/*-
* 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.
*
* Copyright (c) 2010 Kip Macy. All rights reserved.
* Copyright (c) 2013 Patrick Kelsey. All rights reserved.
* Copyright (C) 2017-2021 THL A29 Limited, a Tencent company.
* All rights reserved.
*
* 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.
*
* From: @(#)kern_clock.c 8.5 (Berkeley) 1/21/94
*
* Derived in part from libplebnet's pn_kern_timeout.c and libuinet's uinet_timecounter.c.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_callout_profiling.h"
#include "opt_ddb.h"
#if defined(__arm__)
#include "opt_timer.h"
#endif
#include "opt_rss.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/callout.h>
#include <sys/file.h>
#include <sys/interrupt.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/sdt.h>
#include <sys/sleepqueue.h>
#include <sys/sysctl.h>
#include <sys/smp.h>
#include <sys/timetc.h>
SDT_PROVIDER_DEFINE(callout_execute);
SDT_PROBE_DEFINE1(callout_execute, , , callout__start, "struct callout *");
SDT_PROBE_DEFINE1(callout_execute, , , callout__end, "struct callout *");
#ifdef CALLOUT_PROFILING
static int avg_depth;
SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0,
"Average number of items examined per softclock call. Units = 1/1000");
static int avg_gcalls;
SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0,
"Average number of Giant callouts made per softclock call. Units = 1/1000");
static int avg_lockcalls;
SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls, CTLFLAG_RD, &avg_lockcalls, 0,
"Average number of lock callouts made per softclock call. Units = 1/1000");
static int avg_mpcalls;
SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0,
"Average number of MP callouts made per softclock call. Units = 1/1000");
#endif
static int ncallout;
SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &ncallout, 0,
"Number of entries in callwheel and size of timeout() preallocation");
#ifdef RSS
static int pin_default_swi = 1;
static int pin_pcpu_swi = 1;
#else
static int pin_default_swi = 0;
static int pin_pcpu_swi = 0;
#endif
SYSCTL_INT(_kern, OID_AUTO, pin_default_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_default_swi,
0, "Pin the default (non-per-cpu) swi (shared with PCPU 0 swi)");
SYSCTL_INT(_kern, OID_AUTO, pin_pcpu_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_pcpu_swi,
0, "Pin the per-CPU swis (except PCPU 0, which is also default");
#define sleepq_lock(w) do {} while(0)
#define sleepq_release(w) do {} while(0)
#define sleepq_add(a, b, c, d, e) do {} while(0)
#define sleepq_wait(w, p) do {} while(0)
#define CC_HASH_SHIFT 8
/*
* TODO:
* allocate more timeout table slots when table overflows.
*/
u_int callwheelsize, callwheelmask;
/*
* The callout cpu exec entities represent informations necessary for
* describing the state of callouts currently running on the CPU and the ones
* necessary for migrating callouts to the new callout cpu. In particular,
* the first entry of the array cc_exec_entity holds informations for callout
* running in SWI thread context, while the second one holds informations
* for callout running directly from hardware interrupt context.
* The cached informations are very important for deferring migration when
* the migrating callout is already running.
*/
struct cc_exec {
struct callout *cc_curr;
void (*cc_drain)(void *);
bool cc_cancel;
bool cc_waiting;
};
/*
* There is one struct callout_cpu per cpu, holding all relevant
* state for the callout processing thread on the individual CPU.
*/
struct callout_cpu {
struct mtx_padalign cc_lock;
struct cc_exec cc_exec_entity[2];
struct callout *cc_next;
struct callout *cc_callout;
struct callout_list *cc_callwheel;
struct callout_tailq cc_expireq;
struct callout_slist cc_callfree;
int cc_softticks;
void *cc_cookie;
u_int cc_bucket;
u_int cc_inited;
char cc_ktr_event_name[20];
};
#define callout_migrating(c) ((c)->c_iflags & CALLOUT_DFRMIGRATION)
#define cc_exec_curr(cc, dir) cc->cc_exec_entity[dir].cc_curr
#define cc_exec_drain(cc, dir) cc->cc_exec_entity[dir].cc_drain
#define cc_exec_next(cc) cc->cc_next
#define cc_exec_cancel(cc, dir) cc->cc_exec_entity[dir].cc_cancel
#define cc_exec_waiting(cc, dir) cc->cc_exec_entity[dir].cc_waiting
struct callout_cpu cc_cpu;
#define CC_CPU(cpu) &cc_cpu
#define CC_SELF() &cc_cpu
#define CC_LOCK(cc) mtx_lock_spin(&(cc)->cc_lock)
#define CC_UNLOCK(cc) mtx_unlock_spin(&(cc)->cc_lock)
#define CC_LOCK_ASSERT(cc) mtx_assert(&(cc)->cc_lock, MA_OWNED)
static int timeout_cpu;
static void callout_cpu_init(struct callout_cpu *cc, int cpu);
static void softclock_call_cc(struct callout *c, struct callout_cpu *cc,
#ifdef CALLOUT_PROFILING
int *mpcalls, int *lockcalls, int *gcalls,
#endif
int direct);
static MALLOC_DEFINE(M_CALLOUT, "callout", "Callout datastructures");
/**
* Locked by cc_lock:
* cc_curr - If a callout is in progress, it is cc_curr.
