ef5f88c357
p_sched is unused. The struct td_sched is always co-allocated with the struct thread, except for the thread0. Avoid useless indirection, instead calculate td_sched location using simple pointer arithmetic in td_get_sched(9). For thread0, which is statically allocated, create a structure to emulate layout of the dynamic allocation. Reviewed by: jhb (previous version) Sponsored by: The FreeBSD Foundation Differential revision: https://reviews.freebsd.org/D6711
1798 lines
46 KiB
C
1798 lines
46 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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* 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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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_hwpmc_hooks.h"
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#include "opt_sched.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/cpuset.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/kthread.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/sched.h>
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#include <sys/sdt.h>
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#include <sys/smp.h>
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#include <sys/sysctl.h>
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#include <sys/sx.h>
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#include <sys/turnstile.h>
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#include <sys/umtx.h>
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#include <machine/pcb.h>
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#include <machine/smp.h>
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#ifdef HWPMC_HOOKS
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#include <sys/pmckern.h>
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#endif
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#ifdef KDTRACE_HOOKS
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#include <sys/dtrace_bsd.h>
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int dtrace_vtime_active;
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dtrace_vtime_switch_func_t dtrace_vtime_switch_func;
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#endif
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/*
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* INVERSE_ESTCPU_WEIGHT is only suitable for statclock() frequencies in
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* the range 100-256 Hz (approximately).
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*/
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#define ESTCPULIM(e) \
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min((e), INVERSE_ESTCPU_WEIGHT * (NICE_WEIGHT * (PRIO_MAX - PRIO_MIN) - \
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RQ_PPQ) + INVERSE_ESTCPU_WEIGHT - 1)
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#ifdef SMP
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#define INVERSE_ESTCPU_WEIGHT (8 * smp_cpus)
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#else
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#define INVERSE_ESTCPU_WEIGHT 8 /* 1 / (priorities per estcpu level). */
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#endif
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#define NICE_WEIGHT 1 /* Priorities per nice level. */
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#define TS_NAME_LEN (MAXCOMLEN + sizeof(" td ") + sizeof(__XSTRING(UINT_MAX)))
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/*
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* The schedulable entity that runs a context.
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* This is an extension to the thread structure and is tailored to
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* the requirements of this scheduler.
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* All fields are protected by the scheduler lock.
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*/
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struct td_sched {
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fixpt_t ts_pctcpu; /* %cpu during p_swtime. */
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u_int ts_estcpu; /* Estimated cpu utilization. */
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int ts_cpticks; /* Ticks of cpu time. */
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int ts_slptime; /* Seconds !RUNNING. */
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int ts_slice; /* Remaining part of time slice. */
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int ts_flags;
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struct runq *ts_runq; /* runq the thread is currently on */
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#ifdef KTR
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char ts_name[TS_NAME_LEN];
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#endif
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};
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/* flags kept in td_flags */
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#define TDF_DIDRUN TDF_SCHED0 /* thread actually ran. */
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#define TDF_BOUND TDF_SCHED1 /* Bound to one CPU. */
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#define TDF_SLICEEND TDF_SCHED2 /* Thread time slice is over. */
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/* flags kept in ts_flags */
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#define TSF_AFFINITY 0x0001 /* Has a non-"full" CPU set. */
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#define SKE_RUNQ_PCPU(ts) \
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((ts)->ts_runq != 0 && (ts)->ts_runq != &runq)
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#define THREAD_CAN_SCHED(td, cpu) \
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CPU_ISSET((cpu), &(td)->td_cpuset->cs_mask)
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_Static_assert(sizeof(struct thread) + sizeof(struct td_sched) <=
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sizeof(struct thread0_storage),
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"increase struct thread0_storage.t0st_sched size");
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static struct mtx sched_lock;
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static int realstathz = 127; /* stathz is sometimes 0 and run off of hz. */
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static int sched_tdcnt; /* Total runnable threads in the system. */
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static int sched_slice = 12; /* Thread run time before rescheduling. */
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static void setup_runqs(void);
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static void schedcpu(void);
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static void schedcpu_thread(void);
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static void sched_priority(struct thread *td, u_char prio);
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static void sched_setup(void *dummy);
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static void maybe_resched(struct thread *td);
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static void updatepri(struct thread *td);
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static void resetpriority(struct thread *td);
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static void resetpriority_thread(struct thread *td);
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#ifdef SMP
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static int sched_pickcpu(struct thread *td);
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static int forward_wakeup(int cpunum);
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static void kick_other_cpu(int pri, int cpuid);
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#endif
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static struct kproc_desc sched_kp = {
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"schedcpu",
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schedcpu_thread,
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NULL
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};
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SYSINIT(schedcpu, SI_SUB_LAST, SI_ORDER_FIRST, kproc_start,
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&sched_kp);
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SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL);
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static void sched_initticks(void *dummy);
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SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks,
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NULL);
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/*
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* Global run queue.
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*/
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static struct runq runq;
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#ifdef SMP
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/*
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* Per-CPU run queues
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*/
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static struct runq runq_pcpu[MAXCPU];
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long runq_length[MAXCPU];
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static cpuset_t idle_cpus_mask;
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#endif
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struct pcpuidlestat {
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u_int idlecalls;
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u_int oldidlecalls;
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};
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static DPCPU_DEFINE(struct pcpuidlestat, idlestat);
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static void
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setup_runqs(void)
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{
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#ifdef SMP
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int i;
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for (i = 0; i < MAXCPU; ++i)
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runq_init(&runq_pcpu[i]);
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#endif
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runq_init(&runq);
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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, period;
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period = 1000000 / realstathz;
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new_val = period * sched_slice;
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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 <= 0)
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return (EINVAL);
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sched_slice = imax(1, (new_val + period / 2) / period);
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hogticks = imax(1, (2 * hz * sched_slice + realstathz / 2) /
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realstathz);
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return (0);
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}
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SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RD, 0, "Scheduler");
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SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "4BSD", 0,
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"Scheduler name");
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SYSCTL_PROC(_kern_sched, OID_AUTO, quantum, CTLTYPE_INT | CTLFLAG_RW,
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NULL, 0, sysctl_kern_quantum, "I",
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"Quantum for timeshare threads in microseconds");
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SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0,
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"Quantum for timeshare threads in stathz ticks");
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#ifdef SMP
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/* Enable forwarding of wakeups to all other cpus */
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static SYSCTL_NODE(_kern_sched, OID_AUTO, ipiwakeup, CTLFLAG_RD, NULL,
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"Kernel SMP");
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static int runq_fuzz = 1;
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SYSCTL_INT(_kern_sched, OID_AUTO, runq_fuzz, CTLFLAG_RW, &runq_fuzz, 0, "");
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static int forward_wakeup_enabled = 1;
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SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, enabled, CTLFLAG_RW,
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&forward_wakeup_enabled, 0,
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"Forwarding of wakeup to idle CPUs");
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static int forward_wakeups_requested = 0;
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SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, requested, CTLFLAG_RD,
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&forward_wakeups_requested, 0,
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"Requests for Forwarding of wakeup to idle CPUs");
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static int forward_wakeups_delivered = 0;
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SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, delivered, CTLFLAG_RD,
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&forward_wakeups_delivered, 0,
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"Completed Forwarding of wakeup to idle CPUs");
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static int forward_wakeup_use_mask = 1;
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SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, usemask, CTLFLAG_RW,
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&forward_wakeup_use_mask, 0,
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"Use the mask of idle cpus");
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static int forward_wakeup_use_loop = 0;
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SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, useloop, CTLFLAG_RW,
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&forward_wakeup_use_loop, 0,
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"Use a loop to find idle cpus");
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#endif
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#if 0
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static int sched_followon = 0;
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SYSCTL_INT(_kern_sched, OID_AUTO, followon, CTLFLAG_RW,
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&sched_followon, 0,
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"allow threads to share a quantum");
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#endif
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SDT_PROVIDER_DEFINE(sched);
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SDT_PROBE_DEFINE3(sched, , , change__pri, "struct thread *",
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"struct proc *", "uint8_t");
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SDT_PROBE_DEFINE3(sched, , , dequeue, "struct thread *",
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"struct proc *", "void *");
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SDT_PROBE_DEFINE4(sched, , , enqueue, "struct thread *",
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"struct proc *", "void *", "int");
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SDT_PROBE_DEFINE4(sched, , , lend__pri, "struct thread *",
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"struct proc *", "uint8_t", "struct thread *");
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SDT_PROBE_DEFINE2(sched, , , load__change, "int", "int");
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SDT_PROBE_DEFINE2(sched, , , off__cpu, "struct thread *",
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"struct proc *");
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SDT_PROBE_DEFINE(sched, , , on__cpu);
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SDT_PROBE_DEFINE(sched, , , remain__cpu);
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SDT_PROBE_DEFINE2(sched, , , surrender, "struct thread *",
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"struct proc *");
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static __inline void
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sched_load_add(void)
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{
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sched_tdcnt++;
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KTR_COUNTER0(KTR_SCHED, "load", "global load", sched_tdcnt);
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SDT_PROBE2(sched, , , load__change, NOCPU, sched_tdcnt);
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}
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static __inline void
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sched_load_rem(void)
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{
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sched_tdcnt--;
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KTR_COUNTER0(KTR_SCHED, "load", "global load", sched_tdcnt);
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SDT_PROBE2(sched, , , load__change, NOCPU, sched_tdcnt);
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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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static void
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maybe_resched(struct thread *td)
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{
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THREAD_LOCK_ASSERT(td, MA_OWNED);
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if (td->td_priority < curthread->td_priority)
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curthread->td_flags |= TDF_NEEDRESCHED;
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}
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/*
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* This function is called when a thread is about to be put on run queue
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* because it has been made runnable or its priority has been adjusted. It
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* determines if the new thread should be immediately preempted to. If so,
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* it switches to it and eventually returns true. If not, it returns false
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* so that the caller may place the thread on an appropriate run queue.
