freebsd-skq/sys/kern/kern_clock.c
John Baldwin e0f66ef861 Reorganize the interrupt handling code a bit to make a few things cleaner
and increase flexibility to allow various different approaches to be tried
in the future.
- Split struct ithd up into two pieces.  struct intr_event holds the list
  of interrupt handlers associated with interrupt sources.
  struct intr_thread contains the data relative to an interrupt thread.
  Currently we still provide a 1:1 relationship of events to threads
  with the exception that events only have an associated thread if there
  is at least one threaded interrupt handler attached to the event.  This
  means that on x86 we no longer have 4 bazillion interrupt threads with
  no handlers.  It also means that interrupt events with only INTR_FAST
  handlers no longer have an associated thread either.
- Renamed struct intrhand to struct intr_handler to follow the struct
  intr_foo naming convention.  This did require renaming the powerpc
  MD struct intr_handler to struct ppc_intr_handler.
- INTR_FAST no longer implies INTR_EXCL on all architectures except for
  powerpc.  This means that multiple INTR_FAST handlers can attach to the
  same interrupt and that INTR_FAST and non-INTR_FAST handlers can attach
  to the same interrupt.  Sharing INTR_FAST handlers may not always be
  desirable, but having sio(4) and uhci(4) fight over an IRQ isn't fun
  either.  Drivers can always still use INTR_EXCL to ask for an interrupt
  exclusively.  The way this sharing works is that when an interrupt
  comes in, all the INTR_FAST handlers are executed first, and if any
  threaded handlers exist, the interrupt thread is scheduled afterwards.
  This type of layout also makes it possible to investigate using interrupt
  filters ala OS X where the filter determines whether or not its companion
  threaded handler should run.
- Aside from the INTR_FAST changes above, the impact on MD interrupt code
  is mostly just 's/ithread/intr_event/'.
- A new MI ddb command 'show intrs' walks the list of interrupt events
  dumping their state.  It also has a '/v' verbose switch which dumps
  info about all of the handlers attached to each event.
- We currently don't destroy an interrupt thread when the last threaded
  handler is removed because it would suck for things like ppbus(8)'s
  braindead behavior.  The code is present, though, it is just under
  #if 0 for now.
- Move the code to actually execute the threaded handlers for an interrrupt
  event into a separate function so that ithread_loop() becomes more
  readable.  Previously this code was all in the middle of ithread_loop()
  and indented halfway across the screen.
- Made struct intr_thread private to kern_intr.c and replaced td_ithd
  with a thread private flag TDP_ITHREAD.
- In statclock, check curthread against idlethread directly rather than
  curthread's proc against idlethread's proc. (Not really related to intr
  changes)

Tested on:	alpha, amd64, i386, sparc64
Tested on:	arm, ia64 (older version of patch by cognet and marcel)
2005-10-25 19:48:48 +00:00

589 lines
15 KiB
C

/*-
* 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.
* 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.
*
* @(#)kern_clock.c 8.5 (Berkeley) 1/21/94
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_device_polling.h"
#include "opt_hwpmc_hooks.h"
#include "opt_ntp.h"
#include "opt_watchdog.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/callout.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/ktr.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/resource.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/signalvar.h>
#include <sys/smp.h>
#include <vm/vm.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <sys/sysctl.h>
#include <sys/bus.h>
#include <sys/interrupt.h>
#include <sys/limits.h>
#include <sys/timetc.h>
#include <machine/cpu.h>
#ifdef GPROF
#include <sys/gmon.h>
#endif
#ifdef HWPMC_HOOKS
#include <sys/pmckern.h>
#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)
/* Some of these don't belong here, but it's easiest to concentrate them. */
long cp_time[CPUSTATES];
static int
sysctl_kern_cp_time(SYSCTL_HANDLER_ARGS)
{
int error;
#ifdef SCTL_MASK32
int i;
unsigned int cp_time32[CPUSTATES];
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,
0,0, sysctl_kern_cp_time, "LU", "CPU time statistics");
#ifdef SW_WATCHDOG
#include <sys/watchdog.h>
static int watchdog_ticks;
static int watchdog_enabled;
static void watchdog_fire(void);
static void watchdog_config(void *, u_int, int *);
#endif /* SW_WATCHDOG */
/*
* 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;
int ticks;
int psratio;
/*
* Initialize clock frequencies and start both clocks running.