* If cc_curr is non-NULL, threads waiting in
* callout_drain() will be woken up as soon as the
* relevant callout completes.
* cc_cancel - Changing to 1 with both callout_lock and cc_lock held
* guarantees that the current callout will not run.
* The softclock() function sets this to 0 before it
* drops callout_lock to acquire c_lock, and it calls
* the handler only if curr_cancelled is still 0 after
* cc_lock is successfully acquired.
* cc_waiting - If a thread is waiting in callout_drain(), then
* callout_wait is nonzero. Set only when
* cc_curr is non-NULL.
*/
/*
* Resets the execution entity tied to a specific callout cpu.
*/
static void
cc_cce_cleanup(struct callout_cpu *cc, int direct)
{
cc_exec_curr(cc, direct) = NULL;
cc_exec_cancel(cc, direct) = false;
cc_exec_waiting(cc, direct) = false;
}
/*
* Checks if migration is requested by a specific callout cpu.
*/
static int
cc_cce_migrating(struct callout_cpu *cc, int direct)
{
return (0);
}
/*
* Kernel low level callwheel initialization
* called on cpu0 during kernel startup.
*/
static void
callout_callwheel_init(void *dummy)
{
struct callout_cpu *cc;
/*
* Calculate the size of the callout wheel and the preallocated
* timeout() structures.
* XXX: Clip callout to result of previous function of maxusers
* maximum 384. This is still huge, but acceptable.
*/
memset(CC_CPU(0), 0, sizeof(cc_cpu));
ncallout = imin(16 + maxproc + maxfiles, 18508);
TUNABLE_INT_FETCH("kern.ncallout", &ncallout);
/*
* Calculate callout wheel size, should be next power of two higher
* than 'ncallout'.
*/
callwheelsize = 1 << fls(ncallout);
callwheelmask = callwheelsize - 1;
/*
* Fetch whether we're pinning the swi's or not.
*/
TUNABLE_INT_FETCH("kern.pin_default_swi", &pin_default_swi);
TUNABLE_INT_FETCH("kern.pin_pcpu_swi", &pin_pcpu_swi);
/*
* Only cpu0 handles timeout(9) and receives a preallocation.
*
* XXX: Once all timeout(9) consumers are converted this can
* be removed.
*/
timeout_cpu = PCPU_GET(cpuid);
cc = CC_CPU(timeout_cpu);
cc->cc_callout = malloc(ncallout * sizeof(struct callout),
M_CALLOUT, M_WAITOK);
callout_cpu_init(cc, timeout_cpu);
}
SYSINIT(callwheel_init, SI_SUB_CPU, SI_ORDER_ANY, callout_callwheel_init, NULL);
/*
* Initialize the per-cpu callout structures.
*/
static void
callout_cpu_init(struct callout_cpu *cc, int cpu)
{
struct callout *c;
int i;
mtx_init(&cc->cc_lock, "callout", NULL, MTX_SPIN | MTX_RECURSE);
SLIST_INIT(&cc->cc_callfree);
cc->cc_inited = 1;
cc->cc_callwheel = malloc(sizeof(struct callout_list) * callwheelsize,
M_CALLOUT, M_WAITOK);
for (i = 0; i < callwheelsize; i++)
LIST_INIT(&cc->cc_callwheel[i]);
TAILQ_INIT(&cc->cc_expireq);
for (i = 0; i < 2; i++)
cc_cce_cleanup(cc, i);
snprintf(cc->cc_ktr_event_name, sizeof(cc->cc_ktr_event_name),
"callwheel cpu %d", cpu);
if (cc->cc_callout == NULL) /* Only cpu0 handles timeout(9) */
return;
for (i = 0; i < ncallout; i++) {
c = &cc->cc_callout[i];
callout_init(c, 0);
c->c_iflags = CALLOUT_LOCAL_ALLOC;
SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle);
}
}
static inline u_int
callout_get_bucket(int to_ticks)
{
return (to_ticks & callwheelmask);
}
void
callout_tick(void)
{
struct callout_cpu *cc;
int need_softclock;
int bucket;
/*
* Process callouts at a very low cpu priority, so we don't keep the
* relatively high clock interrupt priority any longer than necessary.