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*/
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int
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maybe_preempt(struct thread *td)
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{
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#ifdef PREEMPTION
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struct thread *ctd;
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int cpri, pri;
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/*
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* The new thread should not preempt the current thread if any of the
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* following conditions are true:
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*
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* - The kernel is in the throes of crashing (panicstr).
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* - The current thread has a higher (numerically lower) or
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* equivalent priority. Note that this prevents curthread from
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* trying to preempt to itself.
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* - It is too early in the boot for context switches (cold is set).
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* - The current thread has an inhibitor set or is in the process of
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* exiting. In this case, the current thread is about to switch
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* out anyways, so there's no point in preempting. If we did,
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* the current thread would not be properly resumed as well, so
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* just avoid that whole landmine.
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* - If the new thread's priority is not a realtime priority and
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* the current thread's priority is not an idle priority and
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* FULL_PREEMPTION is disabled.
|
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*
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* If all of these conditions are false, but the current thread is in
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* a nested critical section, then we have to defer the preemption
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* until we exit the critical section. Otherwise, switch immediately
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* to the new thread.
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*/
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ctd = curthread;
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THREAD_LOCK_ASSERT(td, MA_OWNED);
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KASSERT((td->td_inhibitors == 0),
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("maybe_preempt: trying to run inhibited thread"));
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pri = td->td_priority;
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cpri = ctd->td_priority;
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if (panicstr != NULL || pri >= cpri || cold /* || dumping */ ||
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TD_IS_INHIBITED(ctd))
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return (0);
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#ifndef FULL_PREEMPTION
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if (pri > PRI_MAX_ITHD && cpri < PRI_MIN_IDLE)
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return (0);
|
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#endif
|
|
|
|
if (ctd->td_critnest > 1) {
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CTR1(KTR_PROC, "maybe_preempt: in critical section %d",
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ctd->td_critnest);
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ctd->td_owepreempt = 1;
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return (0);
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}
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/*
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* Thread is runnable but not yet put on system run queue.
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*/
|
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MPASS(ctd->td_lock == td->td_lock);
|
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MPASS(TD_ON_RUNQ(td));
|
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TD_SET_RUNNING(td);
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CTR3(KTR_PROC, "preempting to thread %p (pid %d, %s)\n", td,
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td->td_proc->p_pid, td->td_name);
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mi_switch(SW_INVOL | SW_PREEMPT | SWT_PREEMPT, td);
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/*
|
|
* td's lock pointer may have changed. We have to return with it
|
|
* locked.
|
|
*/
|
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spinlock_enter();
|
|
thread_unlock(ctd);
|
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thread_lock(td);
|
|
spinlock_exit();
|
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return (1);
|
|
#else
|
|
return (0);
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Constants for digital decay and forget:
|
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* 90% of (ts_estcpu) usage in 5 * loadav time
|
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* 95% of (ts_pctcpu) usage in 60 seconds (load insensitive)
|
|
* Note that, as ps(1) mentions, this can let percentages
|
|
* total over 100% (I've seen 137.9% for 3 processes).
|
|
*
|
|
* Note that schedclock() updates ts_estcpu and p_cpticks asynchronously.
|
|
*
|
|
* We wish to decay away 90% of ts_estcpu in (5 * loadavg) seconds.
|
|
* That is, the system wants to compute a value of decay such
|
|
* that the following for loop:
|
|
* for (i = 0; i < (5 * loadavg); i++)
|
|
* ts_estcpu *= decay;
|
|
* will compute
|
|
* ts_estcpu *= 0.1;
|
|
* for all values of loadavg:
|
|
*
|
|
* Mathematically this loop can be expressed by saying:
|
|
* decay ** (5 * loadavg) ~= .1
|
|
*
|
|
* The system computes decay as:
|
|
* decay = (2 * loadavg) / (2 * loadavg + 1)
|
|
*
|
|
* We wish to prove that the system's computation of decay
|
|
* will always fulfill the equation:
|
|
* decay ** (5 * loadavg) ~= .1
|
|
*
|
|
* If we compute b as:
|
|
* b = 2 * loadavg
|
|
* then
|
|
* decay = b / (b + 1)
|
|
*
|
|
* We now need to prove two things:
|
|
* 1) Given factor ** (5 * loadavg) ~= .1, prove factor == b/(b+1)
|
|
* 2) Given b/(b+1) ** power ~= .1, prove power == (5 * loadavg)
|
|
*
|
|
* Facts:
|
|
* For x close to zero, exp(x) =~ 1 + x, since
|
|
* exp(x) = 0! + x**1/1! + x**2/2! + ... .
|
|
* therefore exp(-1/b) =~ 1 - (1/b) = (b-1)/b.
|
|
* For x close to zero, ln(1+x) =~ x, since
|
|
* ln(1+x) = x - x**2/2 + x**3/3 - ... -1 < x < 1
|
|
* therefore ln(b/(b+1)) = ln(1 - 1/(b+1)) =~ -1/(b+1).
|
|
* ln(.1) =~ -2.30
|
|
*
|
|
* Proof of (1):
|
|
* Solve (factor)**(power) =~ .1 given power (5*loadav):
|
|
* solving for factor,
|
|
* ln(factor) =~ (-2.30/5*loadav), or
|
|
* factor =~ exp(-1/((5/2.30)*loadav)) =~ exp(-1/(2*loadav)) =
|
|
* exp(-1/b) =~ (b-1)/b =~ b/(b+1). QED
|
|
*
|
|
* Proof of (2):
|
|
* Solve (factor)**(power) =~ .1 given factor == (b/(b+1)):
|
|
* solving for power,
|
|
* power*ln(b/(b+1)) =~ -2.30, or
|
|
* power =~ 2.3 * (b + 1) = 4.6*loadav + 2.3 =~ 5*loadav. QED
|
|
*
|
|
* Actual power values for the implemented algorithm are as follows:
|
|
* loadav: 1 2 3 4
|
|
* power: 5.68 10.32 14.94 19.55
|
|
*/
|
|
|
|
/* calculations for digital decay to forget 90% of usage in 5*loadav sec */
|
|
#define loadfactor(loadav) (2 * (loadav))
|
|
#define decay_cpu(loadfac, cpu) (((loadfac) * (cpu)) / ((loadfac) + FSCALE))
|
|
|
|
/* decay 95% of `ts_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */
|
|
static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */
|
|
SYSCTL_UINT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, "");
|
|
|
|
/*
|
|
* If `ccpu' is not equal to `exp(-1/20)' and you still want to use the
|
|
* faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below
|
|
* and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT).
