812 lines
21 KiB
C
812 lines
21 KiB
C
/* $NetBSD: sched_4bsd.c,v 1.15 2008/04/02 17:40:15 ad Exp $ */
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/*-
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* Copyright (c) 1999, 2000, 2004, 2006, 2007 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
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* NASA Ames Research Center, by Charles M. Hannum, Andrew Doran, and
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* Daniel Sieger.
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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 NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*-
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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. 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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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: sched_4bsd.c,v 1.15 2008/04/02 17:40:15 ad Exp $");
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#include "opt_ddb.h"
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#include "opt_lockdebug.h"
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#include "opt_perfctrs.h"
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#define __MUTEX_PRIVATE
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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/cpu.h>
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#include <sys/proc.h>
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#include <sys/kernel.h>
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#include <sys/signalvar.h>
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#include <sys/resourcevar.h>
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#include <sys/sched.h>
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#include <sys/sysctl.h>
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#include <sys/kauth.h>
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#include <sys/lockdebug.h>
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#include <sys/kmem.h>
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#include <sys/intr.h>
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#include <uvm/uvm_extern.h>
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/*
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* Run queues.
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*
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* We maintain bitmasks of non-empty queues in order speed up finding
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* the first runnable process. Since there can be (by definition) few
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* real time LWPs in the the system, we maintain them on a linked list,
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* sorted by priority.
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*/
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#define PPB_SHIFT 5
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#define PPB_MASK 31
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#define NUM_Q (NPRI_KERNEL + NPRI_USER)
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#define NUM_PPB (1 << PPB_SHIFT)
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#define NUM_B (NUM_Q / NUM_PPB)
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typedef struct runqueue {
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TAILQ_HEAD(, lwp) rq_fixedpri; /* realtime, kthread */
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u_int rq_count; /* total # jobs */
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uint32_t rq_bitmap[NUM_B]; /* bitmap of queues */
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TAILQ_HEAD(, lwp) rq_queue[NUM_Q]; /* user+kernel */
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} runqueue_t;
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static runqueue_t global_queue;
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static void updatepri(struct lwp *);
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static void resetpriority(struct lwp *);
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fixpt_t decay_cpu(fixpt_t, fixpt_t);
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extern unsigned int sched_pstats_ticks; /* defined in kern_synch.c */
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/* The global scheduler state */
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kmutex_t runqueue_lock;
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/* Number of hardclock ticks per sched_tick() */
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static int rrticks;
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const int schedppq = 1;
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/*
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* Force switch among equal priority processes every 100ms.
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* Called from hardclock every hz/10 == rrticks hardclock ticks.
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*
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* There's no need to lock anywhere in this routine, as it's
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* CPU-local and runs at IPL_SCHED (called from clock interrupt).
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*/
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/* ARGSUSED */
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void
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sched_tick(struct cpu_info *ci)
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{
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struct schedstate_percpu *spc = &ci->ci_schedstate;
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spc->spc_ticks = rrticks;
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if (CURCPU_IDLE_P()) {
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cpu_need_resched(ci, 0);
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return;
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}
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if (spc->spc_flags & SPCF_SEENRR) {
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/*
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* The process has already been through a roundrobin
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* without switching and may be hogging the CPU.
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* Indicate that the process should yield.
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*/
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spc->spc_flags |= SPCF_SHOULDYIELD;
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cpu_need_resched(ci, 0);
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} else
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spc->spc_flags |= SPCF_SEENRR;
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}
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/*
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* Why PRIO_MAX - 2? From setpriority(2):
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*
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* prio is a value in the range -20 to 20. The default priority is
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* 0; lower priorities cause more favorable scheduling. A value of
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* 19 or 20 will schedule a process only when nothing at priority <=
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* 0 is runnable.
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*
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* This gives estcpu influence over 18 priority levels, and leaves nice
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* with 40 levels. One way to think about it is that nice has 20 levels
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* either side of estcpu's 18.
