diff options
Diffstat (limited to 'kernel/delayacct.c')
| -rw-r--r-- | kernel/delayacct.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/kernel/delayacct.c b/kernel/delayacct.c new file mode 100644 index 000000000..27725754a --- /dev/null +++ b/kernel/delayacct.c @@ -0,0 +1,177 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* delayacct.c - per-task delay accounting + * + * Copyright (C) Shailabh Nagar, IBM Corp. 2006 + */ + +#include <linux/sched.h> +#include <linux/sched/task.h> +#include <linux/sched/cputime.h> +#include <linux/slab.h> +#include <linux/taskstats.h> +#include <linux/time.h> +#include <linux/sysctl.h> +#include <linux/delayacct.h> +#include <linux/module.h> + +int delayacct_on __read_mostly = 1; /* Delay accounting turned on/off */ +EXPORT_SYMBOL_GPL(delayacct_on); +struct kmem_cache *delayacct_cache; + +static int __init delayacct_setup_disable(char *str) +{ + delayacct_on = 0; + return 1; +} +__setup("nodelayacct", delayacct_setup_disable); + +void delayacct_init(void) +{ + delayacct_cache = KMEM_CACHE(task_delay_info, SLAB_PANIC|SLAB_ACCOUNT); + delayacct_tsk_init(&init_task); +} + +void __delayacct_tsk_init(struct task_struct *tsk) +{ + tsk->delays = kmem_cache_zalloc(delayacct_cache, GFP_KERNEL); + if (tsk->delays) + raw_spin_lock_init(&tsk->delays->lock); +} + +/* + * Finish delay accounting for a statistic using its timestamps (@start), + * accumalator (@total) and @count + */ +static void delayacct_end(raw_spinlock_t *lock, u64 *start, u64 *total, + u32 *count) +{ + s64 ns = ktime_get_ns() - *start; + unsigned long flags; + + if (ns > 0) { + raw_spin_lock_irqsave(lock, flags); + *total += ns; + (*count)++; + raw_spin_unlock_irqrestore(lock, flags); + } +} + +void __delayacct_blkio_start(void) +{ + current->delays->blkio_start = ktime_get_ns(); +} + +/* + * We cannot rely on the `current` macro, as we haven't yet switched back to + * the process being woken. + */ +void __delayacct_blkio_end(struct task_struct *p) +{ + struct task_delay_info *delays = p->delays; + u64 *total; + u32 *count; + + if (p->delays->flags & DELAYACCT_PF_SWAPIN) { + total = &delays->swapin_delay; + count = &delays->swapin_count; + } else { + total = &delays->blkio_delay; + count = &delays->blkio_count; + } + + delayacct_end(&delays->lock, &delays->blkio_start, total, count); +} + +int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk) +{ + u64 utime, stime, stimescaled, utimescaled; + unsigned long long t2, t3; + unsigned long flags, t1; + s64 tmp; + + task_cputime(tsk, &utime, &stime); + tmp = (s64)d->cpu_run_real_total; + tmp += utime + stime; + d->cpu_run_real_total = (tmp < (s64)d->cpu_run_real_total) ? 0 : tmp; + + task_cputime_scaled(tsk, &utimescaled, &stimescaled); + tmp = (s64)d->cpu_scaled_run_real_total; + tmp += utimescaled + stimescaled; + d->cpu_scaled_run_real_total = + (tmp < (s64)d->cpu_scaled_run_real_total) ? 0 : tmp; + + /* + * No locking available for sched_info (and too expensive to add one) + * Mitigate by taking snapshot of values + */ + t1 = tsk->sched_info.pcount; + t2 = tsk->sched_info.run_delay; + t3 = tsk->se.sum_exec_runtime; + + d->cpu_count += t1; + + tmp = (s64)d->cpu_delay_total + t2; + d->cpu_delay_total = (tmp < (s64)d->cpu_delay_total) ? 0 : tmp; + + tmp = (s64)d->cpu_run_virtual_total + t3; + d->cpu_run_virtual_total = + (tmp < (s64)d->cpu_run_virtual_total) ? 0 : tmp; + + /* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */ + + raw_spin_lock_irqsave(&tsk->delays->lock, flags); + tmp = d->blkio_delay_total + tsk->delays->blkio_delay; + d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp; + tmp = d->swapin_delay_total + tsk->delays->swapin_delay; + d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp; + tmp = d->freepages_delay_total + tsk->delays->freepages_delay; + d->freepages_delay_total = (tmp < d->freepages_delay_total) ? 0 : tmp; + tmp = d->thrashing_delay_total + tsk->delays->thrashing_delay; + d->thrashing_delay_total = (tmp < d->thrashing_delay_total) ? 0 : tmp; + d->blkio_count += tsk->delays->blkio_count; + d->swapin_count += tsk->delays->swapin_count; + d->freepages_count += tsk->delays->freepages_count; + d->thrashing_count += tsk->delays->thrashing_count; + raw_spin_unlock_irqrestore(&tsk->delays->lock, flags); + + return 0; +} + +__u64 __delayacct_blkio_ticks(struct task_struct *tsk) +{ + __u64 ret; + unsigned long flags; + + raw_spin_lock_irqsave(&tsk->delays->lock, flags); + ret = nsec_to_clock_t(tsk->delays->blkio_delay + + tsk->delays->swapin_delay); + raw_spin_unlock_irqrestore(&tsk->delays->lock, flags); + return ret; +} + +void __delayacct_freepages_start(void) +{ + current->delays->freepages_start = ktime_get_ns(); +} + +void __delayacct_freepages_end(void) +{ + delayacct_end( + ¤t->delays->lock, + ¤t->delays->freepages_start, + ¤t->delays->freepages_delay, + ¤t->delays->freepages_count); +} + +void __delayacct_thrashing_start(void) +{ + current->delays->thrashing_start = ktime_get_ns(); +} + +void __delayacct_thrashing_end(void) +{ + delayacct_end(¤t->delays->lock, + ¤t->delays->thrashing_start, + ¤t->delays->thrashing_delay, + ¤t->delays->thrashing_count); +} |