|
|
*
|
|
* To estimate CCPU_SHIFT for exp(-1/20), the following formula was used:
|
|
* 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits).
|
|
*
|
|
* If you don't want to bother with the faster/more-accurate formula, you
|
|
* can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate
|
|
* (more general) method of calculating the %age of CPU used by a process.
|
|
*/
|
|
#define CCPU_SHIFT 11
|
|
|
|
/*
|
|
* Recompute process priorities, every hz ticks.
|
|
* MP-safe, called without the Giant mutex.
|
|
*/
|
|
/* ARGSUSED */
|
|
static void
|
|
schedcpu(void)
|
|
{
|
|
register fixpt_t loadfac = loadfactor(averunnable.ldavg[0]);
|
|
struct thread *td;
|
|
struct proc *p;
|
|
struct td_sched *ts;
|
|
int awake;
|
|
|
|
sx_slock(&allproc_lock);
|
|
FOREACH_PROC_IN_SYSTEM(p) {
|
|
PROC_LOCK(p);
|
|
if (p->p_state == PRS_NEW) {
|
|
PROC_UNLOCK(p);
|
|
continue;
|
|
}
|
|
FOREACH_THREAD_IN_PROC(p, td) {
|
|
awake = 0;
|
|
ts = td_get_sched(td);
|
|
thread_lock(td);
|
|
/*
|
|
* Increment sleep time (if sleeping). We
|
|
* ignore overflow, as above.
|
|
*/
|
|
/*
|
|
* The td_sched slptimes are not touched in wakeup
|
|
* because the thread may not HAVE everything in
|
|
* memory? XXX I think this is out of date.
|
|
*/
|
|
if (TD_ON_RUNQ(td)) {
|
|
awake = 1;
|
|
td->td_flags &= ~TDF_DIDRUN;
|
|
} else if (TD_IS_RUNNING(td)) {
|
|
awake = 1;
|
|
/* Do not clear TDF_DIDRUN */
|
|
} else if (td->td_flags & TDF_DIDRUN) {
|
|
awake = 1;
|
|
td->td_flags &= ~TDF_DIDRUN;
|
|
}
|
|
|
|
/*
|
|
* ts_pctcpu is only for ps and ttyinfo().
|
|
*/
|
|
ts->ts_pctcpu = (ts->ts_pctcpu * ccpu) >> FSHIFT;
|
|
/*
|
|
* If the td_sched has been idle the entire second,
|
|
* stop recalculating its priority until
|
|
* it wakes up.
|
|
*/
|
|
if (ts->ts_cpticks != 0) {
|
|
#if (FSHIFT >= CCPU_SHIFT)
|
|
ts->ts_pctcpu += (realstathz == 100)
|
|
? ((fixpt_t) ts->ts_cpticks) <<
|
|
(FSHIFT - CCPU_SHIFT) :
|
|
100 * (((fixpt_t) ts->ts_cpticks)
|
|
<< (FSHIFT - CCPU_SHIFT)) / realstathz;
|
|
#else
|
|
ts->ts_pctcpu += ((FSCALE - ccpu) *
|
|
(ts->ts_cpticks *
|
|
FSCALE / realstathz)) >> FSHIFT;
|
|
#endif
|
|
ts->ts_cpticks = 0;
|
|
}
|
|
/*
|
|
* If there are ANY running threads in this process,
|
|
* then don't count it as sleeping.
|
|
* XXX: this is broken.
|
|
*/
|
|
if (awake) {
|
|
if (ts->ts_slptime > 1) {
|
|
/*
|
|
* In an ideal world, this should not
|
|
* happen, because whoever woke us
|
|
* up from the long sleep should have
|
|
* unwound the slptime and reset our
|
|
* priority before we run at the stale
|
|
* priority. Should KASSERT at some
|
|
* point when all the cases are fixed.
|
|
*/
|
|
updatepri(td);
|
|
}
|
|
ts->ts_slptime = 0;
|
|
} else
|
|
ts->ts_slptime++;
|
|
if (ts->ts_slptime > 1) {
|
|
thread_unlock(td);
|
|
continue;
|
|
}
|
|
ts->ts_estcpu = decay_cpu(loadfac, ts->ts_estcpu);
|
|
resetpriority(td);
|
|
resetpriority_thread(td);
|
|
thread_unlock(td);
|
|
}
|
|
PROC_UNLOCK(p);
|
|
}
|
|
sx_sunlock(&allproc_lock);
|
|
}
|
|
|
|
/*
|
|
* Main loop for a kthread that executes schedcpu once a second.
|
|
*/
|
|
static void
|
|
schedcpu_thread(void)
|
|
{
|
|
|
|
for (;;) {
|
|
schedcpu();
|
|
pause("-", hz);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Recalculate the priority of a process after it has slept for a while.
|
|
* For all load averages >= 1 and max ts_estcpu of 255, sleeping for at
|
|
* least six times the loadfactor will decay ts_estcpu to zero.
|
|
*/
|
|
static void
|
|
updatepri(struct thread *td)
|
|
{
|
|
struct td_sched *ts;
|
|
fixpt_t loadfac;
|
|
unsigned int newcpu;
|
|
|
|
ts = td_get_sched(td);
|
|
loadfac = loadfactor(averunnable.ldavg[0]);
|
|
if (ts->ts_slptime > 5 * loadfac)
|
|
ts->ts_estcpu = 0;
|
|
else {
|
|
newcpu = ts->ts_estcpu;
|
|
ts->ts_slptime--; /* was incremented in schedcpu() */
|
|
while (newcpu && --ts->ts_slptime)
|
|
newcpu = decay_cpu(loadfac, newcpu);
|
|
ts->ts_estcpu = newcpu;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
static void
|
|
resetpriority(struct thread *td)
|
|
{
|
|
u_int newpriority;
|
|
|
|
if (td->td_pri_class != PRI_TIMESHARE)
|
|
return;
|
|
newpriority = PUSER +
|
|
td_get_sched(td)->ts_estcpu / INVERSE_ESTCPU_WEIGHT +
|
|
NICE_WEIGHT * (td->td_proc->p_nice - PRIO_MIN);
|
|
newpriority = min(max(newpriority, PRI_MIN_TIMESHARE),
|
|
PRI_MAX_TIMESHARE);
|
|
sched_user_prio(td, newpriority);
|
|
}
|
|
|
|
/*
|
|
* Update the thread's priority when the associated process's user
|
|
* priority changes.
|
|
*/
|
|
static void
|
|
resetpriority_thread(struct thread *td)
|
|
{
|
|
|
|
/* Only change threads with a time sharing user priority. */
|
|
if (td->td_priority < PRI_MIN_TIMESHARE ||
|
|
td->td_priority > PRI_MAX_TIMESHARE)
|
|
return;
|
|
|
|
/* XXX the whole needresched thing is broken, but not silly. */
|
|
maybe_resched(td);
|
|
|
|
sched_prio(td, td->td_user_pri);
|
|
}
|
|
|
|
/* ARGSUSED */
|
|
static void
|
|
sched_setup(void *dummy)
|
|
{
|
|
|
|
setup_runqs();
|
|
|
|
/* Account for thread0. */
|
|
sched_load_add();
|
|
}
|
|
|
|
/*
|
|
* This routine determines time constants after stathz and hz are setup.
|
|
*/
|
|
static void
|
|
sched_initticks(void *dummy)
|
|
{
|
|
|
|
realstathz = stathz ? stathz : hz;
|
|
sched_slice = realstathz / 10; /* ~100ms */
|
|
hogticks = imax(1, (2 * hz * sched_slice + realstathz / 2) /
|
|
realstathz);
|
|
}
|
|
|
|
/* External interfaces start here */
|
|
|
|
/*
|
|
* Very early in the boot some setup of scheduler-specific
|
|
* parts of proc0 and of some scheduler resources needs to be done.
|
|
* Called from:
|
|
* proc0_init()
|
|
*/
|
|
void
|
|
schedinit(void)
|
|
{
|
|
|
|
/*
|
|
* Set up the scheduler specific parts of thread0.