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*/
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#define ESTCPU_SHIFT 11
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#define ESTCPU_MAX ((PRIO_MAX - 2) << ESTCPU_SHIFT)
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#define ESTCPU_ACCUM (1 << (ESTCPU_SHIFT - 1))
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#define ESTCPULIM(e) min((e), ESTCPU_MAX)
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/*
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* Constants for digital decay and forget:
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* 90% of (l_estcpu) usage in 5 * loadav time
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* 95% of (l_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 hardclock updates l_estcpu and l_cpticks independently.
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*
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* We wish to decay away 90% of l_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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* l_estcpu *= decay;
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* will compute
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* l_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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fixpt_t
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decay_cpu(fixpt_t loadfac, fixpt_t estcpu)
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{
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if (estcpu == 0) {
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return 0;
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}
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#if !defined(_LP64)
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/* avoid 64bit arithmetics. */
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#define FIXPT_MAX ((fixpt_t)((UINTMAX_C(1) << sizeof(fixpt_t) * CHAR_BIT) - 1))
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if (__predict_true(loadfac <= FIXPT_MAX / ESTCPU_MAX)) {
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return estcpu * loadfac / (loadfac + FSCALE);
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}
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#endif /* !defined(_LP64) */
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return (uint64_t)estcpu * loadfac / (loadfac + FSCALE);
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}
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/*
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* For all load averages >= 1 and max l_estcpu of (255 << ESTCPU_SHIFT),
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* sleeping for at least seven times the loadfactor will decay l_estcpu to
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* less than (1 << ESTCPU_SHIFT).
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*
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* note that our ESTCPU_MAX is actually much smaller than (255 << ESTCPU_SHIFT).
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*/
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static fixpt_t
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decay_cpu_batch(fixpt_t loadfac, fixpt_t estcpu, unsigned int n)
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{
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if ((n << FSHIFT) >= 7 * loadfac) {
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return 0;
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}
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while (estcpu != 0 && n > 1) {
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estcpu = decay_cpu(loadfac, estcpu);
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n--;
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}
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return estcpu;
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}
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/*
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* sched_pstats_hook:
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*
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* Periodically called from sched_pstats(); used to recalculate priorities.
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*/
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void
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sched_pstats_hook(struct lwp *l)
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{
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fixpt_t loadfac;
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int sleeptm;
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/*
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* If the LWP has slept an entire second, stop recalculating
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* its priority until it wakes up.
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*/
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if (l->l_stat == LSSLEEP || l->l_stat == LSSTOP ||
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l->l_stat == LSSUSPENDED) {
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l->l_slptime++;
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sleeptm = 1;
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} else {
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sleeptm = 0x7fffffff;
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}
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if (l->l_slptime <= sleeptm) {
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loadfac = 2 * (averunnable.ldavg[0]);
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l->l_estcpu = decay_cpu(loadfac, l->l_estcpu);
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resetpriority(l);
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}
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}
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/*
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* Recalculate the priority of a process after it has slept for a while.
