/*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1982, 1986, 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. * 3. 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. * * @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 */ #include __FBSDID("$FreeBSD$"); #include "opt_kdb.h" #include "opt_device_polling.h" #include "opt_hwpmc_hooks.h" #include "opt_ntp.h" #include "opt_watchdog.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef GPROF #include #endif #ifdef HWPMC_HOOKS #include PMC_SOFT_DEFINE( , , clock, hard); PMC_SOFT_DEFINE( , , clock, stat); PMC_SOFT_DEFINE_EX( , , clock, prof, \ cpu_startprofclock, cpu_stopprofclock); #endif #ifdef DEVICE_POLLING extern void hardclock_device_poll(void); #endif /* DEVICE_POLLING */ static void initclocks(void *dummy); SYSINIT(clocks, SI_SUB_CLOCKS, SI_ORDER_FIRST, initclocks, NULL); /* Spin-lock protecting profiling statistics. */ static struct mtx time_lock; SDT_PROVIDER_DECLARE(sched); SDT_PROBE_DEFINE2(sched, , , tick, "struct thread *", "struct proc *"); static int sysctl_kern_cp_time(SYSCTL_HANDLER_ARGS) { int error; long cp_time[CPUSTATES]; #ifdef SCTL_MASK32 int i; unsigned int cp_time32[CPUSTATES]; #endif read_cpu_time(cp_time); #ifdef SCTL_MASK32 if (req->flags & SCTL_MASK32) { if (!req->oldptr) return SYSCTL_OUT(req, 0, sizeof(cp_time32)); for (i = 0; i < CPUSTATES; i++) cp_time32[i] = (unsigned int)cp_time[i]; error = SYSCTL_OUT(req, cp_time32, sizeof(cp_time32)); } else #endif { if (!req->oldptr) return SYSCTL_OUT(req, 0, sizeof(cp_time)); error = SYSCTL_OUT(req, cp_time, sizeof(cp_time)); } return error; } SYSCTL_PROC(_kern, OID_AUTO, cp_time, CTLTYPE_LONG|CTLFLAG_RD|CTLFLAG_MPSAFE, 0,0, sysctl_kern_cp_time, "LU", "CPU time statistics"); static long empty[CPUSTATES]; static int sysctl_kern_cp_times(SYSCTL_HANDLER_ARGS) { struct pcpu *pcpu; int error; int c; long *cp_time; #ifdef SCTL_MASK32 unsigned int cp_time32[CPUSTATES]; int i; #endif if (!req->oldptr) { #ifdef SCTL_MASK32 if (req->flags & SCTL_MASK32) return SYSCTL_OUT(req, 0, sizeof(cp_time32) * (mp_maxid + 1)); else #endif return SYSCTL_OUT(req, 0, sizeof(long) * CPUSTATES * (mp_maxid + 1)); } for (error = 0, c = 0; error == 0 && c <= mp_maxid; c++) { if (!CPU_ABSENT(c)) { pcpu = pcpu_find(c); cp_time = pcpu->pc_cp_time; } else { cp_time = empty; } #ifdef SCTL_MASK32 if (req->flags & SCTL_MASK32) { for (i = 0; i < CPUSTATES; i++) cp_time32[i] = (unsigned int)cp_time[i]; error = SYSCTL_OUT(req, cp_time32, sizeof(cp_time32)); } else #endif error = SYSCTL_OUT(req, cp_time, sizeof(long) * CPUSTATES); } return error; } SYSCTL_PROC(_kern, OID_AUTO, cp_times, CTLTYPE_LONG|CTLFLAG_RD|CTLFLAG_MPSAFE, 0,0, sysctl_kern_cp_times, "LU", "per-CPU time statistics"); #ifdef DEADLKRES static const char *blessed[] = { "getblk", "so_snd_sx", "so_rcv_sx", NULL }; static int slptime_threshold = 1800; static int blktime_threshold = 900; static int sleepfreq = 3; static void deadlres_td_on_lock(struct proc *p, struct thread *td, int blkticks) { int tticks; sx_assert(&allproc_lock, SX_LOCKED); PROC_LOCK_ASSERT(p, MA_OWNED); THREAD_LOCK_ASSERT(td, MA_OWNED); /* * The thread should be blocked on a turnstile, simply check * if the turnstile channel is in good state. */ MPASS(td->td_blocked != NULL); tticks = ticks - td->td_blktick; if (tticks > blkticks) /* * Accordingly with provided thresholds, this thread is stuck * for too long on a turnstile. */ panic("%s: possible deadlock detected for %p (%s), " "blocked for %d ticks\n", __func__, td, sched_tdname(td), tticks); } static void deadlres_td_sleep_q(struct proc *p, struct thread *td, int slpticks) { const