8088699f79
type of software interrupt. Roughly, what used to be a bit in spending now maps to a swi thread. Each thread can have multiple handlers, just like a hardware interrupt thread. - Instead of using a bitmask of pending interrupts, we schedule the specific software interrupt thread to run, so spending, NSWI, and the shandlers array are no longer needed. We can now have an arbitrary number of software interrupt threads. When you register a software interrupt thread via sinthand_add(), you get back a struct intrhand that you pass to sched_swi() when you wish to schedule your swi thread to run. - Convert the name of 'struct intrec' to 'struct intrhand' as it is a bit more intuitive. Also, prefix all the members of struct intrhand with 'ih_'. - Make swi_net() a MI function since there is now no point in it being MD. Submitted by: cp
359 lines
10 KiB
C
359 lines
10 KiB
C
/*-
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* Copyright (c) 1982, 1986, 1991, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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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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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, 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, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* From: @(#)kern_clock.c 8.5 (Berkeley) 1/21/94
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* $FreeBSD$
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/callout.h>
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#include <sys/kernel.h>
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/*
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* TODO:
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* allocate more timeout table slots when table overflows.
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*/
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/* Exported to machdep.c and/or kern_clock.c. */
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struct callout *callout;
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struct callout_list callfree;
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int callwheelsize, callwheelbits, callwheelmask;
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struct callout_tailq *callwheel;
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int softticks; /* Like ticks, but for softclock(). */
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static struct callout *nextsoftcheck; /* Next callout to be checked. */
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/*
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* The callout mechanism is based on the work of Adam M. Costello and
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* George Varghese, published in a technical report entitled "Redesigning
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* the BSD Callout and Timer Facilities" and modified slightly for inclusion
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* in FreeBSD by Justin T. Gibbs. The original work on the data structures
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* used in this implementation was published by G.Varghese and A. Lauck in
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* the paper "Hashed and Hierarchical Timing Wheels: Data Structures for
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* the Efficient Implementation of a Timer Facility" in the Proceedings of
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* the 11th ACM Annual Symposium on Operating Systems Principles,
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* Austin, Texas Nov 1987.
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*/
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/*
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* Software (low priority) clock interrupt.
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* Run periodic events from timeout queue.
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*/
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void
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softclock(void *dummy)
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{
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register struct callout *c;
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register struct callout_tailq *bucket;
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register int s;
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register int curticks;
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register int steps; /* #steps since we last allowed interrupts */
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#ifndef MAX_SOFTCLOCK_STEPS
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#define MAX_SOFTCLOCK_STEPS 100 /* Maximum allowed value of steps. */
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#endif /* MAX_SOFTCLOCK_STEPS */
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steps = 0;
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s = splhigh();
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while (softticks != ticks) {
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softticks++;
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/*
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* softticks may be modified by hard clock, so cache
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* it while we work on a given bucket.
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*/
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curticks = softticks;
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bucket = &callwheel[curticks & callwheelmask];
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c = TAILQ_FIRST(bucket);
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while (c) {
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if (c->c_time != curticks) {
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c = TAILQ_NEXT(c, c_links.tqe);
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++steps;
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if (steps >= MAX_SOFTCLOCK_STEPS) {
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nextsoftcheck = c;
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/* Give interrupts a chance. */
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splx(s);
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s = splhigh();
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c = nextsoftcheck;
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steps = 0;
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}
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} else {
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void (*c_func)(void *);
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void *c_arg;
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nextsoftcheck = TAILQ_NEXT(c, c_links.tqe);
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TAILQ_REMOVE(bucket, c, c_links.tqe);
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c_func = c->c_func;
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c_arg = c->c_arg;
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c->c_func = NULL;
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if (c->c_flags & CALLOUT_LOCAL_ALLOC) {
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c->c_flags = CALLOUT_LOCAL_ALLOC;
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SLIST_INSERT_HEAD(&callfree, c,
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c_links.sle);
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} else {
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c->c_flags =
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(c->c_flags & ~CALLOUT_PENDING);
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}
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splx(s);
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c_func(c_arg);
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s = splhigh();
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steps = 0;
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c = nextsoftcheck;
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}
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}
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}
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nextsoftcheck = NULL;
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splx(s);
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}
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/*
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* timeout --
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* Execute a function after a specified length of time.
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*
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* untimeout --
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* Cancel previous timeout function call.
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*
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* callout_handle_init --
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* Initialize a handle so that using it with untimeout is benign.
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*
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* See AT&T BCI Driver Reference Manual for specification. This
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* implementation differs from that one in that although an
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* identification value is returned from timeout, the original
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* arguments to timeout as well as the identifier are used to
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* identify entries for untimeout.
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*/
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struct callout_handle
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timeout(ftn, arg, to_ticks)
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timeout_t *ftn;
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void *arg;
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register int to_ticks;
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{
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int s;
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struct callout *new;
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struct callout_handle handle;
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s = splhigh();
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/* Fill in the next free callout structure. */
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new = SLIST_FIRST(&callfree);
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if (new == NULL)
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/* XXX Attempt to malloc first */
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panic("timeout table full");
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SLIST_REMOVE_HEAD(&callfree, c_links.sle);
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callout_reset(new, to_ticks, ftn, arg);
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handle.callout = new;
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splx(s);
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return (handle);
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}
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void
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untimeout(ftn, arg, handle)
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timeout_t *ftn;
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void *arg;
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struct callout_handle handle;
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{
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register int s;
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/*
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* Check for a handle that was initialized
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* by callout_handle_init, but never used
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* for a real timeout.
