1ce407b675
mutex releases to not require flags for the cases when preemption is not allowed: The purpose of the MTX_NOSWITCH and SWI_NOSWITCH flags is to prevent switching to a higher priority thread on mutex releease and swi schedule, respectively when that switch is not safe. Now that the critical section API maintains a per-thread nesting count, the kernel can easily check whether or not it should switch without relying on flags from the programmer. This fixes a few bugs in that all current callers of swi_sched() used SWI_NOSWITCH, when in fact, only the ones called from fast interrupt handlers and the swi_sched of softclock needed this flag. Note that to ensure that swi_sched()'s in clock and fast interrupt handlers do not switch, these handlers have to be explicitly wrapped in critical_enter/exit pairs. Presently, just wrapping the handlers is sufficient, but in the future with the fully preemptive kernel, the interrupt must be EOI'd before critical_exit() is called. (critical_exit() can switch due to a deferred preemption in a fully preemptive kernel.) I've tested the changes to the interrupt code on i386 and alpha. I have not tested ia64, but the interrupt code is almost identical to the alpha code, so I expect it will work fine. PowerPC and ARM do not yet have interrupt code in the tree so they shouldn't be broken. Sparc64 is broken, but that's been ok'd by jake and tmm who will be fixing the interrupt code for sparc64 shortly. Reviewed by: peter Tested on: i386, alpha
974 lines
27 KiB
C
974 lines
27 KiB
C
/*-
|
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* Copyright (c) 1982, 1986, 1990, 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
|
|
* must display the following acknowledgement:
|
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* This product includes software developed by the University of
|
|
* 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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* @(#)kern_synch.c 8.9 (Berkeley) 5/19/95
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* $FreeBSD$
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*/
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#include "opt_ddb.h"
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#include "opt_ktrace.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/condvar.h>
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#include <sys/kernel.h>
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#include <sys/ktr.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/resourcevar.h>
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#include <sys/signalvar.h>
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#include <sys/smp.h>
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#include <sys/sx.h>
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#include <sys/sysctl.h>
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#include <sys/sysproto.h>
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#include <sys/vmmeter.h>
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#ifdef DDB
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#include <ddb/ddb.h>
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#endif
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#ifdef KTRACE
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#include <sys/uio.h>
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#include <sys/ktrace.h>
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#endif
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#include <machine/cpu.h>
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static void sched_setup __P((void *dummy));
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SYSINIT(sched_setup, SI_SUB_KICK_SCHEDULER, SI_ORDER_FIRST, sched_setup, NULL)
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int hogticks;
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int lbolt;
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int sched_quantum; /* Roundrobin scheduling quantum in ticks. */
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static struct callout loadav_callout;
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static struct callout schedcpu_callout;
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static struct callout roundrobin_callout;
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struct loadavg averunnable =
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{ {0, 0, 0}, FSCALE }; /* load average, of runnable procs */
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/*
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* Constants for averages over 1, 5, and 15 minutes
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* when sampling at 5 second intervals.
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*/
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static fixpt_t cexp[3] = {
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0.9200444146293232 * FSCALE, /* exp(-1/12) */
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0.9834714538216174 * FSCALE, /* exp(-1/60) */
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0.9944598480048967 * FSCALE, /* exp(-1/180) */
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};
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|
|
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static void endtsleep __P((void *));
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static void loadav __P((void *arg));
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static void roundrobin __P((void *arg));
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static void schedcpu __P((void *arg));
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|
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static int
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sysctl_kern_quantum(SYSCTL_HANDLER_ARGS)
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{
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int error, new_val;
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|
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new_val = sched_quantum * tick;
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error = sysctl_handle_int(oidp, &new_val, 0, req);
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if (error != 0 || req->newptr == NULL)
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return (error);
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if (new_val < tick)
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return (EINVAL);
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sched_quantum = new_val / tick;
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hogticks = 2 * sched_quantum;
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return (0);
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}
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SYSCTL_PROC(_kern, OID_AUTO, quantum, CTLTYPE_INT|CTLFLAG_RW,
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0, sizeof sched_quantum, sysctl_kern_quantum, "I",
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"Roundrobin scheduling quantum in microseconds");
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|
|
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/*
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* Arrange to reschedule if necessary, taking the priorities and
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* schedulers into account.
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*/
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void
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maybe_resched(kg)
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struct ksegrp *kg;
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{
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|
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mtx_assert(&sched_lock, MA_OWNED);
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if (kg->kg_pri.pri_level < curthread->td_ksegrp->kg_pri.pri_level)
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curthread->td_kse->ke_flags |= KEF_NEEDRESCHED;
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}
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|
|
|
int
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roundrobin_interval(void)
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{
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return (sched_quantum);
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|
}
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|
|
|
/*
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* Force switch among equal priority processes every 100ms.
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* We don't actually need to force a context switch of the current process.
