/*- * Copyright (c) 1982, 1986, 1990, 1991, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include __FBSDID("$FreeBSD$"); #define kse td_sched #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * INVERSE_ESTCPU_WEIGHT is only suitable for statclock() frequencies in * the range 100-256 Hz (approximately). */ #define ESTCPULIM(e) \ min((e), INVERSE_ESTCPU_WEIGHT * (NICE_WEIGHT * (PRIO_MAX - PRIO_MIN) - \ RQ_PPQ) + INVERSE_ESTCPU_WEIGHT - 1) #ifdef SMP #define INVERSE_ESTCPU_WEIGHT (8 * smp_cpus) #else #define INVERSE_ESTCPU_WEIGHT 8 /* 1 / (priorities per estcpu level). */ #endif #define NICE_WEIGHT 1 /* Priorities per nice level. */ /* * The schedulable entity that can be given a context to run. * A process may have several of these. Probably one per processor * but posibly a few more. In this universe they are grouped * with a KSEG that contains the priority and niceness * for the group. */ struct kse { TAILQ_ENTRY(kse) ke_procq; /* (j/z) Run queue. */ struct thread *ke_thread; /* (*) Active associated thread. */ fixpt_t ke_pctcpu; /* (j) %cpu during p_swtime. */ char ke_rqindex; /* (j) Run queue index. */ enum { KES_THREAD = 0x0, /* slaved to thread state */ KES_ONRUNQ } ke_state; /* (j) KSE status. */ int ke_cpticks; /* (j) Ticks of cpu time. */ struct runq *ke_runq; /* runq the kse is currently on */ }; #define ke_proc ke_thread->td_proc #define ke_ksegrp ke_thread->td_ksegrp #define td_kse td_sched /* flags kept in td_flags */ #define TDF_DIDRUN TDF_SCHED0 /* KSE actually ran. */ #define TDF_EXIT TDF_SCHED1 /* KSE is being killed. */ #define TDF_BOUND TDF_SCHED2 #define ke_flags ke_thread->td_flags #define KEF_DIDRUN TDF_DIDRUN /* KSE actually ran. */ #define KEF_EXIT TDF_EXIT /* KSE is being killed. */ #define KEF_BOUND TDF_BOUND /* stuck to one CPU */ #define SKE_RUNQ_PCPU(ke) \ ((ke)->ke_runq != 0 && (ke)->ke_runq != &runq) struct kg_sched { struct thread *skg_last_assigned; /* (j) Last thread assigned to */ /* the system scheduler. */ int skg_avail_opennings; /* (j) Num KSEs requested in group. */ int skg_concurrency; /* (j) Num KSEs requested in group. */ }; #define kg_last_assigned kg_sched->skg_last_assigned #define kg_avail_opennings kg_sched->skg_avail_opennings #define kg_concurrency kg_sched->skg_concurrency #define SLOT_RELEASE(kg) \ do { \ kg->kg_avail_opennings++; \ CTR3(KTR_RUNQ, "kg %p(%d) Slot released (->%d)", \ kg, \ kg->kg_concurrency, \ kg->kg_avail_opennings); \ /* KASSERT((kg->kg_avail_opennings <= kg->kg_concurrency), \ ("slots out of whack"));*/ \ } while (0) #define SLOT_USE(kg) \ do { \ kg->kg_avail_opennings--; \ CTR3(KTR_RUNQ, "kg %p(%d) Slot used (->%d)", \ kg, \ kg->kg_concurrency, \ kg->kg_avail_opennings); \ /* KASSERT((kg->kg_avail_opennings >= 0), \ ("slots out of whack"));*/ \ } while (0) /* * KSE_CAN_MIGRATE macro returns true if the kse can migrate between * cpus. */ #define KSE_CAN_MIGRATE(ke) \ ((ke)->ke_thread->td_pinned == 0 && ((ke)->ke_flags & KEF_BOUND) == 0) static struct kse kse0; static struct kg_sched kg_sched0; static int sched_tdcnt; /* Total runnable threads in the system. */ static int sched_quantum; /* Roundrobin scheduling quantum in ticks. */ #define SCHED_QUANTUM (hz / 10) /* Default sched quantum */ static struct callout roundrobin_callout; static void slot_fill(struct ksegrp *kg); static struct kse *sched_choose(void); /* XXX Should be thread * */ static void setup_runqs(void); static void roundrobin(void *arg); static void schedcpu(void); static void schedcpu_thread(void); static void sched_priority(struct thread *td, u_char