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*/
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if (handle.callout == NULL)
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return;
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s = splhigh();
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if (handle.callout->c_func == ftn && handle.callout->c_arg == arg)
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callout_stop(handle.callout);
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splx(s);
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}
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void
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callout_handle_init(struct callout_handle *handle)
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{
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handle->callout = NULL;
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}
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/*
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* New interface; clients allocate their own callout structures.
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*
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* callout_reset() - establish or change a timeout
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* callout_stop() - disestablish a timeout
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* callout_init() - initialize a callout structure so that it can
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* safely be passed to callout_reset() and callout_stop()
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*
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* <sys/callout.h> defines three convenience macros:
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*
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* callout_active() - returns truth if callout has not been serviced
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* callout_pending() - returns truth if callout is still waiting for timeout
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* callout_deactivate() - marks the callout as having been serviced
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*/
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void
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callout_reset(c, to_ticks, ftn, arg)
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struct callout *c;
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int to_ticks;
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void (*ftn) __P((void *));
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void *arg;
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{
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int s;
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s = splhigh();
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if (c->c_flags & CALLOUT_PENDING)
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callout_stop(c);
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/*
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* We could spl down here and back up at the TAILQ_INSERT_TAIL,
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* but there's no point since doing this setup doesn't take much
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* time.
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*/
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if (to_ticks <= 0)
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to_ticks = 1;
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c->c_arg = arg;
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c->c_flags |= (CALLOUT_ACTIVE | CALLOUT_PENDING);
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c->c_func = ftn;
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c->c_time = ticks + to_ticks;
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TAILQ_INSERT_TAIL(&callwheel[c->c_time & callwheelmask],
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c, c_links.tqe);
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splx(s);
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}
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void
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callout_stop(c)
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struct callout *c;
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{
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int s;
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s = splhigh();
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/*
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* Don't attempt to delete a callout that's not on the queue.
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*/
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if (!(c->c_flags & CALLOUT_PENDING)) {
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c->c_flags &= ~CALLOUT_ACTIVE;
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splx(s);
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return;
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}
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c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING);
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if (nextsoftcheck == c) {
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nextsoftcheck = TAILQ_NEXT(c, c_links.tqe);
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}
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TAILQ_REMOVE(&callwheel[c->c_time & callwheelmask], c, c_links.tqe);
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c->c_func = NULL;
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if (c->c_flags & CALLOUT_LOCAL_ALLOC) {
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SLIST_INSERT_HEAD(&callfree, c, c_links.sle);
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}
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splx(s);
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}
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void
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callout_init(c)
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struct callout *c;
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{
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bzero(c, sizeof *c);
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}
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#ifdef APM_FIXUP_CALLTODO
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/*
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* Adjust the kernel calltodo timeout list. This routine is used after
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* an APM resume to recalculate the calltodo timer list values with the
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* number of hz's we have been sleeping. The next hardclock() will detect
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* that there are fired timers and run softclock() to execute them.
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*
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* Please note, I have not done an exhaustive analysis of what code this
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* might break. I am motivated to have my select()'s and alarm()'s that
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* have expired during suspend firing upon resume so that the applications
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* which set the timer can do the maintanence the timer was for as close
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* as possible to the originally intended time. Testing this code for a
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* week showed that resuming from a suspend resulted in 22 to 25 timers
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* firing, which seemed independant on whether the suspend was 2 hours or
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* 2 days. Your milage may vary. - Ken Key <key@cs.utk.edu>
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*/
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void
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adjust_timeout_calltodo(time_change)
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struct timeval *time_change;
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{
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register struct callout *p;
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unsigned long delta_ticks;
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int s;
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/*
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* How many ticks were we asleep?
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* (stolen from tvtohz()).
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*/
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/* Don't do anything */
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if (time_change->tv_sec < 0)
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return;
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else if (time_change->tv_sec <= LONG_MAX / 1000000)
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delta_ticks = (time_change->tv_sec * 1000000 +
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time_change->tv_usec + (tick - 1)) / tick + 1;
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else if (time_change->tv_sec <= LONG_MAX / hz)
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delta_ticks = time_change->tv_sec * hz +
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(time_change->tv_usec + (tick - 1)) / tick + 1;
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else
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delta_ticks = LONG_MAX;
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if (delta_ticks > INT_MAX)
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delta_ticks = INT_MAX;
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/*
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* Now rip through the timer calltodo list looking for timers
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* to expire.
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*/
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/* don't collide with softclock() */
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s = splhigh();
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for (p = calltodo.c_next; p != NULL; p = p->c_next) {
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p->c_time -= delta_ticks;
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/* Break if the timer had more time on it than delta_ticks */
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if (p->c_time > 0)
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break;
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/* take back the ticks the timer didn't use (p->c_time <= 0) */
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delta_ticks = -p->c_time;
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}
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splx(s);
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return;
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}
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#endif /* APM_FIXUP_CALLTODO */
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