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* The act of firing the event triggers a context switch to softclock() and
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* then switching back out again which is equivalent to a preemption, thus
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* no further work is needed on the local CPU.
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*/
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/* ARGSUSED */
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static void
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roundrobin(arg)
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void *arg;
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{
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#ifdef SMP
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mtx_lock_spin(&sched_lock);
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forward_roundrobin();
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mtx_unlock_spin(&sched_lock);
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#endif
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callout_reset(&roundrobin_callout, sched_quantum, roundrobin, NULL);
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}
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|
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/*
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* Constants for digital decay and forget:
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* 90% of (p_estcpu) usage in 5 * loadav time
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* 95% of (p_pctcpu) usage in 60 seconds (load insensitive)
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* Note that, as ps(1) mentions, this can let percentages
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* total over 100% (I've seen 137.9% for 3 processes).
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*
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* Note that schedclock() updates p_estcpu and p_cpticks asynchronously.
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*
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* We wish to decay away 90% of p_estcpu in (5 * loadavg) seconds.
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* That is, the system wants to compute a value of decay such
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* that the following for loop:
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* for (i = 0; i < (5 * loadavg); i++)
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* p_estcpu *= decay;
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* will compute
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* p_estcpu *= 0.1;
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* for all values of loadavg:
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*
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* Mathematically this loop can be expressed by saying:
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* decay ** (5 * loadavg) ~= .1
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*
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* The system computes decay as:
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* decay = (2 * loadavg) / (2 * loadavg + 1)
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*
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* We wish to prove that the system's computation of decay
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* will always fulfill the equation:
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* decay ** (5 * loadavg) ~= .1
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*
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* If we compute b as:
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* b = 2 * loadavg
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* then
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* decay = b / (b + 1)
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*
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* We now need to prove two things:
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* 1) Given factor ** (5 * loadavg) ~= .1, prove factor == b/(b+1)
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* 2) Given b/(b+1) ** power ~= .1, prove power == (5 * loadavg)
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*
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* Facts:
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* For x close to zero, exp(x) =~ 1 + x, since
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* exp(x) = 0! + x**1/1! + x**2/2! + ... .
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* therefore exp(-1/b) =~ 1 - (1/b) = (b-1)/b.
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* For x close to zero, ln(1+x) =~ x, since
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* ln(1+x) = x - x**2/2 + x**3/3 - ... -1 < x < 1
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* therefore ln(b/(b+1)) = ln(1 - 1/(b+1)) =~ -1/(b+1).
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* ln(.1) =~ -2.30
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*
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* Proof of (1):
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* Solve (factor)**(power) =~ .1 given power (5*loadav):
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* solving for factor,
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* ln(factor) =~ (-2.30/5*loadav), or
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* factor =~ exp(-1/((5/2.30)*loadav)) =~ exp(-1/(2*loadav)) =
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* exp(-1/b) =~ (b-1)/b =~ b/(b+1). QED
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*
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* Proof of (2):
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* Solve (factor)**(power) =~ .1 given factor == (b/(b+1)):
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* solving for power,
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* power*ln(b/(b+1)) =~ -2.30, or
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* power =~ 2.3 * (b + 1) = 4.6*loadav + 2.3 =~ 5*loadav. QED
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*
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* Actual power values for the implemented algorithm are as follows:
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* loadav: 1 2 3 4
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* power: 5.68 10.32 14.94 19.55
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*/
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/* calculations for digital decay to forget 90% of usage in 5*loadav sec */
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#define loadfactor(loadav) (2 * (loadav))
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#define decay_cpu(loadfac, cpu) (((loadfac) * (cpu)) / ((loadfac) + FSCALE))
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/* decay 95% of `p_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */
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static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */
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SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, "");
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|
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/* kernel uses `FSCALE', userland (SHOULD) use kern.fscale */
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static int fscale __unused = FSCALE;
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SYSCTL_INT(_kern, OID_AUTO, fscale, CTLFLAG_RD, 0, FSCALE, "");
|
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/*
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* If `ccpu' is not equal to `exp(-1/20)' and you still want to use the
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* faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below
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* and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT).
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*
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* To estimate CCPU_SHIFT for exp(-1/20), the following formula was used:
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* 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits).
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*
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* If you don't want to bother with the faster/more-accurate formula, you
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* can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate
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* (more general) method of calculating the %age of CPU used by a process.
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*/
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#define CCPU_SHIFT 11
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|
/*
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* Recompute process priorities, every hz ticks.
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* MP-safe, called without the Giant mutex.
