kernel/sched.c
/*
* linux/kernel/sched.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* 1996-04-21 Modified by Ulrich Windl to make NTP work
*/
/*
* 'sched.c' is the main kernel file. It contains scheduling primitives
* (sleep_on, wakeup, schedule etc) as well as a number of simple system
* call functions (type getpid()), which just extract a field from
* current-task
*/
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/kernel.h>
#include <linux/kernel_stat.h>
#include <linux/fdreg.h>
#include <linux/errno.h>
#include <linux/time.h>
#include <linux/ptrace.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/tqueue.h>
#include <linux/resource.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/segment.h>
#include <asm/pgtable.h>
#include <asm/mmu_context.h>
#include <linux/timex.h>
/*
* kernel variables
*/
int securelevel = 0; /* system security level */
long tick = 1000000 / HZ; /* timer interrupt period */
volatile struct timeval xtime; /* The current time */
int tickadj = 500/HZ; /* microsecs */
DECLARE_TASK_QUEUE(tq_timer);
DECLARE_TASK_QUEUE(tq_immediate);
DECLARE_TASK_QUEUE(tq_scheduler);
/*
* phase-lock loop variables
*/
/* TIME_ERROR prevents overwriting the CMOS clock */
int time_state = TIME_ERROR; /* clock synchronization status */
int time_status = STA_UNSYNC; /* clock status bits */
long time_offset = 0; /* time adjustment (us) */
long time_constant = 2; /* pll time constant */
long time_tolerance = MAXFREQ; /* frequency tolerance (ppm) */
long time_precision = 1; /* clock precision (us) */
long time_maxerror = MAXPHASE; /* maximum error (us) */
long time_esterror = MAXPHASE; /* estimated error (us) */
long time_phase = 0; /* phase offset (scaled us) */
long time_freq = 0; /* frequency offset (scaled ppm) */
long time_adj = 0; /* tick adjust (scaled 1 / HZ) */
long time_reftime = 0; /* time at last adjustment (s) */
long time_adjust = 0;
long time_adjust_step = 0;
int need_resched = 0;
unsigned long event = 0;
extern int _setitimer(int, struct itimerval *, struct itimerval *);
unsigned int * prof_buffer = NULL;
unsigned long prof_len = 0;
unsigned long prof_shift = 0;
#define _S(nr) (1<<((nr)-1))
extern void mem_use(void);
static unsigned long init_kernel_stack[1024] = { STACK_MAGIC, };
unsigned long init_user_stack[1024] = { STACK_MAGIC, };
static struct vm_area_struct init_mmap = INIT_MMAP;
static struct fs_struct init_fs = INIT_FS;
static struct files_struct init_files = INIT_FILES;
static struct signal_struct init_signals = INIT_SIGNALS;
struct mm_struct init_mm = INIT_MM;
struct task_struct init_task = INIT_TASK;
unsigned long volatile jiffies=0;
struct task_struct *current_set[NR_CPUS];
struct task_struct *last_task_used_math = NULL;
struct task_struct * task[NR_TASKS] = {&init_task, };
struct kernel_stat kstat = { 0 };
static inline void add_to_runqueue(struct task_struct * p)
{
#ifdef __SMP__
int cpu=smp_processor_id();
#endif
#if 1 /* sanity tests */
if (p->next_run || p->prev_run) {
printk("task already on run-queue\n");
return;
}
#endif
if (p->counter > current->counter + 3)
need_resched = 1;
nr_running++;
(p->prev_run = init_task.prev_run)->next_run = p;
p->next_run = &init_task;
init_task.prev_run = p;
#ifdef __SMP__
/* this is safe only if called with cli()*/
while(set_bit(31,&smp_process_available))
{
while(test_bit(31,&smp_process_available))
{
if(clear_bit(cpu,&smp_invalidate_needed))
{
local_flush_tlb();
set_bit(cpu,&cpu_callin_map[0]);
}
}
}
smp_process_available++;
clear_bit(31,&smp_process_available);
if ((0!=p->pid) && smp_threads_ready)
{
int i;
for (i=0;i<smp_num_cpus;i++)
{
if (0==current_set[cpu_logical_map[i]]->pid)
{
smp_message_pass(cpu_logical_map[i], MSG_RESCHEDULE, 0L, 0);
break;
}
}
}
#endif
}
static inline void del_from_runqueue(struct task_struct * p)
{
struct task_struct *next = p->next_run;
struct task_struct *prev = p->prev_run;
#if 1 /* sanity tests */
if (!next || !prev) {
printk("task not on run-queue\n");
return;
}
#endif
if (p == &init_task) {
static int nr = 0;
if (nr < 5) {
nr++;
printk("idle task may not sleep\n");
}
return;
}
nr_running--;
next->prev_run = prev;
prev->next_run = next;
p->next_run = NULL;
p->prev_run = NULL;
}
static inline void move_last_runqueue(struct task_struct * p)
{
struct task_struct *next = p->next_run;
struct task_struct *prev = p->prev_run;
/* remove from list */
next->prev_run = prev;
prev->next_run = next;
/* add back to list */
p->next_run = &init_task;
prev = init_task.prev_run;
init_task.prev_run = p;
p->prev_run = prev;
prev->next_run = p;
}
/*
* Wake up a process. Put it on the run-queue if it's not
* already there. The "current" process is always on the
* run-queue (except when the actual re-schedule is in
* progress), and as such you're allowed to do the simpler
* "current->state = TASK_RUNNING" to mark yourself runnable
* without the overhead of this.