*/
need_softclock = 0;
cc = CC_SELF();
mtx_lock(&cc->cc_lock);
for (; (cc->cc_softticks - ticks) < 0; cc->cc_softticks++) {
bucket = cc->cc_softticks & callwheelmask;
if (!LIST_EMPTY(&cc->cc_callwheel[bucket])) {
need_softclock = 1;
break;
}
}
mtx_unlock(&cc->cc_lock);
/*
* swi_sched acquires the thread lock, so we don't want to call it
* with cc_lock held; incorrect locking order.
*/
if (need_softclock)
softclock(cc);
}
static struct callout_cpu *
callout_lock(struct callout *c)
{
struct callout_cpu *cc;
int cpu;
for (;;) {
cpu = c->c_cpu;
cc = CC_CPU(cpu);
CC_LOCK(cc);
if (cpu == c->c_cpu)
break;
CC_UNLOCK(cc);
}
return (cc);
}
static void
callout_cc_add(struct callout *c, struct callout_cpu *cc,
int to_ticks, void (*func)(void *), void *arg, int cpu, int flags)
{
int bucket;
CC_LOCK_ASSERT(cc);
c->c_arg = arg;
c->c_iflags |= CALLOUT_PENDING;
c->c_iflags &= ~CALLOUT_PROCESSED;
c->c_flags |= CALLOUT_ACTIVE;
if (flags & C_DIRECT_EXEC)
c->c_iflags |= CALLOUT_DIRECT;
c->c_func = func;
c->c_time = ticks + to_ticks;
bucket = callout_get_bucket(c->c_time);
LIST_INSERT_HEAD(&cc->cc_callwheel[bucket], c, c_links.le);
if (cc->cc_bucket == bucket)
cc_exec_next(cc) = c;
}
static void
callout_cc_del(struct callout *c, struct callout_cpu *cc)
{
if ((c->c_iflags & CALLOUT_LOCAL_ALLOC) == 0)
return;
c->c_func = NULL;
SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle);
}
static void
softclock_call_cc(struct callout *c, struct callout_cpu *cc,
#ifdef CALLOUT_PROFILING
int *mpcalls, int *lockcalls, int *gcalls,
#endif
int direct)
{
struct rm_priotracker tracker;
void (*c_func)(void *);
void *c_arg;
struct lock_class *class;
struct lock_object *c_lock;
uintptr_t lock_status;
int c_iflags;
#if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING)
sbintime_t sbt1, sbt2;
struct timespec ts2;
static sbintime_t maxdt = 2 * SBT_1MS; /* 2 msec */
static timeout_t *lastfunc;
#endif
KASSERT((c->c_iflags & CALLOUT_PENDING) == CALLOUT_PENDING,
("softclock_call_cc: pend %p %x", c, c->c_iflags));
KASSERT((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE,
("softclock_call_cc: act %p %x", c, c->c_flags));
class = (c->c_lock != NULL) ? LOCK_CLASS(c->c_lock) : NULL;
lock_status = 0;
if (c->c_flags & CALLOUT_SHAREDLOCK) {
if (class == &lock_class_rm)
lock_status = (uintptr_t)&tracker;
else
lock_status = 1;
}
c_lock = c->c_lock;
c_func = c->c_func;
c_arg = c->c_arg;
c_iflags = c->c_iflags;
if (c->c_iflags & CALLOUT_LOCAL_ALLOC)
c->c_iflags = CALLOUT_LOCAL_ALLOC;
else
c->c_iflags &= ~CALLOUT_PENDING;
cc_exec_curr(cc, direct) = c;
cc_exec_cancel(cc, direct) = false;
cc_exec_drain(cc, direct) = NULL;
CC_UNLOCK(cc);
if (c_lock != NULL) {
class->lc_lock(c_lock, lock_status);
/*
* The callout may have been cancelled
* while we switched locks.