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*/
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static void
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updatepri(struct lwp *l)
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{
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fixpt_t loadfac;
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KASSERT(lwp_locked(l, NULL));
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KASSERT(l->l_slptime > 1);
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loadfac = loadfactor(averunnable.ldavg[0]);
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l->l_slptime--; /* the first time was done in sched_pstats */
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l->l_estcpu = decay_cpu_batch(loadfac, l->l_estcpu, l->l_slptime);
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resetpriority(l);
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}
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static void
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runqueue_init(runqueue_t *rq)
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{
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int i;
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for (i = 0; i < NUM_Q; i++)
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TAILQ_INIT(&rq->rq_queue[i]);
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for (i = 0; i < NUM_B; i++)
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rq->rq_bitmap[i] = 0;
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TAILQ_INIT(&rq->rq_fixedpri);
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rq->rq_count = 0;
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}
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static void
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runqueue_enqueue(runqueue_t *rq, struct lwp *l)
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{
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pri_t pri;
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lwp_t *l2;
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KASSERT(lwp_locked(l, l->l_cpu->ci_schedstate.spc_mutex));
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pri = lwp_eprio(l);
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rq->rq_count++;
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if (pri >= PRI_KTHREAD) {
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TAILQ_FOREACH(l2, &rq->rq_fixedpri, l_runq) {
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if (lwp_eprio(l2) < pri) {
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TAILQ_INSERT_BEFORE(l2, l, l_runq);
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return;
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}
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}
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TAILQ_INSERT_TAIL(&rq->rq_fixedpri, l, l_runq);
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return;
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}
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rq->rq_bitmap[pri >> PPB_SHIFT] |=
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(0x80000000U >> (pri & PPB_MASK));
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TAILQ_INSERT_TAIL(&rq->rq_queue[pri], l, l_runq);
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}
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static void
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runqueue_dequeue(runqueue_t *rq, struct lwp *l)
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{
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pri_t pri;
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KASSERT(lwp_locked(l, l->l_cpu->ci_schedstate.spc_mutex));
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pri = lwp_eprio(l);
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rq->rq_count--;
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if (pri >= PRI_KTHREAD) {
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TAILQ_REMOVE(&rq->rq_fixedpri, l, l_runq);
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return;
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}
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TAILQ_REMOVE(&rq->rq_queue[pri], l, l_runq);
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if (TAILQ_EMPTY(&rq->rq_queue[pri]))
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rq->rq_bitmap[pri >> PPB_SHIFT] ^=
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(0x80000000U >> (pri & PPB_MASK));
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}
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#if (NUM_B != 3) || (NUM_Q != 96)
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#error adjust runqueue_nextlwp
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#endif
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static struct lwp *
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runqueue_nextlwp(runqueue_t *rq)
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{
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pri_t pri;
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KASSERT(rq->rq_count != 0);
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if (!TAILQ_EMPTY(&rq->rq_fixedpri))
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return TAILQ_FIRST(&rq->rq_fixedpri);
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if (rq->rq_bitmap[2] != 0)
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pri = 96 - ffs(rq->rq_bitmap[2]);
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else if (rq->rq_bitmap[1] != 0)
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pri = 64 - ffs(rq->rq_bitmap[1]);
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else
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pri = 32 - ffs(rq->rq_bitmap[0]);
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return TAILQ_FIRST(&rq->rq_queue[pri]);
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}
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#if defined(DDB)
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static void
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runqueue_print(const runqueue_t *rq, void (*pr)(const char *, ...))
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{
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CPU_INFO_ITERATOR cii;
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struct cpu_info *ci;
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lwp_t *l;
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int i;
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printf("PID\tLID\tPRI\tIPRI\tEPRI\tLWP\t\t NAME\n");
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TAILQ_FOREACH(l, &rq->rq_fixedpri, l_runq) {
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(*pr)("%d\t%d\%d\t%d\t%d\t%016lx %s\n",
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l->l_proc->p_pid, l->l_lid, (int)l->l_priority,
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(int)l->l_inheritedprio, lwp_eprio(l),
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(long)l, l->l_proc->p_comm);
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}
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for (i = NUM_Q - 1; i >= 0; i--) {
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TAILQ_FOREACH(l, &rq->rq_queue[i], l_runq) {
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(*pr)("%d\t%d\t%d\t%d\t%d\t%016lx %s\n",
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l->l_proc->p_pid, l->l_lid, (int)l->l_priority,
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(int)l->l_inheritedprio, lwp_eprio(l),
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(long)l, l->l_proc->p_comm);
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}
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}
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printf("CPUIDX\tRESCHED\tCURPRI\tFLAGS\n");
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for (CPU_INFO_FOREACH(cii, ci)) {
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printf("%d\t%d\t%d\t%04x\n", (int)ci->ci_index,
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(int)ci->ci_want_resched,
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(int)ci->ci_schedstate.spc_curpriority,
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(int)ci->ci_schedstate.spc_flags);
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}
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printf("NEXTLWP\n%016lx\n", (long)sched_nextlwp());
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}
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#endif /* defined(DDB) */
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/*
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* Initialize the (doubly-linked) run queues
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* to be empty.