*/
inline void wake_up_process(struct task_struct * p)
{
unsigned long flags;
save_flags(flags);
cli();
p->state = TASK_RUNNING;
if (!p->next_run)
add_to_runqueue(p);
restore_flags(flags);
}
static void process_timeout(unsigned long __data)
{
struct task_struct * p = (struct task_struct *) __data;
p->timeout = 0;
wake_up_process(p);
}
/*
* This is the function that decides how desirable a process is..
* You can weigh different processes against each other depending
* on what CPU they've run on lately etc to try to handle cache
* and TLB miss penalties.
*
* Return values:
* -1000: never select this
* 0: out of time, recalculate counters (but it might still be
* selected)
* +ve: "goodness" value (the larger, the better)
* +1000: realtime process, select this.
*/
static inline int goodness(struct task_struct * p, struct task_struct * prev, int this_cpu)
{
int weight;
#ifdef __SMP__
/* We are not permitted to run a task someone else is running */
if (p->processor != NO_PROC_ID)
return -1000;
#ifdef PAST_2_0
/* This process is locked to a processor group */
if (p->processor_mask && !(p->processor_mask & (1<<this_cpu))
return -1000;
#endif
#endif
/*
* Realtime process, select the first one on the
* runqueue (taking priorities within processes
* into account).
*/
if (p->policy != SCHED_OTHER)
return 1000 + p->rt_priority;
/*
* Give the process a first-approximation goodness value
* according to the number of clock-ticks it has left.
*
* Don't do any other calculations if the time slice is
* over..
*/
weight = p->counter;
if (weight) {
#ifdef __SMP__
/* Give a largish advantage to the same processor... */
/* (this is equivalent to penalizing other processors) */
if (p->last_processor == this_cpu)
weight += PROC_CHANGE_PENALTY;
#endif
/* .. and a slight advantage to the current process */
if (p == prev)
weight += 1;
}
return weight;
}
/*
* 'schedule()' is the scheduler function. It's a very simple and nice
* scheduler: it's not perfect, but certainly works for most things.
*
* The goto is "interesting".
*
* NOTE!! Task 0 is the 'idle' task, which gets called when no other
* tasks can run. It can not be killed, and it cannot sleep. The 'state'
* information in task[0] is never used.
*/
asmlinkage void schedule(void)
{
int c;
struct task_struct * p;
struct task_struct * prev, * next;
unsigned long timeout = 0;
int this_cpu=smp_processor_id();
/* check alarm, wake up any interruptible tasks that have got a signal */
if (intr_count)
goto scheduling_in_interrupt;
if (bh_active & bh_mask) {
intr_count = 1;
do_bottom_half();
intr_count = 0;
}
run_task_queue(&tq_scheduler);
need_resched = 0;
prev = current;
cli();
/* move an exhausted RR process to be last.. */
if (!prev->counter && prev->policy == SCHED_RR) {
prev->counter = prev->priority;
move_last_runqueue(prev);
}
switch (prev->state) {
case TASK_INTERRUPTIBLE:
if (prev->signal & ~prev->blocked)
goto makerunnable;
timeout = prev->timeout;
if (timeout && (timeout <= jiffies)) {
prev->timeout = 0;
timeout = 0;
makerunnable:
prev->state = TASK_RUNNING;
break;
}
default:
del_from_runqueue(prev);
case TASK_RUNNING:
}
p = init_task.next_run;
sti();
#ifdef __SMP__
/*
* This is safe as we do not permit re-entry of schedule()
*/
prev->processor = NO_PROC_ID;
#define idle_task (task[cpu_number_map[this_cpu]])
#else
#define idle_task (&init_task)
#endif
/*
* Note! there may appear new tasks on the run-queue during this, as
* interrupts are enabled. However, they will be put on front of the
* list, so our list starting at "p" is essentially fixed.