void *wchan; int i, slptype, tticks; sx_assert(&allproc_lock, SX_LOCKED); PROC_LOCK_ASSERT(p, MA_OWNED); THREAD_LOCK_ASSERT(td, MA_OWNED); /* * Check if the thread is sleeping on a lock, otherwise skip the check. * Drop the thread lock in order to avoid a LOR with the sleepqueue * spinlock. */ wchan = td->td_wchan; tticks = ticks - td->td_slptick; slptype = sleepq_type(wchan); if ((slptype == SLEEPQ_SX || slptype == SLEEPQ_LK) && tticks > slpticks) { /* * Accordingly with provided thresholds, this thread is stuck * for too long on a sleepqueue. * However, being on a sleepqueue, we might still check for the * blessed list. */ for (i = 0; blessed[i] != NULL; i++) if (!strcmp(blessed[i], td->td_wmesg)) return; panic("%s: possible deadlock detected for %p (%s), " "blocked for %d ticks\n", __func__, td, sched_tdname(td), tticks); } } static void deadlkres(void) { struct proc *p; struct thread *td; int blkticks, slpticks, tryl; tryl = 0; for (;;) { blkticks = blktime_threshold * hz; slpticks = slptime_threshold * hz; /* * Avoid to sleep on the sx_lock in order to avoid a * possible priority inversion problem leading to * starvation. * If the lock can't be held after 100 tries, panic. */ if (!sx_try_slock(&allproc_lock)) { if (tryl > 100) panic("%s: possible deadlock detected " "on allproc_lock\n", __func__); tryl++; pause("allproc", sleepfreq * hz); continue; } tryl = 0; FOREACH_PROC_IN_SYSTEM(p) { PROC_LOCK(p); if (p->p_state == PRS_NEW) { PROC_UNLOCK(p); continue; } FOREACH_THREAD_IN_PROC(p, td) { thread_lock(td); if (TD_ON_LOCK(td)) deadlres_td_on_lock(p, td, blkticks); else if (TD_IS_SLEEPING(td)) deadlres_td_sleep_q(p, td, slpticks); thread_unlock(td); } PROC_UNLOCK(p); } sx_sunlock(&allproc_lock); /* Sleep for sleepfreq seconds. */ pause("-", sleepfreq * hz); } } static struct kthread_desc deadlkres_kd = { "deadlkres", deadlkres, (struct thread **)NULL }; SYSINIT(deadlkres, SI_SUB_CLOCKS, SI_ORDER_ANY, kthread_start, &deadlkres_kd); static SYSCTL_NODE(_debug, OID_AUTO, deadlkres, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, "Deadlock resolver"); SYSCTL_INT(_debug_deadlkres, OID_AUTO, slptime_threshold, CTLFLAG_RW, &slptime_threshold, 0, "Number of seconds within is valid to sleep on a sleepqueue"); SYSCTL_INT(_debug_deadlkres, OID_AUTO, blktime_threshold, CTLFLAG_RW, &blktime_threshold, 0, "Number of seconds within is valid to block on a turnstile"); SYSCTL_INT(_debug_deadlkres, OID_AUTO, sleepfreq, CTLFLAG_RW, &sleepfreq, 0, "Number of seconds between any deadlock resolver thread run"); #endif /* DEADLKRES */ void read_cpu_time(long *cp_time) { struct pcpu *pc; int i, j; /* Sum up global cp_time[]. */ bzero(cp_time, sizeof(long) * CPUSTATES); CPU_FOREACH(i) { pc = pcpu_find(i); for (j = 0; j < CPUSTATES; j++) cp_time[j] += pc->pc_cp_time[j]; } } #include static int watchdog_ticks; static int watchdog_enabled; static void watchdog_fire(void); static void watchdog_config(void *, u_int, int *); static void watchdog_attach(void) { EVENTHANDLER_REGISTER(watchdog_list, watchdog_config, NULL, 0); } /* * Clock handling routines. * * This code is written to operate with two timers that run independently of * each other. * * The main timer, running hz times per second, is used to trigger interval * timers, timeouts and rescheduling as needed. * * The second timer handles kernel and user profiling, * and does resource use estimation. If the second timer is programmable, * it is randomized to avoid aliasing between the two clocks. For example, * the randomization prevents an adversary from always giving up the cpu * just before its quantum expires. Otherwise, it