*/
if (cc_exec_cancel(cc, direct)) {
class->lc_unlock(c_lock);
goto skip;
}
/* The callout cannot be stopped now. */
cc_exec_cancel(cc, direct) = true;
if (c_lock == &Giant.lock_object) {
#ifdef CALLOUT_PROFILING
(*gcalls)++;
#endif
CTR3(KTR_CALLOUT, "callout giant %p func %p arg %p",
c, c_func, c_arg);
} else {
#ifdef CALLOUT_PROFILING
(*lockcalls)++;
#endif
CTR3(KTR_CALLOUT, "callout lock %p func %p arg %p",
c, c_func, c_arg);
}
} else {
#ifdef CALLOUT_PROFILING
(*mpcalls)++;
#endif
CTR3(KTR_CALLOUT, "callout %p func %p arg %p",
c, c_func, c_arg);
}
KTR_STATE3(KTR_SCHED, "callout", cc->cc_ktr_event_name, "running",
"func:%p", c_func, "arg:%p", c_arg, "direct:%d", direct);
#if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING)
sbt1 = sbinuptime();
#endif
THREAD_NO_SLEEPING();
SDT_PROBE1(callout_execute, , , callout__start, c);
c_func(c_arg);
SDT_PROBE1(callout_execute, , , callout__end, c);
THREAD_SLEEPING_OK();
#if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING)
sbt2 = sbinuptime();
sbt2 -= sbt1;
if (sbt2 > maxdt) {
if (lastfunc != c_func || sbt2 > maxdt * 2) {
ts2 = sbttots(sbt2);
printf(
"Expensive timeout(9) function: %p(%p) %jd.%09ld s\n",
c_func, c_arg, (intmax_t)ts2.tv_sec, ts2.tv_nsec);
}
maxdt = sbt2;
lastfunc = c_func;
}
#endif
KTR_STATE0(KTR_SCHED, "callout", cc->cc_ktr_event_name, "idle");
CTR1(KTR_CALLOUT, "callout %p finished", c);
if ((c_iflags & CALLOUT_RETURNUNLOCKED) == 0)
class->lc_unlock(c_lock);
skip:
CC_LOCK(cc);
KASSERT(cc_exec_curr(cc, direct) == c, ("mishandled cc_curr"));
cc_exec_curr(cc, direct) = NULL;
if (cc_exec_drain(cc, direct)) {
void (*drain)(void *);
drain = cc_exec_drain(cc, direct);
cc_exec_drain(cc, direct) = NULL;
CC_UNLOCK(cc);
drain(c_arg);
CC_LOCK(cc);
}
if (cc_exec_waiting(cc, direct)) {
/*
* There is someone waiting for the
* callout to complete.
* If the callout was scheduled for
* migration just cancel it.
*/
if (cc_cce_migrating(cc, direct)) {
cc_cce_cleanup(cc, direct);
/*
* It should be assert here that the callout is not
* destroyed but that is not easy.
*/
c->c_iflags &= ~CALLOUT_DFRMIGRATION;
}
cc_exec_waiting(cc, direct) = false;
CC_UNLOCK(cc);
wakeup(&cc_exec_waiting(cc, direct));
CC_LOCK(cc);
} else if (cc_cce_migrating(cc, direct)) {
KASSERT((c_iflags & CALLOUT_LOCAL_ALLOC) == 0,
("Migrating legacy callout %p", c));
panic("migration should not happen");
}
/*
* If the current callout is locally allocated (from
* timeout(9)) then put it on the freelist.
*
* Note: we need to check the cached copy of c_iflags because
* if it was not local, then it's not safe to deref the
* callout pointer.
*/
KASSERT((c_iflags & CALLOUT_LOCAL_ALLOC) == 0 ||
c->c_iflags == CALLOUT_LOCAL_ALLOC,
("corrupted callout"));
if (c_iflags & CALLOUT_LOCAL_ALLOC)
callout_cc_del(c, cc);
}
/*
* The callout mechanism is based on the work of Adam M. Costello and
* George Varghese, published in a technical report entitled "Redesigning
* the BSD Callout and Timer Facilities" and modified slightly for inclusion
* in FreeBSD by Justin T. Gibbs. The original work on the data structures
* used in this implementation was published by G. Varghese and T. Lauck in
* the paper "Hashed and Hierarchical Timing Wheels: Data Structures for
* the Efficient Implementation of a Timer Facility" in the Proceedings of
* the 11th ACM Annual Symposium on Operating Systems Principles,
* Austin, Texas Nov 1987.
*/
/*
* Software (low priority) clock interrupt.
* Run periodic events from timeout queue.
*/
void
softclock(void *arg)
{
struct callout *c;
struct callout_cpu *cc;
struct callout_list *sc;
int curticks;
#ifdef CALLOUT_PROFILING
int depth = 0, gcalls = 0, mpcalls = 0, lockcalls = 0;
#endif
cc = (struct callout_cpu *)arg;
CC_LOCK(cc);
while (cc->cc_softticks != ticks) {
/*
* cc_softticks may be modified by hard clock, so cache
* it while we work on a given bucket.
*/
curticks = cc->cc_softticks;
cc->cc_softticks++;
sc = &cc->cc_callwheel[curticks & callwheelmask];
c = LIST_FIRST(sc);
while (c) {
#ifdef CALLOUT_PROFILING
depth++;
#endif
if (c->c_time != curticks) {
c = LIST_NEXT(c, c_links.le);
} else {
cc_exec_next(cc) =
LIST_NEXT(c, c_links.le);
cc->cc_bucket = callout_get_bucket(curticks);
LIST_REMOVE(c, c_links.le);
softclock_call_cc(c, cc,
#ifdef CALLOUT_PROFILING
&mpcalls, &lockcalls, &gcalls,
#endif
1);
c = cc_exec_next(cc);
cc_exec_next(cc) = NULL;
}
}
}
#ifdef CALLOUT_PROFILING
avg_depth += (depth * 1000 - avg_depth) >> 8;
avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8;
avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8;
avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8;
#endif
CC_UNLOCK(cc);
}
#if 0
/*
* timeout --
* Execute a function after a specified length of time.