prio); static void sched_setup(void *dummy); static void maybe_resched(struct thread *td); static void updatepri(struct ksegrp *kg); static void resetpriority(struct ksegrp *kg); static void resetpriority_thread(struct thread *td, struct ksegrp *kg); #ifdef SMP static int forward_wakeup(int cpunum); #endif static struct kproc_desc sched_kp = { "schedcpu", schedcpu_thread, NULL }; SYSINIT(schedcpu, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, kproc_start, &sched_kp) SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL) /* * Global run queue. */ static struct runq runq; #ifdef SMP /* * Per-CPU run queues */ static struct runq runq_pcpu[MAXCPU]; #endif static void setup_runqs(void) { #ifdef SMP int i; for (i = 0; i < MAXCPU; ++i) runq_init(&runq_pcpu[i]); #endif runq_init(&runq); } static int sysctl_kern_quantum(SYSCTL_HANDLER_ARGS) { int error, new_val; new_val = sched_quantum * tick; error = sysctl_handle_int(oidp, &new_val, 0, req); if (error != 0 || req->newptr == NULL) return (error); if (new_val < tick) return (EINVAL); sched_quantum = new_val / tick; hogticks = 2 * sched_quantum; return (0); } SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RD, 0, "Scheduler"); SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "4BSD", 0, "Scheduler name"); SYSCTL_PROC(_kern_sched, OID_AUTO, quantum, CTLTYPE_INT | CTLFLAG_RW, 0, sizeof sched_quantum, sysctl_kern_quantum, "I", "Roundrobin scheduling quantum in microseconds"); #ifdef SMP /* Enable forwarding of wakeups to all other cpus */ SYSCTL_NODE(_kern_sched, OID_AUTO, ipiwakeup, CTLFLAG_RD, NULL, "Kernel SMP"); static int forward_wakeup_enabled = 1; SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, enabled, CTLFLAG_RW, &forward_wakeup_enabled, 0, "Forwarding of wakeup to idle CPUs"); static int forward_wakeups_requested = 0; SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, requested, CTLFLAG_RD, &forward_wakeups_requested, 0, "Requests for Forwarding of wakeup to idle CPUs"); static int forward_wakeups_delivered = 0; SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, delivered, CTLFLAG_RD, &forward_wakeups_delivered, 0, "Completed Forwarding of wakeup to idle CPUs"); static int forward_wakeup_use_mask = 1; SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, usemask, CTLFLAG_RW, &forward_wakeup_use_mask, 0, "Use the mask of idle cpus"); static int forward_wakeup_use_loop = 0; SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, useloop, CTLFLAG_RW, &forward_wakeup_use_loop, 0, "Use a loop to find idle cpus"); static int forward_wakeup_use_single = 0; SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, onecpu, CTLFLAG_RW, &forward_wakeup_use_single, 0, "Only signal one idle cpu"); static int forward_wakeup_use_htt = 0; SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, htt2, CTLFLAG_RW, &forward_wakeup_use_htt, 0, "account for htt"); #endif static int sched_followon = 0; SYSCTL_INT(_kern_sched, OID_AUTO, followon, CTLFLAG_RW, &sched_followon, 0, "allow threads to share a quantum"); static int sched_pfollowons = 0; SYSCTL_INT(_kern_sched, OID_AUTO, pfollowons, CTLFLAG_RD, &sched_pfollowons, 0, "number of followons done to a different ksegrp"); static int sched_kgfollowons = 0; SYSCTL_INT(_kern_sched, OID_AUTO, kgfollowons, CTLFLAG_RD, &sched_kgfollowons, 0, "number of followons done in a ksegrp"); static __inline void sched_load_add(void) { sched_tdcnt++; CTR1(KTR_SCHED, "global load: %d", sched_tdcnt); } static __inline void sched_load_rem(void) { sched_tdcnt--; CTR1(KTR_SCHED, "global load: %d", sched_tdcnt); } /* * Arrange to reschedule if necessary, taking the priorities and * schedulers into account. */ static void maybe_resched(struct thread *td) { mtx_assert(&sched_lock, MA_OWNED); if (td->td_priority < curthread->td_priority) curthread->td_flags |= TDF_NEEDRESCHED; } /* * Force switch among equal priority processes every 100ms. * We don't actually need to force a context switch of the current process. * The act of firing the event triggers a context switch to softclock() and * then switching back out again which is equivalent to a preemption, thus * no further work is needed on the local CPU. */ /* ARGSUSED */ static void roundrobin(void *arg) { #ifdef SMP mtx_lock_spin(&sched_lock); forward_roundrobin(); mtx_unlock_spin(&sched_lock); #endif callout_reset(&roundrobin_callout, sched_quantum, roundrobin, NULL); } /* * Constants for digital decay and forget: * 90% of (kg_estcpu) usage in 5 * loadav time * 95% of (ke_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 kg_estcpu and p_cpticks asynchronously. * * We wish to decay away 90% of kg_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++) * kg_estcpu *= decay; * will compute * kg_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 `ke_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */ static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */ SYSCTL_INT(_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 kse *ke; struct ksegrp *kg; int awake, realstathz; realstathz = stathz ? stathz : hz; sx_slock(&allproc_lock); FOREACH_PROC_IN_SYSTEM(p) { /* * Prevent state changes and protect run queue. */ mtx_lock_spin(&sched_lock); /* * Increment time in/out of memory. We ignore overflow; with * 16-bit int's (remember them?) overflow takes 45 days. */ p->p_swtime++; FOREACH_KSEGRP_IN_PROC(p, kg) { awake = 0; FOREACH_THREAD_IN_GROUP(kg, td) { ke = td->td_kse; /* * Increment sleep time (if sleeping). We * ignore overflow, as above. */ /* * The kse slptimes are not touched in wakeup * because the thread may not HAVE a KSE. */ if (ke->ke_state == KES_ONRUNQ) { awake = 1; ke->ke_flags &= ~KEF_DIDRUN; } else if ((ke->ke_state == KES_THREAD) && (TD_IS_RUNNING(td))) { awake = 1; /* Do not clear KEF_DIDRUN */ } else if (ke->ke_flags & KEF_DIDRUN) { awake = 1; ke->ke_flags &= ~KEF_DIDRUN; } /* * ke_pctcpu is only for ps and ttyinfo(). * Do it per kse, and add them up at the end? * XXXKSE */ ke->ke_pctcpu = (ke->ke_pctcpu * ccpu) >> FSHIFT; /* * If the kse has been idle the entire second, * stop recalculating its priority until * it wakes up. */ if (ke->ke_cpticks == 0) continue; #if (FSHIFT >= CCPU_SHIFT) ke->ke_pctcpu += (realstathz == 100) ? ((fixpt_t) ke->ke_cpticks) << (FSHIFT - CCPU_SHIFT) : 100 * (((fixpt_t) ke->ke_cpticks) << (FSHIFT - CCPU_SHIFT)) / realstathz; #else ke->ke_pctcpu += ((FSCALE - ccpu) * (ke->ke_cpticks * FSCALE / realstathz)) >> FSHIFT; #endif ke->ke_cpticks = 0; } /* end of kse loop */ /* * If there are ANY running threads in this KSEGRP, * then don't count it as sleeping. */ if (awake) { if (kg->kg_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(kg); } kg->kg_slptime = 0; } else kg->kg_slptime++; if (kg->kg_slptime > 1) continue; kg->kg_estcpu = decay_cpu(loadfac, kg->kg_estcpu); resetpriority(kg); FOREACH_THREAD_IN_GROUP(kg, td) { resetpriority_thread(td, kg); } } /* end of ksegrp loop */ mtx_unlock_spin(&sched_lock); } /* end of process loop */ sx_sunlock(&allproc_lock); } /* * Main loop for a kthread that executes schedcpu once a second. */ static void schedcpu_thread(void) { int nowake; for (;;) { schedcpu(); tsleep(&nowake, curthread->td_priority, "-", hz); } } /* * Recalculate the priority of a process after it has slept for a while. * For all load averages >= 1 and max kg_estcpu of 255, sleeping for at * least six times the loadfactor will decay kg_estcpu to zero. */ static void updatepri(struct ksegrp *kg) { register fixpt_t loadfac; register unsigned int newcpu; loadfac = loadfactor(averunnable.ldavg[0]); if (kg->kg_slptime > 5 * loadfac) kg->kg_estcpu = 0; else { newcpu = kg->kg_estcpu; kg->kg_slptime--; /* was incremented in schedcpu() */ while (newcpu && --kg->kg_slptime) newcpu = decay_cpu(loadfac, newcpu); kg->kg_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 ksegrp *kg) { register unsigned int newpriority; if (kg->kg_pri_class == PRI_TIMESHARE) { newpriority = PUSER + kg->kg_estcpu / INVERSE_ESTCPU_WEIGHT + NICE_WEIGHT * (kg->kg_proc->p_nice - PRIO_MIN); newpriority = min(max(newpriority, PRI_MIN_TIMESHARE), PRI_MAX_TIMESHARE); kg->kg_user_pri = newpriority; } } /* * Update the thread's priority when the associated ksegroup's user * priority changes. */ static void resetpriority_thread(struct thread *td, struct ksegrp *kg) { /* 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, kg->kg_user_pri); } /* ARGSUSED */ static void sched_setup(void *dummy) { setup_runqs(); if (sched_quantum == 0) sched_quantum = SCHED_QUANTUM; hogticks = 2 * sched_quantum; callout_init(&roundrobin_callout, CALLOUT_MPSAFE); /* Kick off timeout driven events by calling first time. */ roundrobin(NULL); /* Account for thread0. */ sched_load_add(); } /* External interfaces start here */ /* * Very early in the boot some setup of scheduler-specific * parts of proc0 and of soem scheduler resources needs to be done. * Called from: * proc0_init() */ void schedinit(void) { /* * Set up the scheduler specific parts of proc0. */ proc0.p_sched = NULL; /* XXX */ ksegrp0.kg_sched = &kg_sched0; thread0.td_sched = &kse0; kse0.ke_thread = &thread0; kse0.ke_state = KES_THREAD; kg_sched0.skg_concurrency = 1; kg_sched0.skg_avail_opennings = 0; /* we are already running */ } 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) { if (sched_quantum == 0) sched_quantum = SCHED_QUANTUM; return (sched_quantum); } /* * We adjust the priority of the current process. The priority of * a process gets worse as it accumulates CPU time. The cpu usage * estimator (kg_estcpu) is increased here. resetpriority() will * compute a different priority each time kg_estcpu increases by * INVERSE_ESTCPU_WEIGHT * (until MAXPRI is reached). The cpu usage estimator ramps up * quite quickly when the process is running (linearly), and decays * away exponentially, at a rate which is proportionally slower when * the system is busy. The basic principle is that the system will * 90% forget that the process used a lot of CPU time in 5 * loadav * seconds. This causes the system to favor processes which haven't * run much recently, and to round-robin among other processes. */ void sched_clock(struct thread *td) { struct ksegrp *kg; struct kse *ke; mtx_assert(&sched_lock, MA_OWNED); kg = td->td_ksegrp; ke = td->td_kse; ke->ke_cpticks++; kg->kg_estcpu = ESTCPULIM(kg->kg_estcpu + 1); if ((kg->kg_estcpu % INVERSE_ESTCPU_WEIGHT) == 0) { resetpriority(kg); resetpriority_thread(td, kg); } } /* * charge childs scheduling cpu usage to parent. * * XXXKSE assume only one thread & kse & ksegrp keep estcpu in each ksegrp. * Charge it to the ksegrp that did the wait since process estcpu is sum of * all ksegrps, this is strictly as expected. Assume that