|
|
*/
|
|
thread0.td_lock = &sched_lock;
|
|
td_get_sched(&thread0)->ts_slice = sched_slice;
|
|
mtx_init(&sched_lock, "sched lock", NULL, MTX_SPIN | MTX_RECURSE);
|
|
}
|
|
|
|
int
|
|
sched_runnable(void)
|
|
{
|
|
#ifdef SMP
|
|
return runq_check(&runq) + runq_check(&runq_pcpu[PCPU_GET(cpuid)]);
|
|
#else
|
|
return runq_check(&runq);
|
|
#endif
|
|
}
|
|
|
|
int
|
|
sched_rr_interval(void)
|
|
{
|
|
|
|
/* Convert sched_slice from stathz to hz. */
|
|
return (imax(1, (sched_slice * hz + realstathz / 2) / realstathz));
|
|
}
|
|
|
|
/*
|
|
* We adjust the priority of the current process. The priority of a
|
|
* process gets worse as it accumulates CPU time. The cpu usage
|
|
* estimator (ts_estcpu) is increased here. resetpriority() will
|
|
* compute a different priority each time ts_estcpu increases by
|
|
* INVERSE_ESTCPU_WEIGHT (until PRI_MAX_TIMESHARE 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
|
|
sched_clock(struct thread *td)
|
|
{
|
|
struct pcpuidlestat *stat;
|
|
struct td_sched *ts;
|
|
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
ts = td_get_sched(td);
|
|
|
|
ts->ts_cpticks++;
|
|
ts->ts_estcpu = ESTCPULIM(ts->ts_estcpu + 1);
|
|
if ((ts->ts_estcpu % INVERSE_ESTCPU_WEIGHT) == 0) {
|
|
resetpriority(td);
|
|
resetpriority_thread(td);
|
|
}
|
|
|
|
/*
|
|
* Force a context switch if the current thread has used up a full
|
|
* time slice (default is 100ms).
|
|
*/
|
|
if (!TD_IS_IDLETHREAD(td) && --ts->ts_slice <= 0) {
|
|
ts->ts_slice = sched_slice;
|
|
td->td_flags |= TDF_NEEDRESCHED | TDF_SLICEEND;
|
|
}
|
|
|
|
stat = DPCPU_PTR(idlestat);
|
|
stat->oldidlecalls = stat->idlecalls;
|
|
stat->idlecalls = 0;
|
|
}
|
|
|
|
/*
|
|
* Charge child's scheduling CPU usage to parent.
|
|
*/
|
|
void
|
|
sched_exit(struct proc *p, struct thread *td)
|
|
{
|
|
|
|
KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "proc exit",
|
|
"prio:%d", td->td_priority);
|
|
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
sched_exit_thread(FIRST_THREAD_IN_PROC(p), td);
|
|
}
|
|
|
|
void
|
|
sched_exit_thread(struct thread *td, struct thread *child)
|
|
{
|
|
|
|
KTR_STATE1(KTR_SCHED, "thread", sched_tdname(child), "exit",
|
|
"prio:%d", child->td_priority);
|
|
thread_lock(td);
|
|
td_get_sched(td)->ts_estcpu = ESTCPULIM(td_get_sched(td)->ts_estcpu +
|
|
td_get_sched(child)->ts_estcpu);
|
|
thread_unlock(td);
|
|
thread_lock(child);
|
|
if ((child->td_flags & TDF_NOLOAD) == 0)
|
|
sched_load_rem();
|
|
thread_unlock(child);
|
|
}
|
|
|
|
void
|
|
sched_fork(struct thread *td, struct thread *childtd)
|
|
{
|
|
sched_fork_thread(td, childtd);
|
|
}
|
|
|
|
void
|
|
sched_fork_thread(struct thread *td, struct thread *childtd)
|
|
{
|
|
struct td_sched *ts, *tsc;
|
|
|
|
childtd->td_oncpu = NOCPU;
|
|
childtd->td_lastcpu = NOCPU;
|
|
childtd->td_lock = &sched_lock;
|
|
childtd->td_cpuset = cpuset_ref(td->td_cpuset);
|
|
childtd->td_priority = childtd->td_base_pri;
|
|
ts = td_get_sched(childtd);
|
|
bzero(ts, sizeof(*ts));
|
|
tsc = td_get_sched(td);
|
|
ts->ts_estcpu = tsc->ts_estcpu;
|
|
ts->ts_flags |= (tsc->ts_flags & TSF_AFFINITY);
|
|
ts->ts_slice = 1;
|
|
}
|
|
|
|
void
|
|
sched_nice(struct proc *p, int nice)
|
|
{
|
|
struct thread *td;
|
|
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
p->p_nice = nice;
|
|
FOREACH_THREAD_IN_PROC(p, td) {
|
|
thread_lock(td);
|
|
resetpriority(td);
|
|
resetpriority_thread(td);
|
|
thread_unlock(td);
|
|
}
|
|
}
|
|
|
|
void
|
|
sched_class(struct thread *td, int class)
|
|
{
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
td->td_pri_class = class;
|
|
}
|
|
|
|
/*
|
|
* Adjust the priority of a thread.
|
|
*/
|
|
static void
|
|
sched_priority(struct thread *td, u_char prio)
|
|
{
|
|
|
|
|
|
KTR_POINT3(KTR_SCHED, "thread", sched_tdname(td), "priority change",
|
|
"prio:%d", td->td_priority, "new prio:%d", prio, KTR_ATTR_LINKED,
|
|
sched_tdname(curthread));
|
|
SDT_PROBE3(sched, , , change__pri, td, td->td_proc, prio);
|
|
if (td != curthread && prio > td->td_priority) {
|
|
KTR_POINT3(KTR_SCHED, "thread", sched_tdname(curthread),
|
|
"lend prio", "prio:%d", td->td_priority, "new prio:%d",
|
|
prio, KTR_ATTR_LINKED, sched_tdname(td));
|
|
SDT_PROBE4(sched, , , lend__pri, td, td->td_proc, prio,
|
|
curthread);
|
|
}
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
if (td->td_priority == prio)
|
|
return;
|
|
td->td_priority = prio;
|
|
if (TD_ON_RUNQ(td) && td->td_rqindex != (prio / RQ_PPQ)) {
|
|
sched_rem(td);
|
|
sched_add(td, SRQ_BORING);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Update a thread's priority when it is lent another thread's
|
|
* priority.
|
|
*/
|
|
void
|
|
sched_lend_prio(struct thread *td, u_char prio)
|
|
{
|
|
|
|
td->td_flags |= TDF_BORROWING;
|
|
sched_priority(td, prio);
|
|
}
|
|
|
|
/*
|
|
* Restore a thread's priority when priority propagation is
|
|
* over. The prio argument is the minimum priority the thread
|
|
* needs to have to satisfy other possible priority lending
|
|
* requests. If the thread's regulary priority is less
|
|
* important than prio the thread will keep a priority boost
|
|
* of prio.
|
|
*/
|
|
void
|
|
sched_unlend_prio(struct thread *td, u_char prio)
|
|
{
|
|
u_char base_pri;
|
|
|
|
if (td->td_base_pri >= PRI_MIN_TIMESHARE &&
|
|
td->td_base_pri <= PRI_MAX_TIMESHARE)
|
|
base_pri = td->td_user_pri;
|
|
else
|
|
base_pri = td->td_base_pri;
|
|
if (prio >= base_pri) {
|
|
td->td_flags &= ~TDF_BORROWING;
|
|
sched_prio(td, base_pri);
|
|
} else
|
|
sched_lend_prio(td, prio);
|
|
}
|
|
|
|
void
|
|
sched_prio(struct thread *td, u_char prio)
|
|
{
|
|
u_char oldprio;
|
|
|
|
/* First, update the base priority. */
|
|
td->td_base_pri = prio;
|
|
|
|
/*
|
|
* If the thread is borrowing another thread's priority, don't ever
|
|
* lower the priority.
|
|
*/
|
|
if (td->td_flags & TDF_BORROWING && td->td_priority < prio)
|
|
return;
|
|
|
|
/* Change the real priority. */
|
|
oldprio = td->td_priority;
|
|
sched_priority(td, prio);
|
|
|
|
/*
|
|
* If the thread is on a turnstile, then let the turnstile update
|
|
* its state.