*/
/* this is the scheduler proper: */
c = -1000;
next = idle_task;
while (p != &init_task) {
int weight = goodness(p, prev, this_cpu);
if (weight > c)
c = weight, next = p;
p = p->next_run;
}
/* if all runnable processes have "counter == 0", re-calculate counters */
if (!c) {
for_each_task(p)
p->counter = (p->counter >> 1) + p->priority;
}
#ifdef __SMP__
/*
* Allocate process to CPU
*/
next->processor = this_cpu;
next->last_processor = this_cpu;
#endif
#ifdef __SMP_PROF__
/* mark processor running an idle thread */
if (0==next->pid)
set_bit(this_cpu,&smp_idle_map);
else
clear_bit(this_cpu,&smp_idle_map);
#endif
if (prev != next) {
struct timer_list timer;
kstat.context_swtch++;
if (timeout) {
init_timer(&timer);
timer.expires = timeout;
timer.data = (unsigned long) prev;
timer.function = process_timeout;
add_timer(&timer);
}
get_mmu_context(next);
switch_to(prev,next);
if (timeout)
del_timer(&timer);
}
return;
scheduling_in_interrupt:
printk("Aiee: scheduling in interrupt %p\n",
__builtin_return_address(0));
}
#ifndef __alpha__
/*
* For backwards compatibility? This can be done in libc so Alpha
* and all newer ports shouldn't need it.
*/
asmlinkage int sys_pause(void)
{
current->state = TASK_INTERRUPTIBLE;
schedule();
return -ERESTARTNOHAND;
}
#endif
/*
* wake_up doesn't wake up stopped processes - they have to be awakened
* with signals or similar.
*
* Note that this doesn't need cli-sti pairs: interrupts may not change
* the wait-queue structures directly, but only call wake_up() to wake
* a process. The process itself must remove the queue once it has woken.
*/
void wake_up(struct wait_queue **q)
{
struct wait_queue *tmp;
struct task_struct * p;
if (!q || !(tmp = *q))
return;
do {
if ((p = tmp->task) != NULL) {
if ((p->state == TASK_UNINTERRUPTIBLE) ||
(p->state == TASK_INTERRUPTIBLE))
wake_up_process(p);
}
if (!tmp->next) {
printk("wait_queue is bad (eip = %p)\n",
__builtin_return_address(0));
printk(" q = %p\n",q);
printk(" *q = %p\n",*q);
printk(" tmp = %p\n",tmp);
break;
}
tmp = tmp->next;
} while (tmp != *q);
}
void wake_up_interruptible(struct wait_queue **q)
{
struct wait_queue *tmp;
struct task_struct * p;
if (!q || !(tmp = *q))
return;
do {
if ((p = tmp->task) != NULL) {
if (p->state == TASK_INTERRUPTIBLE)
wake_up_process(p);
}
if (!tmp->next) {
printk("wait_queue is bad (eip = %p)\n",
__builtin_return_address(0));
printk(" q = %p\n",q);
printk(" *q = %p\n",*q);
printk(" tmp = %p\n",tmp);
break;
}
tmp = tmp->next;
} while (tmp != *q);
}
void __down(struct semaphore * sem)
{
struct wait_queue wait = { current, NULL };
add_wait_queue(&sem->wait, &wait);
current->state = TASK_UNINTERRUPTIBLE;
while (sem->count <= 0) {
schedule();
current->state = TASK_UNINTERRUPTIBLE;
}
current->state = TASK_RUNNING;
remove_wait_queue(&sem->wait, &wait);
}
static inline void __sleep_on(struct wait_queue **p, int state)
{
unsigned long flags;
struct wait_queue wait = { current, NULL };
if (!p)
return;
if (current == task[0])
panic("task[0] trying to sleep");
current->state = state;
add_wait_queue(p, &wait);
save_flags(flags);
sti();
schedule();
remove_wait_queue(p, &wait);
restore_flags(flags);
}
void interruptible_sleep_on(struct wait_queue **p)
{
__sleep_on(p,TASK_INTERRUPTIBLE);
}
void sleep_on(struct wait_queue **p)
{
__sleep_on(p,TASK_UNINTERRUPTIBLE);
}
/*
* The head for the timer-list has a "expires" field of MAX_UINT,
* and the sorting routine counts on this..