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*/
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/* ARGSUSED */
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|
static void
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schedcpu(arg)
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void *arg;
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{
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register fixpt_t loadfac = loadfactor(averunnable.ldavg[0]);
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register struct proc *p;
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|
register struct kse *ke;
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register struct ksegrp *kg;
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register int realstathz;
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int awake;
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|
realstathz = stathz ? stathz : hz;
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sx_slock(&allproc_lock);
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FOREACH_PROC_IN_SYSTEM(p) {
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mtx_lock_spin(&sched_lock);
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p->p_swtime++;
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FOREACH_KSEGRP_IN_PROC(p, kg) {
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awake = 0;
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FOREACH_KSE_IN_GROUP(kg, ke) {
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|
/*
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|
* Increment time in/out of memory and sleep
|
|
* time (if sleeping). We ignore overflow;
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|
* with 16-bit int's (remember them?)
|
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* overflow takes 45 days.
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|
*/
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/* XXXKSE */
|
|
/* if ((ke->ke_flags & KEF_ONRUNQ) == 0) */
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if (p->p_stat == SSLEEP || p->p_stat == SSTOP) {
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ke->ke_slptime++;
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|
} else {
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|
ke->ke_slptime = 0;
|
|
awake = 1;
|
|
}
|
|
|
|
/*
|
|
* pctcpu is only for ps?
|
|
* Do it per kse.. and add them up at the end?
|
|
* XXXKSE
|
|
*/
|
|
ke->ke_pctcpu = (ke->ke_pctcpu * ccpu) >> FSHIFT;
|
|
/*
|
|
* If the kse has been idle the entire second,
|
|
* stop recalculating its priority until
|
|
* it wakes up.
|
|
*/
|
|
if (ke->ke_slptime > 1) {
|
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continue;
|
|
}
|
|
|
|
#if (FSHIFT >= CCPU_SHIFT)
|
|
ke->ke_pctcpu += (realstathz == 100) ?
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|
((fixpt_t) ke->ke_cpticks) <<
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|
(FSHIFT - CCPU_SHIFT) :
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100 * (((fixpt_t) ke->ke_cpticks) <<
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(FSHIFT - CCPU_SHIFT)) / realstathz;
|
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#else
|
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ke->ke_pctcpu += ((FSCALE - ccpu) *
|
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(ke->ke_cpticks * FSCALE / realstathz)) >>
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FSHIFT;
|
|
#endif
|
|
ke->ke_cpticks = 0;
|
|
} /* end of kse loop */
|
|
if (awake == 0) {
|
|
kg->kg_slptime++;
|
|
} else {
|
|
kg->kg_slptime = 0;
|
|
}
|
|
kg->kg_estcpu = decay_cpu(loadfac, kg->kg_estcpu);
|
|
resetpriority(kg);
|
|
if (kg->kg_pri.pri_level >= PUSER &&
|
|
(p->p_sflag & PS_INMEM)) {
|
|
int changedqueue =
|
|
((kg->kg_pri.pri_level / RQ_PPQ) !=
|
|
(kg->kg_pri.pri_user / RQ_PPQ));
|
|
|
|
kg->kg_pri.pri_level = kg->kg_pri.pri_user;
|
|
FOREACH_KSE_IN_GROUP(kg, ke) {
|
|
if ((ke->ke_oncpu == NOCPU) && /* idle */
|
|
(p->p_stat == SRUN) && /* XXXKSE */
|
|
changedqueue) {
|
|
remrunqueue(ke->ke_thread);
|
|
setrunqueue(ke->ke_thread);
|
|
}
|
|
}
|
|
}
|
|
} /* end of ksegrp loop */
|
|
mtx_unlock_spin(&sched_lock);
|
|
} /* end of process loop */
|
|
sx_sunlock(&allproc_lock);
|
|
wakeup((caddr_t)&lbolt);
|
|
callout_reset(&schedcpu_callout, hz, schedcpu, NULL);
|
|
}
|
|
|
|
/*
|
|
* Recalculate the priority of a process after it has slept for a while.
|
|
* For all load averages >= 1 and max p_estcpu of 255, sleeping for at
|
|
* least six times the loadfactor will decay p_estcpu to zero.
|
|
*/
|
|
void
|
|
updatepri(td)
|
|
register struct thread *td;
|
|
{
|
|
register struct ksegrp *kg;
|
|
register unsigned int newcpu;
|
|
register fixpt_t loadfac = loadfactor(averunnable.ldavg[0]);
|
|
|
|
if (td == NULL)
|
|
return;
|
|
kg = td->td_ksegrp;
|
|
newcpu = kg->kg_estcpu;
|
|
if (kg->kg_slptime > 5 * loadfac)
|
|
kg->kg_estcpu = 0;
|
|
else {
|
|
kg->kg_slptime--; /* the first time was done in schedcpu */
|
|
while (newcpu && --kg->kg_slptime)
|
|
newcpu = decay_cpu(loadfac, newcpu);
|
|
kg->kg_estcpu = newcpu;
|
|
}
|
|
resetpriority(td->td_ksegrp);
|
|
}
|
|
|
|
/*
|
|
* We're only looking at 7 bits of the address; everything is
|
|
* aligned to 4, lots of things are aligned to greater powers
|
|
* of 2. Shift right by 8, i.e. drop the bottom 256 worth.
