diff options
Diffstat (limited to 'cddl/usr.sbin/zfsd/callout.cc')
| -rw-r--r-- | cddl/usr.sbin/zfsd/callout.cc | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/cddl/usr.sbin/zfsd/callout.cc b/cddl/usr.sbin/zfsd/callout.cc new file mode 100644 index 000000000000..c141e6550f41 --- /dev/null +++ b/cddl/usr.sbin/zfsd/callout.cc @@ -0,0 +1,218 @@ +/*- + * Copyright (c) 2011, 2012, 2013 Spectra Logic Corporation + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions, and the following disclaimer, + * without modification. + * 2. Redistributions in binary form must reproduce at minimum a disclaimer + * substantially similar to the "NO WARRANTY" disclaimer below + * ("Disclaimer") and any redistribution must be conditioned upon + * including a substantially similar Disclaimer requirement for further + * binary redistribution. + * + * NO WARRANTY + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING + * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGES. + * + * Authors: Justin T. Gibbs (Spectra Logic Corporation) + */ + +/** + * \file callout.cc + * + * \brief Implementation of the Callout class - multi-client + * timer services built on top of the POSIX interval timer. + */ + +#include <sys/byteorder.h> +#include <sys/time.h> + +#include <signal.h> +#include <syslog.h> + +#include <climits> +#include <list> +#include <map> +#include <string> + +#include <devdctl/guid.h> +#include <devdctl/event.h> +#include <devdctl/event_factory.h> +#include <devdctl/consumer.h> +#include <devdctl/exception.h> + +#include "callout.h" +#include "vdev_iterator.h" +#include "zfsd.h" +#include "zfsd_exception.h" + +std::list<Callout *> Callout::s_activeCallouts; +bool Callout::s_alarmFired(false); + +void +Callout::Init() +{ + signal(SIGALRM, Callout::AlarmSignalHandler); +} + +bool +Callout::Stop() +{ + if (!IsPending()) + return (false); + + for (std::list<Callout *>::iterator it(s_activeCallouts.begin()); + it != s_activeCallouts.end(); it++) { + if (*it != this) + continue; + + it = s_activeCallouts.erase(it); + if (it != s_activeCallouts.end()) { + + /* + * Maintain correct interval for the + * callouts that follow the just removed + * entry. + */ + timeradd(&(*it)->m_interval, &m_interval, + &(*it)->m_interval); + } + break; + } + m_pending = false; + return (true); +} + +bool +Callout::Reset(const timeval &interval, CalloutFunc_t *func, void *arg) +{ + bool cancelled(false); + + if (!timerisset(&interval)) + throw ZfsdException("Callout::Reset: interval of 0"); + + cancelled = Stop(); + + m_interval = interval; + m_func = func; + m_arg = arg; + m_pending = true; + + std::list<Callout *>::iterator it(s_activeCallouts.begin()); + for (; it != s_activeCallouts.end(); it++) { + + if (timercmp(&(*it)->m_interval, &m_interval, <=)) { + /* + * Decrease our interval by those that come + * before us. + */ + timersub(&m_interval, &(*it)->m_interval, &m_interval); + } else { + /* + * Account for the time between the newly + * inserted event and those that follow. + */ + timersub(&(*it)->m_interval, &m_interval, + &(*it)->m_interval); + break; + } + } + s_activeCallouts.insert(it, this); + + + if (s_activeCallouts.front() == this) { + itimerval timerval = { {0, 0}, m_interval }; + + setitimer(ITIMER_REAL, &timerval, NULL); + } + + return (cancelled); +} + +void +Callout::AlarmSignalHandler(int) +{ + s_alarmFired = true; + ZfsDaemon::WakeEventLoop(); +} + +void +Callout::ExpireCallouts() +{ + if (!s_alarmFired) + return; + + s_alarmFired = false; + if (s_activeCallouts.empty()) { + /* Callout removal/SIGALRM race was lost. */ + return; + } + + /* + * Expire the first callout (the one we used to set the + * interval timer) as well as any callouts following that + * expire at the same time (have a zero interval from + * the callout before it). + */ + do { + Callout *cur(s_activeCallouts.front()); + s_activeCallouts.pop_front(); + cur->m_pending = false; + cur->m_func(cur->m_arg); + } while (!s_activeCallouts.empty() + && timerisset(&s_activeCallouts.front()->m_interval) == 0); + + if (!s_activeCallouts.empty()) { + Callout *next(s_activeCallouts.front()); + itimerval timerval = { { 0, 0 }, next->m_interval }; + + setitimer(ITIMER_REAL, &timerval, NULL); + } +} + +timeval +Callout::TimeRemaining() const +{ + /* + * Outline: Add the m_interval for each callout in s_activeCallouts + * ahead of this, except for the first callout. Add to that the result + * of getitimer (That's because the first callout stores its original + * interval setting while the timer is ticking). + */ + itimerval timervalToAlarm; + timeval timeToExpiry; + std::list<Callout *>::iterator it; + + if (!IsPending()) { + timeToExpiry.tv_sec = INT_MAX; + timeToExpiry.tv_usec = 999999; /*maximum normalized value*/ + return (timeToExpiry); + } + + timerclear(&timeToExpiry); + getitimer(ITIMER_REAL, &timervalToAlarm); + timeval& timeToAlarm = timervalToAlarm.it_value; + timeradd(&timeToExpiry, &timeToAlarm, &timeToExpiry); + + it =s_activeCallouts.begin(); + it++; /*skip the first callout in the list*/ + for (; it != s_activeCallouts.end(); it++) { + timeradd(&timeToExpiry, &(*it)->m_interval, &timeToExpiry); + if ((*it) == this) + break; + } + return (timeToExpiry); +} |