*/
static struct timer_list timer_head = { &timer_head, &timer_head, ~0, 0, NULL };
#define SLOW_BUT_DEBUGGING_TIMERS 0
void add_timer(struct timer_list * timer)
{
unsigned long flags;
struct timer_list *p;
#if SLOW_BUT_DEBUGGING_TIMERS
if (timer->next || timer->prev) {
printk("add_timer() called with non-zero list from %p\n",
__builtin_return_address(0));
return;
}
#endif
p = &timer_head;
save_flags(flags);
cli();
do {
p = p->next;
} while (timer->expires > p->expires);
timer->next = p;
timer->prev = p->prev;
p->prev = timer;
timer->prev->next = timer;
restore_flags(flags);
}
int del_timer(struct timer_list * timer)
{
int ret = 0;
if (timer->next) {
unsigned long flags;
struct timer_list * next;
save_flags(flags);
cli();
if ((next = timer->next) != NULL) {
(next->prev = timer->prev)->next = next;
timer->next = timer->prev = NULL;
ret = 1;
}
restore_flags(flags);
}
return ret;
}
static inline void run_timer_list(void)
{
struct timer_list * timer;
while ((timer = timer_head.next) != &timer_head && timer->expires <= jiffies) {
void (*fn)(unsigned long) = timer->function;
unsigned long data = timer->data;
timer->next->prev = timer->prev;
timer->prev->next = timer->next;
timer->next = timer->prev = NULL;
sti();
fn(data);
cli();
}
}
static inline void run_old_timers(void)
{
struct timer_struct *tp;
unsigned long mask;
for (mask = 1, tp = timer_table+0 ; mask ; tp++,mask += mask) {
if (mask > timer_active)
break;
if (!(mask & timer_active))
continue;
if (tp->expires > jiffies)
continue;
timer_active &= ~mask;
tp->fn();
sti();
}
}
void tqueue_bh(void)
{
run_task_queue(&tq_timer);
}
void immediate_bh(void)
{
run_task_queue(&tq_immediate);
}
unsigned long timer_active = 0;
struct timer_struct timer_table[32];
/*
* Hmm.. Changed this, as the GNU make sources (load.c) seems to
* imply that avenrun[] is the standard name for this kind of thing.
* Nothing else seems to be standardized: the fractional size etc
* all seem to differ on different machines.
*/
unsigned long avenrun[3] = { 0,0,0 };
/*
* Nr of active tasks - counted in fixed-point numbers
*/
static unsigned long count_active_tasks(void)
{
struct task_struct **p;
unsigned long nr = 0;
for(p = &LAST_TASK; p > &FIRST_TASK; --p)
if (*p && ((*p)->state == TASK_RUNNING ||
(*p)->state == TASK_UNINTERRUPTIBLE ||
(*p)->state == TASK_SWAPPING))
nr += FIXED_1;
#ifdef __SMP__
nr-=(smp_num_cpus-1)*FIXED_1;
#endif
return nr;
}
static inline void calc_load(unsigned long ticks)
{
unsigned long active_tasks; /* fixed-point */
static int count = LOAD_FREQ;
count -= ticks;
if (count < 0) {
count += LOAD_FREQ;
active_tasks = count_active_tasks();
CALC_LOAD(avenrun[0], EXP_1, active_tasks);
CALC_LOAD(avenrun[1], EXP_5, active_tasks);
CALC_LOAD(avenrun[2], EXP_15, active_tasks);
}
}
/*
* this routine handles the overflow of the microsecond field
*
* The tricky bits of code to handle the accurate clock support
* were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame.
* They were originally developed for SUN and DEC kernels.
* All the kudos should go to Dave for this stuff.
*
*/
static void second_overflow(void)
{
long ltemp;
/* Bump the maxerror field */
time_maxerror += time_tolerance >> SHIFT_USEC;
if ( time_maxerror > MAXPHASE )
time_maxerror = MAXPHASE;
/*
* Leap second processing. If in leap-insert state at
* the end of the day, the system clock is set back one
* second; if in leap-delete state, the system clock is
* set ahead one second. The microtime() routine or
* external clock driver will insure that reported time
* is always monotonic. The ugly divides should be
* replaced.
*/
switch (time_state) {
case TIME_OK:
if (time_status & STA_INS)
time_state = TIME_INS;
else if (time_status & STA_DEL)
time_state = TIME_DEL;
break;
case TIME_INS:
if (xtime.tv_sec % 86400 == 0) {
xtime.tv_sec--;
time_state = TIME_OOP;
printk("Clock: inserting leap second 23:59:60 UTC\n");
}
break;
case TIME_DEL:
if ((xtime.tv_sec + 1) % 86400 == 0) {
xtime.tv_sec++;
time_state = TIME_WAIT;
printk("Clock: deleting leap second 23:59:59 UTC\n");
}
break;
case TIME_OOP:
time_state = TIME_WAIT;
break;
case TIME_WAIT:
if (!(time_status & (STA_INS | STA_DEL)))
time_state = TIME_OK;
}
/*
* Compute the phase adjustment for the next second. In
* PLL mode, the offset is reduced by a fixed factor
* times the time constant. In FLL mode the offset is
* used directly. In either mode, the maximum phase
* adjustment for each second is clamped so as to spread
* the adjustment over not more than the number of
* seconds between updates.
