X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fposix-cpu-timers.c;h=00bb252f29a29210270bc47167755f9bd8b307e0;hb=6c5e303afdf2910e58aeda56c10506342545a5af;hp=12161f74744e052b09e088c930ca8e5a1a43e397;hpb=f71bb0ac5e85410601b0db29d7b1635345ea61a4;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c index 12161f7..00bb252 100644 --- a/kernel/posix-cpu-timers.c +++ b/kernel/posix-cpu-timers.c @@ -8,21 +8,21 @@ #include #include #include +#include /* - * Called after updating RLIMIT_CPU to set timer expiration if necessary. + * Called after updating RLIMIT_CPU to run cpu timer and update + * tsk->signal->cputime_expires expiration cache if necessary. Needs + * siglock protection since other code may update expiration cache as + * well. */ void update_rlimit_cpu(unsigned long rlim_new) { cputime_t cputime = secs_to_cputime(rlim_new); - struct signal_struct *const sig = current->signal; - if (cputime_eq(sig->it[CPUCLOCK_PROF].expires, cputime_zero) || - cputime_gt(sig->it[CPUCLOCK_PROF].expires, cputime)) { - spin_lock_irq(¤t->sighand->siglock); - set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL); - spin_unlock_irq(¤t->sighand->siglock); - } + spin_lock_irq(¤t->sighand->siglock); + set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL); + spin_unlock_irq(¤t->sighand->siglock); } static int check_clock(const clockid_t which_clock) @@ -383,7 +383,8 @@ int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp) /* * Validate the clockid_t for a new CPU-clock timer, and initialize the timer. - * This is called from sys_timer_create with the new timer already locked. + * This is called from sys_timer_create() and do_cpu_nanosleep() with the + * new timer already all-zeros initialized. */ int posix_cpu_timer_create(struct k_itimer *new_timer) { @@ -395,8 +396,6 @@ int posix_cpu_timer_create(struct k_itimer *new_timer) return -EINVAL; INIT_LIST_HEAD(&new_timer->it.cpu.entry); - new_timer->it.cpu.incr.sched = 0; - new_timer->it.cpu.expires.sched = 0; read_lock(&tasklist_lock); if (CPUCLOCK_PERTHREAD(new_timer->it_clock)) { @@ -548,111 +547,62 @@ static inline int expires_gt(cputime_t expires, cputime_t new_exp) cputime_gt(expires, new_exp); } -static inline int expires_le(cputime_t expires, cputime_t new_exp) -{ - return !cputime_eq(expires, cputime_zero) && - cputime_le(expires, new_exp); -} /* * Insert the timer on the appropriate list before any timers that * expire later. This must be called with the tasklist_lock held - * for reading, and interrupts disabled. + * for reading, interrupts disabled and p->sighand->siglock taken. */ -static void arm_timer(struct k_itimer *timer, union cpu_time_count now) +static void arm_timer(struct k_itimer *timer) { struct task_struct *p = timer->it.cpu.task; struct list_head *head, *listpos; + struct task_cputime *cputime_expires; struct cpu_timer_list *const nt = &timer->it.cpu; struct cpu_timer_list *next; - unsigned long i; - head = (CPUCLOCK_PERTHREAD(timer->it_clock) ? - p->cpu_timers : p->signal->cpu_timers); + if (CPUCLOCK_PERTHREAD(timer->it_clock)) { + head = p->cpu_timers; + cputime_expires = &p->cputime_expires; + } else { + head = p->signal->cpu_timers; + cputime_expires = &p->signal->cputime_expires; + } head += CPUCLOCK_WHICH(timer->it_clock); - BUG_ON(!irqs_disabled()); - spin_lock(&p->sighand->siglock); - listpos = head; - if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) { - list_for_each_entry(next, head, entry) { - if (next->expires.sched > nt->expires.sched) - break; - listpos = &next->entry; - } - } else { - list_for_each_entry(next, head, entry) { - if (cputime_gt(next->expires.cpu, nt->expires.cpu)) - break; - listpos = &next->entry; - } + list_for_each_entry(next, head, entry) { + if (cpu_time_before(timer->it_clock, nt->expires, next->expires)) + break; + listpos = &next->entry; } list_add(&nt->entry, listpos); if (listpos == head) { + union cpu_time_count *exp = &nt->expires; + /* - * We