220 lines
5.5 KiB
C++
220 lines
5.5 KiB
C++
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/*-
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* Copyright (c) 2011, 2012, 2013 Spectra Logic Corporation
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions, and the following disclaimer,
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* without modification.
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* 2. Redistributions in binary form must reproduce at minimum a disclaimer
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* substantially similar to the "NO WARRANTY" disclaimer below
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* ("Disclaimer") and any redistribution must be conditioned upon
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* including a substantially similar Disclaimer requirement for further
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* binary redistribution.
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*
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* NO WARRANTY
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGES.
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*
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* Authors: Justin T. Gibbs (Spectra Logic Corporation)
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*
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* $FreeBSD$
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*/
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/**
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* \file callout.cc
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*
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* \brief Implementation of the Callout class - multi-client
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* timer services built on top of the POSIX interval timer.
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*/
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#include <sys/time.h>
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#include <signal.h>
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#include <syslog.h>
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#include <climits>
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#include <list>
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#include <map>
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#include <string>
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#include <devdctl/guid.h>
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#include <devdctl/event.h>
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#include <devdctl/event_factory.h>
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#include <devdctl/consumer.h>
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#include <devdctl/exception.h>
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#include "callout.h"
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#include "vdev_iterator.h"
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#include "zfsd.h"
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#include "zfsd_exception.h"
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std::list<Callout *> Callout::s_activeCallouts;
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bool Callout::s_alarmFired(false);
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void
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Callout::Init()
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{
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signal(SIGALRM, Callout::AlarmSignalHandler);
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}
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bool
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Callout::Stop()
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{
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if (!IsPending())
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return (false);
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for (std::list<Callout *>::iterator it(s_activeCallouts.begin());
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it != s_activeCallouts.end(); it++) {
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if (*it != this)
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continue;
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it = s_activeCallouts.erase(it);
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if (it != s_activeCallouts.end()) {
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/*
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* Maintain correct interval for the
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* callouts that follow the just removed
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* entry.
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*/
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timeradd(&(*it)->m_interval, &m_interval,
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&(*it)->m_interval);
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}
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break;
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}
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m_pending = false;
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return (true);
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}
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bool
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Callout::Reset(const timeval &interval, CalloutFunc_t *func, void *arg)
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{
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bool cancelled(false);
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if (!timerisset(&interval))
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throw ZfsdException("Callout::Reset: interval of 0");
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cancelled = Stop();
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m_interval = interval;
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m_func = func;
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m_arg = arg;
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m_pending = true;
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std::list<Callout *>::iterator it(s_activeCallouts.begin());
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for (; it != s_activeCallouts.end(); it++) {
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if (timercmp(&(*it)->m_interval, &m_interval, <=)) {
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/*
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* Decrease our interval by those that come
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* before us.
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*/
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timersub(&m_interval, &(*it)->m_interval, &m_interval);
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} else {
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/*
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* Account for the time between the newly
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* inserted event and those that follow.
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*/
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timersub(&(*it)->m_interval, &m_interval,
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&(*it)->m_interval);
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break;
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}
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}
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s_activeCallouts.insert(it, this);
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if (s_activeCallouts.front() == this) {
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itimerval timerval = { {0, 0}, m_interval };
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setitimer(ITIMER_REAL, &timerval, NULL);
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}
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return (cancelled);
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}
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void
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Callout::AlarmSignalHandler(int)
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{
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s_alarmFired = true;
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ZfsDaemon::WakeEventLoop();
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}
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void
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Callout::ExpireCallouts()
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{
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if (!s_alarmFired)
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return;
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s_alarmFired = false;
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if (s_activeCallouts.empty()) {
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/* Callout removal/SIGALRM race was lost. */
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return;
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}
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/*
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* Expire the first callout (the one we used to set the
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* interval timer) as well as any callouts following that
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* expire at the same time (have a zero interval from
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* the callout before it).
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*/
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do {
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Callout *cur(s_activeCallouts.front());
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s_activeCallouts.pop_front();
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cur->m_pending = false;
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cur->m_func(cur->m_arg);
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} while (!s_activeCallouts.empty()
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&& timerisset(&s_activeCallouts.front()->m_interval) == 0);
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if (!s_activeCallouts.empty()) {
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Callout *next(s_activeCallouts.front());
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itimerval timerval = { { 0, 0 }, next->m_interval };
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setitimer(ITIMER_REAL, &timerval, NULL);
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}
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}
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timeval
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Callout::TimeRemaining() const
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{
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/*
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* Outline: Add the m_interval for each callout in s_activeCallouts
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* ahead of this, except for the first callout. Add to that the result
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* of getitimer (That's because the first callout stores its original
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* interval setting while the timer is ticking).
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*/
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itimerval timervalToAlarm;
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timeval timeToExpiry;
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std::list<Callout *>::iterator it;
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if (!IsPending()) {
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timeToExpiry.tv_sec = INT_MAX;
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timeToExpiry.tv_usec = 999999; /*maximum normalized value*/
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return (timeToExpiry);
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}
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timerclear(&timeToExpiry);
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getitimer(ITIMER_REAL, &timervalToAlarm);
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timeval& timeToAlarm = timervalToAlarm.it_value;
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timeradd(&timeToExpiry, &timeToAlarm, &timeToExpiry);
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it =s_activeCallouts.begin();
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it++; /*skip the first callout in the list*/
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for (; it != s_activeCallouts.end(); it++) {
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timeradd(&timeToExpiry, &(*it)->m_interval, &timeToExpiry);
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if ((*it) == this)
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break;
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}
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return (timeToExpiry);
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}
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