*
* untimeout --
* Cancel previous timeout function call.
*
* callout_handle_init --
* Initialize a handle so that using it with untimeout is benign.
*
* See AT&T BCI Driver Reference Manual for specification. This
* implementation differs from that one in that although an
* identification value is returned from timeout, the original
* arguments to timeout as well as the identifier are used to
* identify entries for untimeout.
*/
struct callout_handle
timeout(timeout_t *ftn, void *arg, int to_ticks)
{
struct callout_cpu *cc;
struct callout *new;
struct callout_handle handle;
cc = CC_CPU(timeout_cpu);
CC_LOCK(cc);
/* Fill in the next free callout structure. */
new = SLIST_FIRST(&cc->cc_callfree);
if (new == NULL)
/* XXX Attempt to malloc first */
panic("timeout table full");
SLIST_REMOVE_HEAD(&cc->cc_callfree, c_links.sle);
callout_reset(new, to_ticks, ftn, arg);
handle.callout = new;
CC_UNLOCK(cc);
return (handle);
}
void
untimeout(timeout_t *ftn, void *arg, struct callout_handle handle)
{
struct callout_cpu *cc;
/*
* Check for a handle that was initialized
* by callout_handle_init, but never used
* for a real timeout.
*/
if (handle.callout == NULL)
return;
cc = callout_lock(handle.callout);
if (handle.callout->c_func == ftn && handle.callout->c_arg == arg)
callout_stop(handle.callout);
CC_UNLOCK(cc);
}
void
callout_handle_init(struct callout_handle *handle)
{
handle->callout = NULL;
}
#endif
/*
* New interface; clients allocate their own callout structures.
*
* callout_reset() - establish or change a timeout
* callout_stop() - disestablish a timeout
* callout_init() - initialize a callout structure so that it can
* safely be passed to callout_reset() and callout_stop()
*
* <sys/callout.h> defines three convenience macros:
*
* callout_active() - returns truth if callout has not been stopped,
* drained, or deactivated since the last time the callout was
* reset.
* callout_pending() - returns truth if callout is still waiting for timeout
* callout_deactivate() - marks the callout as having been serviced
*/
int
callout_reset_tick_on(struct callout *c, int to_ticks,
void (*ftn)(void *), void *arg, int cpu, int flags)
{
struct callout_cpu *cc;
int cancelled, direct;
int ignore_cpu=0;
cancelled = 0;
if (cpu == -1) {
ignore_cpu = 1;
} else if ((cpu >= MAXCPU) ||
((CC_CPU(cpu))->cc_inited == 0)) {
/* Invalid CPU spec */
panic("Invalid CPU in callout %d", cpu);
}
/*
* This flag used to be added by callout_cc_add, but the
* first time you call this we could end up with the
* wrong direct flag if we don't do it before we add.
*/
if (flags & C_DIRECT_EXEC) {
direct = 1;
} else {
direct = 0;
}
KASSERT(!direct || c->c_lock == NULL,
("%s: direct callout %p has lock", __func__, c));
cc = callout_lock(c);
/*
* Don't allow migration of pre-allocated callouts lest they
* become unbalanced or handle the case where the user does
* not care.
*/
if ((c->c_iflags & CALLOUT_LOCAL_ALLOC) ||
ignore_cpu) {
cpu = c->c_cpu;
}
if (cc_exec_curr(cc, direct) == c) {
/*
* We're being asked to reschedule a callout which is
* currently in progress. If there is a lock then we
* can cancel the callout if it has not really started.
*/
if (c->c_lock != NULL && !cc_exec_cancel(cc, direct))
cancelled = cc_exec_cancel(cc, direct) = true;
if (cc_exec_waiting(cc, direct)) {
/*
* Someone has called callout_drain to kill this
* callout. Don't reschedule.
*/
CTR4(KTR_CALLOUT, "%s %p func %p arg %p",
cancelled ? "cancelled" : "failed to cancel",
c, c->c_func, c->c_arg);
CC_UNLOCK(cc);
return (cancelled);
}
}
if (c->c_iflags & CALLOUT_PENDING) {
if ((c->c_iflags & CALLOUT_PROCESSED) == 0) {
if (cc_exec_next(cc) == c)
cc_exec_next(cc) = LIST_NEXT(c, c_links.le);
LIST_REMOVE(c, c_links.le);
} else {
TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe);
}
cancelled = 1;
c->c_iflags &= ~ CALLOUT_PENDING;
c->c_flags &= ~ CALLOUT_ACTIVE;
}
if (to_ticks <= 0)
to_ticks = 1;
callout_cc_add(c, cc, to_ticks, ftn, arg, cpu, flags);
CTR5(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d",
cancelled ? "re" : "", c, c->c_func, c->c_arg, to_ticks);
CC_UNLOCK(cc);
return (cancelled);
}
/*
* Common idioms that can be optimized in the future.