are the new earliest-expiring timer. - * If we are a thread timer, there can always - * be a process timer telling us to stop earlier. + * We are the new earliest-expiring POSIX 1.b timer, hence + * need to update expiration cache. Take into account that + * for process timers we share expiration cache with itimers + * and RLIMIT_CPU and for thread timers with RLIMIT_RTTIME. */ - if (CPUCLOCK_PERTHREAD(timer->it_clock)) { - union cpu_time_count *exp = &nt->expires; - - switch (CPUCLOCK_WHICH(timer->it_clock)) { - default: - BUG(); - case CPUCLOCK_PROF: - if (expires_gt(p->cputime_expires.prof_exp, - exp->cpu)) - p->cputime_expires.prof_exp = exp->cpu; - break; - case CPUCLOCK_VIRT: - if (expires_gt(p->cputime_expires.virt_exp, - exp->cpu)) - p->cputime_expires.virt_exp = exp->cpu; - break; - case CPUCLOCK_SCHED: - if (p->cputime_expires.sched_exp == 0 || - p->cputime_expires.sched_exp > exp->sched) - p->cputime_expires.sched_exp = - exp->sched; - break; - } - } else { - struct signal_struct *const sig = p->signal; - union cpu_time_count *exp = &timer->it.cpu.expires; - - /* - * For a process timer, set the cached expiration time. - */ - switch (CPUCLOCK_WHICH(timer->it_clock)) { - default: - BUG(); - case CPUCLOCK_VIRT: - if (expires_le(sig->it[CPUCLOCK_VIRT].expires, - exp->cpu)) - break; - sig->cputime_expires.virt_exp = exp->cpu; - break; - case CPUCLOCK_PROF: - if (expires_le(sig->it[CPUCLOCK_PROF].expires, - exp->cpu)) - break; - i = sig->rlim[RLIMIT_CPU].rlim_cur; - if (i != RLIM_INFINITY && - i <= cputime_to_secs(exp->cpu)) - break; - sig->cputime_expires.prof_exp = exp->cpu; - break; - case CPUCLOCK_SCHED: - sig->cputime_expires.sched_exp = exp->sched; - break; - } + switch (CPUCLOCK_WHICH(timer->it_clock)) { + case CPUCLOCK_PROF: + if (expires_gt(cputime_expires->prof_exp, exp->cpu)) + cputime_expires->prof_exp = exp->cpu; + break; + case CPUCLOCK_VIRT: + if (expires_gt(cputime_expires->virt_exp, exp->cpu)) + cputime_expires->virt_exp = exp->cpu; + break; + case CPUCLOCK_SCHED: + if (cputime_expires->sched_exp == 0 || + cputime_expires->sched_exp > exp->sched) + cputime_expires->sched_exp = exp->sched; + break; } } - - spin_unlock(&p->sighand->siglock); } /* @@ -660,7 +610,12 @@ static void arm_timer(struct k_itimer *timer, union cpu_time_count now) */ static void cpu_timer_fire(struct k_itimer *timer) { - if (unlikely(timer->sigq == NULL)) { + if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) { + /* + * User don't want any signal. + */ + timer->it.cpu.expires.sched = 0; + } else if (unlikely(timer->sigq == NULL)) { /* * This a special case for clock_nanosleep, * not a normal timer from sys_timer_create. @@ -721,7 +676,7 @@ int posix_cpu_timer_set(struct k_itimer *timer, int flags, struct itimerspec *new, struct itimerspec *old) { struct task_struct *p = timer->it.cpu.task; - union cpu_time_count old_expires, new_expires, val; + union cpu_time_count old_expires, new_expires, old_incr, val; int ret; if (unlikely(p == NULL)) { @@ -752,6 +707,7 @@ int posix_cpu_timer_set(struct k_itimer *timer, int flags, BUG_ON(!irqs_disabled()); ret = 0; + old_incr = timer->it.cpu.incr; spin_lock(&p->sighand->siglock); old_expires = timer->it.cpu.expires; if (unlikely(timer->it.cpu.firing)) { @@ -759,7 +715,6 @@ int posix_cpu_timer_set(struct k_itimer *timer, int flags, ret = TIMER_RETRY; } else list_del_init(&timer->it.cpu.entry); - spin_unlock(&p->sighand->siglock); /* * We need to sample the current value to convert the new @@ -813,6 +768,7 @@ int posix_cpu_timer_set(struct k_itimer *timer, int flags, * disable this firing since we are already reporting * it as an overrun (thanks to bump_cpu_timer above). */ + spin_unlock(&p->sighand->siglock); read_unlock(&tasklist_lock); goto out; } @@ -828,11 +784,11 @@ int posix_cpu_timer_set(struct k_itimer *timer, int flags, */ timer->it.cpu.expires = new_expires; if (new_expires.sched != 0 && - (timer->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE && cpu_time_before(timer->it_clock, val, new_expires)) { - arm_timer(timer, val); + arm_timer(timer); } + spin_unlock(&p->sighand->siglock); read_unlock(&tasklist_lock); /* @@ -853,7 +809,6 @@ int posix_cpu_timer_set(struct k_itimer *timer, int flags, timer->it_overrun = -1; if (new_expires.sched != 0 && - (timer->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE && !cpu_time_before(timer->it_clock, val, new_expires)) { /* * The designated time already passed, so we notify @@ -867,7 +822,7 @@ int posix_cpu_timer_set(struct k_itimer *timer, int flags, out: if (old) { sample_to_timespec(timer->it_clock, - timer->it.cpu.incr, &old->it_interval); + old_incr, &old->it_interval); } return ret; } @@ -927,25 +882,6 @@ void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp) read_unlock(&tasklist_lock); } - if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) { - if (timer->it.cpu.incr.sched == 0 && - cpu_time_before(timer->it_clock, - timer->it.cpu.expires, now)) { - /* - * Do-nothing timer expired and has no reload, - * so it's as if it was never set. - */ - timer->it.cpu.expires.sched = 0; - itp->it_value.tv_sec = itp->it_value.tv_nsec = 0; - return; - } - /* - * Account for any expirations and reloads that should - * have happened. - */ - bump_cpu_timer(timer, now); - } - if (unlikely(clear_dead)) { /* * We've noticed that the thread is dead, but @@ -982,6 +918,7 @@ static void check_thread_timers(struct task_struct *tsk, int maxfire; struct list_head *timers = tsk->cpu_timers; struct signal_struct *const sig = tsk->signal; + unsigned long soft; maxfire = 20; tsk->cputime_expires.prof_exp = cputime_zero; @@ -1030,9 +967,10 @@ static void check_thread_timers(struct task_struct *tsk, /* * Check for the special case thread timers. */ - if (sig->rlim[RLIMIT_RTTIME].rlim_cur != RLIM_INFINITY) { - unsigned long hard = sig->rlim[RLIMIT_RTTIME].rlim_max; - unsigned long *soft = &sig->rlim[RLIMIT_RTTIME].rlim_cur; + soft = ACCESS_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_cur); + if (soft != RLIM_INFINITY) { + unsigned long hard = + ACCESS_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_max); if (hard != RLIM_INFINITY && tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) { @@ -1043,14 +981,13 @@ static void check_thread_timers(struct task_struct *tsk, __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk); return; } - if (tsk->rt.timeout > DIV_ROUND_UP(*soft, USEC_PER_SEC/HZ)) { + if (tsk->rt.timeout > DIV_ROUND_UP(soft, USEC_PER_SEC/HZ)) { /* * At the soft limit, send a SIGXCPU every second. */ - if (sig->rlim[RLIMIT_RTTIME].rlim_cur - < sig->rlim[RLIMIT_RTTIME].rlim_max) { - sig->rlim[RLIMIT_RTTIME].rlim_cur += - USEC_PER_SEC; + if (soft < hard) { + soft += USEC_PER_SEC; + sig->rlim[RLIMIT_RTTIME].rlim_cur = soft; } printk(KERN_INFO "RT Watchdog Timeout: %s[%d]\n", @@ -1060,14 +997,11 @@ static void check_thread_timers(struct task_struct *tsk, } } -static void stop_process_timers(struct task_struct *tsk) +static void stop_process_timers(struct signal_struct *sig) { - struct thread_group_cputimer *cputimer = &tsk->signal->cputimer; + struct thread_group_cputimer *cputimer = &sig->cputimer; unsigned long flags; - if (!cputimer->running) - return; - spin_lock_irqsave(&cputimer->lock, flags); cputimer->running = 0; spin_unlock_irqrestore(&cputimer->lock, flags); @@ -1090,9 +1024,13 @@ static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it, cputime_one_jiffy); it->error -= onecputick; } - } else + } else { it->expires = cputime_zero; + } + trace_itimer_expire(signo == SIGPROF ? + ITIMER_PROF : ITIMER_VIRTUAL, + tsk->signal->leader_pid, cur_time); __group_send_sig_info(signo, SEND_SIG_PRIV, tsk); } @@ -1103,6 +1041,23 @@ static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it, } } +/** + * task_cputime_zero - Check a task_cputime struct for all zero fields. + * + * @cputime: The struct to