|
|
*/
|
|
if (TD_ON_LOCK(td) && oldprio != prio)
|
|
turnstile_adjust(td, oldprio);
|
|
}
|
|
|
|
void
|
|
sched_user_prio(struct thread *td, u_char prio)
|
|
{
|
|
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
td->td_base_user_pri = prio;
|
|
if (td->td_lend_user_pri <= prio)
|
|
return;
|
|
td->td_user_pri = prio;
|
|
}
|
|
|
|
void
|
|
sched_lend_user_prio(struct thread *td, u_char prio)
|
|
{
|
|
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
td->td_lend_user_pri = prio;
|
|
td->td_user_pri = min(prio, td->td_base_user_pri);
|
|
if (td->td_priority > td->td_user_pri)
|
|
sched_prio(td, td->td_user_pri);
|
|
else if (td->td_priority != td->td_user_pri)
|
|
td->td_flags |= TDF_NEEDRESCHED;
|
|
}
|
|
|
|
void
|
|
sched_sleep(struct thread *td, int pri)
|
|
{
|
|
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
td->td_slptick = ticks;
|
|
td_get_sched(td)->ts_slptime = 0;
|
|
if (pri != 0 && PRI_BASE(td->td_pri_class) == PRI_TIMESHARE)
|
|
sched_prio(td, pri);
|
|
if (TD_IS_SUSPENDED(td) || pri >= PSOCK)
|
|
td->td_flags |= TDF_CANSWAP;
|
|
}
|
|
|
|
void
|
|
sched_switch(struct thread *td, struct thread *newtd, int flags)
|
|
{
|
|
struct mtx *tmtx;
|
|
struct td_sched *ts;
|
|
struct proc *p;
|
|
int preempted;
|
|
|
|
tmtx = NULL;
|
|
ts = td_get_sched(td);
|
|
p = td->td_proc;
|
|
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
|
|
/*
|
|
* Switch to the sched lock to fix things up and pick
|
|
* a new thread.
|
|
* Block the td_lock in order to avoid breaking the critical path.
|
|
*/
|
|
if (td->td_lock != &sched_lock) {
|
|
mtx_lock_spin(&sched_lock);
|
|
tmtx = thread_lock_block(td);
|
|
}
|
|
|
|
if ((td->td_flags & TDF_NOLOAD) == 0)
|
|
sched_load_rem();
|
|
|
|
td->td_lastcpu = td->td_oncpu;
|
|
preempted = !((td->td_flags & TDF_SLICEEND) ||
|
|
(flags & SWT_RELINQUISH));
|
|
td->td_flags &= ~(TDF_NEEDRESCHED | TDF_SLICEEND);
|
|
td->td_owepreempt = 0;
|
|
td->td_oncpu = NOCPU;
|
|
|
|
/*
|
|
* At the last moment, if this thread is still marked RUNNING,
|
|
* then put it back on the run queue as it has not been suspended
|
|
* or stopped or any thing else similar. We never put the idle
|
|
* threads on the run queue, however.
|
|
*/
|
|
if (td->td_flags & TDF_IDLETD) {
|
|
TD_SET_CAN_RUN(td);
|
|
#ifdef SMP
|
|
CPU_CLR(PCPU_GET(cpuid), &idle_cpus_mask);
|
|
#endif
|
|
} else {
|
|
if (TD_IS_RUNNING(td)) {
|
|
/* Put us back on the run queue. */
|
|
sched_add(td, preempted ?
|
|
SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED :
|
|
SRQ_OURSELF|SRQ_YIELDING);
|
|
}
|
|
}
|
|
if (newtd) {
|
|
/*
|
|
* The thread we are about to run needs to be counted
|
|
* as if it had been added to the run queue and selected.
|
|
* It came from:
|
|
* * A preemption
|
|
* * An upcall
|
|
* * A followon
|
|
*/
|
|
KASSERT((newtd->td_inhibitors == 0),
|
|
("trying to run inhibited thread"));
|
|
newtd->td_flags |= TDF_DIDRUN;
|
|
TD_SET_RUNNING(newtd);
|
|
if ((newtd->td_flags & TDF_NOLOAD) == 0)
|
|
sched_load_add();
|
|
} else {
|
|
newtd = choosethread();
|
|
MPASS(newtd->td_lock == &sched_lock);
|
|
}
|
|
|
|
if (td != newtd) {
|
|
#ifdef HWPMC_HOOKS
|
|
if (PMC_PROC_IS_USING_PMCS(td->td_proc))
|
|
PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT);
|
|
#endif
|
|
|
|
SDT_PROBE2(sched, , , off__cpu, newtd, newtd->td_proc);
|
|
|
|
/* I feel sleepy */
|
|
lock_profile_release_lock(&sched_lock.lock_object);
|
|
#ifdef KDTRACE_HOOKS
|
|
/*
|
|
* If DTrace has set the active vtime enum to anything
|
|
* other than INACTIVE (0), then it should have set the
|
|
* function to call.
|
|
*/
|
|
if (dtrace_vtime_active)
|
|
(*dtrace_vtime_switch_func)(newtd);
|
|
#endif
|
|
|
|
cpu_switch(td, newtd, tmtx != NULL ? tmtx : td->td_lock);
|
|
lock_profile_obtain_lock_success(&sched_lock.lock_object,
|
|
0, 0, __FILE__, __LINE__);
|
|
/*
|
|
* Where am I? What year is it?
|
|
* We are in the same thread that went to sleep above,
|
|
* but any amount of time may have passed. All our context
|
|
* will still be available as will local variables.
|
|
* PCPU values however may have changed as we may have
|
|
* changed CPU so don't trust cached values of them.
|
|
* New threads will go to fork_exit() instead of here
|
|
* so if you change things here you may need to change
|
|
* things there too.
|
|
*
|
|
* If the thread above was exiting it will never wake
|
|
* up again here, so either it has saved everything it
|
|
* needed to, or the thread_wait() or wait() will
|
|
* need to reap it.
|
|
*/
|
|
|
|
SDT_PROBE0(sched, , , on__cpu);
|
|
#ifdef HWPMC_HOOKS
|
|
if (PMC_PROC_IS_USING_PMCS(td->td_proc))
|
|
PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN);
|
|
#endif
|
|
} else
|
|
SDT_PROBE0(sched, , , remain__cpu);
|
|
|
|
#ifdef SMP
|
|
if (td->td_flags & TDF_IDLETD)
|
|
CPU_SET(PCPU_GET(cpuid), &idle_cpus_mask);
|
|
#endif
|
|
sched_lock.mtx_lock = (uintptr_t)td;
|
|
td->td_oncpu = PCPU_GET(cpuid);
|
|
MPASS(td->td_lock == &sched_lock);
|
|
}
|
|
|
|
void
|
|
sched_wakeup(struct thread *td)
|
|
{
|
|
struct td_sched *ts;
|
|
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
ts = td_get_sched(td);
|
|
td->td_flags &= ~TDF_CANSWAP;
|
|
if (ts->ts_slptime > 1) {
|
|
updatepri(td);
|
|
resetpriority(td);
|
|
}
|
|
td->td_slptick = 0;
|
|
ts->ts_slptime = 0;
|
|
ts->ts_slice = sched_slice;
|
|
sched_add(td, SRQ_BORING);
|
|
}
|
|
|
|
#ifdef SMP
|
|
static int
|
|
forward_wakeup(int cpunum)
|
|
{
|
|
struct pcpu *pc;
|
|
cpuset_t dontuse, map, map2;
|
|
u_int id, me;
|
|
int iscpuset;
|
|
|
|
mtx_assert(&sched_lock, MA_OWNED);
|
|
|
|
CTR0(KTR_RUNQ, "forward_wakeup()");
|
|
|
|
if ((!forward_wakeup_enabled) ||
|
|
(forward_wakeup_use_mask == 0 && forward_wakeup_use_loop == 0))
|
|
return (0);
|
|
if (!smp_started || cold || panicstr)
|
|
return (0);
|
|
|
|
forward_wakeups_requested++;
|
|
|
|
/*
|
|
* Check the idle mask we received against what we calculated
|
|
* before in the old version.