*/
if (time_offset < 0) {
ltemp = -time_offset;
if (!(time_status & STA_FLL))
ltemp >>= SHIFT_KG + time_constant;
if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE)
ltemp = (MAXPHASE / MINSEC) << SHIFT_UPDATE;
time_offset += ltemp;
time_adj = -ltemp << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE);
} else {
ltemp = time_offset;
if (!(time_status & STA_FLL))
ltemp >>= SHIFT_KG + time_constant;
if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE)
ltemp = (MAXPHASE / MINSEC) << SHIFT_UPDATE;
time_offset -= ltemp;
time_adj = ltemp << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE);
}
/*
* Compute the frequency estimate and additional phase
* adjustment due to frequency error for the next
* second. When the PPS signal is engaged, gnaw on the
* watchdog counter and update the frequency computed by
* the pll and the PPS signal.
*/
pps_valid++;
if (pps_valid == PPS_VALID) {
pps_jitter = MAXTIME;
pps_stabil = MAXFREQ;
time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER |
STA_PPSWANDER | STA_PPSERROR);
}
ltemp = time_freq + pps_freq;
if (ltemp < 0)
time_adj -= -ltemp >>
(SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE);
else
time_adj += ltemp >>
(SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE);
#if HZ == 100
/* compensate for (HZ==100) != 128. Add 25% to get 125; => only 3% error */
if (time_adj < 0)
time_adj -= -time_adj >> 2;
else
time_adj += time_adj >> 2;
#endif
}
/* in the NTP reference this is called "hardclock()" */
static void update_wall_time_one_tick(void)
{
/*
* Advance the phase, once it gets to one microsecond, then
* advance the tick more.
*/
time_phase += time_adj;
if (time_phase <= -FINEUSEC) {
long ltemp = -time_phase >> SHIFT_SCALE;
time_phase += ltemp << SHIFT_SCALE;
xtime.tv_usec += tick + time_adjust_step - ltemp;
}
else if (time_phase >= FINEUSEC) {
long ltemp = time_phase >> SHIFT_SCALE;
time_phase -= ltemp << SHIFT_SCALE;
xtime.tv_usec += tick + time_adjust_step + ltemp;
} else
xtime.tv_usec += tick + time_adjust_step;
if (time_adjust) {
/* We are doing an adjtime thing.
*
* Modify the value of the tick for next time.
* Note that a positive delta means we want the clock
* to run fast. This means that the tick should be bigger
*
* Limit the amount of the step for *next* tick to be
* in the range -tickadj .. +tickadj
*/
if (time_adjust > tickadj)
time_adjust_step = tickadj;
else if (time_adjust < -tickadj)
time_adjust_step = -tickadj;
else
time_adjust_step = time_adjust;
/* Reduce by this step the amount of time left */
time_adjust -= time_adjust_step;
}
else
time_adjust_step = 0;
}
/*
* Using a loop looks inefficient, but "ticks" is
* usually just one (we shouldn't be losing ticks,
* we're doing this this way mainly for interrupt
* latency reasons, not because we think we'll
* have lots of lost timer ticks
*/
static void update_wall_time(unsigned long ticks)
{
do {
ticks--;
update_wall_time_one_tick();
} while (ticks);
if (xtime.tv_usec >= 1000000) {
xtime.tv_usec -= 1000000;
xtime.tv_sec++;
second_overflow();
}
}
static inline void do_process_times(struct task_struct *p,
unsigned long user, unsigned long system)
{
long psecs;
p->utime += user;
p->stime += system;
psecs = (p->stime + p->utime) / HZ;
if (psecs > p->rlim[RLIMIT_CPU].rlim_cur) {
/* Send SIGXCPU every second.. */
if (psecs * HZ == p->stime + p->utime)
send_sig(SIGXCPU, p, 1);
/* and SIGKILL when we go over max.. */
if (psecs > p->rlim[RLIMIT_CPU].rlim_max)
send_sig(SIGKILL, p, 1);
}
}
static inline void do_it_virt(struct task_struct * p, unsigned long ticks)
{
unsigned long it_virt = p->it_virt_value;
if (it_virt) {
