mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-24 11:29:10 +00:00
258 lines
8.0 KiB
C
258 lines
8.0 KiB
C
/*
|
|
* Copyright (c) 1999 Peter Wemm <peter@FreeBSD.org>
|
|
* 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.
|
|
* 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.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
|
|
*
|
|
* $FreeBSD$
|
|
*/
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/ktr.h>
|
|
#include <sys/proc.h>
|
|
#include <sys/rtprio.h>
|
|
#include <sys/queue.h>
|
|
|
|
#include <machine/mutex.h>
|
|
|
|
/*
|
|
* We have NQS (32) run queues per scheduling class. For the normal
|
|
* class, there are 128 priorities scaled onto these 32 queues. New
|
|
* processes are added to the last entry in each queue, and processes
|
|
* are selected for running by taking them from the head and maintaining
|
|
* a simple FIFO arrangement.
|
|
*
|
|
* Interrupt, real time and idle priority processes have and explicit
|
|
* 0-31 priority which maps directly onto their class queue index.
|
|
* When a queue has something in it, the corresponding bit is set in
|
|
* the queuebits variable, allowing a single read to determine the
|
|
* state of all 32 queues and then a ffs() to find the first busy
|
|
* queue.
|
|
*
|
|
* XXX This needs fixing. First, we only have one idle process, so we
|
|
* hardly need 32 queues for it. Secondly, the number of classes
|
|
* makes things unwieldy. We should be able to merge them into a
|
|
* single 96 or 128 entry queue.
|
|
*/
|
|
struct rq itqueues[NQS]; /* interrupt threads */
|
|
struct rq rtqueues[NQS]; /* real time processes */
|
|
struct rq queues[NQS]; /* time sharing processes */
|
|
struct rq idqueues[NQS]; /* idle process */
|
|
u_int32_t itqueuebits;
|
|
u_int32_t rtqueuebits;
|
|
u_int32_t queuebits;
|
|
u_int32_t idqueuebits;
|
|
|
|
/*
|
|
* Initialize the run queues at boot time.
|
|
*/
|
|
static void
|
|
rqinit(void *dummy)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < NQS; i++) {
|
|
TAILQ_INIT(&itqueues[i]);
|
|
TAILQ_INIT(&rtqueues[i]);
|
|
TAILQ_INIT(&queues[i]);
|
|
TAILQ_INIT(&idqueues[i]);
|
|
}
|
|
}
|
|
SYSINIT(runqueue, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, rqinit, NULL)
|
|
|
|
/*
|
|
* setrunqueue() examines a process priority and class and inserts it on
|
|
* the tail of it's appropriate run queue (based on class and priority).
|
|
* This sets the queue busy bit.
|
|
* The process must be runnable.
|
|
* This must be called at splhigh().
|
|
*/
|
|
void
|
|
setrunqueue(struct proc *p)
|
|
{
|
|
struct rq *q;
|
|
u_int8_t pri;
|
|
|
|
mtx_assert(&sched_lock, MA_OWNED);
|
|
KASSERT(p->p_stat == SRUN, ("setrunqueue: proc %p (%s) not SRUN", p, \
|
|
p->p_comm));
|
|
|
|
/*
|
|
* Decide which class we want to run. We now have four
|
|
* queues, and this is becoming ugly. We should be able to
|
|
* collapse the first three classes into a single contiguous
|
|
* queue. XXX FIXME.
|
|
*/
|
|
CTR4(KTR_PROC, "setrunqueue: proc %p (pid %d, %s), schedlock %lx",
|
|
p, p->p_pid, p->p_comm, (long)sched_lock.mtx_lock);
|
|
if (p->p_rtprio.type == RTP_PRIO_ITHREAD) { /* interrupt thread */
|
|
pri = p->p_rtprio.prio;
|
|
q = &itqueues[pri];
|
|
itqueuebits |= 1 << pri;
|
|
} else if (p->p_rtprio.type == RTP_PRIO_REALTIME || /* real time */
|
|
p->p_rtprio.type == RTP_PRIO_FIFO) {
|
|
pri = p->p_rtprio.prio;
|
|
q = &rtqueues[pri];
|
|
rtqueuebits |= 1 << pri;
|
|
} else if (p->p_rtprio.type == RTP_PRIO_NORMAL) { /* time sharing */
|
|
pri = p->p_priority >> 2;
|
|
q = &queues[pri];
|
|
queuebits |= 1 << pri;
|
|
} else if (p->p_rtprio.type == RTP_PRIO_IDLE) { /* idle proc */
|
|
pri = p->p_rtprio.prio;
|
|
q = &idqueues[pri];
|
|
idqueuebits |= 1 << pri;
|
|
} else {
|
|
panic("setrunqueue: invalid rtprio type %d", p->p_rtprio.type);
|
|
}
|
|
p->p_rqindex = pri; /* remember the queue index */
|
|
TAILQ_INSERT_TAIL(q, p, p_procq);
|
|
}
|
|
|
|
/*
|
|
* remrunqueue() removes a given process from the run queue that it is on,
|
|
* clearing the queue busy bit if it becomes empty.
|
|
* This must be called at splhigh().