|
|
*/
|
|
me = PCPU_GET(cpuid);
|
|
|
|
/* Don't bother if we should be doing it ourself. */
|
|
if (CPU_ISSET(me, &idle_cpus_mask) &&
|
|
(cpunum == NOCPU || me == cpunum))
|
|
return (0);
|
|
|
|
CPU_SETOF(me, &dontuse);
|
|
CPU_OR(&dontuse, &stopped_cpus);
|
|
CPU_OR(&dontuse, &hlt_cpus_mask);
|
|
CPU_ZERO(&map2);
|
|
if (forward_wakeup_use_loop) {
|
|
STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) {
|
|
id = pc->pc_cpuid;
|
|
if (!CPU_ISSET(id, &dontuse) &&
|
|
pc->pc_curthread == pc->pc_idlethread) {
|
|
CPU_SET(id, &map2);
|
|
}
|
|
}
|
|
}
|
|
|
|
if (forward_wakeup_use_mask) {
|
|
map = idle_cpus_mask;
|
|
CPU_NAND(&map, &dontuse);
|
|
|
|
/* If they are both on, compare and use loop if different. */
|
|
if (forward_wakeup_use_loop) {
|
|
if (CPU_CMP(&map, &map2)) {
|
|
printf("map != map2, loop method preferred\n");
|
|
map = map2;
|
|
}
|
|
}
|
|
} else {
|
|
map = map2;
|
|
}
|
|
|
|
/* If we only allow a specific CPU, then mask off all the others. */
|
|
if (cpunum != NOCPU) {
|
|
KASSERT((cpunum <= mp_maxcpus),("forward_wakeup: bad cpunum."));
|
|
iscpuset = CPU_ISSET(cpunum, &map);
|
|
if (iscpuset == 0)
|
|
CPU_ZERO(&map);
|
|
else
|
|
CPU_SETOF(cpunum, &map);
|
|
}
|
|
if (!CPU_EMPTY(&map)) {
|
|
forward_wakeups_delivered++;
|
|
STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) {
|
|
id = pc->pc_cpuid;
|
|
if (!CPU_ISSET(id, &map))
|
|
continue;
|
|
if (cpu_idle_wakeup(pc->pc_cpuid))
|
|
CPU_CLR(id, &map);
|
|
}
|
|
if (!CPU_EMPTY(&map))
|
|
ipi_selected(map, IPI_AST);
|
|
return (1);
|
|
}
|
|
if (cpunum == NOCPU)
|
|
printf("forward_wakeup: Idle processor not found\n");
|
|
return (0);
|
|
}
|
|
|
|
static void
|
|
kick_other_cpu(int pri, int cpuid)
|
|
{
|
|
struct pcpu *pcpu;
|
|
int cpri;
|
|
|
|
pcpu = pcpu_find(cpuid);
|
|
if (CPU_ISSET(cpuid, &idle_cpus_mask)) {
|
|
forward_wakeups_delivered++;
|
|
if (!cpu_idle_wakeup(cpuid))
|
|
ipi_cpu(cpuid, IPI_AST);
|
|
return;
|
|
}
|
|
|
|
cpri = pcpu->pc_curthread->td_priority;
|
|
if (pri >= cpri)
|
|
return;
|
|
|
|
#if defined(IPI_PREEMPTION) && defined(PREEMPTION)
|
|
#if !defined(FULL_PREEMPTION)
|
|
if (pri <= PRI_MAX_ITHD)
|
|
#endif /* ! FULL_PREEMPTION */
|
|
{
|
|
ipi_cpu(cpuid, IPI_PREEMPT);
|
|
return;
|
|
}
|
|
#endif /* defined(IPI_PREEMPTION) && defined(PREEMPTION) */
|
|
|
|
pcpu->pc_curthread->td_flags |= TDF_NEEDRESCHED;
|
|
ipi_cpu(cpuid, IPI_AST);
|
|
return;
|
|
}
|
|
#endif /* SMP */
|
|
|
|
#ifdef SMP
|
|
static int
|
|
sched_pickcpu(struct thread *td)
|
|
{
|
|
int best, cpu;
|
|
|
|
mtx_assert(&sched_lock, MA_OWNED);
|
|
|
|
if (THREAD_CAN_SCHED(td, td->td_lastcpu))
|
|
best = td->td_lastcpu;
|
|
else
|
|
best = NOCPU;
|
|
CPU_FOREACH(cpu) {
|
|
if (!THREAD_CAN_SCHED(td, cpu))
|
|
continue;
|
|
|
|
if (best == NOCPU)
|
|
best = cpu;
|
|
else if (runq_length[cpu] < runq_length[best])
|
|
best = cpu;
|
|
}
|
|
KASSERT(best != NOCPU, ("no valid CPUs"));
|
|
|
|
return (best);
|
|
}
|
|
#endif
|
|
|
|
void
|
|
sched_add(struct thread *td, int flags)
|
|
#ifdef SMP
|
|
{
|
|
cpuset_t tidlemsk;
|
|
struct td_sched *ts;
|
|
u_int cpu, cpuid;
|
|
int forwarded = 0;
|
|
int single_cpu = 0;
|
|
|
|
ts = td_get_sched(td);
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
KASSERT((td->td_inhibitors == 0),
|
|
("sched_add: trying to run inhibited thread"));
|
|
KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)),
|
|
("sched_add: bad thread state"));
|
|
KASSERT(td->td_flags & TDF_INMEM,
|
|
("sched_add: thread swapped out"));
|
|
|
|
KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add",
|
|
"prio:%d", td->td_priority, KTR_ATTR_LINKED,
|
|
sched_tdname(curthread));
|
|
KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup",
|
|
KTR_ATTR_LINKED, sched_tdname(td));
|
|
SDT_PROBE4(sched, , , enqueue, td, td->td_proc, NULL,
|
|
flags & SRQ_PREEMPTED);
|
|
|
|
|
|
/*
|
|
* Now that the thread is moving to the run-queue, set the lock
|
|
* to the scheduler's lock.
|
|
*/
|
|
if (td->td_lock != &sched_lock) {
|
|
mtx_lock_spin(&sched_lock);
|
|
thread_lock_set(td, &sched_lock);
|
|
}
|
|
TD_SET_RUNQ(td);
|
|
|
|
/*
|
|
* If SMP is started and the thread is pinned or otherwise limited to
|
|
* a specific set of CPUs, queue the thread to a per-CPU run queue.
|
|
* Otherwise, queue the thread to the global run queue.
|
|
*
|
|
* If SMP has not yet been started we must use the global run queue
|
|
* as per-CPU state may not be initialized yet and we may crash if we
|
|
* try to access the per-CPU run queues.