if (it_virt <= ticks) {
it_virt = ticks + p->it_virt_incr;
send_sig(SIGVTALRM, p, 1);
}
p->it_virt_value = it_virt - ticks;
}
}
static inline void do_it_prof(struct task_struct * p, unsigned long ticks)
{
unsigned long it_prof = p->it_prof_value;
if (it_prof) {
if (it_prof <= ticks) {
it_prof = ticks + p->it_prof_incr;
send_sig(SIGPROF, p, 1);
}
p->it_prof_value = it_prof - ticks;
}
static __inline__ void update_one_process(struct task_struct *p,
unsigned long ticks, unsigned long user, unsigned long system)
{
do_process_times(p, user, system);
do_it_virt(p, user);
do_it_prof(p, ticks);
}
static void update_process_times(unsigned long ticks, unsigned long system)
{
#ifndef __SMP__
struct task_struct * p = current;
unsigned long user = ticks - system;
if (p->pid) {
p->counter -= ticks;
p->counter = 0;
need_resched = 1;
}
if (p->priority < DEF_PRIORITY)
kstat.cpu_nice += user;
else
kstat.cpu_user += user;
kstat.cpu_system += system;
}
update_one_process(p, ticks, user, system);
#else
int cpu,j;
cpu = smp_processor_id();
for (j=0;j<smp_num_cpus;j++)
{
int i = cpu_logical_map[j];
struct task_struct *p;
#ifdef __SMP_PROF__
if (test_bit(i,&smp_idle_map))
smp_idle_count[i]++;
#endif
p = current_set[i];
/*
* Do we have a real process?
*/
if (p->pid) {
/* assume user-mode process */
unsigned long utime = ticks;
unsigned long stime = 0;
if (cpu == i) {
utime = ticks-system;
stime = system;
} else if (smp_proc_in_lock[i]) {
utime = 0;
stime = ticks;
}
update_one_process(p, ticks, utime, stime);
p->counter -= ticks;
if (p->counter >= 0)
continue;
p->counter = 0;
} else {
/*
* Idle processor found, do we have anything
* we could run?
*/
if (!(0x7fffffff & smp_process_available))
continue;
}
/* Ok, we should reschedule, do the magic */
if (i==cpu)
need_resched = 1;
else
smp_message_pass(i, MSG_RESCHEDULE, 0L, 0);
}
#endif
}
static unsigned long lost_ticks = 0;
static unsigned long lost_ticks_system = 0;
static void timer_bh(void)
{
unsigned long ticks, system;
run_old_timers();
cli();
run_timer_list();
ticks = lost_ticks;
lost_ticks = 0;
system = lost_ticks_system;
lost_ticks_system = 0;
sti();
if (ticks) {
calc_load(ticks);
update_wall_time(ticks);
update_process_times(ticks, system);
}
}
/*
* Run the bottom half stuff only about 100 times a second,
* we'd just use up unnecessary CPU time for timer handling
* otherwise
*/
#if HZ > 100
#define should_run_timers(x) ((x) >= HZ/100)
#else
#define should_run_timers(x) (1)
#endif
void do_timer(struct pt_regs * regs)
{
(*(unsigned long *)&jiffies)++;
lost_ticks++;
if (should_run_timers(lost_ticks))
mark_bh(TIMER_BH);
if (!user_mode(regs)) {
lost_ticks_system++;
if (prof_buffer && current->pid) {
extern int _stext;
unsigned long ip = instruction_pointer(regs);
ip -= (unsigned long) &_stext;
ip >>= prof_shift;
if (ip < prof_len)
prof_buffer[ip]++;
}
}
if (tq_timer)
mark_bh(TQUEUE_BH);
}
#ifndef __alpha__
/*
* For backwards compatibility? This can be done in libc so Alpha
* and all newer ports shouldn't need it.
*/
asmlinkage unsigned int sys_alarm(unsigned int seconds)
{
struct itimerval it_new, it_old;
unsigned int oldalarm;
it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0;
it_new.it_value.tv_sec = seconds;
it_new.it_value.tv_usec = 0;
_setitimer(ITIMER_REAL, &it_new, &it_old);
oldalarm = it_old.it_value.tv_sec;
/* ehhh.. We can't return 0 if we have an alarm pending.. */
/* And we'd better return too much than too little anyway */
if (it_old.it_value.tv_usec)
oldalarm++;
return oldalarm;
}
/*
* The Alpha uses getxpid, getxuid, and getxgid instead. Maybe this
* should be moved into arch/i386 instead?
