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author | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2015-03-24 10:08:40 +0100 |
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committer | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2015-03-24 15:20:56 +0100 |
commit | f661c797324df9783fa7f747c06bc674176d2940 (patch) | |
tree | 9992916132e28c5017faa9c7c8da071e47f4ecef | |
parent | Update due to Newlib <sys/time.h> etc. changes (diff) | |
download | rtems-libbsd-f661c797324df9783fa7f747c06bc674176d2940.tar.bz2 |
SLEEP(9): Import from FreeBSD
-rw-r--r-- | freebsd/sys/kern/kern_synch.c | 625 |
1 files changed, 625 insertions, 0 deletions
diff --git a/freebsd/sys/kern/kern_synch.c b/freebsd/sys/kern/kern_synch.c new file mode 100644 index 00000000..6ee12097 --- /dev/null +++ b/freebsd/sys/kern/kern_synch.c @@ -0,0 +1,625 @@ +#include <machine/rtems-bsd-kernel-space.h> + +/*- + * Copyright (c) 1982, 1986, 1990, 1991, 1993 + * The Regents of the University of California. All rights reserved. + * (c) UNIX System Laboratories, Inc. + * All or some portions of this file are derived from material licensed + * to the University of California by American Telephone and Telegraph + * Co. or Unix System Laboratories, Inc. and are reproduced herein with + * the permission of UNIX System Laboratories, Inc. + * + * 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. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, 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 DAMAGE. + * + * @(#)kern_synch.c 8.9 (Berkeley) 5/19/95 + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include <rtems/bsd/local/opt_kdtrace.h> +#include <rtems/bsd/local/opt_ktrace.h> +#include <rtems/bsd/local/opt_sched.h> + +#include <rtems/bsd/sys/param.h> +#include <sys/systm.h> +#include <sys/condvar.h> +#include <sys/kdb.h> +#include <sys/kernel.h> +#include <sys/ktr.h> +#include <rtems/bsd/sys/lock.h> +#include <sys/mutex.h> +#include <sys/proc.h> +#include <sys/resourcevar.h> +#include <sys/sched.h> +#include <sys/sdt.h> +#include <sys/signalvar.h> +#include <sys/sleepqueue.h> +#include <sys/smp.h> +#include <sys/sx.h> +#include <sys/sysctl.h> +#include <sys/sysproto.h> +#include <sys/vmmeter.h> +#ifdef KTRACE +#include <sys/uio.h> +#include <sys/ktrace.h> +#endif + +#include <machine/cpu.h> + +#ifdef XEN +#include <vm/vm.h> +#include <vm/vm_param.h> +#include <vm/pmap.h> +#endif + +#define KTDSTATE(td) \ + (((td)->td_inhibitors & TDI_SLEEPING) != 0 ? "sleep" : \ + ((td)->td_inhibitors & TDI_SUSPENDED) != 0 ? "suspended" : \ + ((td)->td_inhibitors & TDI_SWAPPED) != 0 ? "swapped" : \ + ((td)->td_inhibitors & TDI_LOCK) != 0 ? "blocked" : \ + ((td)->td_inhibitors & TDI_IWAIT) != 0 ? "iwait" : "yielding") + +static void synch_setup(void *dummy); +SYSINIT(synch_setup, SI_SUB_KICK_SCHEDULER, SI_ORDER_FIRST, synch_setup, + NULL); + +int hogticks; +static int pause_wchan; + +static struct callout loadav_callout; + +struct loadavg averunnable = + { {0, 0, 0}, FSCALE }; /* load average, of runnable procs */ +/* + * Constants for averages over 1, 5, and 15 minutes + * when sampling at 5 second intervals. + */ +static fixpt_t cexp[3] = { + 0.9200444146293232 * FSCALE, /* exp(-1/12) */ + 0.9834714538216174 * FSCALE, /* exp(-1/60) */ + 0.9944598480048967 * FSCALE, /* exp(-1/180) */ +}; + +/* kernel uses `FSCALE', userland (SHOULD) use kern.fscale */ +static int fscale __unused = FSCALE; +SYSCTL_INT(_kern, OID_AUTO, fscale, CTLFLAG_RD, 0, FSCALE, ""); + +static void loadav(void *arg); + +SDT_PROVIDER_DECLARE(sched); +SDT_PROBE_DEFINE(sched, , , preempt); + +/* + * These probes reference Solaris features that are not implemented in FreeBSD. + * Create the probes anyway for compatibility with existing D scripts; they'll + * just never fire. + */ +SDT_PROBE_DEFINE(sched, , , cpucaps__sleep); +SDT_PROBE_DEFINE(sched, , , cpucaps__wakeup); +SDT_PROBE_DEFINE(sched, , , schedctl__nopreempt); +SDT_PROBE_DEFINE(sched, , , schedctl__preempt); +SDT_PROBE_DEFINE(sched, , , schedctl__yield); + +void +sleepinit(void) +{ + + hogticks = (hz / 10) * 2; /* Default only. */ + init_sleepqueues(); +} + +/* + * General sleep call. Suspends the current thread until a wakeup is + * performed on the specified identifier. The thread will then be made + * runnable with the specified priority. Sleeps at most timo/hz seconds + * (0 means no timeout). If pri includes PCATCH flag, signals are checked + * before and after sleeping, else signals are not checked. Returns 0 if + * awakened, EWOULDBLOCK if the timeout expires. If PCATCH is set and a + * signal needs to be delivered, ERESTART is returned if the current system + * call should be restarted if possible, and EINTR is returned if the system + * call should be interrupted by the signal (return EINTR). + * + * The lock argument is unlocked before the caller is suspended, and + * re-locked before _sleep() returns. If priority includes the PDROP + * flag the lock is not re-locked before returning. + */ +int +_sleep(void *ident, struct lock_object *lock, int priority, + const char *wmesg, int timo) +{ + struct thread *td; + struct proc *p; + struct lock_class *class; + int catch, flags, lock_state, pri, rval; + WITNESS_SAVE_DECL(lock_witness); + + td = curthread; + p = td->td_proc; +#ifdef KTRACE + if (KTRPOINT(td, KTR_CSW)) + ktrcsw(1, 0, wmesg); +#endif + WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, lock, + "Sleeping on \"%s\"", wmesg); + KASSERT(timo != 0 || mtx_owned(&Giant) || lock != NULL, + ("sleeping without a lock")); + KASSERT(p != NULL, ("msleep1")); + KASSERT(ident != NULL && TD_IS_RUNNING(td), ("msleep")); + if (priority & PDROP) + KASSERT(lock != NULL && lock != &Giant.lock_object, + ("PDROP requires a non-Giant lock")); + if (lock != NULL) + class = LOCK_CLASS(lock); + else + class = NULL; + + if (cold || SCHEDULER_STOPPED()) { + /* + * During autoconfiguration, just return; + * don't run any other threads or panic below, + * in case this is the idle thread and already asleep. + * XXX: this used to do "s = splhigh(); splx(safepri); + * splx(s);" to give interrupts a chance, but there is + * no way to give interrupts a chance now. + */ + if (lock != NULL && priority & PDROP) + class->lc_unlock(lock); + return (0); + } + catch = priority & PCATCH; + pri = priority & PRIMASK; + + /* + * If we are already on a sleep queue, then remove us from that + * sleep queue first. We have to do this to handle recursive + * sleeps. + */ + if (TD_ON_SLEEPQ(td)) + sleepq_remove(td, td->td_wchan); + + if (ident == &pause_wchan) + flags = SLEEPQ_PAUSE; + else + flags = SLEEPQ_SLEEP; + if (catch) + flags |= SLEEPQ_INTERRUPTIBLE; + if (priority & PBDRY) + flags |= SLEEPQ_STOP_ON_BDRY; + + sleepq_lock(ident); + CTR5(KTR_PROC, "sleep: thread %ld (pid %ld, %s) on %s (%p)", + td->td_tid, p->p_pid, td->td_name, wmesg, ident); + + if (lock == &Giant.lock_object) + mtx_assert(&Giant, MA_OWNED); + DROP_GIANT(); + if (lock != NULL && lock != &Giant.lock_object && + !