*/
/* ARGSUSED*/
static void
initclocks(dummy)
void *dummy;
{
register int i;
/*
* Set divisors to 1 (normal case) and let the machine-specific
* code do its bit.
*/
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
EVENTHANDLER_REGISTER(watchdog_list, watchdog_config, NULL, 0);
#endif
}
/*
* Each time the real-time timer fires, this function is called on all CPUs.
* Note that hardclock() calls hardclock_process() for the boot CPU, so only
* the other CPUs in the system need to call this function.
*/
void
hardclock_process(frame)
register struct clockframe *frame;
{
struct pstats *pstats;
struct thread *td = curthread;
struct proc *p = td->td_proc;
/*
* Run current process's virtual and profile time, as needed.
*/
mtx_lock_spin_flags(&sched_lock, MTX_QUIET);
if (p->p_flag & P_SA) {
/* XXXKSE What to do? */
} else {
pstats = p->p_stats;
if (CLKF_USERMODE(frame) &&
timevalisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value) &&
itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL], tick) == 0) {
p->p_sflag |= PS_ALRMPEND;
td->td_flags |= TDF_ASTPENDING;
}
if (timevalisset(&pstats->p_timer[ITIMER_PROF].it_value) &&
itimerdecr(&pstats->p_timer[ITIMER_PROF], tick) == 0) {
p->p_sflag |= PS_PROFPEND;
td->td_flags |= TDF_ASTPENDING;
}
}
mtx_unlock_spin_flags(&sched_lock, MTX_QUIET);
#ifdef HWPMC_HOOKS
if (PMC_CPU_HAS_SAMPLES(PCPU_GET(cpuid)))
PMC_CALL_HOOK_UNLOCKED(curthread, PMC_FN_DO_SAMPLES, NULL);
#endif
}
/*
* The real-time timer, interrupting hz times per second.
*/
void
hardclock(frame)
register struct clockframe *frame;
{
int need_softclock = 0;
CTR0(KTR_CLK, "hardclock fired");
hardclock_process(frame);
tc_ticktock();
/*
* If no separate statistics clock is available, run it from here.
*
* XXX: this only works for UP
*/
if (stathz == 0) {
profclock(frame);
statclock(frame);
}
#ifdef DEVICE_POLLING
hardclock_device_poll(); /* this is very short and quick */
#endif /* DEVICE_POLLING */
/*
* Process callouts at a very low cpu priority, so we don't keep the
* relatively high clock interrupt priority any longer than necessary.
*/
mtx_lock_spin_flags(&callout_lock, MTX_QUIET);
ticks++;
if (TAILQ_FIRST(&callwheel[ticks & callwheelmask]) != NULL) {
need_softclock = 1;
} else if (softticks + 1 == ticks)
++softticks;
mtx_unlock_spin_flags(&callout_lock, MTX_QUIET);
/*
* swi_sched acquires sched_lock, so we don't want to call it with
* callout_lock held; incorrect locking order.
*/
if (need_softclock)
swi_sched(softclock_ih, 0);
#ifdef SW_WATCHDOG
if (watchdog_enabled > 0 && --watchdog_ticks <= 0)
watchdog_fire();
#endif /* SW_WATCHDOG */
}
/*
* Compute number of ticks in the specified amount of time.
*/
int
tvtohz(tv)
struct timeval *tv;
{
register unsigned long ticks;
register 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 = (sec * 1000000 + (unsigned long)usec + (tick - 1))
/ tick + 1;
else if (sec <= LONG_MAX / hz)
ticks = sec * hz
+ ((unsigned long)usec + (tick - 1)) / 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(p)
register struct proc *p;
{
/*
* XXX; Right now sched_lock protects statclock(), but perhaps
* it should be protected later on by a time_lock, which would
* cover psdiv, etc. as well.
*/
PROC_LOCK_ASSERT(p, MA_OWNED);
if (p->p_flag & P_STOPPROF)
return;
if ((p->p_flag & P_PROFIL) == 0) {
mtx_lock_spin(&sched_lock);
p->p_flag |= P_PROFIL;
if (++profprocs == 1)
cpu_startprofclock();
mtx_unlock_spin(&sched_lock);
}
}
/*
* Stop profiling on a process.