*/
asmlinkage int sys_getpid(void)
{
return current->pid;
}
asmlinkage int sys_getppid(void)
{
return current->p_opptr->pid;
}
asmlinkage int sys_getuid(void)
{
return current->uid;
}
asmlinkage int sys_geteuid(void)
{
return current->euid;
}
asmlinkage int sys_getgid(void)
{
return current->gid;
}
asmlinkage int sys_getegid(void)
{
return current->egid;
}
/*
* This has been replaced by sys_setpriority. Maybe it should be
* moved into the arch dependent tree for those ports that require
* it for backward compatibility?
*/
asmlinkage int sys_nice(int increment)
{
unsigned long newprio;
int increase = 0;
newprio = increment;
if (increment < 0) {
if (!suser())
return -EPERM;
newprio = -increment;
increase = 1;
}
if (newprio > 40)
newprio = 40;
/*
* do a "normalization" of the priority (traditionally
* unix nice values are -20..20, linux doesn't really
* use that kind of thing, but uses the length of the
* timeslice instead (default 150 msec). The rounding is
* why we want to avoid negative values.
*/
newprio = (newprio * DEF_PRIORITY + 10) / 20;
increment = newprio;
if (increase)
increment = -increment;
newprio = current->priority - increment;
if (newprio < 1)
newprio = 1;
if (newprio > DEF_PRIORITY*2)
newprio = DEF_PRIORITY*2;
current->priority = newprio;
return 0;
}
#endif
static struct task_struct *find_process_by_pid(pid_t pid) {
struct task_struct *p, *q;
if (pid == 0)
p = current;
else {
p = 0;
for_each_task(q) {
if (q && q->pid == pid) {
p = q;
break;
}
}
}
return p;
}
static int setscheduler(pid_t pid, int policy,
struct sched_param *param)
{
int error;
struct sched_param lp;
struct task_struct *p;
if (!param || pid < 0)
return -EINVAL;
error = verify_area(VERIFY_READ, param, sizeof(struct sched_param));
if (error)
return error;
memcpy_fromfs(&lp, param, sizeof(struct sched_param));
p = find_process_by_pid(pid);
if (!p)
return -ESRCH;
if (policy < 0)
policy = p->policy;
else if (policy != SCHED_FIFO && policy != SCHED_RR &&
policy != SCHED_OTHER)
return -EINVAL;
/*
* Valid priorities for SCHED_FIFO and SCHED_RR are 1..99, valid
* priority for SCHED_OTHER is 0.
*/
if (lp.sched_priority < 0 || lp.sched_priority > 99)
return -EINVAL;
if ((policy == SCHED_OTHER) != (lp.sched_priority == 0))
return -EINVAL;
if ((policy == SCHED_FIFO || policy == SCHED_RR) && !suser())
return -EPERM;
if ((current->euid != p->euid) && (current->euid != p->uid) &&
!suser())
return -EPERM;
p->policy = policy;
p->rt_priority = lp.sched_priority;
if (p->next_run)
move_last_runqueue(p);
schedule();
return 0;
}
asmlinkage int sys_sched_setscheduler(pid_t pid, int policy,
struct sched_param *param)
{
return setscheduler(pid, policy, param);
}
asmlinkage int sys_sched_setparam(pid_t pid, struct sched_param *param)
{
return setscheduler(pid, -1, param);
}
asmlinkage int sys_sched_getscheduler(pid_t pid)
{
struct task_struct *p;
if (pid < 0)
return -EINVAL;
p = find_process_by_pid(pid);
if (!p)
return -ESRCH;
return p->policy;
}
asmlinkage int sys_sched_getparam(pid_t pid, struct sched_param *param)
{
int error;
struct task_struct *p;
struct sched_param lp;
if (!param || pid < 0)
return -EINVAL;
error = verify_area(VERIFY_WRITE, param, sizeof(struct sched_param));
if (error)
return error;
p = find_process_by_pid(pid);
if (!p)
return -ESRCH;
lp.sched_priority = p->rt_priority;
memcpy_tofs(param, &lp, sizeof(struct sched_param));
return 0;
}
asmlinkage int sys_sched_yield(void)
{
move_last_runqueue(current);
return 0;
}
asmlinkage int sys_sched_get_priority_max(int policy)
{
switch (policy) {
case SCHED_FIFO:
case SCHED_RR:
return 99;
case SCHED_OTHER:
return 0;
}
return -EINVAL;
}
asmlinkage int sys_sched_get_priority_min(int policy)
{
switch (policy) {
case SCHED_FIFO:
case SCHED_RR:
return 1;
case SCHED_OTHER:
return 0;
}
return -EINVAL;
}
asmlinkage int sys_sched_rr_get_interval(pid_t pid, struct timespec *interval)
{
int error;
struct timespec t;
error = verify_area(VERIFY_WRITE, interval, sizeof(struct timespec));
if (error)
return error;
t.tv_sec = 0;
t.tv_nsec = 0; /* <-- Linus, please fill correct value in here */
return -ENOSYS; /* and then delete this line. Thanks! */
memcpy_tofs(interval, &t, sizeof(struct timespec));
return 0;
}
/*
* change timeval to jiffies, trying to avoid the
* most obvious overflows..