|
|
*/
|
|
#define TABLESIZE 128
|
|
static TAILQ_HEAD(slpquehead, thread) slpque[TABLESIZE];
|
|
#define LOOKUP(x) (((intptr_t)(x) >> 8) & (TABLESIZE - 1))
|
|
|
|
void
|
|
sleepinit(void)
|
|
{
|
|
int i;
|
|
|
|
sched_quantum = hz/10;
|
|
hogticks = 2 * sched_quantum;
|
|
for (i = 0; i < TABLESIZE; i++)
|
|
TAILQ_INIT(&slpque[i]);
|
|
}
|
|
|
|
/*
|
|
* General sleep call. Suspends the current process until a wakeup is
|
|
* performed on the specified identifier. The process 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 mutex argument is exited before the caller is suspended, and
|
|
* entered before msleep returns. If priority includes the PDROP
|
|
* flag the mutex is not entered before returning.
|
|
*/
|
|
int
|
|
msleep(ident, mtx, priority, wmesg, timo)
|
|
void *ident;
|
|
struct mtx *mtx;
|
|
int priority, timo;
|
|
const char *wmesg;
|
|
{
|
|
struct proc *p = curproc;
|
|
struct thread *td = curthread;
|
|
int sig, catch = priority & PCATCH;
|
|
int rval = 0;
|
|
WITNESS_SAVE_DECL(mtx);
|
|
|
|
#ifdef KTRACE
|
|
if (p && KTRPOINT(p, KTR_CSW))
|
|
ktrcsw(p->p_tracep, 1, 0);
|
|
#endif
|
|
WITNESS_SLEEP(0, &mtx->mtx_object);
|
|
KASSERT(timo != 0 || mtx_owned(&Giant) || mtx != NULL,
|
|
("sleeping without a mutex"));
|
|
mtx_lock_spin(&sched_lock);
|
|
if (cold || panicstr) {
|
|
/*
|
|
* After a panic, or during autoconfiguration,
|
|
* just give interrupts a chance, then just return;
|
|
* don't run any other procs or panic below,
|
|
* in case this is the idle process and already asleep.
|
|
*/
|
|
if (mtx != NULL && priority & PDROP)
|
|
mtx_unlock(mtx);
|
|
mtx_unlock_spin(&sched_lock);
|
|
return (0);
|
|
}
|
|
|
|
DROP_GIANT();
|
|
|
|
if (mtx != NULL) {
|
|
mtx_assert(mtx, MA_OWNED | MA_NOTRECURSED);
|
|
WITNESS_SAVE(&mtx->mtx_object, mtx);
|
|
mtx_unlock(mtx);
|
|
if (priority & PDROP)
|
|
mtx = NULL;
|
|
}
|
|
|
|
KASSERT(p != NULL, ("msleep1"));
|
|
KASSERT(ident != NULL && td->td_proc->p_stat == SRUN, ("msleep"));
|
|
|
|
td->td_wchan = ident;
|
|
td->td_wmesg = wmesg;
|
|
td->td_kse->ke_slptime = 0; /* XXXKSE */
|
|
td->td_ksegrp->kg_slptime = 0;
|
|
td->td_ksegrp->kg_pri.pri_level = priority & PRIMASK;
|
|
CTR5(KTR_PROC, "msleep: thread %p (pid %d, %s) on %s (%p)",
|
|
td, p->p_pid, p->p_comm, wmesg, ident);
|
|
TAILQ_INSERT_TAIL(&slpque[LOOKUP(ident)], td, td_slpq);
|
|
if (timo)
|
|
callout_reset(&td->td_slpcallout, timo, endtsleep, td);
|
|
/*
|
|
* We put ourselves on the sleep queue and start our timeout
|
|
* before calling CURSIG, as we could stop there, and a wakeup
|
|
* or a SIGCONT (or both) could occur while we were stopped.
|
|
* A SIGCONT would cause us to be marked as SSLEEP
|
|
* without resuming us, thus we must be ready for sleep
|
|
* when CURSIG is called. If the wakeup happens while we're
|
|
* stopped, td->td_wchan will be 0 upon return from CURSIG.
