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-rw-r--r--sys/kern/kern_timeout.c468
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diff --git a/sys/kern/kern_timeout.c b/sys/kern/kern_timeout.c
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+/*-
+ * Copyright (c) 1982, 1986, 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.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the University of
+ * California, Berkeley and its contributors.
+ * 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.
+ *
+ * From: @(#)kern_clock.c 8.5 (Berkeley) 1/21/94
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/callout.h>
+#include <sys/kernel.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
+#include <sys/sysctl.h>
+
+static int avg_depth;
+SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0,
+ "Average number of items examined per softclock call. Units = 1/1000");
+static int avg_gcalls;
+SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0,
+ "Average number of Giant callouts made per softclock call. Units = 1/1000");
+static int avg_mpcalls;
+SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0,
+ "Average number of MP callouts made per softclock call. Units = 1/1000");
+/*
+ * TODO:
+ * allocate more timeout table slots when table overflows.
+ */
+
+/* Exported to machdep.c and/or kern_clock.c. */
+struct callout *callout;
+struct callout_list callfree;
+int callwheelsize, callwheelbits, callwheelmask;
+struct callout_tailq *callwheel;
+int softticks; /* Like ticks, but for softclock(). */
+struct mtx callout_lock;
+#ifdef DIAGNOSTIC
+struct mtx callout_dont_sleep;
+#endif
+
+static struct callout *nextsoftcheck; /* Next callout to be checked. */
+
+/*
+ * kern_timeout_callwheel_alloc() - kernel low level callwheel initialization
+ *
+ * This code is called very early in the kernel initialization sequence,
+ * and may be called more then once.
+ */
+caddr_t
+kern_timeout_callwheel_alloc(caddr_t v)
+{
+ /*
+ * Calculate callout wheel size
+ */
+ for (callwheelsize = 1, callwheelbits = 0;
+ callwheelsize < ncallout;
+ callwheelsize <<= 1, ++callwheelbits)
+ ;
+ callwheelmask = callwheelsize - 1;
+
+ callout = (struct callout *)v;
+ v = (caddr_t)(callout + ncallout);
+ callwheel = (struct callout_tailq *)v;
+ v = (caddr_t)(callwheel + callwheelsize);
+ return(v);
+}
+
+/*
+ * kern_timeout_callwheel_init() - initialize previously reserved callwheel
+ * space.
+ *
+ * This code is called just once, after the space reserved for the
+ * callout wheel has been finalized.
+ */
+void
+kern_timeout_callwheel_init(void)
+{
+ int i;
+
+ SLIST_INIT(&callfree);
+ for (i = 0; i < ncallout; i++) {
+ callout_init(&callout[i], 0);
+ callout[i].c_flags = CALLOUT_LOCAL_ALLOC;
+ SLIST_INSERT_HEAD(&callfree, &callout[i], c_links.sle);
+ }
+ for (i = 0; i < callwheelsize; i++) {
+ TAILQ_INIT(&callwheel[i]);
+ }
+ mtx_init(&callout_lock, "callout", NULL, MTX_SPIN | MTX_RECURSE);
+#ifdef DIAGNOSTIC
+ mtx_init(&callout_dont_sleep, "callout_dont_sleep", NULL, MTX_DEF);
+#endif
+}
+
+/*
+ * The callout mechanism is based on the work of Adam M. Costello and
+ * George Varghese, published in a technical report entitled "Redesigning
+ * the BSD Callout and Timer Facilities" and modified slightly for inclusion
+ * in FreeBSD by Justin T. Gibbs. The original work on the data structures
+ * used in this implementation was published by G.Varghese and A. Lauck in
+ * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for
+ * the Efficient Implementation of a Timer Facility" in the Proceedings of
+ * the 11th ACM Annual Symposium on Operating Systems Principles,
+ * Austin, Texas Nov 1987.
+ */
+
+/*
+ * Software (low priority) clock interrupt.
+ * Run periodic events from timeout queue.
+ */
+void
+softclock(void *dummy)
+{
+ struct callout *c;
+ struct callout_tailq *bucket;
+ int curticks;
+ int steps; /* #steps since we last allowed interrupts */
+ int depth;
+ int mpcalls;
+ int gcalls;
+#ifdef DIAGNOSTIC
+ struct bintime bt1, bt2;
+ struct timespec ts2;
+ static uint64_t maxdt = 18446744073709551LL; /* 1 msec */
+#endif
+
+#ifndef MAX_SOFTCLOCK_STEPS
+#define MAX_SOFTCLOCK_STEPS 100 /* Maximum allowed value of steps. */
+#endif /* MAX_SOFTCLOCK_STEPS */
+
+ mpcalls = 0;
+ gcalls = 0;
+ depth = 0;
+ steps = 0;
+ mtx_lock_spin(&callout_lock);
+ while (softticks != ticks) {
+ softticks++;
+ /*
+ * softticks may be modified by hard clock, so cache
+ * it while we work on a given bucket.