*/
static unsigned long timespectojiffies(struct timespec *value)
{
unsigned long sec = (unsigned) value->tv_sec;
long nsec = value->tv_nsec;
if (sec > (LONG_MAX / HZ))
return LONG_MAX;
nsec += 1000000000L / HZ - 1;
nsec /= 1000000000L / HZ;
return HZ * sec + nsec;
}
static void jiffiestotimespec(unsigned long jiffies, struct timespec *value)
{
value->tv_nsec = (jiffies % HZ) * (1000000000L / HZ);
value->tv_sec = jiffies / HZ;
return;
}
asmlinkage int sys_nanosleep(struct timespec *rqtp, struct timespec *rmtp)
{
int error;
struct timespec t;
unsigned long expire;
error = verify_area(VERIFY_READ, rqtp, sizeof(struct timespec));
if (error)
return error;
memcpy_fromfs(&t, rqtp, sizeof(struct timespec));
if (rmtp) {
error = verify_area(VERIFY_WRITE, rmtp,
sizeof(struct timespec));
if (error)
return error;
}
if (t.tv_nsec >= 1000000000L || t.tv_nsec < 0 || t.tv_sec < 0)
return -EINVAL;
if (t.tv_sec == 0 && t.tv_nsec <= 2000000L &&
current->policy != SCHED_OTHER) {
/*
* Short delay requests up to 2 ms will be handled with
* high precision by a busy wait for all real-time processes.
*/
udelay((t.tv_nsec + 999) / 1000);
return 0;
}
expire = timespectojiffies(&t) + (t.tv_sec || t.tv_nsec) + jiffies;
current->timeout = expire;
current->state = TASK_INTERRUPTIBLE;
schedule();
if (expire > jiffies) {
if (rmtp) {
jiffiestotimespec(expire - jiffies -
(expire > jiffies + 1), &t);
memcpy_tofs(rmtp, &t, sizeof(struct timespec));
}
return -EINTR;
}
return 0;
}
static void show_task(int nr,struct task_struct * p)
{
unsigned long free;
static const char * stat_nam[] = { "R", "S", "D", "Z", "T", "W" };
printk("%-8s %3d ", p->comm, (p == current) ? -nr : nr);
if (((unsigned) p->state) < sizeof(stat_nam)/sizeof(char *))
printk(stat_nam[p->state]);
else
printk(" ");
#if ((~0UL) == 0xffffffff)
if (p == current)
printk(" current ");
else
printk(" %08lX ", thread_saved_pc(&p->tss));
#else
if (p == current)
printk(" current task ");
else
printk(" %016lx ", thread_saved_pc(&p->tss));
#endif
for (free = 1; free < PAGE_SIZE/sizeof(long) ; free++) {
if (((unsigned long *)p->kernel_stack_page)[free])
break;
}
printk("%5lu %5d %6d ", free*sizeof(long), p->pid, p->p_pptr->pid);
if (p->p_cptr)
printk("%5d ", p->p_cptr->pid);
else
printk(" ");
if (p->p_ysptr)
printk("%7d", p->p_ysptr->pid);
else
printk(" ");
if (p->p_osptr)
printk(" %5d\n", p->p_osptr->pid);
else
printk("\n");
}
void show_state(void)
{
int i;
#if ((~0UL) == 0xffffffff)
printk("\n"
" free sibling\n");
printk(" task PC stack pid father child younger older\n");
#else
printk("\n"
" free sibling\n");
printk(" task PC stack pid father child younger older\n");
#endif
for (i=0 ; i<NR_TASKS ; i++)
if (task[i])
show_task(i,task[i]);
}
void sched_init(void)
{
/*
* We have to do a little magic to get the first
* process right in SMP mode.
*/
int cpu=smp_processor_id();
#ifndef __SMP__
current_set[cpu]=&init_task;
#else
init_task.processor=cpu;
for(cpu = 0; cpu < NR_CPUS; cpu++)
current_set[cpu] = &init_task;
#endif
init_bh(TIMER_BH, timer_bh);
init_bh(TQUEUE_BH, tqueue_bh);
init_bh(IMMEDIATE_BH, immediate_bh);
}
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