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*/
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void
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sched_rqinit(void)
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{
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runqueue_init(&global_queue);
|
|
mutex_init(&runqueue_lock, MUTEX_DEFAULT, IPL_SCHED);
|
|
}
|
|
|
|
void
|
|
sched_cpuattach(struct cpu_info *ci)
|
|
{
|
|
runqueue_t *rq;
|
|
|
|
if (lwp0.l_cpu == ci) {
|
|
/* Initialize the lock pointer for lwp0 */
|
|
lwp0.l_mutex = curcpu()->ci_schedstate.spc_lwplock;
|
|
}
|
|
|
|
ci->ci_schedstate.spc_mutex = &runqueue_lock;
|
|
rq = kmem_zalloc(sizeof(*rq), KM_SLEEP);
|
|
runqueue_init(rq);
|
|
ci->ci_schedstate.spc_sched_info = rq;
|
|
}
|
|
|
|
void
|
|
sched_setup(void)
|
|
{
|
|
|
|
rrticks = hz / 10;
|
|
}
|
|
|
|
void
|
|
sched_setrunnable(struct lwp *l)
|
|
{
|
|
|
|
if (l->l_slptime > 1)
|
|
updatepri(l);
|
|
}
|
|
|
|
bool
|
|
sched_curcpu_runnable_p(void)
|
|
{
|
|
struct schedstate_percpu *spc;
|
|
struct cpu_info *ci;
|
|
int bits;
|
|
|
|
ci = curcpu();
|
|
spc = &ci->ci_schedstate;
|
|
#ifndef __HAVE_FAST_SOFTINTS
|
|
bits = ci->ci_data.cpu_softints;
|
|
bits |= ((runqueue_t *)spc->spc_sched_info)->rq_count;
|
|
#else
|
|
bits = ((runqueue_t *)spc->spc_sched_info)->rq_count;
|
|
#endif
|
|
if (__predict_true((spc->spc_flags & SPCF_OFFLINE) == 0))
|
|
bits |= global_queue.rq_count;
|
|
return bits != 0;
|
|
}
|
|
|
|
void
|
|
sched_nice(struct proc *p, int n)
|
|
{
|
|
struct lwp *l;
|
|
|
|
KASSERT(mutex_owned(&p->p_smutex));
|
|
|
|
p->p_nice = n;
|
|
LIST_FOREACH(l, &p->p_lwps, l_sibling) {
|
|
lwp_lock(l);
|
|
resetpriority(l);
|
|
lwp_unlock(l);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Recompute the priority of an LWP. Arrange to reschedule if
|
|
* the resulting priority is better than that of the current LWP.
|
|
*/
|
|
static void
|
|
resetpriority(struct lwp *l)
|
|
{
|
|
pri_t pri;
|
|
struct proc *p = l->l_proc;
|
|
|
|
KASSERT(lwp_locked(l, NULL));
|
|
|
|
if (l->l_class != SCHED_OTHER)
|
|
return;
|
|
|
|
/* See comments above ESTCPU_SHIFT definition. */
|
|
pri = (PRI_KERNEL - 1) - (l->l_estcpu >> ESTCPU_SHIFT) - p->p_nice;
|
|
pri = imax(pri, 0);
|
|
if (pri != l->l_priority)
|
|
lwp_changepri(l, pri);
|
|
}
|
|
|
|
/*
|
|
* We adjust the priority of the current process. The priority of a process
|
|
* gets worse as it accumulates CPU time. The CPU usage estimator (l_estcpu)
|
|
* is increased here. The formula for computing priorities (in kern_synch.c)
|
|
* will compute a different value each time l_estcpu increases. This can
|
|
* cause a switch, but unless the priority crosses a PPQ boundary the actual
|
|
* queue will not change. 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
|
|
sched_schedclock(struct lwp *l)
|
|
{
|
|
|
|
if (l->l_class != SCHED_OTHER)
|
|
return;
|
|
|
|
KASSERT(!CURCPU_IDLE_P());
|
|
l->l_estcpu = ESTCPULIM(l->l_estcpu + ESTCPU_ACCUM);
|
|
lwp_lock(l);
|
|
resetpriority(l);
|
|
lwp_unlock(l);
|
|
}
|
|
|
|
/*
|
|
* sched_proc_fork:
|
|
*
|
|
* Inherit the parent's scheduler history.