*/
int
callout_schedule_on(struct callout *c, int to_ticks, int cpu)
{
return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu);
}
int
callout_schedule(struct callout *c, int to_ticks)
{
return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu);
}
int
_callout_stop_safe(struct callout *c, int flags, void (*drain)(void *))
{
struct callout_cpu *cc, *old_cc;
struct lock_class *class;
int direct, sq_locked, use_lock;
int cancelled, not_on_a_list;
if ((flags & CS_DRAIN) != 0)
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, c->c_lock,
"calling %s", __func__);
/*
* Some old subsystems don't hold Giant while running a callout_stop(),
* so just discard this check for the moment.
*/
if ((flags & CS_DRAIN) == 0 && c->c_lock != NULL) {
if (c->c_lock == &Giant.lock_object)
use_lock = mtx_owned(&Giant);
else {
use_lock = 1;
class = LOCK_CLASS(c->c_lock);
class->lc_assert(c->c_lock, LA_XLOCKED);
}
} else
use_lock = 0;
if (c->c_iflags & CALLOUT_DIRECT) {
direct = 1;
} else {
direct = 0;
}
sq_locked = 0;
old_cc = NULL;
again:
cc = callout_lock(c);
if ((c->c_iflags & (CALLOUT_DFRMIGRATION | CALLOUT_PENDING)) ==
(CALLOUT_DFRMIGRATION | CALLOUT_PENDING) &&
((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE)) {
/*
* Special case where this slipped in while we
* were migrating *as* the callout is about to
* execute. The caller probably holds the lock
* the callout wants.
*
* Get rid of the migration first. Then set
* the flag that tells this code *not* to
* try to remove it from any lists (its not
* on one yet). When the callout wheel runs,
* it will ignore this callout.
*/
c->c_iflags &= ~CALLOUT_PENDING;
c->c_flags &= ~CALLOUT_ACTIVE;
not_on_a_list = 1;
} else {
not_on_a_list = 0;
}
/*
* If the callout was migrating while the callout cpu lock was
* dropped, just drop the sleepqueue lock and check the states
* again.
*/
if (sq_locked != 0 && cc != old_cc) {
panic("migration should not happen");
}
/*
* If the callout is running, try to stop it or drain it.
*/
if (cc_exec_curr(cc, direct) == c) {
/*
* Succeed we to stop it or not, we must clear the
* active flag - this is what API users expect.
*/
c->c_flags &= ~CALLOUT_ACTIVE;
if ((flags & CS_DRAIN) != 0) {
/*
* The current callout is running (or just
* about to run) and blocking is allowed, so
* just wait for the current invocation to
* finish.
*/
while (cc_exec_curr(cc, direct) == c) {
/*
* Use direct calls to sleepqueue interface
* instead of cv/msleep in order to avoid
* a LOR between cc_lock and sleepqueue
* chain spinlocks. This piece of code
* emulates a msleep_spin() call actually.
*
* If we already have the sleepqueue chain
* locked, then we can safely block. If we
* don't already have it locked, however,
* we have to drop the cc_lock to lock
* it. This opens several races, so we
* restart at the beginning once we have
* both locks. If nothing has changed, then
* we will end up back here with sq_locked
* set.
*/
if (!sq_locked) {
CC_UNLOCK(cc);
sleepq_lock(
&cc_exec_waiting(cc, direct));
sq_locked = 1;
old_cc = cc;
goto again;
}
/*
* Migration could be cancelled here, but
* as long as it is still not sure when it
* will be packed up, just let softclock()
* take care of it.
*/
cc_exec_waiting(cc, direct) = true;
DROP_GIANT();
CC_UNLOCK(cc);
sleepq_add(
&cc_exec_waiting(cc, direct),
&cc->cc_lock.lock_object, "codrain",
SLEEPQ_SLEEP, 0);
sleepq_wait(
&cc_exec_waiting(cc, direct),
0);
sq_locked = 0;
old_cc = NULL;
/* Reacquire locks previously released. */
PICKUP_GIANT();
CC_LOCK(cc);
}
} else if (use_lock &&
!cc_exec_cancel(cc, direct) && (drain == NULL)) {
/*
* The current callout is waiting for its
* lock which we hold. Cancel the callout
* and return. After our caller drops the
* lock, the callout will be skipped in
* softclock(). This *only* works with a
* callout_stop() *not* callout_drain() or
* callout_async_drain().
