From 858cf3a8c59968e7c5f7c1a1192459a0d52d1ab4 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Tue, 31 Jan 2017 04:09:35 +0100 Subject: [PATCH] timers/itimer: Convert internal cputime_t units to nsec Use the new nsec based cputime accessors as part of the whole cputime conversion from cputime_t to nsecs. Also convert itimers to use nsec based internal counters. This simplifies it and removes the whole game with error/inc_error which served to deal with cputime_t random granularity. Signed-off-by: Frederic Weisbecker Cc: Benjamin Herrenschmidt Cc: Fenghua Yu Cc: Heiko Carstens Cc: Linus Torvalds Cc: Martin Schwidefsky Cc: Michael Ellerman Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Rik van Riel Cc: Stanislaw Gruszka Cc: Thomas Gleixner Cc: Tony Luck Cc: Wanpeng Li Link: http://lkml.kernel.org/r/1485832191-26889-20-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar --- include/linux/posix-timers.h | 2 +- include/linux/sched.h | 6 ++-- include/trace/events/timer.h | 26 +++++++------- kernel/time/itimer.c | 64 ++++++++++++---------------------- kernel/time/posix-cpu-timers.c | 43 +++++++++-------------- 5 files changed, 55 insertions(+), 86 deletions(-) diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h index 890de52362d0..64aa189efe21 100644 --- a/include/linux/posix-timers.h +++ b/include/linux/posix-timers.h @@ -119,7 +119,7 @@ void run_posix_cpu_timers(struct task_struct *task); void posix_cpu_timers_exit(struct task_struct *task); void posix_cpu_timers_exit_group(struct task_struct *task); void set_process_cpu_timer(struct task_struct *task, unsigned int clock_idx, - cputime_t *newval, cputime_t *oldval); + u64 *newval, u64 *oldval); long clock_nanosleep_restart(struct restart_block *restart_block); diff --git a/include/linux/sched.h b/include/linux/sched.h index baa6a2834e0f..268fdd713089 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -568,10 +568,8 @@ struct pacct_struct { }; struct cpu_itimer { - cputime_t expires; - cputime_t incr; - u32 error; - u32 incr_error; + u64 expires; + u64 incr; }; /** diff --git a/include/trace/events/timer.h b/include/trace/events/timer.h index 1448637616d6..1bca99dbb98f 100644 --- a/include/trace/events/timer.h +++ b/include/trace/events/timer.h @@ -269,17 +269,17 @@ DEFINE_EVENT(hrtimer_class, hrtimer_cancel, TRACE_EVENT(itimer_state, TP_PROTO(int which, const struct itimerval *const value, - cputime_t expires), + unsigned long long expires), TP_ARGS(which, value, expires), TP_STRUCT__entry( - __field( int, which ) - __field( cputime_t, expires ) - __field( long, value_sec ) - __field( long, value_usec ) - __field( long, interval_sec ) - __field( long, interval_usec ) + __field( int, which ) + __field( unsigned long long, expires ) + __field( long, value_sec ) + __field( long, value_usec ) + __field( long, interval_sec ) + __field( long, interval_usec ) ), TP_fast_assign( @@ -292,7 +292,7 @@ TRACE_EVENT(itimer_state, ), TP_printk("which=%d expires=%llu it_value=%ld.%ld it_interval=%ld.%ld", - __entry->which, (unsigned long long)__entry->expires, + __entry->which, __entry->expires, __entry->value_sec, __entry->value_usec, __entry->interval_sec, __entry->interval_usec) ); @@ -305,14 +305,14 @@ TRACE_EVENT(itimer_state, */ TRACE_EVENT(itimer_expire, - TP_PROTO(int which, struct pid *pid, cputime_t now), + TP_PROTO(int which, struct pid *pid, unsigned long long now), TP_ARGS(which, pid, now), TP_STRUCT__entry( - __field( int , which ) - __field( pid_t, pid ) - __field( cputime_t, now ) + __field( int , which ) + __field( pid_t, pid ) + __field( unsigned long long, now ) ), TP_fast_assign( @@ -322,7 +322,7 @@ TRACE_EVENT(itimer_expire, ), TP_printk("which=%d pid=%d now=%llu", __entry->which, - (int) __entry->pid, (unsigned long long)__entry->now) + (int) __entry->pid, __entry->now) ); #ifdef CONFIG_NO_HZ_COMMON diff --git a/kernel/time/itimer.c b/kernel/time/itimer.c index bb01ff445ce9..a95f13c31464 100644 --- a/kernel/time/itimer.c +++ b/kernel/time/itimer.c @@ -45,35 +45,35 @@ static struct timeval itimer_get_remtime(struct hrtimer *timer) static void get_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, struct itimerval *const value) { - cputime_t cval, cinterval; + u64 val, interval; struct cpu_itimer *it = &tsk->signal->it[clock_id]; spin_lock_irq(&tsk->sighand->siglock); - cval = it->expires; - cinterval = it->incr; - if (cval) { + val = it->expires; + interval = it->incr; + if (val) { struct task_cputime cputime; - cputime_t t; + u64 t; thread_group_cputimer(tsk, &cputime); if (clock_id == CPUCLOCK_PROF) - t = nsecs_to_cputime(cputime.utime + cputime.stime); + t = cputime.utime + cputime.stime; else /* CPUCLOCK_VIRT */ - t = nsecs_to_cputime(cputime.utime); + t = cputime.utime; - if (cval < t) + if (val < t) /* about to fire */ - cval = cputime_one_jiffy; + val = TICK_NSEC; else - cval = cval - t; + val -= t; } spin_unlock_irq(&tsk->sighand->siglock); - cputime_to_timeval(cval, &value->it_value); - cputime_to_timeval(cinterval, &value->it_interval); + value->it_value = ns_to_timeval(val); + value->it_interval = ns_to_timeval(interval); } int do_getitimer(int which, struct itimerval *value) @@ -129,55 +129,35 @@ enum hrtimer_restart it_real_fn(struct hrtimer *timer) return HRTIMER_NORESTART; } -static inline u32 cputime_sub_ns(cputime_t ct, s64 real_ns) -{ - struct timespec ts; - s64 cpu_ns; - - cputime_to_timespec(ct, &ts); - cpu_ns = timespec_to_ns(&ts); - - return (cpu_ns <= real_ns) ? 