+ */
+ curticks = softticks;
+ bucket = &callwheel[curticks & callwheelmask];
+ c = TAILQ_FIRST(bucket);
+ while (c) {
+ depth++;
+ if (c->c_time != curticks) {
+ c = TAILQ_NEXT(c, c_links.tqe);
+ ++steps;
+ if (steps >= MAX_SOFTCLOCK_STEPS) {
+ nextsoftcheck = c;
+ /* Give interrupts a chance. */
+ mtx_unlock_spin(&callout_lock);
+ ; /* nothing */
+ mtx_lock_spin(&callout_lock);
+ c = nextsoftcheck;
+ steps = 0;
+ }
+ } else {
+ void (*c_func)(void *);
+ void *c_arg;
+ int c_flags;
+
+ nextsoftcheck = TAILQ_NEXT(c, c_links.tqe);
+ TAILQ_REMOVE(bucket, c, c_links.tqe);
+ c_func = c->c_func;
+ c_arg = c->c_arg;
+ c_flags = c->c_flags;
+ c->c_func = NULL;
+ if (c->c_flags & CALLOUT_LOCAL_ALLOC) {
+ c->c_flags = CALLOUT_LOCAL_ALLOC;
+ SLIST_INSERT_HEAD(&callfree, c,
+ c_links.sle);
+ } else {
+ c->c_flags =
+ (c->c_flags & ~CALLOUT_PENDING);
+ }
+ mtx_unlock_spin(&callout_lock);
+ if (!(c_flags & CALLOUT_MPSAFE)) {
+ mtx_lock(&Giant);
+ gcalls++;
+ } else {
+ mpcalls++;
+ }
+#ifdef DIAGNOSTIC
+ binuptime(&bt1);
+ mtx_lock(&callout_dont_sleep);
+#endif
+ c_func(c_arg);
+#ifdef DIAGNOSTIC
+ mtx_unlock(&callout_dont_sleep);
+ binuptime(&bt2);
+ bintime_sub(&bt2, &bt1);
+ if (bt2.frac > maxdt) {
+ maxdt = bt2.frac;
+ bintime2timespec(&bt2, &ts2);
+ printf(
+ "Expensive timeout(9) function: %p(%p) %d.%09ld s\n",
+ c_func, c_arg,
+ ts2.tv_sec, ts2.tv_nsec);
+ }
+#endif
+ if (!(c_flags & CALLOUT_MPSAFE))
+ mtx_unlock(&Giant);
+ mtx_lock_spin(&callout_lock);
+ steps = 0;
+ c = nextsoftcheck;
+ }
+ }
+ }
+ avg_depth += (depth * 1000 - avg_depth) >> 8;
+ avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8;
+ avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8;
+ nextsoftcheck = NULL;
+ mtx_unlock_spin(&callout_lock);
+}
+
+/*
+ * timeout --
+ * Execute a function after a specified length of time.
+ *
+ * untimeout --
+ * Cancel previous timeout function call.
+ *
+ * callout_handle_init --
+ * Initialize a handle so that using it with untimeout is benign.
+ *
+ * See AT&T BCI Driver Reference Manual for specification. This
+ * implementation differs from that one in that although an
+ * identification value is returned from timeout, the original
+ * arguments to timeout as well as the identifier are used to
+ * identify entries for untimeout.
+ */
+struct callout_handle
+timeout(ftn, arg, to_ticks)
+ timeout_t *ftn;
+ void *arg;
+ int to_ticks;
+{
+ struct callout *new;
+ struct callout_handle handle;
+
+ mtx_lock_spin(&callout_lock);
+
+ /* Fill in the next free callout structure. */
+ new = SLIST_FIRST(&callfree);
+ if (new == NULL)
+ /* XXX Attempt to malloc first */
+ panic("timeout table full");
+ SLIST_REMOVE_HEAD(&callfree, c_links.sle);
+
+ callout_reset(new, to_ticks, ftn, arg);
+
+ handle.callout = new;
+ mtx_unlock_spin(&callout_lock);
+ return (handle);
+}
+
+void
+untimeout(ftn, arg, handle)
+ timeout_t *ftn;
+ void *arg;
+ struct callout_handle handle;
+{
+
+ /*
+ * Check for a handle that was initialized
+ * by callout_handle_init, but never used
+ * for a real timeout.
+ */
+ if (handle.callout == NULL)
+ return;
+
+ mtx_lock_spin(&callout_lock);
+ if (handle.callout->c_func == ftn && handle.callout->c_arg == arg)
+ callout_stop(handle.callout);
+ mtx_unlock_spin(&callout_lock);
+}
+
+void
+callout_handle_init(struct callout_handle *handle)
+{
+ handle->callout = NULL;
+}
+
+/*
+ * New interface; clients allocate their own callout structures.