*/
cc_exec_cancel(cc, direct) = true;
CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p",
c, c->c_func, c->c_arg);
KASSERT(!cc_cce_migrating(cc, direct),
("callout wrongly scheduled for migration"));
if (callout_migrating(c)) {
c->c_iflags &= ~CALLOUT_DFRMIGRATION;
}
CC_UNLOCK(cc);
KASSERT(!sq_locked, ("sleepqueue chain locked"));
return (1);
} else if (callout_migrating(c)) {
/*
* The callout is currently being serviced
* and the "next" callout is scheduled at
* its completion with a migration. We remove
* the migration flag so it *won't* get rescheduled,
* but we can't stop the one thats running so
* we return 0.
*/
c->c_iflags &= ~CALLOUT_DFRMIGRATION;
CTR3(KTR_CALLOUT, "postponing stop %p func %p arg %p",
c, c->c_func, c->c_arg);
if (drain) {
cc_exec_drain(cc, direct) = drain;
}
CC_UNLOCK(cc);
return ((flags & CS_EXECUTING) != 0);
}
CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p",
c, c->c_func, c->c_arg);
if (drain) {
cc_exec_drain(cc, direct) = drain;
}
KASSERT(!sq_locked, ("sleepqueue chain still locked"));
cancelled = ((flags & CS_EXECUTING) != 0);
} else
cancelled = 1;
if (sq_locked)
sleepq_release(&cc_exec_waiting(cc, direct));
if ((c->c_iflags & CALLOUT_PENDING) == 0) {
CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p",
c, c->c_func, c->c_arg);
/*
* For not scheduled and not executing callout return
* negative value.
*/
if (cc_exec_curr(cc, direct) != c)
cancelled = -1;
CC_UNLOCK(cc);
return (cancelled);
}
c->c_iflags &= ~CALLOUT_PENDING;
c->c_flags &= ~CALLOUT_ACTIVE;
CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p",
c, c->c_func, c->c_arg);
if (not_on_a_list == 0) {
if ((c->c_iflags & CALLOUT_PROCESSED) == 0) {
if (cc_exec_next(cc) == c)
cc_exec_next(cc) = LIST_NEXT(c, c_links.le);
LIST_REMOVE(c, c_links.le);
} else {
TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe);
}
}
callout_cc_del(c, cc);
CC_UNLOCK(cc);
return (cancelled);
}
void
callout_init(struct callout *c, int mpsafe)
{
bzero(c, sizeof *c);
if (mpsafe) {
c->c_lock = NULL;
c->c_iflags = CALLOUT_RETURNUNLOCKED;
} else {
c->c_lock = &Giant.lock_object;
c->c_iflags = 0;
}
c->c_cpu = timeout_cpu;
}
void
_callout_init_lock(struct callout *c, struct lock_object *lock, int flags)
{
bzero(c, sizeof *c);
c->c_lock = lock;
KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0,
("callout_init_lock: bad flags %d", flags));
KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0,
("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock"));
KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags &
(LC_SPINLOCK | LC_SLEEPABLE)), ("%s: invalid lock class",
__func__));
c->c_iflags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK);
c->c_cpu = timeout_cpu;
}
#ifdef APM_FIXUP_CALLTODO
/*
* Adjust the kernel calltodo timeout list. This routine is used after
* an APM resume to recalculate the calltodo timer list values with the
* number of hz's we have been sleeping. The next hardclock() will detect
* that there are fired timers and run softclock() to execute them.
*
* Please note, I have not done an exhaustive analysis of what code this
* might break. I am motivated to have my select()'s and alarm()'s that
* have expired during suspend firing upon resume so that the applications
* which set the timer can do the maintanence the timer was for as close
* as possible to the originally intended time. Testing this code for a
* week showed that resuming from a suspend resulted in 22 to 25 timers
* firing, which seemed independent on whether the suspend was 2 hours or
* 2 days. Your milage may vary. - Ken Key <key@cs.utk.edu>
*/
void
adjust_timeout_calltodo(struct timeval *time_change)
{
register struct callout *p;
unsigned long delta_ticks;
/*
* How many ticks were we asleep?
* (stolen from tvtohz()).
*/
/* Don't do anything */
if (time_change->tv_sec < 0)
return;
else if (time_change->tv_sec <= LONG_MAX / 1000000)
delta_ticks = howmany(time_change->tv_sec * 1000000 +
time_change->tv_usec, tick) + 1;
else if (time_change->tv_sec <= LONG_MAX / hz)
delta_ticks = time_change->tv_sec * hz +
howmany(time_change->tv_usec, tick) + 1;
else
delta_ticks = LONG_MAX;
if (delta_ticks > INT_MAX)
delta_ticks = INT_MAX;
/*
* Now rip through the timer calltodo list looking for timers
* to expire.