0 : cpu_ns - real_ns; -} - static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, const struct itimerval *const value, struct itimerval *const ovalue) { - cputime_t cval, nval, cinterval, ninterval; - s64 ns_ninterval, ns_nval; - u32 error, incr_error; + u64 oval, nval, ointerval, ninterval; struct cpu_itimer *it = &tsk->signal->it[clock_id]; - nval = timeval_to_cputime(&value->it_value); - ns_nval = timeval_to_ns(&value->it_value); - ninterval = timeval_to_cputime(&value->it_interval); - ns_ninterval = timeval_to_ns(&value->it_interval); - - error = cputime_sub_ns(nval, ns_nval); - incr_error = cputime_sub_ns(ninterval, ns_ninterval); + nval = timeval_to_ns(&value->it_value); + ninterval = timeval_to_ns(&value->it_interval); spin_lock_irq(&tsk->sighand->siglock); - cval = it->expires; - cinterval = it->incr; - if (cval || nval) { + oval = it->expires; + ointerval = it->incr; + if (oval || nval) { if (nval > 0) - nval += cputime_one_jiffy; - set_process_cpu_timer(tsk, clock_id, &nval, &cval); + nval += TICK_NSEC; + set_process_cpu_timer(tsk, clock_id, &nval, &oval); } it->expires = nval; it->incr = ninterval; - it->error = error; - it->incr_error = incr_error; trace_itimer_state(clock_id == CPUCLOCK_VIRT ? ITIMER_VIRTUAL : ITIMER_PROF, value, nval); spin_unlock_irq(&tsk->sighand->siglock); if (ovalue) { - cputime_to_timeval(cval, &ovalue->it_value); - cputime_to_timeval(cinterval, &ovalue->it_interval); + ovalue->it_value = ns_to_timeval(oval); + ovalue->it_interval = ns_to_timeval(ointerval); } } diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c index 45be3cec0dc2..b4377a5e4269 100644 --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -20,10 +20,10 @@ */ void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new) { - cputime_t cputime = secs_to_cputime(rlim_new); + u64 nsecs = rlim_new * NSEC_PER_SEC; spin_lock_irq(&task->sighand->siglock); - set_process_cpu_timer(task, CPUCLOCK_PROF, &cputime, NULL); + set_process_cpu_timer(task, CPUCLOCK_PROF, &nsecs, NULL); spin_unlock_irq(&task->sighand->siglock); } @@ -860,17 +860,11 @@ static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it, if (!it->expires) return; - if (cur_time >= cputime_to_nsecs(it->expires)) { - if (it->incr) { + if (cur_time >= it->expires) { + if (it->incr) it->expires += it->incr; - it->error += it->incr_error; - if (it->error >= TICK_NSEC) { - it->expires -= cputime_one_jiffy; - it->error -= TICK_NSEC; - } - } else { + else it->expires = 0; - } trace_itimer_expire(signo == SIGPROF ? ITIMER_PROF : ITIMER_VIRTUAL, @@ -878,9 +872,8 @@ static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it, __group_send_sig_info(signo, SEND_SIG_PRIV, tsk); } - if (it->expires && (!*expires || cputime_to_nsecs(it->expires) < *expires)) { - *expires = cputime_to_nsecs(it->expires); - } + if (it->expires && (!*expires || it->expires < *expires)) + *expires = it->expires; } /* @@ -1174,9 +1167,9 @@ void run_posix_cpu_timers(struct task_struct *tsk) * The tsk->sighand->siglock must be held by the caller. */ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx, - cputime_t *newval, cputime_t *oldval) + u64 *newval, u64 *oldval) { - u64 now, new; + u64 now; WARN_ON_ONCE(clock_idx == CPUCLOCK_SCHED); cpu_timer_sample_group(clock_idx, tsk, &now); @@ -1188,33 +1181,31 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx, * it to be absolute. */ if (*oldval) { - if (cputime_to_nsecs(*oldval) <= now) { + if (*oldval <= now) { /* Just about to fire. */ - *oldval = cputime_one_jiffy; + *oldval = TICK_NSEC; } else { - *oldval -= nsecs_to_cputime(now); + *oldval -= now; } } if (!*newval) return; - *newval += nsecs_to_cputime(now); + *newval += now; } - new = cputime_to_nsecs(*newval); - /* * Update expiration cache if we are the earliest timer, or eventually * RLIMIT_CPU limit is earlier than prof_exp cpu timer expire. */ switch (clock_idx) { case CPUCLOCK_PROF: - if (expires_gt(tsk->signal->cputime_expires.prof_exp, new)) - tsk->signal->cputime_expires.prof_exp = new; + if (expires_gt(tsk->signal->cputime_expires.prof_exp, *newval)) + tsk->signal->cputime_expires.prof_exp = *newval; break; case CPUCLOCK_VIRT: - if (expires_gt(tsk->signal->cputime_expires.virt_exp, new)) - tsk->signal->cputime_expires.virt_exp = new; + if (expires_gt(tsk->signal->cputime_expires.virt_exp, *newval)) + tsk->signal->cputime_expires.virt_exp = *newval; break; } -- 2.20.1