|
|
*/
|
|
if (catch) {
|
|
CTR3(KTR_PROC, "msleep caught: proc %p (pid %d, %s)", p,
|
|
p->p_pid, p->p_comm);
|
|
td->td_flags |= TDF_SINTR;
|
|
mtx_unlock_spin(&sched_lock);
|
|
PROC_LOCK(p);
|
|
sig = CURSIG(p);
|
|
mtx_lock_spin(&sched_lock);
|
|
PROC_UNLOCK(p);
|
|
if (sig != 0) {
|
|
if (td->td_wchan != NULL)
|
|
unsleep(td);
|
|
} else if (td->td_wchan == NULL)
|
|
catch = 0;
|
|
} else
|
|
sig = 0;
|
|
if (td->td_wchan != NULL) {
|
|
td->td_proc->p_stat = SSLEEP;
|
|
p->p_stats->p_ru.ru_nvcsw++;
|
|
mi_switch();
|
|
}
|
|
CTR3(KTR_PROC, "msleep resume: proc %p (pid %d, %s)", td, p->p_pid,
|
|
p->p_comm);
|
|
KASSERT(td->td_proc->p_stat == SRUN, ("running but not SRUN"));
|
|
td->td_flags &= ~TDF_SINTR;
|
|
if (td->td_flags & TDF_TIMEOUT) {
|
|
td->td_flags &= ~TDF_TIMEOUT;
|
|
if (sig == 0)
|
|
rval = EWOULDBLOCK;
|
|
} else if (td->td_flags & TDF_TIMOFAIL)
|
|
td->td_flags &= ~TDF_TIMOFAIL;
|
|
else if (timo && callout_stop(&td->td_slpcallout) == 0) {
|
|
/*
|
|
* This isn't supposed to be pretty. If we are here, then
|
|
* the endtsleep() callout is currently executing on another
|
|
* CPU and is either spinning on the sched_lock or will be
|
|
* soon. If we don't synchronize here, there is a chance
|
|
* that this process may msleep() again before the callout
|
|
* has a chance to run and the callout may end up waking up
|
|
* the wrong msleep(). Yuck.
|
|
*/
|
|
td->td_flags |= TDF_TIMEOUT;
|
|
p->p_stats->p_ru.ru_nivcsw++;
|
|
mi_switch();
|
|
}
|
|
mtx_unlock_spin(&sched_lock);
|
|
|
|
if (rval == 0 && catch) {
|
|
PROC_LOCK(p);
|
|
/* XXX: shouldn't we always be calling CURSIG() */
|
|
if (sig != 0 || (sig = CURSIG(p))) {
|
|
if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
|
|
rval = EINTR;
|
|
else
|
|
rval = ERESTART;
|
|
}
|
|
PROC_UNLOCK(p);
|
|
}
|
|
PICKUP_GIANT();
|
|
#ifdef KTRACE
|
|
mtx_lock(&Giant);
|
|
if (KTRPOINT(p, KTR_CSW))
|
|
ktrcsw(p->p_tracep, 0, 0);
|
|
mtx_unlock(&Giant);
|
|
#endif
|
|
if (mtx != NULL) {
|
|
mtx_lock(mtx);
|
|
WITNESS_RESTORE(&mtx->mtx_object, mtx);
|
|
}
|
|
return (rval);
|
|
}
|
|
|
|
/*
|
|
* Implement timeout for msleep()
|
|
*
|
|
* If process hasn't been awakened (wchan non-zero),
|
|
* set timeout flag and undo the sleep. If proc
|
|
* is stopped, just unsleep so it will remain stopped.
|
|
* MP-safe, called without the Giant mutex.
|
|
*/
|
|
static void
|
|
endtsleep(arg)
|
|
void *arg;
|
|
{
|
|
register struct thread *td = arg;
|
|
|
|
CTR3(KTR_PROC, "endtsleep: thread %p (pid %d, %s)", td, td->td_proc->p_pid,
|
|
td->td_proc->p_comm);
|
|
mtx_lock_spin(&sched_lock);
|
|
/*
|
|
* This is the other half of the synchronization with msleep()
|
|
* described above. If the PS_TIMEOUT flag is set, we lost the
|
|
* race and just need to put the process back on the runqueue.
|
|
*/
|
|
if ((td->td_flags & TDF_TIMEOUT) != 0) {
|
|
td->td_flags &= ~TDF_TIMEOUT;
|
|
setrunqueue(td);
|
|
} else if (td->td_wchan != NULL) {
|
|
if (td->td_proc->p_stat == SSLEEP) /* XXXKSE */
|
|
setrunnable(td);
|
|
else
|
|
unsleep(td);
|
|
td->td_flags |= TDF_TIMEOUT;
|
|
} else {
|
|
td->td_flags |= TDF_TIMOFAIL;
|
|
}
|
|
mtx_unlock_spin(&sched_lock);
|
|
}
|
|
|
|
/*
|
|
* Remove a process from its wait queue
|
|
*/
|
|
void
|
|
unsleep(struct thread *td)
|
|
{
|
|
|
|
mtx_lock_spin(&sched_lock);
|
|
if (td->td_wchan != NULL) {
|
|
TAILQ_REMOVE(&slpque[LOOKUP(td->td_wchan)], td, td_slpq);
|
|
td->td_wchan = NULL;
|
|
}
|
|
mtx_unlock_spin(&sched_lock);
|
|
}
|
|
|
|
/*
|
|
* Make all processes sleeping on the specified identifier runnable.