would never accumulate * cpu ticks. The mean frequency of the second timer is stathz. * * If no second timer exists, stathz will be zero; in this case we drive * profiling and statistics off the main clock. This WILL NOT be accurate; * do not do it unless absolutely necessary. * * The statistics clock may (or may not) be run at a higher rate while * profiling. This profile clock runs at profhz. We require that profhz * be an integral multiple of stathz. * * If the statistics clock is running fast, it must be divided by the ratio * profhz/stathz for statistics. (For profiling, every tick counts.) * * Time-of-day is maintained using a "timecounter", which may or may * not be related to the hardware generating the above mentioned * interrupts. */ int stathz; int profhz; int profprocs; volatile int ticks; int psratio; DPCPU_DEFINE_STATIC(int, pcputicks); /* Per-CPU version of ticks. */ #ifdef DEVICE_POLLING static int devpoll_run = 0; #endif /* * Initialize clock frequencies and start both clocks running. */ /* ARGSUSED*/ static void initclocks(void *dummy) { int i; /* * Set divisors to 1 (normal case) and let the machine-specific * code do its bit. */ mtx_init(&time_lock, "time lock", NULL, MTX_DEF); cpu_initclocks(); /* * Compute profhz/stathz, and fix profhz if needed. */ i = stathz ? stathz : hz; if (profhz == 0) profhz = i; psratio = profhz / i; #ifdef SW_WATCHDOG /* Enable hardclock watchdog now, even if a hardware watchdog exists. */ watchdog_attach(); #else /* Volunteer to run a software watchdog. */ if (wdog_software_attach == NULL) wdog_software_attach = watchdog_attach; #endif } static __noinline void hardclock_itimer(struct thread *td, struct pstats *pstats, int cnt, int usermode) { struct proc *p; int flags; flags = 0; p = td->td_proc; if (usermode && timevalisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value)) { PROC_ITIMLOCK(p); if (itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL], tick * cnt) == 0) flags |= TDF_ALRMPEND | TDF_ASTPENDING; PROC_ITIMUNLOCK(p); } if (timevalisset(&pstats->p_timer[ITIMER_PROF].it_value)) { PROC_ITIMLOCK(p); if (itimerdecr(&pstats->p_timer[ITIMER_PROF], tick * cnt) == 0) flags |= TDF_PROFPEND | TDF_ASTPENDING; PROC_ITIMUNLOCK(p); } if (flags != 0) { thread_lock(td); td->td_flags |= flags; thread_unlock(td); } } void hardclock(int cnt, int usermode) { struct pstats *pstats; struct thread *td = curthread; struct proc *p = td->td_proc; int *t = DPCPU_PTR(pcputicks); int global, i, newticks; /* * Update per-CPU and possibly global ticks values. */ *t += cnt; global = ticks; do { newticks = *t - global; if (newticks <= 0) { if (newticks < -1) *t = global - 1; newticks = 0; break; } } while (!atomic_fcmpset_int(&ticks, &global, *t)); /* * Run current process's virtual and profile time, as needed. */ pstats = p->p_stats; if (__predict_false( timevalisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value) || timevalisset(&pstats->p_timer[ITIMER_PROF].it_value))) hardclock_itimer(td, pstats, cnt, usermode); #ifdef HWPMC_HOOKS if (PMC_CPU_HAS_SAMPLES(PCPU_GET(cpuid))) PMC_CALL_HOOK_UNLOCKED(curthread, PMC_FN_DO_SAMPLES, NULL); if (td->td_intr_frame != NULL) PMC_SOFT_CALL_TF( , , clock, hard, td->td_intr_frame); #endif /* We are in charge to handle this tick duty. */ if (newticks > 0) { tc_ticktock(newticks); #ifdef DEVICE_POLLING /* Dangerous and no need to call these things concurrently. */ if (atomic_cmpset_acq_int(&devpoll_run, 0, 1)) { /* This is very short and quick. */ hardclock_device_poll(); atomic_store_rel_int(&devpoll_run, 0); } #endif /* DEVICE_POLLING */ if (watchdog_enabled > 0) { i = atomic_fetchadd_int(&watchdog_ticks, -newticks); if (i > 0 && i <= newticks) watchdog_fire(); } intr_event_handle(clk_intr_event, NULL); } if (curcpu == CPU_FIRST()) cpu_tick_calibration(); if (__predict_false(DPCPU_GET(epoch_cb_count))) GROUPTASK_ENQUEUE(DPCPU_PTR(epoch_cb_task)); } void hardclock_sync(int cpu) { int *t; KASSERT(!CPU_ABSENT(cpu), ("Absent CPU %d", cpu)); t = DPCPU_ID_PTR(cpu, pcputicks); *t = ticks; } /* * Compute number of ticks in the specified amount of time. */ int tvtohz(struct timeval *tv) { unsigned long ticks; long sec, usec; /* * If the number of usecs in the whole seconds part of the time * difference fits in a long, then the total number of usecs will * fit in an unsigned long. Compute the total and convert it to * ticks, rounding up and adding 1 to allow for the current tick * to expire. Rounding also depends on unsigned long arithmetic * to avoid overflow. * * Otherwise, if the number of ticks in the whole seconds part of * the time difference fits in a long, then convert the parts to * ticks separately and add, using similar rounding methods and * overflow avoidance. This method would work in the previous * case but it is slightly slower and assumes that hz is integral. * * Otherwise, round the time difference down to the maximum * representable value. * * If ints have 32 bits, then the maximum value for any timeout in * 10ms ticks is 248 days. */ sec = tv->tv_sec; usec = tv->tv_usec; if (usec < 0) { sec--; usec += 1000000; } if (sec < 0) { #ifdef DIAGNOSTIC if (usec > 0) { sec++; usec -= 1000000; } printf("tvotohz: negative time difference %ld sec %ld usec\n", sec, usec); #endif ticks = 1; } else if (sec <= LONG_MAX / 1000000) ticks = howmany(sec * 1000000 + (unsigned long)usec, tick) + 1; else if (sec <= LONG_MAX / hz) ticks = sec * hz + howmany((unsigned long)usec, tick) + 1; else ticks = LONG_MAX; if (ticks > INT_MAX) ticks = INT_MAX; return ((int)ticks); } /* * Start profiling on a process. * * Kernel profiling passes proc0 which never exits and hence * keeps the profile clock running constantly. */ void startprofclock(struct proc *p) { PROC_LOCK_ASSERT(p, MA_OWNED); if (p->p_flag & P_STOPPROF) return; if ((p->p_flag & P_PROFIL) == 0) { p->p_flag |= P_PROFIL; mtx_lock(&time_lock); if (++profprocs == 1) cpu_startprofclock(); mtx_unlock(&time_lock); } } /* * Stop profiling on a process. */ void stopprofclock(struct proc *p) { PROC_LOCK_ASSERT(p, MA_OWNED); if (p->p_flag & P_PROFIL) { if (p->p_profthreads != 0) { while (p->p_profthreads != 0) { p->p_flag |= P_STOPPROF; msleep(&p->p_profthreads, &p->p_mtx, PPAUSE, "stopprof", 0); } } if ((p->p_flag & P_PROFIL) == 0) return; p->p_flag &= ~P_PROFIL; mtx_lock(&time_lock); if (--profprocs == 0) cpu_stopprofclock(); mtx_unlock(&time_lock); } } /* * Statistics clock. Updates rusage information and calls the scheduler * to adjust priorities of the active thread. * * This should be called by all active processors. */ void statclock(int cnt, int usermode) { struct rusage *ru; struct vmspace *vm; struct thread *td; struct proc *p; long rss; long *cp_time; uint64_t runtime, new_switchtime; td = curthread; p = td->td_proc; cp_time = (long *)PCPU_PTR(cp_time); if (usermode) { /* * Charge the time as appropriate. */ td->td_uticks += cnt; if (p->p_nice > NZERO) cp_time[CP_NICE] += cnt; else cp_time[CP_USER] += cnt; } else { /* * Came from kernel mode, so we were: * - handling an interrupt, * - doing syscall or trap work on behalf of the current * user process, or * - spinning in the idle loop. * Whichever it is, charge the time as appropriate. * Note that we charge interrupts to the current