the child process * aggregated all the estcpu into the 'built-in' ksegrp. */ void sched_exit(struct proc *p, struct thread *td) { sched_exit_ksegrp(FIRST_KSEGRP_IN_PROC(p), td); sched_exit_thread(FIRST_THREAD_IN_PROC(p), td); } void sched_exit_ksegrp(struct ksegrp *kg, struct thread *childtd) { mtx_assert(&sched_lock, MA_OWNED); kg->kg_estcpu = ESTCPULIM(kg->kg_estcpu + childtd->td_ksegrp->kg_estcpu); } void sched_exit_thread(struct thread *td, struct thread *child) { CTR3(KTR_SCHED, "sched_exit_thread: %p(%s) prio %d", child, child->td_proc->p_comm, child->td_priority); if ((child->td_proc->p_flag & P_NOLOAD) == 0) sched_load_rem(); } void sched_fork(struct thread *td, struct thread *childtd) { sched_fork_ksegrp(td, childtd->td_ksegrp); sched_fork_thread(td, childtd); } void sched_fork_ksegrp(struct thread *td, struct ksegrp *child) { mtx_assert(&sched_lock, MA_OWNED); child->kg_estcpu = td->td_ksegrp->kg_estcpu; } void sched_fork_thread(struct thread *td, struct thread *childtd) { sched_newthread(childtd); } void sched_nice(struct proc *p, int nice) { struct ksegrp *kg; struct thread *td; PROC_LOCK_ASSERT(p, MA_OWNED); mtx_assert(&sched_lock, MA_OWNED); p->p_nice = nice; FOREACH_KSEGRP_IN_PROC(p, kg) { resetpriority(kg); FOREACH_THREAD_IN_GROUP(kg, td) { resetpriority_thread(td, kg); } } } void sched_class(struct ksegrp *kg, int class) { mtx_assert(&sched_lock, MA_OWNED); kg->kg_pri_class = class; } /* * Adjust the priority of a thread. * This may include moving the thread within the KSEGRP, * changing the assignment of a kse to the thread, * and moving a KSE in the system run queue. */ static void sched_priority(struct thread *td, u_char prio) { CTR6(KTR_SCHED, "sched_prio: %p(%s) prio %d newprio %d by %p(%s)", td, td->td_proc->p_comm, td->td_priority, prio, curthread, curthread->td_proc->p_comm); mtx_assert(&sched_lock, MA_OWNED); if (td->td_priority == prio) return; if (TD_ON_RUNQ(td)) { adjustrunqueue(td, prio); } else { td->td_priority = prio; } } /* * 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_ksegrp->kg_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_sleep(struct thread *td) { mtx_assert(&sched_lock, MA_OWNED); td->td_ksegrp->kg_slptime = 0; } static void remrunqueue(struct thread *td); void sched_switch(struct thread *td, struct thread *newtd, int flags) { struct kse *ke; struct ksegrp *kg; struct proc *p; ke = td->td_kse; p = td->td_proc; mtx_assert(&sched_lock, MA_OWNED); if ((p->p_flag & P_NOLOAD) == 0) sched_load_rem(); /* * We are volunteering to switch out so we get to nominate * a successor for the rest of our quantum * First try another thread in our ksegrp, and then look for * other ksegrps in our process. */ if (sched_followon && (p->p_flag & P_HADTHREADS) && (flags & SW_VOL) && newtd == NULL) { /* lets schedule another thread from this process */ kg = td->td_ksegrp; if ((newtd = TAILQ_FIRST(&kg->kg_runq))) { remrunqueue(newtd); sched_kgfollowons++; } else { FOREACH_KSEGRP_IN_PROC(p, kg) { if ((newtd = TAILQ_FIRST(&kg->kg_runq))) { sched_pfollowons++; remrunqueue(newtd); break; } } } } if (newtd) newtd->td_flags |= (td->td_flags & TDF_NEEDRESCHED); td->td_lastcpu = td->td_oncpu; td->td_flags &= ~TDF_NEEDRESCHED; 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 == PCPU_GET(idlethread)) TD_SET_CAN_RUN(td); else { SLOT_RELEASE(td->td_ksegrp); if (TD_IS_RUNNING(td)) { /* Put us back on the run queue (kse and all). */ setrunqueue(td, (flags & SW_PREEMPT) ? SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED : SRQ_OURSELF|SRQ_YIELDING); } else if (p->p_flag & P_HADTHREADS) { /* * We will not be on the run queue. So we must be * sleeping or similar. As it's available, * someone else can use the KSE if they need it. * It's NOT available if we are about to need it */ if (newtd == NULL || newtd->td_ksegrp != td->td_ksegrp) slot_fill(td->td_ksegrp); } } 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 inhibitted thread")); SLOT_USE(newtd->td_ksegrp); newtd->td_kse->ke_flags |= KEF_DIDRUN; TD_SET_RUNNING(newtd); if ((newtd->td_proc->p_flag & P_NOLOAD) == 0) sched_load_add(); } else { newtd = choosethread(); } if (td != newtd) cpu_switch(td, newtd); sched_lock.mtx_lock = (uintptr_t)td; td->td_oncpu = PCPU_GET(cpuid); } void sched_wakeup(struct thread *td) { struct ksegrp *kg; mtx_assert(&sched_lock, MA_OWNED); kg = td->td_ksegrp; if (kg->kg_slptime > 1) { updatepri(kg); resetpriority(kg); } kg->kg_slptime = 0; setrunqueue(td, SRQ_BORING); } #ifdef SMP /* enable HTT_2 if you have a 2-way HTT cpu.*/ static int forward_wakeup(int cpunum) { cpumask_t map, me, dontuse; cpumask_t map2; struct pcpu *pc; cpumask_t id, map3; 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(cpumask); /* * don't bother if we should be doing it ourself.. */ if ((me & idle_cpus_mask) && (cpunum == NOCPU || me == (1 << cpunum))) return (0); dontuse = me | stopped_cpus | hlt_cpus_mask; map3 = 0; if (forward_wakeup_use_loop) { SLIST_FOREACH(pc, &cpuhead, pc_allcpu) { id = pc->pc_cpumask; if ( (id & dontuse) == 0 && pc->pc_curthread == pc->pc_idlethread) { map3 |= id; } } } if (forward_wakeup_use_mask) { map = 0; map = idle_cpus_mask & ~dontuse; /* If they are both on, compare and use loop if different */ if (forward_wakeup_use_loop) { if (map != map3) { printf("map (%02X) != map3 (%02X)\n", map, map3); map = map3; } } } else { map = map3; } /* If we only allow a specific CPU, then mask off all the others */ if (cpunum != NOCPU) { KASSERT((cpunum <= mp_maxcpus),("forward_wakeup: bad cpunum.")); map &= (1 << cpunum); } else { /* Try choose an idle die. */ if (forward_wakeup_use_htt) { map2 = (map & (map >> 1)) & 0x5555; if (map2) { map = map2; } } /* set only one bit */ if (forward_wakeup_use_single) { map = map & ((~map) + 1); } } if (map) { forward_wakeups_delivered++; ipi_selected(map, IPI_AST); return (1); } if (cpunum == NOCPU) printf("forward_wakeup: Idle processor not found\n"); return (0); } #endif void sched_add(struct thread *td, int flags) { struct kse *ke; #ifdef SMP int forwarded = 0; int cpu; #endif ke = td->td_kse; mtx_assert(&sched_lock, MA_OWNED); KASSERT(ke->ke_state != KES_ONRUNQ, ("sched_add: kse %p (%s) already in run queue", ke, ke->ke_proc->p_comm)); KASSERT(ke->ke_proc->p_sflag & PS_INMEM, ("sched_add: process swapped out")); CTR5(KTR_SCHED, "sched_add: %p(%s) prio %d by %p(%s)", td, td->td_proc->p_comm, td->td_priority, curthread, curthread->td_proc->p_comm); #ifdef SMP if (KSE_CAN_MIGRATE(ke)) { CTR2(KTR_RUNQ, "sched_add: adding kse:%p (td:%p) to gbl runq", ke, td); cpu = NOCPU; ke->ke_runq = &runq; } else { if (!SKE_RUNQ_PCPU(ke)) ke->ke_runq = &runq_pcpu[(cpu = PCPU_GET(cpuid))]; else cpu = td->td_lastcpu; CTR3(KTR_RUNQ, "sched_add: Put kse:%p(td:%p) on cpu%d runq", ke, td, cpu); } #else CTR2(KTR_RUNQ, "sched_add: adding kse:%p (td:%p) to runq", ke, td); ke->ke_runq = &runq; #endif /* * 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 puting ourself on the run queue * which also only happens when we are about to yield. */ if((flags & SRQ_YIELDING) == 0) { #ifdef SMP cpumask_t me = PCPU_GET(cpumask); int idle = idle_cpus_mask & me; /* * Only