|
|
*/
|
|
void
|
|
wakeup(ident)
|
|
register void *ident;
|
|
{
|
|
register struct slpquehead *qp;
|
|
register struct thread *td;
|
|
struct proc *p;
|
|
|
|
mtx_lock_spin(&sched_lock);
|
|
qp = &slpque[LOOKUP(ident)];
|
|
restart:
|
|
TAILQ_FOREACH(td, qp, td_slpq) {
|
|
p = td->td_proc;
|
|
if (td->td_wchan == ident) {
|
|
TAILQ_REMOVE(qp, td, td_slpq);
|
|
td->td_wchan = NULL;
|
|
if (td->td_proc->p_stat == SSLEEP) {
|
|
/* OPTIMIZED EXPANSION OF setrunnable(p); */
|
|
CTR3(KTR_PROC, "wakeup: thread %p (pid %d, %s)",
|
|
td, p->p_pid, p->p_comm);
|
|
if (td->td_ksegrp->kg_slptime > 1)
|
|
updatepri(td);
|
|
td->td_ksegrp->kg_slptime = 0;
|
|
td->td_kse->ke_slptime = 0;
|
|
td->td_proc->p_stat = SRUN;
|
|
if (p->p_sflag & PS_INMEM) {
|
|
setrunqueue(td);
|
|
maybe_resched(td->td_ksegrp);
|
|
} else {
|
|
p->p_sflag |= PS_SWAPINREQ;
|
|
wakeup((caddr_t)&proc0);
|
|
}
|
|
/* END INLINE EXPANSION */
|
|
goto restart;
|
|
}
|
|
}
|
|
}
|
|
mtx_unlock_spin(&sched_lock);
|
|
}
|
|
|
|
/*
|
|
* Make a process sleeping on the specified identifier runnable.
|
|
* May wake more than one process if a target process is currently
|
|
* swapped out.
|
|
*/
|
|
void
|
|
wakeup_one(ident)
|
|
register void *ident;
|
|
{
|
|
register struct slpquehead *qp;
|
|
register struct thread *td;
|
|
register struct proc *p;
|
|
|
|
mtx_lock_spin(&sched_lock);
|
|
qp = &slpque[LOOKUP(ident)];
|
|
|
|
TAILQ_FOREACH(td, qp, td_slpq) {
|
|
p = td->td_proc;
|
|
if (td->td_wchan == ident) {
|
|
TAILQ_REMOVE(qp, td, td_slpq);
|
|
td->td_wchan = NULL;
|
|
if (td->td_proc->p_stat == SSLEEP) {
|
|
/* OPTIMIZED EXPANSION OF setrunnable(p); */
|
|
CTR3(KTR_PROC, "wakeup1: proc %p (pid %d, %s)",
|
|
p, p->p_pid, p->p_comm);
|
|
if (td->td_ksegrp->kg_slptime > 1)
|
|
updatepri(td);
|
|
td->td_ksegrp->kg_slptime = 0;
|
|
td->td_kse->ke_slptime = 0;
|
|
td->td_proc->p_stat = SRUN;
|
|
if (p->p_sflag & PS_INMEM) {
|
|
setrunqueue(td);
|
|
maybe_resched(td->td_ksegrp);
|
|
break;
|
|
} else {
|
|
p->p_sflag |= PS_SWAPINREQ;
|
|
wakeup((caddr_t)&proc0);
|
|
}
|
|
/* END INLINE EXPANSION */
|
|
}
|
|
}
|
|
}
|
|
mtx_unlock_spin(&sched_lock);
|
|
}
|
|
|
|
/*
|
|
* The machine independent parts of mi_switch().
|
|
*/
|
|
void
|
|
mi_switch()
|
|
{
|
|
struct timeval new_switchtime;
|
|
struct thread *td = curthread; /* XXX */
|
|
register struct proc *p = td->td_proc; /* XXX */
|
|
#if 0
|
|
register struct rlimit *rlim;
|
|
#endif
|
|
u_int sched_nest;
|
|
|
|
mtx_assert(&sched_lock, MA_OWNED | MA_NOTRECURSED);
|
|
#ifdef INVARIANTS
|
|
if (p->p_stat != SMTX && p->p_stat != SRUN)
|
|
mtx_assert(&Giant, MA_NOTOWNED);
|
|
#endif
|
|
|
|
/*
|
|
* Compute the amount of time during which the current
|
|
* process was running, and add that to its total so far.
|
|
*/
|
|
microuptime(&new_switchtime);
|
|
if (timevalcmp(&new_switchtime, PCPU_PTR(switchtime), <)) {
|
|
#if 0
|
|
/* XXX: This doesn't play well with sched_lock right now. */
|
|
printf("microuptime() went backwards (%ld.%06ld -> %ld.%06ld)\n",
|
|
PCPU_GET(switchtime.tv_sec), PCPU_GET(switchtime.tv_usec),
|
|
new_switchtime.tv_sec, new_switchtime.tv_usec);
|
|
#endif
|
|
new_switchtime = PCPU_GET(switchtime);
|
|
} else {
|
|
p->p_runtime += (new_switchtime.tv_usec - PCPU_GET(switchtime.tv_usec)) +
|
|
(new_switchtime.tv_sec - PCPU_GET(switchtime.tv_sec)) *
|
|
(int64_t)1000000;
|
|
}
|
|
|
|
#ifdef DDB
|
|
/*
|
|
* Don't perform context switches from the debugger.