compare. + * + * Checks @cputime to see if all fields are zero. Returns true if all fields + * are zero, false if any field is nonzero. + */ +static inline int task_cputime_zero(const struct task_cputime *cputime) +{ + if (cputime_eq(cputime->utime, cputime_zero) && + cputime_eq(cputime->stime, cputime_zero) && + cputime->sum_exec_runtime == 0) + return 1; + return 0; +} + /* * Check for any per-thread CPU timers that have fired and move them * off the tsk->*_timers list onto the firing list. Per-thread timers @@ -1117,19 +1072,7 @@ static void check_process_timers(struct task_struct *tsk, unsigned long long sum_sched_runtime, sched_expires; struct list_head *timers = sig->cpu_timers; struct task_cputime cputime; - - /* - * Don't sample the current process CPU clocks if there are no timers. - */ - if (list_empty(&timers[CPUCLOCK_PROF]) && - cputime_eq(sig->it[CPUCLOCK_PROF].expires, cputime_zero) && - sig->rlim[RLIMIT_CPU].rlim_cur == RLIM_INFINITY && - list_empty(&timers[CPUCLOCK_VIRT]) && - cputime_eq(sig->it[CPUCLOCK_VIRT].expires, cputime_zero) && - list_empty(&timers[CPUCLOCK_SCHED])) { - stop_process_timers(tsk); - return; - } + unsigned long soft; /* * Collect the current process totals. @@ -1189,11 +1132,13 @@ static void check_process_timers(struct task_struct *tsk, SIGPROF); check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime, SIGVTALRM); - - if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) { + soft = ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur); + if (soft != RLIM_INFINITY) { unsigned long psecs = cputime_to_secs(ptime); + unsigned long hard = + ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_max); cputime_t x; - if (psecs >= sig->rlim[RLIMIT_CPU].rlim_max) { + if (psecs >= hard) { /* * At the hard limit, we just die. * No need to calculate anything else now. @@ -1201,35 +1146,28 @@ static void check_process_timers(struct task_struct *tsk, __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk); return; } - if (psecs >= sig->rlim[RLIMIT_CPU].rlim_cur) { + if (psecs >= soft) { /* * At the soft limit, send a SIGXCPU every second. */ __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk); - if (sig->rlim[RLIMIT_CPU].rlim_cur - < sig->rlim[RLIMIT_CPU].rlim_max) { - sig->rlim[RLIMIT_CPU].rlim_cur++; + if (soft < hard) { + soft++; + sig->rlim[RLIMIT_CPU].rlim_cur = soft; } } - x = secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur); + x = secs_to_cputime(soft); if (cputime_eq(prof_expires, cputime_zero) || cputime_lt(x, prof_expires)) { prof_expires = x; } } - if (!cputime_eq(prof_expires, cputime_zero) && - (cputime_eq(sig->cputime_expires.prof_exp, cputime_zero) || - cputime_gt(sig->cputime_expires.prof_exp, prof_expires))) - sig->cputime_expires.prof_exp = prof_expires; - if (!cputime_eq(virt_expires, cputime_zero) && - (cputime_eq(sig->cputime_expires.virt_exp, cputime_zero) || - cputime_gt(sig->cputime_expires.virt_exp, virt_expires))) - sig->cputime_expires.virt_exp = virt_expires; - if (sched_expires != 0 && - (sig->cputime_expires.sched_exp == 0 || - sig->cputime_expires.sched_exp > sched_expires)) - sig->cputime_expires.sched_exp = sched_expires; + sig->cputime_expires.prof_exp = prof_expires; + sig->cputime_expires.virt_exp = virt_expires; + sig->cputime_expires.sched_exp = sched_expires; + if (task_cputime_zero(&sig->cputime_expires)) + stop_process_timers(sig); } /* @@ -1258,6 +1196,7 @@ void posix_cpu_timer_schedule(struct k_itimer *timer) goto out; } read_lock(&tasklist_lock); /* arm_timer needs it. */ + spin_lock(&p->sighand->siglock); } else { read_lock(&tasklist_lock); if (unlikely(p->signal == NULL)) { @@ -1278,6 +1217,7 @@ void posix_cpu_timer_schedule(struct k_itimer *timer) clear_dead_task(timer, now); goto out_unlock; } + spin_lock(&p->sighand->siglock); cpu_timer_sample_group(timer->it_clock, p, &now); bump_cpu_timer(timer, now); /* Leave the tasklist_lock locked for the call below. */ @@ -1286,7 +1226,9 @@ void posix_cpu_timer_schedule(struct k_itimer *timer) /* * Now re-arm for the new expiry time. */ - arm_timer(timer, now); + BUG_ON(!irqs_disabled()); + arm_timer(timer); + spin_unlock(&p->sighand->siglock); out_unlock: read_unlock(&tasklist_lock); @@ -1298,23 +1240,6 @@ out: } /** - * task_cputime_zero - Check a task_cputime struct for all zero fields. - * - * @cputime: The struct to compare. - * - * Checks @cputime to see if all fields are zero. Returns true if all fields - * are zero, false if any field is nonzero. - */ -static inline int task_cputime_zero(const struct task_cputime *cputime) -{ - if (cputime_eq(cputime->utime, cputime_zero) && - cputime_eq(cputime->stime, cputime_zero) && - cputime->sum_exec_runtime == 0) - return 1; - return 0; -} - -/** * task_cputime_expired - Compare two task_cputime entities. * * @sample: The task_cputime structure to be checked for expiration. @@ -1370,7 +1295,7 @@ static inline int fastpath_timer_check(struct task_struct *tsk) } sig = tsk->signal; - if (!task_cputime_zero(&sig->cputime_expires)) { + if (sig->cputimer.running) { struct task_cputime group_sample; thread_group_cputimer(tsk, &group_sample); @@ -1378,7 +1303,7 @@ static inline int fastpath_timer_check(struct task_struct *tsk) return 1; } - return sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY; + return 0; } /* @@ -1407,7 +1332,12 @@ void run_posix_cpu_timers(struct task_struct *tsk) * put them on the firing list. */ check_thread_timers(tsk, &firing); - check_process_timers(tsk, &firing); + /* + * If there are any active process wide timers (POSIX 1.b, itimers, + * RLIMIT_CPU) cputimer must be running. + */ + if (tsk->signal->cputimer.running) + check_process_timers(tsk, &firing); /* * We must release these locks before taking any timer's lock. @@ -1444,21 +1374,23 @@ void run_posix_cpu_timers(struct task_struct *tsk) } /* - * Set one of the process-wide special case CPU timers. + * Set one of the process-wide special case CPU timers or RLIMIT_CPU. * The tsk->sighand->siglock must be held by the caller. - * The *newval argument is relative and we update it to be absolute, *oldval - * is absolute and we update it to be relative. */ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx, cputime_t *newval, cputime_t *oldval) { union cpu_time_count now; - struct list_head *head; BUG_ON(clock_idx == CPUCLOCK_SCHED); cpu_timer_sample_group(clock_idx, tsk, &now); if (oldval) { + /* + * We are setting itimer. The *oldval is absolute and we update + * it to be relative, *newval argument is relative and we update + * it to be absolute. + */ if (!cputime_eq(*oldval, cputime_zero)) { if (cputime_le(*oldval, now.cpu)) { /* Just about to fire. */ @@ -1471,33 +1403,21 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx, if (cputime_eq(*newval, cputime_zero)) return; *newval = cputime_add(*newval, now.cpu); - - /* - * If the RLIMIT_CPU timer will expire before the - * ITIMER_PROF timer, we have nothing else to do. - */ - if (tsk->signal->rlim[RLIMIT_CPU].rlim_cur - < cputime_to_secs(*newval)) - return; } /* - * Check whether there are any process timers already set to fire - * before this one. If so, we don't have anything more to do. + * Update expiration cache if we are the earliest timer, or eventually + * RLIMIT_CPU limit is earlier than prof_exp cpu timer expire. */ - head = &tsk->signal->cpu_timers[clock_idx]; - if (list_empty(head) || - cputime_ge(list_first_entry(head, - struct cpu_timer_list, entry)->expires.cpu, - *newval)) { - switch (clock_idx) { - case CPUCLOCK_PROF: + switch (clock_idx) { + case CPUCLOCK_PROF: + if (expires_gt(tsk->signal->cputime_expires.prof_exp, *newval)) tsk->signal->cputime_expires.prof_exp = *newval; - break; - case CPUCLOCK_VIRT: + break; + case CPUCLOCK_VIRT: + if (expires_gt(tsk->signal->cputime_expires.virt_exp, *newval)) tsk->signal->cputime_expires.virt_exp = *newval; - break; - } + break; } }