*/
void
stopprofclock(p)
register struct proc *p;
{
PROC_LOCK_ASSERT(p, MA_OWNED);
if (p->p_flag & P_PROFIL) {
if (p->p_profthreads != 0) {
p->p_flag |= P_STOPPROF;
while (p->p_profthreads != 0)
msleep(&p->p_profthreads, &p->p_mtx, PPAUSE,
"stopprof", 0);
p->p_flag &= ~P_STOPPROF;
}
if ((p->p_flag & P_PROFIL) == 0)
return;
mtx_lock_spin(&sched_lock);
p->p_flag &= ~P_PROFIL;
if (--profprocs == 0)
cpu_stopprofclock();
mtx_unlock_spin(&sched_lock);
}
}
/*
* Statistics clock. Grab profile sample, and if divider reaches 0,
* do process and kernel statistics. Most of the statistics are only
* used by user-level statistics programs. The main exceptions are
* ke->ke_uticks, p->p_rux.rux_sticks, p->p_rux.rux_iticks, and p->p_estcpu.
* This should be called by all active processors.
*/
void
statclock(frame)
register struct clockframe *frame;
{
struct rusage *ru;
struct vmspace *vm;
struct thread *td;
struct proc *p;
long rss;
td = curthread;
p = td->td_proc;
mtx_lock_spin_flags(&sched_lock, MTX_QUIET);
if (CLKF_USERMODE(frame)) {
/*
* Charge the time as appropriate.
*/
if (p->p_flag & P_SA)
thread_statclock(1);
p->p_rux.rux_uticks++;
if (p->p_nice > NZERO)
cp_time[CP_NICE]++;
else
cp_time[CP_USER]++;
} 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) {
p->p_rux.rux_iticks++;
cp_time[CP_INTR]++;
} else {
if (p->p_flag & P_SA)
thread_statclock(0);
td->td_sticks++;
p->p_rux.rux_sticks++;
if (td != PCPU_GET(idlethread))
cp_time[CP_SYS]++;
else
cp_time[CP_IDLE]++;
}
}
CTR4(KTR_SCHED, "statclock: %p(%s) prio %d stathz %d",
td, td->td_proc->p_comm, td->td_priority, (stathz)?stathz:hz);
sched_clock(td);
/* Update resource usage integrals and maximums. */
MPASS(p->p_stats != NULL);
MPASS(p->p_vmspace != NULL);
vm = p->p_vmspace;
ru = &p->p_stats->p_ru;
ru->ru_ixrss += pgtok(vm->vm_tsize);
ru->ru_idrss += pgtok(vm->vm_dsize);
ru->ru_isrss += pgtok(vm->vm_ssize);
rss = pgtok(vmspace_resident_count(vm));
if (ru->ru_maxrss < rss)
ru->ru_maxrss = rss;
mtx_unlock_spin_flags(&sched_lock, MTX_QUIET);
}
void
profclock(frame)
register struct clockframe *frame;
{
struct thread *td;
#ifdef GPROF
struct gmonparam *g;
int i;
#endif
td = curthread;
if (CLKF_USERMODE(frame)) {
/*
* 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, CLKF_PC(frame), 1);
}
#ifdef GPROF
else {
/*
* Kernel statistics are just like addupc_intr, only easier.
*/
g = &_gmonparam;
if (g->state == GMON_PROF_ON) {
i = CLKF_PC(frame) - g->lowpc;
if (i < g->textsize) {
i /= HISTFRACTION * sizeof(*g->kcount);
g->kcount[i]++;
}
}
}
#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,
0, 0, sysctl_kern_clockrate, "S,clockinfo",
"Rate and period of various kernel clocks");
#ifdef SW_WATCHDOG
static void
watchdog_config(void *unused __unused, u_int cmd, int *err)
{
u_int u;
u = cmd & WD_INTERVAL;
if (cmd && u >= WD_TO_1SEC) {
u = cmd & WD_INTERVAL;
watchdog_ticks = (1 << (u - WD_TO_1SEC)) * hz;
watchdog_enabled = 1;
*err = 0;
} else {
watchdog_enabled = 0;
}
}
/*
* Handle a watchdog timeout by dumping interrupt information and
* then either dropping to DDB or panicing.
*/
static void
watchdog_fire(void)
{
int nintr;
u_int64_t inttotal;
u_long *curintr;
char *curname;
curintr = intrcnt;
curname = intrnames;
inttotal = 0;
nintr = eintrcnt - intrcnt;
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);
#ifdef KDB
kdb_backtrace();
kdb_enter("watchdog timeout");
#else
panic("watchdog timeout");
#endif /* KDB */
}
#endif /* SW_WATCHDOG */