|
|
*/
|
|
if (db_active) {
|
|
mtx_unlock_spin(&sched_lock);
|
|
db_error("Context switches not allowed in the debugger.");
|
|
}
|
|
#endif
|
|
|
|
#if 0
|
|
/*
|
|
* Check if the process exceeds its cpu resource allocation.
|
|
* If over max, kill it.
|
|
*
|
|
* XXX drop sched_lock, pickup Giant
|
|
*/
|
|
if (p->p_stat != SZOMB && p->p_limit->p_cpulimit != RLIM_INFINITY &&
|
|
p->p_runtime > p->p_limit->p_cpulimit) {
|
|
rlim = &p->p_rlimit[RLIMIT_CPU];
|
|
if (p->p_runtime / (rlim_t)1000000 >= rlim->rlim_max) {
|
|
mtx_unlock_spin(&sched_lock);
|
|
PROC_LOCK(p);
|
|
killproc(p, "exceeded maximum CPU limit");
|
|
mtx_lock_spin(&sched_lock);
|
|
PROC_UNLOCK(p);
|
|
} else {
|
|
mtx_unlock_spin(&sched_lock);
|
|
PROC_LOCK(p);
|
|
psignal(p, SIGXCPU);
|
|
mtx_lock_spin(&sched_lock);
|
|
PROC_UNLOCK(p);
|
|
if (rlim->rlim_cur < rlim->rlim_max) {
|
|
/* XXX: we should make a private copy */
|
|
rlim->rlim_cur += 5;
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Pick a new current process and record its start time.
|
|
*/
|
|
cnt.v_swtch++;
|
|
PCPU_SET(switchtime, new_switchtime);
|
|
CTR3(KTR_PROC, "mi_switch: old proc %p (pid %d, %s)", p, p->p_pid,
|
|
p->p_comm);
|
|
sched_nest = sched_lock.mtx_recurse;
|
|
td->td_lastcpu = td->td_kse->ke_oncpu;
|
|
td->td_kse->ke_oncpu = NOCPU;
|
|
td->td_kse->ke_flags &= ~KEF_NEEDRESCHED;
|
|
cpu_switch();
|
|
td->td_kse->ke_oncpu = PCPU_GET(cpuid);
|
|
sched_lock.mtx_recurse = sched_nest;
|
|
sched_lock.mtx_lock = (uintptr_t)td;
|
|
CTR3(KTR_PROC, "mi_switch: new proc %p (pid %d, %s)", p, p->p_pid,
|
|
p->p_comm);
|
|
if (PCPU_GET(switchtime.tv_sec) == 0)
|
|
microuptime(PCPU_PTR(switchtime));
|
|
PCPU_SET(switchticks, ticks);
|
|
}
|
|
|
|
/*
|
|
* Change process state to be runnable,
|
|
* placing it on the run queue if it is in memory,
|
|
* and awakening the swapper if it isn't in memory.
|
|
*/
|
|
void
|
|
setrunnable(struct thread *td)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
|
|
mtx_lock_spin(&sched_lock);
|
|
switch (p->p_stat) {
|
|
case SZOMB: /* not a thread flag XXXKSE */
|
|
panic("setrunnable(1)");
|
|
}
|
|
switch (td->td_proc->p_stat) {
|
|
case 0:
|
|
case SRUN:
|
|
case SWAIT:
|
|
default:
|
|
panic("setrunnable(2)");
|
|
case SSTOP:
|
|
case SSLEEP: /* e.g. when sending signals */
|
|
if (td->td_flags & TDF_CVWAITQ)
|
|
cv_waitq_remove(td);
|
|
else
|
|
unsleep(td);
|
|
break;
|
|
|
|
case SIDL:
|
|
break;
|
|
}
|
|
td->td_proc->p_stat = SRUN;
|
|
if (td->td_ksegrp->kg_slptime > 1)
|
|
updatepri(td);
|
|
td->td_ksegrp->kg_slptime = 0;
|
|
td->td_kse->ke_slptime = 0;
|
|
if ((p->p_sflag & PS_INMEM) == 0) {
|
|
p->p_sflag |= PS_SWAPINREQ;
|
|
wakeup((caddr_t)&proc0);
|
|
} else {
|
|
setrunqueue(td);
|
|
maybe_resched(td->td_ksegrp);
|
|
}
|
|
mtx_unlock_spin(&sched_lock);
|
|
}
|
|
|
|
/*
|
|
* Compute the priority of a process when running in user mode.
|
|
* Arrange to reschedule if the resulting priority is better
|
|
* than that of the current process.