|
|
*/
|
|
void
|
|
sched_proc_fork(struct proc *parent, struct proc *child)
|
|
{
|
|
lwp_t *pl;
|
|
|
|
KASSERT(mutex_owned(&parent->p_smutex));
|
|
|
|
pl = LIST_FIRST(&parent->p_lwps);
|
|
child->p_estcpu_inherited = pl->l_estcpu;
|
|
child->p_forktime = sched_pstats_ticks;
|
|
}
|
|
|
|
/*
|
|
* sched_proc_exit:
|
|
*
|
|
* Chargeback parents for the sins of their children.
|
|
*/
|
|
void
|
|
sched_proc_exit(struct proc *parent, struct proc *child)
|
|
{
|
|
fixpt_t loadfac = loadfactor(averunnable.ldavg[0]);
|
|
fixpt_t estcpu;
|
|
lwp_t *pl, *cl;
|
|
|
|
/* XXX Only if parent != init?? */
|
|
|
|
mutex_enter(&parent->p_smutex);
|
|
pl = LIST_FIRST(&parent->p_lwps);
|
|
cl = LIST_FIRST(&child->p_lwps);
|
|
estcpu = decay_cpu_batch(loadfac, child->p_estcpu_inherited,
|
|
sched_pstats_ticks - child->p_forktime);
|
|
if (cl->l_estcpu > estcpu) {
|
|
lwp_lock(pl);
|
|
pl->l_estcpu = ESTCPULIM(pl->l_estcpu + cl->l_estcpu - estcpu);
|
|
lwp_unlock(pl);
|
|
}
|
|
mutex_exit(&parent->p_smutex);
|
|
}
|
|
|
|
void
|
|
sched_enqueue(struct lwp *l, bool ctxswitch)
|
|
{
|
|
|
|
if (__predict_false(l->l_target_cpu != NULL)) {
|
|
/* Global mutex is used - just change the CPU */
|
|
l->l_cpu = l->l_target_cpu;
|
|
l->l_target_cpu = NULL;
|
|
}
|
|
|
|
if ((l->l_flag & LW_BOUND) != 0)
|
|
runqueue_enqueue(l->l_cpu->ci_schedstate.spc_sched_info, l);
|
|
else
|
|
runqueue_enqueue(&global_queue, l);
|
|
}
|
|
|
|
/*
|
|
* XXXSMP When LWP dispatch (cpu_switch()) is changed to use sched_dequeue(),
|
|
* drop of the effective priority level from kernel to user needs to be
|
|
* moved here from userret(). The assignment in userret() is currently
|
|
* done unlocked.
|
|
*/
|
|
void
|
|
sched_dequeue(struct lwp *l)
|
|
{
|
|
|
|
if ((l->l_flag & LW_BOUND) != 0)
|
|
runqueue_dequeue(l->l_cpu->ci_schedstate.spc_sched_info, l);
|
|
else
|
|
runqueue_dequeue(&global_queue, l);
|
|
}
|
|
|
|
struct lwp *
|
|
sched_nextlwp(void)
|
|
{
|
|
struct schedstate_percpu *spc;
|
|
runqueue_t *rq;
|
|
lwp_t *l1, *l2;
|
|
|
|
spc = &curcpu()->ci_schedstate;
|
|
|
|
/* For now, just pick the highest priority LWP. */
|
|
rq = spc->spc_sched_info;
|
|
l1 = NULL;
|
|
if (rq->rq_count != 0)
|
|
l1 = runqueue_nextlwp(rq);
|
|
|
|
rq = &global_queue;
|
|
if (__predict_false((spc->spc_flags & SPCF_OFFLINE) != 0) ||
|
|
rq->rq_count == 0)
|
|