*/
/* don't collide with softclock() */
CC_LOCK(cc);
for (p = calltodo.c_next; p != NULL; p = p->c_next) {
p->c_time -= delta_ticks;
/* Break if the timer had more time on it than delta_ticks */
if (p->c_time > 0)
break;
/* take back the ticks the timer didn't use (p->c_time <= 0) */
delta_ticks = -p->c_time;
}
CC_UNLOCK(cc);
return;
}
#endif /* APM_FIXUP_CALLTODO */
static int
flssbt(sbintime_t sbt)
{
sbt += (uint64_t)sbt >> 1;
if (sizeof(long) >= sizeof(sbintime_t))
return (flsl(sbt));
if (sbt >= SBT_1S)
return (flsl(((uint64_t)sbt) >> 32) + 32);
return (flsl(sbt));
}
/*
* Dump immediate statistic snapshot of the scheduled callouts.
*/
static int
sysctl_kern_callout_stat(SYSCTL_HANDLER_ARGS)
{
struct callout *tmp;
struct callout_cpu *cc;
struct callout_list *sc;
int st, maxt, tick, now;
sbintime_t medt;
int ct[64], ccpbk[32];
int error, val, i, count, tcum, pcum, maxc, c, medc;
val = 0;
error = sysctl_handle_int(oidp, &val, 0, req);
if (error != 0 || req->newptr == NULL)
return (error);
count = maxc = 0;
st = maxt = 0;
bzero(ccpbk, sizeof(ccpbk));
bzero(ct, sizeof(ct));
now = ticks;
cc = CC_CPU(timeout_cpu);
CC_LOCK(cc);
for (i = 0; i < callwheelsize; i++) {
sc = &cc->cc_callwheel[i];
c = 0;
LIST_FOREACH(tmp, sc, c_links.le) {
c++;
tick = tmp->c_time - now;
if (tick < 0)
tick = 0;
st += tick*(1000/hz);
if (tick > maxt)
maxt = tick;
ct[flssbt(tick)]++;
}
if (c > maxc)
maxc = c;
ccpbk[fls(c + c / 2)]++;
count += c;
}
CC_UNLOCK(cc);
for (i = 0, tcum = 0; i < 64 && tcum < count / 2; i++)
tcum += ct[i];
medt = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0;
for (i = 0, c = 0; i < 32 && c < count / 2; i++)
c += ccpbk[i];
medc = (i >= 2) ? (1 << (i - 2)) : 0;
printf("Scheduled callouts statistic snapshot:\n");
printf(" Callouts: %6d Buckets: %6d*%-3d Bucket size: 0.%06ds\n",
count, callwheelsize, mp_ncpus, 1000000 >> CC_HASH_SHIFT);
printf(" C/Bk: med %5d avg %6d.%06jd max %6d\n",
medc,
count / callwheelsize / mp_ncpus,
(uint64_t)count * 1000000 / callwheelsize / mp_ncpus % 1000000,
maxc);
printf(" Time: med %5jd.%06jds avg %6d.%06ds max %ds\n",
medt / SBT_1S, (medt & 0xffffffff) * 1000000 >> 32,
st / count / 1000, (st / count) % 1000, maxt);
printf(" Distribution: \tbuckets\t time\t tcum\n");
for (i = 0, tcum = pcum = 0; i < 64; i++) {
if (ct[i] == 0)
continue;
sbintime_t t;
t = (i != 0) ? (((sbintime_t)1) << (i - 1)) : 0;
tcum += ct[i];
printf(" %10jd.%06jds\t 2**%d\t%7d\t%7d\n",
t / SBT_1S, (t & 0xffffffff) * 1000000 >> 32,
i - 1 - (32 - CC_HASH_SHIFT), ct[i], tcum);
}
return (error);
}
SYSCTL_PROC(_kern, OID_AUTO, callout_stat,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
0, 0, sysctl_kern_callout_stat, "I",
"Dump immediate statistic snapshot of the scheduled callouts");
#ifdef FSTACK
void ff_hardclock(void);
void
ff_hardclock(void)
{
atomic_add_int(&ticks, 1);
callout_tick();
tc_ticktock((hz + 999)/1000);
cpu_tick_calibration();
#ifdef DEVICE_POLLING
hardclock_device_poll(); /* this is very short and quick */
#endif /* DEVICE_POLLING */
}
static unsigned int
ff_tc_get_timecount(struct timecounter *tc)
{
uint64_t ns;
ns = ff_get_tsc_ns();
return ((ns * tc->tc_frequency) / ff_NSEC_PER_SEC);
}
static struct timecounter ff_timecounter = {
ff_tc_get_timecount, 0, ~0u, 100, "ff_clock", 1
};
static void
ff_tc_init(void)
{
ff_timecounter.tc_frequency = hz;
tc_init(&ff_timecounter);
}
SYSINIT(ff_tc, SI_SUB_SMP, SI_ORDER_ANY, ff_tc_init, NULL);
#endif