|
|
*/
|
|
void
|
|
resetpriority(kg)
|
|
register struct ksegrp *kg;
|
|
{
|
|
register unsigned int newpriority;
|
|
|
|
mtx_lock_spin(&sched_lock);
|
|
if (kg->kg_pri.pri_class == PRI_TIMESHARE) {
|
|
newpriority = PUSER + kg->kg_estcpu / INVERSE_ESTCPU_WEIGHT +
|
|
NICE_WEIGHT * (kg->kg_nice - PRIO_MIN);
|
|
newpriority = min(max(newpriority, PRI_MIN_TIMESHARE),
|
|
PRI_MAX_TIMESHARE);
|
|
kg->kg_pri.pri_user = newpriority;
|
|
}
|
|
maybe_resched(kg);
|
|
mtx_unlock_spin(&sched_lock);
|
|
}
|
|
|
|
/*
|
|
* Compute a tenex style load average of a quantity on
|
|
* 1, 5 and 15 minute intervals.
|
|
* XXXKSE Needs complete rewrite when correct info is available.
|
|
* Completely Bogus.. only works with 1:1 (but compiles ok now :-)
|
|
*/
|
|
static void
|
|
loadav(void *arg)
|
|
{
|
|
int i, nrun;
|
|
struct loadavg *avg;
|
|
struct proc *p;
|
|
struct ksegrp *kg;
|
|
|
|
avg = &averunnable;
|
|
sx_slock(&allproc_lock);
|
|
nrun = 0;
|
|
FOREACH_PROC_IN_SYSTEM(p) {
|
|
FOREACH_KSEGRP_IN_PROC(p, kg) {
|
|
switch (p->p_stat) {
|
|
case SRUN:
|
|
if ((p->p_flag & P_NOLOAD) != 0)
|
|
goto nextproc;
|
|
/* FALLTHROUGH */
|
|
case SIDL:
|
|
nrun++;
|
|
}
|
|
nextproc:
|
|
}
|
|
}
|
|
sx_sunlock(&allproc_lock);
|
|
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
|
|
sched_setup(dummy)
|
|
void *dummy;
|
|
{
|
|
|
|
callout_init(&schedcpu_callout, 1);
|
|
callout_init(&roundrobin_callout, 0);
|
|
callout_init(&loadav_callout, 0);
|
|
|
|
/* Kick off timeout driven events by calling first time. */
|
|
roundrobin(NULL);
|
|
schedcpu(NULL);
|
|
loadav(NULL);
|
|
}
|
|
|
|
/*
|
|
* We adjust the priority of the current process. The priority of
|
|
* a process gets worse as it accumulates CPU time. The cpu usage
|
|
* estimator (p_estcpu) is increased here. resetpriority() will
|
|
* compute a different priority each time p_estcpu increases by
|
|
* INVERSE_ESTCPU_WEIGHT
|
|
* (until MAXPRI is reached). The cpu usage estimator ramps up
|
|
* quite quickly when the process is running (linearly), and decays
|
|
* away exponentially, at a rate which is proportionally slower when
|
|
* the system is busy. The basic principle is that the system will
|
|
* 90% forget that the process used a lot of CPU time in 5 * loadav
|
|
* seconds. This causes the system to favor processes which haven't
|
|
* run much recently, and to round-robin among other processes.
|
|
*/
|
|
void
|
|
schedclock(td)
|
|
struct thread *td;
|
|
{
|
|
struct kse *ke = td->td_kse;
|
|
struct ksegrp *kg = td->td_ksegrp;
|
|
|
|
if (td) {
|
|
ke->ke_cpticks++;
|
|
kg->kg_estcpu = ESTCPULIM(kg->kg_estcpu + 1);
|
|
if ((kg->kg_estcpu % INVERSE_ESTCPU_WEIGHT) == 0) {
|
|
resetpriority(td->td_ksegrp);
|
|
if (kg->kg_pri.pri_level >= PUSER)
|
|
kg->kg_pri.pri_level = kg->kg_pri.pri_user;
|
|
}
|
|
} else {
|
|
panic("schedclock");
|
|
}
|
|
}
|
|
|
|
/*
|
|
* General purpose yield system call
|
|
*/
|
|
int
|
|
yield(struct thread *td, struct yield_args *uap)
|
|
{
|
|
struct ksegrp *kg = td->td_ksegrp;
|
|
|
|
mtx_assert(&Giant, MA_NOTOWNED);
|
|
mtx_lock_spin(&sched_lock);
|
|
kg->kg_pri.pri_level = PRI_MAX_TIMESHARE;
|
|
setrunqueue(td);
|
|
kg->kg_proc->p_stats->p_ru.ru_nvcsw++;
|
|
mi_switch();
|
|
mtx_unlock_spin(&sched_lock);
|
|
td->td_retval[0] = 0;
|
|
|
|
return (0);
|
|
}
|
|
|