+ *
+ * callout_reset() - establish or change a timeout
+ * callout_stop() - disestablish a timeout
+ * callout_init() - initialize a callout structure so that it can
+ * safely be passed to callout_reset() and callout_stop()
+ *
+ * <sys/callout.h> defines three convenience macros:
+ *
+ * callout_active() - returns truth if callout has not been serviced
+ * callout_pending() - returns truth if callout is still waiting for timeout
+ * callout_deactivate() - marks the callout as having been serviced
+ */
+void
+callout_reset(c, to_ticks, ftn, arg)
+ struct callout *c;
+ int to_ticks;
+ void (*ftn)(void *);
+ void *arg;
+{
+
+ mtx_lock_spin(&callout_lock);
+ if (c->c_flags & CALLOUT_PENDING)
+ callout_stop(c);
+
+ /*
+ * We could unlock callout_lock here and lock it again before the
+ * TAILQ_INSERT_TAIL, but there's no point since doing this setup
+ * doesn't take much time.
+ */
+ if (to_ticks <= 0)
+ to_ticks = 1;
+
+ c->c_arg = arg;
+ c->c_flags |= (CALLOUT_ACTIVE | CALLOUT_PENDING);
+ c->c_func = ftn;
+ c->c_time = ticks + to_ticks;
+ TAILQ_INSERT_TAIL(&callwheel[c->c_time & callwheelmask],
+ c, c_links.tqe);
+ mtx_unlock_spin(&callout_lock);
+}
+
+int
+callout_stop(c)
+ struct callout *c;
+{
+
+ mtx_lock_spin(&callout_lock);
+ /*
+ * Don't attempt to delete a callout that's not on the queue.
+ */
+ if (!(c->c_flags & CALLOUT_PENDING)) {
+ c->c_flags &= ~CALLOUT_ACTIVE;
+ mtx_unlock_spin(&callout_lock);
+ return (0);
+ }
+ c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING);
+
+ if (nextsoftcheck == c) {
+ nextsoftcheck = TAILQ_NEXT(c, c_links.tqe);
+ }
+ TAILQ_REMOVE(&callwheel[c->c_time & callwheelmask], c, c_links.tqe);
+ c->c_func = NULL;
+
+ if (c->c_flags & CALLOUT_LOCAL_ALLOC) {
+ SLIST_INSERT_HEAD(&callfree, c, c_links.sle);
+ }
+ mtx_unlock_spin(&callout_lock);
+ return (1);
+}
+
+void
+callout_init(c, mpsafe)
+ struct callout *c;
+ int mpsafe;
+{
+ bzero(c, sizeof *c);
+ if (mpsafe)
+ c->c_flags |= CALLOUT_MPSAFE;
+}
+
+#ifdef APM_FIXUP_CALLTODO
+/*
+ * Adjust the kernel calltodo timeout list. This routine is used after
+ * an APM resume to recalculate the calltodo timer list values with the
+ * number of hz's we have been sleeping. The next hardclock() will detect
+ * that there are fired timers and run softclock() to execute them.
+ *
+ * Please note, I have not done an exhaustive analysis of what code this
+ * might break. I am motivated to have my select()'s and alarm()'s that
+ * have expired during suspend firing upon resume so that the applications
+ * which set the timer can do the maintanence the timer was for as close
+ * as possible to the originally intended time. Testing this code for a
+ * week showed that resuming from a suspend resulted in 22 to 25 timers
+ * firing, which seemed independant on whether the suspend was 2 hours or
+ * 2 days. Your milage may vary. - Ken Key <key@cs.utk.edu>
+ */
+void
+adjust_timeout_calltodo(time_change)
+ struct timeval *time_change;
+{
+ register struct callout *p;
+ unsigned long delta_ticks;
+
+ /*
+ * How many ticks were we asleep?
+ * (stolen from tvtohz()).
+ */
+
+ /* Don't do anything */
+ if (time_change->tv_sec < 0)
+ return;
+ else if (time_change->tv_sec <= LONG_MAX / 1000000)
+ delta_ticks = (time_change->tv_sec * 1000000 +
+ time_change->tv_usec + (tick - 1)) / tick + 1;
+ else if (time_change->tv_sec <= LONG_MAX / hz)
+ delta_ticks = time_change->tv_sec * hz +
+ (time_change->tv_usec + (tick - 1)) / tick + 1;
+ else
+ delta_ticks = LONG_MAX;
+
+ if (delta_ticks > INT_MAX)
+ delta_ticks = INT_MAX;
+
+ /*
+ * Now rip through the timer calltodo list looking for timers
+ * to expire.
+ */
+
+ /* don't collide with softclock() */
+ mtx_lock_spin(&callout_lock);
+ for (p = calltodo.c_next; p != NULL; p = p->c_next) {
+ p->c_time -= delta_ticks;
+
+ /* Break if the timer had more time on it than delta_ticks */
+ if (p->c_time > 0)
+ break;
+
+ /* take back the ticks the timer didn't use (p->c_time <= 0) */
+ delta_ticks = -p->c_time;
+ }
+ mtx_unlock_spin(&callout_lock);
+
+ return;
+}
+#endif /* APM_FIXUP_CALLTODO */
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