return l1;
|
|
l2 = runqueue_nextlwp(rq);
|
|
|
|
if (l1 == NULL)
|
|
return l2;
|
|
if (l2 == NULL)
|
|
return l1;
|
|
if (lwp_eprio(l2) > lwp_eprio(l1))
|
|
return l2;
|
|
else
|
|
return l1;
|
|
}
|
|
|
|
struct cpu_info *
|
|
sched_takecpu(struct lwp *l)
|
|
{
|
|
|
|
return l->l_cpu;
|
|
}
|
|
|
|
void
|
|
sched_wakeup(struct lwp *l)
|
|
{
|
|
|
|
}
|
|
|
|
void
|
|
sched_slept(struct lwp *l)
|
|
{
|
|
|
|
}
|
|
|
|
void
|
|
sched_lwp_fork(struct lwp *l1, struct lwp *l2)
|
|
{
|
|
|
|
l2->l_estcpu = l1->l_estcpu;
|
|
}
|
|
|
|
void
|
|
sched_lwp_exit(struct lwp *l)
|
|
{
|
|
|
|
}
|
|
|
|
void
|
|
sched_lwp_collect(struct lwp *t)
|
|
{
|
|
lwp_t *l;
|
|
|
|
/* Absorb estcpu value of collected LWP. */
|
|
l = curlwp;
|
|
lwp_lock(l);
|
|
l->l_estcpu += t->l_estcpu;
|
|
lwp_unlock(l);
|
|
}
|
|
|
|
/*
|
|
* Sysctl nodes and initialization.
|
|
*/
|
|
|
|
static int
|
|
sysctl_sched_rtts(SYSCTLFN_ARGS)
|
|
{
|
|
struct sysctlnode node;
|
|
int rttsms = hztoms(rrticks);
|
|
|
|
node = *rnode;
|
|
node.sysctl_data = &rttsms;
|
|
return sysctl_lookup(SYSCTLFN_CALL(&node));
|
|
}
|
|
|
|
SYSCTL_SETUP(sysctl_sched_setup, "sysctl kern.sched subtree setup")
|
|
{
|
|
const struct sysctlnode *node = NULL;
|
|
|
|
sysctl_createv(clog, 0, NULL, NULL,
|
|
CTLFLAG_PERMANENT,
|
|
CTLTYPE_NODE, "kern", NULL,
|
|
NULL, 0, NULL, 0,
|
|
CTL_KERN, CTL_EOL);
|
|
sysctl_createv(clog, 0, NULL, &node,
|
|
CTLFLAG_PERMANENT,
|
|
CTLTYPE_NODE, "sched",
|
|
SYSCTL_DESCR("Scheduler options"),
|
|
NULL, 0, NULL, 0,
|
|
CTL_KERN, CTL_CREATE, CTL_EOL);
|
|
|
|
KASSERT(node != NULL);
|
|
|
|
sysctl_createv(clog, 0, &node, NULL,
|
|
CTLFLAG_PERMANENT,
|
|
CTLTYPE_STRING, "name", NULL,
|
|
NULL, 0, __UNCONST("4.4BSD"), 0,
|
|
CTL_CREATE, CTL_EOL);
|
|
sysctl_createv(clog, 0, &node, NULL,
|
|
CTLFLAG_PERMANENT,
|
|
CTLTYPE_INT, "rtts",
|
|
SYSCTL_DESCR("Round-robin time quantum (in miliseconds)"),
|
|
sysctl_sched_rtts, 0, NULL, 0,
|
|
CTL_CREATE, CTL_EOL);
|
|
sysctl_createv(clog, 0, &node, NULL,
|
|
CTLFLAG_READWRITE,
|
|
CTLTYPE_INT, "timesoftints",
|
|
SYSCTL_DESCR("Track CPU time for soft interrupts"),
|
|
NULL, 0, &softint_timing, 0,
|
|
CTL_CREATE, CTL_EOL);
|
|
}
|
|
|
|
#if defined(DDB)
|
|
void
|
|
sched_print_runqueue(void (*pr)(const char *, ...))
|
|
{
|
|
|
|
runqueue_print(&global_queue, pr);
|
|
}
|
|
#endif /* defined(DDB) */
|