287 lines
8.6 KiB
C
287 lines
8.6 KiB
C
/*-
|
|
* 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.
|
|
*
|
|
* @(#)kern_clock.c 8.5 (Berkeley) 1/21/94
|
|
* $Id: kern_timeout.c,v 1.54 1998/02/25 06:13:32 bde Exp $
|
|
*/
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/callout.h>
|
|
#include <sys/kernel.h>
|
|
|
|
/*
|
|
* 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(). */
|
|
|
|
static struct callout *nextsoftcheck; /* Next callout to be checked. */
|
|
|
|
/*
|
|
* 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()
|
|
{
|
|
register struct callout *c;
|
|
register struct callout_tailq *bucket;
|
|
register int s;
|
|
register int curticks;
|
|
register int steps; /* #steps since we last allowed interrupts */
|
|
|
|
#ifndef MAX_SOFTCLOCK_STEPS
|
|
#define MAX_SOFTCLOCK_STEPS 100 /* Maximum allowed value of steps. */
|
|
#endif /* MAX_SOFTCLOCK_STEPS */
|
|
|
|
steps = 0;
|
|
s = splhigh();
|
|
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) {
|
|
if (c->c_time != curticks) {
|
|
c = TAILQ_NEXT(c, c_links.tqe);
|
|
++steps;
|
|
if (steps >= MAX_SOFTCLOCK_STEPS) {
|
|
nextsoftcheck = c;
|
|
/* Give interrupts a chance. */
|
|
splx(s);
|
|
s = splhigh();
|
|
c = nextsoftcheck;
|
|
steps = 0;
|
|
}
|
|
} else {
|
|
void (*c_func)(void *);
|
|
void *c_arg;
|
|
|
|
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->c_func = NULL;
|
|
SLIST_INSERT_HEAD(&callfree, c, c_links.sle);
|
|
splx(s);
|
|
c_func(c_arg);
|
|
s = splhigh();
|
|
steps = 0;
|
|
c = nextsoftcheck;
|
|
}
|
|
}
|
|
}
|
|
nextsoftcheck = NULL;
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
register int to_ticks;
|
|
{
|
|
int s;
|
|
struct callout *new;
|
|
struct callout_handle handle;
|
|
|
|
if (to_ticks <= 0)
|
|
to_ticks = 1;
|
|
|
|
/* Lock out the clock. */
|
|
s = splhigh();
|
|
|
|
/* 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);
|
|
new->c_arg = arg;
|
|
new->c_func = ftn;
|
|
new->c_time = ticks + to_ticks;
|
|
TAILQ_INSERT_TAIL(&callwheel[new->c_time & callwheelmask],
|
|
new, c_links.tqe);
|
|
|
|
splx(s);
|
|
handle.callout = new;
|
|
return (handle);
|
|
}
|
|
|
|
void
|
|
untimeout(ftn, arg, handle)
|
|
timeout_t *ftn;
|
|
void *arg;
|
|
struct callout_handle handle;
|
|
{
|
|
register int s;
|
|
|
|
/*
|
|
* Check for a handle that was initialized
|
|
* by callout_handle_init, but never used
|
|
* for a real timeout.
|
|
*/
|
|
if (handle.callout == NULL)
|
|
return;
|
|
|
|
s = splhigh();
|
|
if ((handle.callout->c_func == ftn)
|
|
&& (handle.callout->c_arg == arg)) {
|
|
if (nextsoftcheck == handle.callout) {
|
|
nextsoftcheck = TAILQ_NEXT(handle.callout, c_links.tqe);
|
|
}
|
|
TAILQ_REMOVE(&callwheel[handle.callout->c_time & callwheelmask],
|
|
handle.callout, c_links.tqe);
|
|
handle.callout->c_func = NULL;
|
|
SLIST_INSERT_HEAD(&callfree, handle.callout, c_links.sle);
|
|
}
|
|
splx(s);
|
|
}
|
|
|
|
void
|
|
callout_handle_init(struct callout_handle *handle)
|
|
{
|
|
handle->callout = NULL;
|
|
}
|
|
|
|
#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;
|
|
int s;
|
|
|
|
/*
|
|
* 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() */
|
|
s = splhigh();
|
|
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;
|
|
}
|
|
splx(s);
|
|
|
|
return;
|
|
}
|
|
#endif /* APM_FIXUP_CALLTODO */
|