|
|
*/
|
|
void
|
|
remrunqueue(struct proc *p)
|
|
{
|
|
struct rq *q;
|
|
u_int32_t *which;
|
|
u_int8_t pri;
|
|
|
|
CTR4(KTR_PROC, "remrunqueue: proc %p (pid %d, %s), schedlock %lx",
|
|
p, p->p_pid, p->p_comm, (long)sched_lock.mtx_lock);
|
|
mtx_assert(&sched_lock, MA_OWNED);
|
|
pri = p->p_rqindex;
|
|
if (p->p_rtprio.type == RTP_PRIO_ITHREAD) {
|
|
q = &itqueues[pri];
|
|
which = &itqueuebits;
|
|
} else if (p->p_rtprio.type == RTP_PRIO_REALTIME ||
|
|
p->p_rtprio.type == RTP_PRIO_FIFO) {
|
|
q = &rtqueues[pri];
|
|
which = &rtqueuebits;
|
|
} else if (p->p_rtprio.type == RTP_PRIO_NORMAL) {
|
|
q = &queues[pri];
|
|
which = &queuebits;
|
|
} else if (p->p_rtprio.type == RTP_PRIO_IDLE) {
|
|
q = &idqueues[pri];
|
|
which = &idqueuebits;
|
|
} else {
|
|
panic("remrunqueue: invalid rtprio type");
|
|
}
|
|
TAILQ_REMOVE(q, p, p_procq);
|
|
if (TAILQ_EMPTY(q)) {
|
|
KASSERT((*which & (1 << pri)) != 0,
|
|
("remrunqueue: remove from empty queue"));
|
|
*which &= ~(1 << pri);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* procrunnable() returns a boolean true (non-zero) value if there are
|
|
* any runnable processes. This is intended to be called from the idle
|
|
* loop to avoid the more expensive (and destructive) chooseproc().
|
|
*
|
|
* MP SAFE. CALLED WITHOUT THE MP LOCK
|
|
*
|
|
* XXX I doubt this. It's possibly fail-safe, but there's obviously
|
|
* the case here where one of the bits words gets loaded, the
|
|
* processor gets preempted, and by the time it returns from this
|
|
* function, some other processor has picked the runnable process.
|
|
* What am I missing? (grog, 23 July 2000).
|
|
*/
|
|
u_int32_t
|
|
procrunnable(void)
|
|
{
|
|
return (itqueuebits || rtqueuebits || queuebits || idqueuebits);
|
|
}
|
|
|
|
/*
|
|
* chooseproc() selects the next process to run. Ideally, cpu_switch()
|
|
* would have determined that there is a process available before calling
|
|
* this, but it is not a requirement. The selected process is removed
|
|
* from it's queue, and the queue busy bit is cleared if it becomes empty.
|
|
* This must be called at splhigh().
|
|
*
|
|
* For SMP, trivial affinity is implemented by locating the first process
|
|
* on the queue that has a matching lastcpu id. Since normal priorities
|
|
* are mapped four priority levels per queue, this may allow the cpu to
|
|
* choose a slightly lower priority process in order to preserve the cpu
|
|
* caches.
|
|
*/
|
|
struct proc *
|
|
chooseproc(void)
|
|
{
|
|
struct proc *p;
|
|
struct rq *q;
|
|
u_int32_t *which;
|
|
u_int32_t pri;
|
|
#ifdef SMP
|
|
u_char id;
|
|
#endif
|
|
|
|
mtx_assert(&sched_lock, MA_OWNED);
|
|
if (itqueuebits) {
|
|
pri = ffs(itqueuebits) - 1;
|
|
q = &itqueues[pri];
|
|
which = &itqueuebits;
|
|
} else if (rtqueuebits) {
|
|
pri = ffs(rtqueuebits) - 1;
|
|
q = &rtqueues[pri];
|
|
which = &rtqueuebits;
|
|
} else if (queuebits) {
|
|
pri = ffs(queuebits) - 1;
|
|
q = &queues[pri];
|
|
which = &queuebits;
|
|
} else if (idqueuebits) {
|
|
pri = ffs(idqueuebits) - 1;
|
|
q = &idqueues[pri];
|
|
which = &idqueuebits;
|
|
} else {
|
|
CTR1(KTR_PROC, "chooseproc: idleproc, schedlock %lx",
|
|
(long)sched_lock.mtx_lock);
|
|
return idleproc;
|
|
}
|
|
p = TAILQ_FIRST(q);
|
|
#ifdef SMP
|
|
/* wander down the current run queue for this pri level for a match */
|
|
id = cpuid;
|
|
while (p->p_lastcpu != id) {
|
|
p = TAILQ_NEXT(p, p_procq);
|
|
if (p == NULL) {
|
|
p = TAILQ_FIRST(q);
|
|
break;
|
|
}
|
|
}
|
|
#endif
|
|
CTR4(KTR_PROC, "chooseproc: proc %p (pid %d, %s), schedlock %lx",
|
|
p, p->p_pid, p->p_comm, (long)sched_lock.mtx_lock);
|
|
KASSERT(p, ("chooseproc: no proc on busy queue"));
|
|
TAILQ_REMOVE(q, p, p_procq);
|
|
if (TAILQ_EMPTY(q))
|
|
*which &= ~(1 << pri);
|
|
return p;
|
|
}
|