|
|
*/
|
|
if (smp_started && (td->td_pinned != 0 || td->td_flags & TDF_BOUND ||
|
|
ts->ts_flags & TSF_AFFINITY)) {
|
|
if (td->td_pinned != 0)
|
|
cpu = td->td_lastcpu;
|
|
else if (td->td_flags & TDF_BOUND) {
|
|
/* Find CPU from bound runq. */
|
|
KASSERT(SKE_RUNQ_PCPU(ts),
|
|
("sched_add: bound td_sched not on cpu runq"));
|
|
cpu = ts->ts_runq - &runq_pcpu[0];
|
|
} else
|
|
/* Find a valid CPU for our cpuset */
|
|
cpu = sched_pickcpu(td);
|
|
ts->ts_runq = &runq_pcpu[cpu];
|
|
single_cpu = 1;
|
|
CTR3(KTR_RUNQ,
|
|
"sched_add: Put td_sched:%p(td:%p) on cpu%d runq", ts, td,
|
|
cpu);
|
|
} else {
|
|
CTR2(KTR_RUNQ,
|
|
"sched_add: adding td_sched:%p (td:%p) to gbl runq", ts,
|
|
td);
|
|
cpu = NOCPU;
|
|
ts->ts_runq = &runq;
|
|
}
|
|
|
|
cpuid = PCPU_GET(cpuid);
|
|
if (single_cpu && cpu != cpuid) {
|
|
kick_other_cpu(td->td_priority, cpu);
|
|
} else {
|
|
if (!single_cpu) {
|
|
tidlemsk = idle_cpus_mask;
|
|
CPU_NAND(&tidlemsk, &hlt_cpus_mask);
|
|
CPU_CLR(cpuid, &tidlemsk);
|
|
|
|
if (!CPU_ISSET(cpuid, &idle_cpus_mask) &&
|
|
((flags & SRQ_INTR) == 0) &&
|
|
!CPU_EMPTY(&tidlemsk))
|
|
forwarded = forward_wakeup(cpu);
|
|
}
|
|
|
|
if (!forwarded) {
|
|
if ((flags & SRQ_YIELDING) == 0 && maybe_preempt(td))
|
|
return;
|
|
else
|
|
maybe_resched(td);
|
|
}
|
|
}
|
|
|
|
if ((td->td_flags & TDF_NOLOAD) == 0)
|
|
sched_load_add();
|
|
runq_add(ts->ts_runq, td, flags);
|
|
if (cpu != NOCPU)
|
|
runq_length[cpu]++;
|
|
}
|
|
#else /* SMP */
|
|
{
|
|
struct td_sched *ts;
|
|
|
|
ts = td_get_sched(td);
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
KASSERT((td->td_inhibitors == 0),
|
|
("sched_add: trying to run inhibited thread"));
|
|
KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)),
|
|
("sched_add: bad thread state"));
|
|
KASSERT(td->td_flags & TDF_INMEM,
|
|
("sched_add: thread swapped out"));
|
|
KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add",
|
|
"prio:%d", td->td_priority, KTR_ATTR_LINKED,
|
|
sched_tdname(curthread));
|
|
KTR_POINT1(KTR_SCHED, "thread", sched_tdname(curthread), "wokeup",
|
|
KTR_ATTR_LINKED, sched_tdname(td));
|
|
SDT_PROBE4(sched, , , enqueue, td, td->td_proc, NULL,
|
|
flags & SRQ_PREEMPTED);
|
|
|
|
/*
|
|
* Now that the thread is moving to the run-queue, set the lock
|
|
* to the scheduler's lock.
|
|
*/
|
|
if (td->td_lock != &sched_lock) {
|
|
mtx_lock_spin(&sched_lock);
|
|
thread_lock_set(td, &sched_lock);
|
|
}
|
|
TD_SET_RUNQ(td);
|
|
CTR2(KTR_RUNQ, "sched_add: adding td_sched:%p (td:%p) to runq", ts, td);
|
|
ts->ts_runq = &runq;
|
|
|
|
/*
|
|
* If we are yielding (on the way out anyhow) or the thread
|
|
* being saved is US, then don't try be smart about preemption
|
|
* or kicking off another CPU as it won't help and may hinder.
|
|
* In the YIEDLING case, we are about to run whoever is being
|
|
* put in the queue anyhow, and in the OURSELF case, we are
|
|
* putting ourself on the run queue which also only happens
|
|
* when we are about to yield.
|
|
*/
|
|
if ((flags & SRQ_YIELDING) == 0) {
|
|
if (maybe_preempt(td))
|
|
return;
|
|
}
|
|
if ((td->td_flags & TDF_NOLOAD) == 0)
|
|
sched_load_add();
|
|
runq_add(ts->ts_runq, td, flags);
|
|
maybe_resched(td);
|
|
}
|
|
#endif /* SMP */
|
|
|
|
void
|
|
sched_rem(struct thread *td)
|
|
{
|
|
struct td_sched *ts;
|
|
|
|
ts = td_get_sched(td);
|
|
KASSERT(td->td_flags & TDF_INMEM,
|
|
("sched_rem: thread swapped out"));
|
|
KASSERT(TD_ON_RUNQ(td),
|
|
("sched_rem: thread not on run queue"));
|
|
mtx_assert(&sched_lock, MA_OWNED);
|
|
KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq rem",
|
|
"prio:%d", td->td_priority, KTR_ATTR_LINKED,
|
|
sched_tdname(curthread));
|
|
SDT_PROBE3(sched, , , dequeue, td, td->td_proc, NULL);
|
|
|
|
if ((td->td_flags & TDF_NOLOAD) == 0)
|
|
sched_load_rem();
|
|
#ifdef SMP
|
|
if (ts->ts_runq != &runq)
|
|
runq_length[ts->ts_runq - runq_pcpu]--;
|
|
#endif
|
|
runq_remove(ts->ts_runq, td);
|
|
TD_SET_CAN_RUN(td);
|
|
}
|
|
|
|
/*
|
|
* Select threads to run. Note that running threads still consume a
|
|
* slot.
|
|
*/
|
|
struct thread *
|
|
sched_choose(void)
|
|
{
|
|
struct thread *td;
|
|
struct runq *rq;
|
|
|
|
mtx_assert(&sched_lock, MA_OWNED);
|
|
#ifdef SMP
|
|
struct thread *tdcpu;
|
|
|
|
rq = &runq;
|
|
td = runq_choose_fuzz(&runq, runq_fuzz);
|
|
tdcpu = runq_choose(&runq_pcpu[PCPU_GET(cpuid)]);
|
|
|
|
if (td == NULL ||
|
|
(tdcpu != NULL &&
|
|
tdcpu->td_priority < td->td_priority)) {
|
|
CTR2(KTR_RUNQ, "choosing td %p from pcpu runq %d", tdcpu,
|
|
PCPU_GET(cpuid));
|
|
td = tdcpu;
|
|
rq = &runq_pcpu[PCPU_GET(cpuid)];
|
|
} else {
|
|
CTR1(KTR_RUNQ, "choosing td_sched %p from main runq", td);
|
|
}
|
|
|
|
#else
|
|
rq = &runq;
|
|
td = runq_choose(&runq);
|
|
#endif
|
|
|
|
if (td) {
|
|
#ifdef SMP
|
|
if (td == tdcpu)
|
|
runq_length[PCPU_GET(cpuid)]--;
|
|
#endif
|
|
runq_remove(rq, td);
|
|
td->td_flags |= TDF_DIDRUN;
|
|
|
|
KASSERT(td->td_flags & TDF_INMEM,
|
|
("sched_choose: thread swapped out"));
|
|
return (td);
|
|
}
|
|
return (PCPU_GET(idlethread));
|
|
}
|
|
|
|
void
|
|
sched_preempt(struct thread *td)
|
|
{
|
|
|
|
SDT_PROBE2(sched, , , surrender, td, td->td_proc);
|
|
thread_lock(td);
|
|
if (td->td_critnest > 1)
|
|
td->td_owepreempt = 1;
|
|
else
|
|
mi_switch(SW_INVOL | SW_PREEMPT | SWT_PREEMPT, NULL);
|
|
thread_unlock(td);
|
|
}
|
|
|
|
void
|
|
sched_userret(struct thread *td)
|
|
{
|
|
/*
|
|
* XXX we cheat slightly on the locking here to avoid locking in
|
|
* the usual case. Setting td_priority here is essentially an
|
|
* incomplete workaround for not setting it properly elsewhere.
|
|
* Now that some interrupt handlers are threads, not setting it
|
|
* properly elsewhere can clobber it in the window between setting
|
|
* it here and returning to user mode, so don't waste time setting
|
|
* it perfectly here.