try to kick off another CPU if * the thread is unpinned * or pinned to another cpu, * and there are other available and idle CPUs. * if we are idle, or it's an interrupt, * then skip straight to preemption. */ if ( (! idle) && ((flags & SRQ_INTR) == 0) && (idle_cpus_mask & ~(hlt_cpus_mask | me)) && ( KSE_CAN_MIGRATE(ke) || ke->ke_runq != &runq_pcpu[PCPU_GET(cpuid)])) { forwarded = forward_wakeup(cpu); } /* * If we failed to kick off another cpu, then look to * see if we should preempt this CPU. Only allow this * if it is not pinned or IS pinned to this CPU. * If we are the idle thread, we also try do preempt. * as it will be quicker and being idle, we won't * lose in doing so.. */ if ((!forwarded) && (ke->ke_runq == &runq || ke->ke_runq == &runq_pcpu[PCPU_GET(cpuid)])) #endif { if (maybe_preempt(td)) return; } } if ((td->td_proc->p_flag & P_NOLOAD) == 0) sched_load_add(); SLOT_USE(td->td_ksegrp); runq_add(ke->ke_runq, ke, flags); ke->ke_state = KES_ONRUNQ; maybe_resched(td); } void sched_rem(struct thread *td) { struct kse *ke; ke = td->td_kse; KASSERT(ke->ke_proc->p_sflag & PS_INMEM, ("sched_rem: process swapped out")); KASSERT((ke->ke_state == KES_ONRUNQ), ("sched_rem: KSE not on run queue")); mtx_assert(&sched_lock, MA_OWNED); CTR5(KTR_SCHED, "sched_rem: %p(%s) prio %d by %p(%s)", td, td->td_proc->p_comm, td->td_priority, curthread, curthread->td_proc->p_comm); if ((td->td_proc->p_flag & P_NOLOAD) == 0) sched_load_rem(); SLOT_RELEASE(td->td_ksegrp); runq_remove(ke->ke_runq, ke); ke->ke_state = KES_THREAD; } /* * Select threads to run. * Notice that the running threads still consume a slot. */ struct kse * sched_choose(void) { struct kse *ke; struct runq *rq; #ifdef SMP struct kse *kecpu; rq = &runq; ke = runq_choose(&runq); kecpu = runq_choose(&runq_pcpu[PCPU_GET(cpuid)]); if (ke == NULL || (kecpu != NULL && kecpu->ke_thread->td_priority < ke->ke_thread->td_priority)) { CTR2(KTR_RUNQ, "choosing kse %p from pcpu runq %d", kecpu, PCPU_GET(cpuid)); ke = kecpu; rq = &runq_pcpu[PCPU_GET(cpuid)]; } else { CTR1(KTR_RUNQ, "choosing kse %p from main runq", ke); } #else rq = &runq; ke = runq_choose(&runq); #endif if (ke != NULL) { runq_remove(rq, ke); ke->ke_state = KES_THREAD; KASSERT(ke->ke_proc->p_sflag & PS_INMEM, ("sched_choose: process swapped out")); } return (ke); } void sched_userret(struct thread *td) { struct ksegrp *kg; /* * 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")); kg = td->td_ksegrp; if (td->td_priority != kg->kg_user_pri) { mtx_lock_spin(&sched_lock); td->td_priority = kg->kg_user_pri; td->td_base_pri = kg->kg_user_pri; mtx_unlock_spin(&sched_lock); } } void sched_bind(struct thread *td, int cpu) { struct kse *ke; mtx_assert(&sched_lock, MA_OWNED); KASSERT(TD_IS_RUNNING(td), ("sched_bind: cannot bind non-running thread")); ke = td->td_kse; ke->ke_flags |= KEF_BOUND; #ifdef SMP ke->ke_runq = &runq_pcpu[cpu]; if (PCPU_GET(cpuid) == cpu) return; ke->ke_state = KES_THREAD; mi_switch(SW_VOL, NULL); #endif } void sched_unbind(struct thread* td) { mtx_assert(&sched_lock, MA_OWNED); td->td_kse->ke_flags &= ~KEF_BOUND; } int sched_load(void) { return (sched_tdcnt); } int sched_sizeof_ksegrp(void) { return (sizeof(struct ksegrp) + sizeof(struct kg_sched)); } int sched_sizeof_proc(void) { return (sizeof(struct proc)); } int sched_sizeof_thread(void) { return (sizeof(struct thread) + sizeof(struct kse)); } fixpt_t sched_pctcpu(struct thread *td) { struct kse *ke; ke = td->td_kse; return (ke->ke_pctcpu); return (0); } #define KERN_SWITCH_INCLUDE 1 #include "kern/kern_switch.c"