process, * regardless of whether they are ``for'' that process, * so that we know how much of its real time was spent * in ``non-process'' (i.e., interrupt) work. */ if ((td->td_pflags & TDP_ITHREAD) || td->td_intr_nesting_level >= 2) { td->td_iticks += cnt; cp_time[CP_INTR] += cnt; } else { td->td_pticks += cnt; td->td_sticks += cnt; if (!TD_IS_IDLETHREAD(td)) cp_time[CP_SYS] += cnt; else cp_time[CP_IDLE] += cnt; } } /* Update resource usage integrals and maximums. */ MPASS(p->p_vmspace != NULL); vm = p->p_vmspace; ru = &td->td_ru; ru->ru_ixrss += pgtok(vm->vm_tsize) * cnt; ru->ru_idrss += pgtok(vm->vm_dsize) * cnt; ru->ru_isrss += pgtok(vm->vm_ssize) * cnt; rss = pgtok(vmspace_resident_count(vm)); if (ru->ru_maxrss < rss) ru->ru_maxrss = rss; KTR_POINT2(KTR_SCHED, "thread", sched_tdname(td), "statclock", "prio:%d", td->td_priority, "stathz:%d", (stathz)?stathz:hz); SDT_PROBE2(sched, , , tick, td, td->td_proc); thread_lock_flags(td, MTX_QUIET); /* * Compute the amount of time during which the current * thread was running, and add that to its total so far. */ new_switchtime = cpu_ticks(); runtime = new_switchtime - PCPU_GET(switchtime); td->td_runtime += runtime; td->td_incruntime += runtime; PCPU_SET(switchtime, new_switchtime); sched_clock(td, cnt); thread_unlock(td); #ifdef HWPMC_HOOKS if (td->td_intr_frame != NULL) PMC_SOFT_CALL_TF( , , clock, stat, td->td_intr_frame); #endif } void profclock(int cnt, int usermode, uintfptr_t pc) { struct thread *td; #ifdef GPROF struct gmonparam *g; uintfptr_t i; #endif td = curthread; if (usermode) { /* * Came from user mode; CPU was in user state. * If this process is being profiled, record the tick. * if there is no related user location yet, don't * bother trying to count it. */ if (td->td_proc->p_flag & P_PROFIL) addupc_intr(td, pc, cnt); } #ifdef GPROF else { /* * Kernel statistics are just like addupc_intr, only easier. */ g = &_gmonparam; if (g->state == GMON_PROF_ON && pc >= g->lowpc) { i = PC_TO_I(g, pc); if (i < g->textsize) { KCOUNT(g, i) += cnt; } } } #endif #ifdef HWPMC_HOOKS if (td->td_intr_frame != NULL) PMC_SOFT_CALL_TF( , , clock, prof, td->td_intr_frame); #endif } /* * Return information about system clocks. */ static int sysctl_kern_clockrate(SYSCTL_HANDLER_ARGS) { struct clockinfo clkinfo; /* * Construct clockinfo structure. */ bzero(&clkinfo, sizeof(clkinfo)); clkinfo.hz = hz; clkinfo.tick = tick; clkinfo.profhz = profhz; clkinfo.stathz = stathz ? stathz : hz; return (sysctl_handle_opaque(oidp, &clkinfo, sizeof clkinfo, req)); } SYSCTL_PROC(_kern, KERN_CLOCKRATE, clockrate, CTLTYPE_STRUCT|CTLFLAG_RD|CTLFLAG_MPSAFE, 0, 0, sysctl_kern_clockrate, "S,clockinfo", "Rate and period of various kernel clocks"); static void watchdog_config(void *unused __unused, u_int cmd, int *error) { u_int u; u = cmd & WD_INTERVAL; if (u >= WD_TO_1SEC) { watchdog_ticks = (1 << (u - WD_TO_1SEC)) * hz; watchdog_enabled = 1; *error = 0; } else { watchdog_enabled = 0; } } /* * Handle a watchdog timeout by dumping interrupt information and * then either dropping to DDB or panicking. */ static void watchdog_fire(void) { int nintr; uint64_t inttotal; u_long *curintr; char *curname; curintr = intrcnt; curname = intrnames; inttotal = 0; nintr = sintrcnt / sizeof(u_long); printf("interrupt total\n"); while (--nintr >= 0) { if (*curintr) printf("%-12s %20lu\n", curname, *curintr); curname += strlen(curname) + 1; inttotal += *curintr++; } printf("Total %20ju\n", (uintmax_t)inttotal); #if defined(KDB) && !defined(KDB_UNATTENDED) kdb_backtrace(); kdb_enter(KDB_WHY_WATCHDOG, "watchdog timeout"); #else panic("watchdog timeout"); #endif }