|
|
*/
|
|
KASSERT((td->td_flags & TDF_BORROWING) == 0,
|
|
("thread with borrowed priority returning to userland"));
|
|
if (td->td_priority != td->td_user_pri) {
|
|
thread_lock(td);
|
|
td->td_priority = td->td_user_pri;
|
|
td->td_base_pri = td->td_user_pri;
|
|
thread_unlock(td);
|
|
}
|
|
}
|
|
|
|
void
|
|
sched_bind(struct thread *td, int cpu)
|
|
{
|
|
struct td_sched *ts;
|
|
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED|MA_NOTRECURSED);
|
|
KASSERT(td == curthread, ("sched_bind: can only bind curthread"));
|
|
|
|
ts = td_get_sched(td);
|
|
|
|
td->td_flags |= TDF_BOUND;
|
|
#ifdef SMP
|
|
ts->ts_runq = &runq_pcpu[cpu];
|
|
if (PCPU_GET(cpuid) == cpu)
|
|
return;
|
|
|
|
mi_switch(SW_VOL, NULL);
|
|
#endif
|
|
}
|
|
|
|
void
|
|
sched_unbind(struct thread* td)
|
|
{
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
KASSERT(td == curthread, ("sched_unbind: can only bind curthread"));
|
|
td->td_flags &= ~TDF_BOUND;
|
|
}
|
|
|
|
int
|
|
sched_is_bound(struct thread *td)
|
|
{
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
return (td->td_flags & TDF_BOUND);
|
|
}
|
|
|
|
void
|
|
sched_relinquish(struct thread *td)
|
|
{
|
|
thread_lock(td);
|
|
mi_switch(SW_VOL | SWT_RELINQUISH, NULL);
|
|
thread_unlock(td);
|
|
}
|
|
|
|
int
|
|
sched_load(void)
|
|
{
|
|
return (sched_tdcnt);
|
|
}
|
|
|
|
int
|
|
sched_sizeof_proc(void)
|
|
{
|
|
return (sizeof(struct proc));
|
|
}
|
|
|
|
int
|
|
sched_sizeof_thread(void)
|
|
{
|
|
return (sizeof(struct thread) + sizeof(struct td_sched));
|
|
}
|
|
|
|
fixpt_t
|
|
sched_pctcpu(struct thread *td)
|
|
{
|
|
struct td_sched *ts;
|
|
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
ts = td_get_sched(td);
|
|
return (ts->ts_pctcpu);
|
|
}
|
|
|
|
#ifdef RACCT
|
|
/*
|
|
* Calculates the contribution to the thread cpu usage for the latest
|
|
* (unfinished) second.
|
|
*/
|
|
fixpt_t
|
|
sched_pctcpu_delta(struct thread *td)
|
|
{
|
|
struct td_sched *ts;
|
|
fixpt_t delta;
|
|
int realstathz;
|
|
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
ts = td_get_sched(td);
|
|
delta = 0;
|
|
realstathz = stathz ? stathz : hz;
|
|
if (ts->ts_cpticks != 0) {
|
|
#if (FSHIFT >= CCPU_SHIFT)
|
|
delta = (realstathz == 100)
|
|
? ((fixpt_t) ts->ts_cpticks) <<
|
|
(FSHIFT - CCPU_SHIFT) :
|
|
100 * (((fixpt_t) ts->ts_cpticks)
|
|
<< (FSHIFT - CCPU_SHIFT)) / realstathz;
|
|
#else
|
|
delta = ((FSCALE - ccpu) *
|
|
(ts->ts_cpticks *
|
|
FSCALE / realstathz)) >> FSHIFT;
|
|
#endif
|
|
}
|
|
|
|
return (delta);
|
|
}
|
|
#endif
|
|
|
|
u_int
|
|
sched_estcpu(struct thread *td)
|
|
{
|
|
|
|
return (td_get_sched(td)->ts_estcpu);
|
|
}
|
|
|
|
/*
|
|
* The actual idle process.
|
|
*/
|
|
void
|
|
sched_idletd(void *dummy)
|
|
{
|
|
struct pcpuidlestat *stat;
|
|
|
|
THREAD_NO_SLEEPING();
|
|
stat = DPCPU_PTR(idlestat);
|
|
for (;;) {
|
|
mtx_assert(&Giant, MA_NOTOWNED);
|
|
|
|
while (sched_runnable() == 0) {
|
|
cpu_idle(stat->idlecalls + stat->oldidlecalls > 64);
|
|
stat->idlecalls++;
|
|
}
|
|
|
|
mtx_lock_spin(&sched_lock);
|
|
mi_switch(SW_VOL | SWT_IDLE, NULL);
|
|
mtx_unlock_spin(&sched_lock);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* A CPU is entering for the first time or a thread is exiting.
|
|
*/
|
|
void
|
|
sched_throw(struct thread *td)
|
|
{
|
|
/*
|
|
* Correct spinlock nesting. The idle thread context that we are
|
|
* borrowing was created so that it would start out with a single
|
|
* spin lock (sched_lock) held in fork_trampoline(). Since we've
|
|
* explicitly acquired locks in this function, the nesting count
|
|
* is now 2 rather than 1. Since we are nested, calling
|
|
* spinlock_exit() will simply adjust the counts without allowing
|
|
* spin lock using code to interrupt us.
|
|
*/
|
|
if (td == NULL) {
|
|
mtx_lock_spin(&sched_lock);
|
|
spinlock_exit();
|
|
PCPU_SET(switchtime, cpu_ticks());
|
|
PCPU_SET(switchticks, ticks);
|
|
} else {
|
|
lock_profile_release_lock(&sched_lock.lock_object);
|
|
MPASS(td->td_lock == &sched_lock);
|
|
td->td_lastcpu = td->td_oncpu;
|
|
td->td_oncpu = NOCPU;
|
|
}
|
|
mtx_assert(&sched_lock, MA_OWNED);
|
|
KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count"));
|
|
cpu_throw(td, choosethread()); /* doesn't return */
|
|
}
|
|
|
|
void
|
|
sched_fork_exit(struct thread *td)
|
|
{
|
|
|
|
/*
|
|
* Finish setting up thread glue so that it begins execution in a
|
|
* non-nested critical section with sched_lock held but not recursed.
|
|
*/
|
|
td->td_oncpu = PCPU_GET(cpuid);
|
|
sched_lock.mtx_lock = (uintptr_t)td;
|
|
lock_profile_obtain_lock_success(&sched_lock.lock_object,
|
|
0, 0, __FILE__, __LINE__);
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED | MA_NOTRECURSED);
|
|
}
|
|
|
|
char *
|
|
sched_tdname(struct thread *td)
|
|
{
|
|
#ifdef KTR
|
|
struct td_sched *ts;
|
|
|
|
ts = td_get_sched(td);
|
|
if (ts->ts_name[0] == '\0')
|
|
snprintf(ts->ts_name, sizeof(ts->ts_name),
|
|
"%s tid %d", td->td_name, td->td_tid);
|
|
return (ts->ts_name);
|
|
#else
|
|
return (td->td_name);
|
|
#endif
|
|
}
|
|
|
|
#ifdef KTR
|
|
void
|
|
sched_clear_tdname(struct thread *td)
|
|
{
|
|
struct td_sched *ts;
|
|
|
|
ts = td_get_sched(td);
|
|
ts->ts_name[0] = '\0';
|
|
}
|
|
#endif
|
|
|
|
void
|
|
sched_affinity(struct thread *td)
|
|
{
|
|
#ifdef SMP
|
|
struct td_sched *ts;
|
|
int cpu;
|
|
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
|
|
/*
|
|
* Set the TSF_AFFINITY flag if there is at least one CPU this
|
|
* thread can't run on.
|
|
*/
|
|
ts = td_get_sched(td);
|
|
ts->ts_flags &= ~TSF_AFFINITY;
|
|
CPU_FOREACH(cpu) {
|
|
if (!THREAD_CAN_SCHED(td, cpu)) {
|
|
ts->ts_flags |= TSF_AFFINITY;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If this thread can run on all CPUs, nothing else to do.
|
|
*/
|
|
if (!(ts->ts_flags & TSF_AFFINITY))
|
|
return;
|
|
|
|
/* Pinned threads and bound threads should be left alone. */
|
|
if (td->td_pinned != 0 || td->td_flags & TDF_BOUND)
|
|
return;
|
|
|
|
switch (td->td_state) {
|
|
case TDS_RUNQ:
|
|
/*
|
|
* If we are on a per-CPU runqueue that is in the set,
|
|
* then nothing needs to be done.
|
|
*/
|
|
if (ts->ts_runq != &runq &&
|
|
THREAD_CAN_SCHED(td, ts->ts_runq - runq_pcpu))
|
|
return;
|
|
|
|
/* Put this thread on a valid per-CPU runqueue. */
|
|
sched_rem(td);
|
|
sched_add(td, SRQ_BORING);
|
|
break;
|
|
case TDS_RUNNING:
|
|
/*
|
|
* See if our current CPU is in the set. If not, force a
|
|
* context switch.
|
|
*/
|
|
if (THREAD_CAN_SCHED(td, td->td_oncpu))
|
|
return;
|
|
|
|
td->td_flags |= TDF_NEEDRESCHED;
|
|
if (td != curthread)
|
|
ipi_cpu(cpu, IPI_AST);
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
#endif
|
|
}
|