The following commit has been merged into the timers/core branch of tip: Commit-ID: b7be4ef1365dcb56fdffc6689e41058b23f5996d Gitweb: https://git.kernel.org/tip/b7be4ef1365dcb56fdffc6689e41058b23f5996d Author: Thomas Gleixner <t...@linutronix.de> AuthorDate: Wed, 21 Aug 2019 21:09:16 +02:00 Committer: Thomas Gleixner <t...@linutronix.de> CommitterDate: Wed, 28 Aug 2019 11:50:39 +02:00
posix-cpu-timers: Switch thread group sampling to array That allows more simplifications in various places. Signed-off-by: Thomas Gleixner <t...@linutronix.de> Reviewed-by: Frederic Weisbecker <frede...@kernel.org> Link: https://lkml.kernel.org/r/20190821192921.988426...@linutronix.de --- include/linux/sched/cputime.h | 2 +- kernel/time/itimer.c | 11 +--- kernel/time/posix-cpu-timers.c | 104 +++++++++++++------------------- 3 files changed, 49 insertions(+), 68 deletions(-) diff --git a/include/linux/sched/cputime.h b/include/linux/sched/cputime.h index 2638fd0..eefa5df 100644 --- a/include/linux/sched/cputime.h +++ b/include/linux/sched/cputime.h @@ -61,7 +61,7 @@ extern void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev, * Thread group CPU time accounting. */ void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times); -void thread_group_sample_cputime(struct task_struct *tsk, struct task_cputime *times); +void thread_group_sample_cputime(struct task_struct *tsk, u64 *samples); /* * The following are functions that support scheduler-internal time accounting. diff --git a/kernel/time/itimer.c b/kernel/time/itimer.c index ae04bc2..77f1e56 100644 --- a/kernel/time/itimer.c +++ b/kernel/time/itimer.c @@ -55,15 +55,10 @@ static void get_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, val = it->expires; interval = it->incr; if (val) { - struct task_cputime cputime; - u64 t; + u64 t, samples[CPUCLOCK_MAX]; - thread_group_sample_cputime(tsk, &cputime); - if (clock_id == CPUCLOCK_PROF) - t = cputime.utime + cputime.stime; - else - /* CPUCLOCK_VIRT */ - t = cputime.utime; + thread_group_sample_cputime(tsk, samples); + t = samples[clock_id]; if (val < t) /* about to fire */ diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c index 9ac601a..e62139a 100644 --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -225,22 +225,14 @@ static inline void __update_gt_cputime(atomic64_t *cputime, u64 sum_cputime) } } -static void update_gt_cputime(struct task_cputime_atomic *cputime_atomic, struct task_cputime *sum) +static void update_gt_cputime(struct task_cputime_atomic *cputime_atomic, + struct task_cputime *sum) { __update_gt_cputime(&cputime_atomic->utime, sum->utime); __update_gt_cputime(&cputime_atomic->stime, sum->stime); __update_gt_cputime(&cputime_atomic->sum_exec_runtime, sum->sum_exec_runtime); } -/* Sample task_cputime_atomic values in "atomic_timers", store results in "times". */ -static inline void sample_cputime_atomic(struct task_cputime *times, - struct task_cputime_atomic *atomic_times) -{ - times->utime = atomic64_read(&atomic_times->utime); - times->stime = atomic64_read(&atomic_times->stime); - times->sum_exec_runtime = atomic64_read(&atomic_times->sum_exec_runtime); -} - /** * thread_group_sample_cputime - Sample cputime for a given task * @tsk: Task for which cputime needs to be started @@ -252,20 +244,19 @@ static inline void sample_cputime_atomic(struct task_cputime *times, * * Updates @times with an uptodate sample of the thread group cputimes. */ -void thread_group_sample_cputime(struct task_struct *tsk, - struct task_cputime *times) +void thread_group_sample_cputime(struct task_struct *tsk, u64 *samples) { struct thread_group_cputimer *cputimer = &tsk->signal->cputimer; WARN_ON_ONCE(!cputimer->running); - sample_cputime_atomic(times, &cputimer->cputime_atomic); + proc_sample_cputime_atomic(&cputimer->cputime_atomic, samples); } /** * thread_group_start_cputime - Start cputime and return a sample * @tsk: Task for which cputime needs to be started - * @iimes: Storage for time samples + * @samples: Storage for time samples * * The thread group cputime accouting is avoided when there are no posix * CPU timers armed. Before starting a timer it's required to check whether @@ -274,14 +265,14 @@ void thread_group_sample_cputime(struct task_struct *tsk, * * Updates @times with an uptodate sample of the thread group cputimes. */ -static void -thread_group_start_cputime(struct task_struct *tsk, struct task_cputime *times) +static void thread_group_start_cputime(struct task_struct *tsk, u64 *samples) { struct thread_group_cputimer *cputimer = &tsk->signal->cputimer; - struct task_cputime sum; /* Check if cputimer isn't running. This is accessed without locking. */ if (!READ_ONCE(cputimer->running)) { + struct task_cputime sum; + /* * The POSIX timer interface allows for absolute time expiry * values through the TIMER_ABSTIME flag, therefore we have @@ -299,7 +290,15 @@ thread_group_start_cputime(struct task_struct *tsk, struct task_cputime *times) */ WRITE_ONCE(cputimer->running, true); } - sample_cputime_atomic(times, &cputimer->cputime_atomic); + proc_sample_cputime_atomic(&cputimer->cputime_atomic, samples); +} + +static void __thread_group_cputime(struct task_struct *tsk, u64 *samples) +{ + struct task_cputime ct; + + thread_group_cputime(tsk, &ct); + store_samples(samples, ct.stime, ct.utime, ct.sum_exec_runtime); } /* @@ -313,28 +312,18 @@ static u64 cpu_clock_sample_group(const clockid_t clkid, struct task_struct *p, bool start) { struct thread_group_cputimer *cputimer = &p->signal->cputimer; - struct task_cputime cputime; + u64 samples[CPUCLOCK_MAX]; if (!READ_ONCE(cputimer->running)) { if (start) - thread_group_start_cputime(p, &cputime); + thread_group_start_cputime(p, samples); else - thread_group_cputime(p, &cputime); + __thread_group_cputime(p, samples); } else { - sample_cputime_atomic(&cputime, &cputimer->cputime_atomic); + proc_sample_cputime_atomic(&cputimer->cputime_atomic, samples); } - switch (clkid) { - case CPUCLOCK_PROF: - return cputime.utime + cputime.stime; - case CPUCLOCK_VIRT: - return cputime.utime; - case CPUCLOCK_SCHED: - return cputime.sum_exec_runtime; - default: - WARN_ON_ONCE(1); - } - return 0; + return samples[clkid]; } static int posix_cpu_clock_get(const clockid_t clock, struct timespec64 *tp) @@ -889,9 +878,7 @@ static void check_process_timers(struct task_struct *tsk, { struct signal_struct *const sig = tsk->signal; struct posix_cputimer_base *base = sig->posix_cputimers.bases; - u64 utime, ptime, virt_expires, prof_expires; - u64 sum_sched_runtime, sched_expires; - struct task_cputime cputime; + u64 virt_exp, prof_exp, sched_exp, samples[CPUCLOCK_MAX]; unsigned long soft; /* @@ -911,30 +898,29 @@ static void check_process_timers(struct task_struct *tsk, * Collect the current process totals. Group accounting is active * so the sample can be taken directly. */ - sample_cputime_atomic(&cputime, &sig->cputimer.cputime_atomic); - utime = cputime.utime; - ptime = utime + cputime.stime; - sum_sched_runtime = cputime.sum_exec_runtime; - - prof_expires = check_timers_list(&base[CPUCLOCK_PROF].cpu_timers, - firing, ptime); - virt_expires = check_timers_list(&base[CPUCLOCK_VIRT].cpu_timers, - firing, utime); - sched_expires = check_timers_list(&base[CPUCLOCK_SCHED].cpu_timers, - firing, sum_sched_runtime); + proc_sample_cputime_atomic(&sig->cputimer.cputime_atomic, samples); + + prof_exp = check_timers_list(&base[CPUCLOCK_PROF].cpu_timers, + firing, samples[CPUCLOCK_PROF]); + virt_exp = check_timers_list(&base[CPUCLOCK_VIRT].cpu_timers, + firing, samples[CPUCLOCK_VIRT]); + sched_exp = check_timers_list(&base[CPUCLOCK_SCHED].cpu_timers, + firing, samples[CPUCLOCK_SCHED]); /* * Check for the special case process timers. */ - check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF], &prof_expires, ptime, - SIGPROF); - check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime, - SIGVTALRM); + check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF], &prof_exp, + samples[CPUCLOCK_PROF], SIGPROF); + check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_exp, + samples[CPUCLOCK_PROF], SIGVTALRM); + soft = task_rlimit(tsk, RLIMIT_CPU); if (soft != RLIM_INFINITY) { - unsigned long psecs = div_u64(ptime, NSEC_PER_SEC); + u64 softns, ptime = samples[CPUCLOCK_PROF]; unsigned long hard = task_rlimit_max(tsk, RLIMIT_CPU); - u64 x; + unsigned long psecs = div_u64(ptime, NSEC_PER_SEC); + if (psecs >= hard) { /* * At the hard limit, we just die. @@ -961,14 +947,14 @@ static void check_process_timers(struct task_struct *tsk, sig->rlim[RLIMIT_CPU].rlim_cur = soft; } } - x = soft * NSEC_PER_SEC; - if (!prof_expires || x < prof_expires) - prof_expires = x; + softns = soft * NSEC_PER_SEC; + if (!prof_exp || softns < prof_exp) + prof_exp = softns; } - base[CPUCLOCK_PROF].nextevt = prof_expires; - base[CPUCLOCK_VIRT].nextevt = virt_expires; - base[CPUCLOCK_SCHED].nextevt = sched_expires; + base[CPUCLOCK_PROF].nextevt = prof_exp; + base[CPUCLOCK_VIRT].nextevt = virt_exp; + base[CPUCLOCK_SCHED].nextevt = sched_exp; if (expiry_cache_is_zero(&sig->posix_cputimers)) stop_process_timers(sig);