(class->lc_flags & LC_SLEEPABLE)) { + WITNESS_SAVE(lock, lock_witness); + lock_state = class->lc_unlock(lock); + } else + /* GCC needs to follow the Yellow Brick Road */ + lock_state = -1; + + /* + * We put ourselves on the sleep queue and start our timeout + * before calling thread_suspend_check, as we could stop there, + * and a wakeup or a SIGCONT (or both) could occur while we were + * stopped without resuming us. Thus, we must be ready for sleep + * when cursig() is called. If the wakeup happens while we're + * stopped, then td will no longer be on a sleep queue upon + * return from cursig(). + */ + sleepq_add(ident, lock, wmesg, flags, 0); + if (timo) + sleepq_set_timeout(ident, timo); + if (lock != NULL && class->lc_flags & LC_SLEEPABLE) { + sleepq_release(ident); + WITNESS_SAVE(lock, lock_witness); + lock_state = class->lc_unlock(lock); + sleepq_lock(ident); + } + if (timo && catch) + rval = sleepq_timedwait_sig(ident, pri); + else if (timo) + rval = sleepq_timedwait(ident, pri); + else if (catch) + rval = sleepq_wait_sig(ident, pri); + else { + sleepq_wait(ident, pri); + rval = 0; + } +#ifdef KTRACE + if (KTRPOINT(td, KTR_CSW)) + ktrcsw(0, 0, wmesg); +#endif + PICKUP_GIANT(); + if (lock != NULL && lock != &Giant.lock_object && !(priority & PDROP)) { + class->lc_lock(lock, lock_state); + WITNESS_RESTORE(lock, lock_witness); + } + return (rval); +} + +int +msleep_spin(void *ident, struct mtx *mtx, const char *wmesg, int timo) +{ + struct thread *td; + struct proc *p; + int rval; + WITNESS_SAVE_DECL(mtx); + + td = curthread; + p = td->td_proc; + KASSERT(mtx != NULL, ("sleeping without a mutex")); + KASSERT(p != NULL, ("msleep1")); + KASSERT(ident != NULL && TD_IS_RUNNING(td), ("msleep")); + + if (cold || SCHEDULER_STOPPED()) { + /* + * During autoconfiguration, just return; + * don't run any other threads or panic below, + * in case this is the idle thread and already asleep. + * XXX: this used to do "s = splhigh(); splx(safepri); + * splx(s);" to give interrupts a chance, but there is + * no way to give interrupts a chance now. + */ + return (0); + } + + sleepq_lock(ident); + CTR5(KTR_PROC, "msleep_spin: thread %ld (pid %ld, %s) on %s (%p)", + td->td_tid, p->p_pid, td->td_name, wmesg, ident); + + DROP_GIANT(); + mtx_assert(mtx, MA_OWNED | MA_NOTRECURSED); + WITNESS_SAVE(&mtx->lock_object, mtx); + mtx_unlock_spin(mtx); + + /* + * We put ourselves on the sleep queue and start our timeout. + */ + sleepq_add(ident, &mtx->lock_object, wmesg, SLEEPQ_SLEEP, 0); + if (timo) + sleepq_set_timeout(ident, timo); + + /* + * Can't call ktrace with any spin locks held so it can lock the + * ktrace_mtx lock, and WITNESS_WARN considers it an error to hold + * any spin lock. Thus, we have to drop the sleepq spin lock while + * we handle those requests. This is safe since we have placed our + * thread on the sleep queue already. + */ +#ifdef KTRACE + if (KTRPOINT(td, KTR_CSW)) { + sleepq_release(ident); + ktrcsw(1, 0, wmesg); + sleepq_lock(ident); + } +#endif +#ifdef WITNESS + sleepq_release(ident); + WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "Sleeping on \"%s\"", + wmesg); + sleepq_lock(ident); +#endif + if (timo) + rval = sleepq_timedwait(ident, 0); + else { + sleepq_wait(ident, 0); + rval = 0; + } +#ifdef KTRACE + if (KTRPOINT(td, KTR_CSW)) + ktrcsw(0, 0, wmesg); +#endif + PICKUP_GIANT(); + mtx_lock_spin(mtx); + WITNESS_RESTORE(&mtx->lock_object, mtx); + return (rval); +} + +/* + * pause() delays the calling thread by the given number of system ticks. + * During cold bootup, pause() uses the DELAY() function instead of + * the tsleep() function to do the waiting. The "timo" argument must be + * greater than or equal to zero. A "timo" value of zero is equivalent + * to a "timo" value of one. + */ +int +pause(const char *wmesg, int timo) +{ + KASSERT(timo >= 0, ("pause: timo must be >= 0")); + + /* silently convert invalid timeouts */ + if (timo < 1) + timo = 1; + + if (cold) { + /* + * We delay one HZ at a time to avoid overflowing the + * system specific DELAY() function(s): + */ + while (timo >= hz) { + DELAY(1000000); + timo -= hz; + } + if (timo > 0) + DELAY(timo * tick); + return (0); + } + return (tsleep(&pause_wchan, 0, wmesg, timo)); +} + +/* + * Make all threads sleeping on the specified identifier runnable. + */ +void +wakeup(void *ident) +{ + int wakeup_swapper; + + sleepq_lock(ident); + wakeup_swapper = sleepq_broadcast(ident, SLEEPQ_SLEEP, 0, 0); + sleepq_release(ident); + if (wakeup_swapper) { + KASSERT(ident != &proc0, + ("wakeup and wakeup_swapper and proc0")); + kick_proc0(); + } +} + +/* + * Make a thread sleeping on the specified identifier runnable. + * May wake more than one thread if a target thread is currently + * swapped out. + */ +void +wakeup_one(void *ident) +{ + int wakeup_swapper; + + sleepq_lock(ident); + wakeup_swapper = sleepq_signal(ident, SLEEPQ_SLEEP, 0, 0); + sleepq_release(ident); + if (wakeup_swapper) + kick_proc0(); +} + +static void +kdb_switch(void) +{ + thread_unlock(curthread); + kdb_backtrace(); + kdb_reenter(); + panic("%s: did not reenter debugger", __func__); +} + +/* + * The machine independent parts of context switching. + */ +void +mi_switch(int flags, struct thread *newtd) +{ + uint64_t runtime, new_switchtime; + struct thread *td; + struct proc *p; + + td = curthread; /* XXX */ + THREAD_LOCK_ASSERT(td, MA_OWNED | MA_NOTRECURSED); + p = td->td_proc; /* XXX */ + KASSERT(!TD_ON_RUNQ(td), ("mi_switch: called by old code")); +#ifdef INVARIANTS + if (!TD_ON_LOCK(td) && !TD_IS_RUNNING(td)) + mtx_assert(&Giant, MA_NOTOWNED); +#endif + KASSERT(td->td_critnest == 1 || panicstr, + ("mi_switch: switch in a critical section")); + KASSERT((flags & (SW_INVOL | SW_VOL)) != 0, + ("mi_switch: switch must be voluntary or involuntary")); + KASSERT(newtd != curthread, ("mi_switch: preempting back to ourself")); + + /* + * Don't perform context switches from the debugger. + */ + if (kdb_active) + kdb_switch(); + if (SCHEDULER_STOPPED()) + return; + if (flags & SW_VOL) { + td->td_ru.ru_nvcsw++; + td->td_swvoltick = ticks; + } else + td->td_ru.ru_nivcsw++; +#ifdef SCHED_STATS + SCHED_STAT_INC(sched_switch_stats[flags & SW_TYPE_MASK]); +#endif + /* + * Compute the amount of time during which the current + * thread was running, and add that to its total so far. + */ + new_switchtime = cpu_ticks(); + runtime = new_switchtime - PCPU_GET(switchtime); + td->td_runtime += runtime; + td->td_incruntime += runtime; + PCPU_SET(switchtime, new_switchtime); + td->td_generation++; /* bump preempt-detect counter */ + PCPU_INC(cnt.v_swtch); + PCPU_SET(switchticks, ticks); + CTR4(KTR_PROC, "mi_switch: old thread %ld (td_sched %p, pid %ld, %s)", + td->td_tid, td->td_sched, p->p_pid, td->td_name); +#if (KTR_COMPILE & KTR_SCHED) != 0 + if (TD_IS_IDLETHREAD(td)) + KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "idle", + "prio:%d", td->td_priority); + else + KTR_STATE3(KTR_SCHED, "thread", sched_tdname(td), KTDSTATE(td), + "prio:%d", td->td_priority, "wmesg:\"%s\"", td->td_wmesg, + "lockname:\"%s\"", td->td_lockname); +#endif + SDT_PROBE0(sched, , , preempt); +#ifdef XEN + PT_UPDATES_FLUSH(); +#endif + sched_switch(td, newtd, flags); + KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "running", + "prio:%d", td->td_priority); + + CTR4(KTR_PROC, "mi_switch: new thread %ld (td_sched %p, pid %ld, %s)", + td->td_tid, td->td_sched, p->p_pid, td->td_name); + + /* + * If the last thread was exiting, finish cleaning it up. + */ + if ((td = PCPU_GET(deadthread))) { + PCPU_SET(deadthread, NULL); + thread_stash(td); + } +} + +/* + * Change thread state to be runnable, placing it on the run queue if + * it is in memory. If it is swapped out, return true so our caller + * will know to awaken the swapper. + */ +int +setrunnable(struct thread *td) +{ + + THREAD_LOCK_ASSERT(td, MA_OWNED); + KASSERT(td->td_proc->p_state != PRS_ZOMBIE, + ("setrunnable: pid %d is a zombie", td->td_proc->p_pid)); + switch (td->td_state) { + case TDS_RUNNING: + case TDS_RUNQ: + return (0); + case TDS_INHIBITED: + /* + * If we are only inhibited because we are swapped out + * then arange to swap in this process. Otherwise just return. + */ + if (td->td_inhibitors != TDI_SWAPPED) + return (0); + /* FALLTHROUGH */ + case TDS_CAN_RUN: + break; + default: + printf("state is 0x%x", td->td_state); + panic("setrunnable(2)"); + } + if ((td->td_flags & TDF_INMEM) == 0) { + if ((td->td_flags & TDF_SWAPINREQ) == 0) { + td->td_flags |= TDF_SWAPINREQ; + return (1); + } + } else + sched_wakeup(td); + return (0); +} + +/* + * Compute a tenex style load average of a quantity on + * 1, 5 and 15 minute intervals. + */ +static void +loadav(void *arg) +{ + int i, nrun; + struct loadavg *avg; + + nrun = sched_load(); + avg = &averunnable; + + for (i = 0; i < 3; i++) + avg->ldavg[i] = (cexp[i] * avg->ldavg[i] + + nrun * FSCALE * (FSCALE - cexp[i])) >> FSHIFT; + + /* + * Schedule the next update to occur after 5 seconds, but add a + * random variation to avoid synchronisation with processes that + * run at regular intervals. + */ + callout_reset(&loadav_callout, hz * 4 + (int)(random() % (hz * 2 + 1)), + loadav, NULL); +} + +/* ARGSUSED */ +static void +synch_setup(void *dummy) +{ + callout_init(&loadav_callout, CALLOUT_MPSAFE); + + /* Kick off timeout driven events by calling first time. */ + loadav(NULL); +} + +int +should_yield(void) +{ + + return ((u_int)ticks - (u_int)curthread->td_swvoltick >= hogticks); +} + +void +maybe_yield(void) +{ + + if (should_yield()) + kern_yield(PRI_USER); +} + +void +kern_yield(int prio) +{ + struct thread *td; + + td = curthread; + DROP_GIANT(); + thread_lock(td); + if (prio == PRI_USER) + prio = td->td_user_pri; + if (prio >= 0) + sched_prio(td, prio); + mi_switch(SW_VOL | SWT_RELINQUISH, NULL); + thread_unlock(td); + PICKUP_GIANT(); +} + +/* + * General purpose yield system call. + */ +int +sys_yield(struct thread *td, struct yield_args *uap) +{ + + thread_lock(td); + if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) + sched_prio(td, PRI_MAX_TIMESHARE); + mi_switch(SW_VOL | SWT_RELINQUISH, NULL); + thread_unlock(td); + td->td_retval[0] = 0; + return (0); +} |