOut(PRIntervalTime now) const;
// Records the epoch timestamp we started polling this socket. If the epoch is already
// recorded, then it does nothing (i.e. does not re-arm) so it's safe to call whenever
// this socket is put into the active polling list.
void StartTimeout(PRIntervalTime now);
// Turns off the timout calculation.
void StopTimeout();
// Returns the number of intervals from "now" after which this socket will timeout,
// or 0 (zero) when it has already timed out. Returns NS_SOCKET_POLL_TIMEOUT
// when there is no timeout set on the socket.
PRIntervalTime TimeoutIn(PRIntervalTime now) const;
// When a socket timeout is set to not time out and later set again to time out, it
// is possible that mPollStartEpoch is not reset in-between. We have to manually
// call this on every iteration over sockets to ensure the epoch timestamp is reset
// and our socket bookkeeping remains accurate.
void ResetTimeout();
};
SocketContext *mActiveList; /* mListSize entries */
@ -203,10 +228,10 @@ private:
PRPollDesc *mPollList; /* mListSize + 1 entries */
PRIntervalTime PollTimeout(); // computes ideal poll timeout
PRIntervalTime PollTimeout(PRIntervalTime now); // computes ideal poll timeout
nsresult DoPollIteration();
// perfoms a single poll iteration
int32_t Poll(uint32_t *interval);
int32_t Poll(PRIntervalTime now);
// calls PR_Poll. the out param
// interval indicates the poll
// duration in seconds.