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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#include <linux/sched.h>#include <linux/sched/task.h>#include <linux/sched/cputime.h>#include <linux/sched/clock.h>#include <linux/slab.h>#include <linux/taskstats.h>#include <linux/sysctl.h>#include <linux/delayacct.h>#include <linux/module.h>
#define UPDATE_DELAY(type) \do { \ d->type##_delay_max = tsk->delays->type##_delay_max; \ d->type##_delay_min = tsk->delays->type##_delay_min; \ d->type##_delay_max_ts.tv_sec = tsk->delays->type##_delay_max_ts.tv_sec; \ d->type##_delay_max_ts.tv_nsec = tsk->delays->type##_delay_max_ts.tv_nsec; \ tmp = d->type##_delay_total + tsk->delays->type##_delay; \ d->type##_delay_total = (tmp < d->type##_delay_total) ? 0 : tmp; \ d->type##_count += tsk->delays->type##_count; \} while (0)
DEFINE_STATIC_KEY_FALSE(delayacct_key);int delayacct_on __read_mostly; /* Delay accounting turned on/off */struct kmem_cache *delayacct_cache;
static void set_delayacct(bool enabled){ if (enabled) { static_branch_enable(&delayacct_key); delayacct_on = 1; } else { delayacct_on = 0; static_branch_disable(&delayacct_key); }}
static int __init delayacct_setup_enable(char *str){ delayacct_on = 1; return 1;}__setup("delayacct", delayacct_setup_enable);
void delayacct_init(void){ delayacct_cache = KMEM_CACHE(task_delay_info, SLAB_PANIC|SLAB_ACCOUNT); delayacct_tsk_init(&init_task); set_delayacct(delayacct_on);}
#ifdef CONFIG_PROC_SYSCTLstatic int sysctl_delayacct(const struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos){ int state = delayacct_on; struct ctl_table t; int err;
if (write && !capable(CAP_SYS_ADMIN)) return -EPERM;
t = *table; t.data = &state; err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos); if (err < 0) return err; if (write) set_delayacct(state); return err;}
static const struct ctl_table kern_delayacct_table[] = { { .procname = "task_delayacct", .data = NULL, .maxlen = sizeof(unsigned int), .mode = 0644, .proc_handler = sysctl_delayacct, .extra1 = SYSCTL_ZERO, .extra2 = SYSCTL_ONE, },};
static __init int kernel_delayacct_sysctls_init(void){ register_sysctl_init("kernel", kern_delayacct_table); return 0;}late_initcall(kernel_delayacct_sysctls_init);#endif
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), * accumulator (@total) and @count */static void delayacct_end(raw_spinlock_t *lock, u64 *start, u64 *total, u32 *count, u64 *max, u64 *min, struct timespec64 *ts){ s64 ns = local_clock() - *start; unsigned long flags;
if (ns > 0) { raw_spin_lock_irqsave(lock, flags); *total += ns; (*count)++; if (ns > *max) { *max = ns; ktime_get_real_ts64(ts); } if (*min == 0 || ns < *min) *min = ns; raw_spin_unlock_irqrestore(lock, flags); }}
void __delayacct_blkio_start(void){ current->delays->blkio_start = local_clock();}
/* * 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){ delayacct_end(&p->delays->lock, &p->delays->blkio_start, &p->delays->blkio_delay, &p->delays->blkio_count, &p->delays->blkio_delay_max, &p->delays->blkio_delay_min, &p->delays->blkio_delay_max_ts);}
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;
d->cpu_delay_max = tsk->sched_info.max_run_delay; d->cpu_delay_min = tsk->sched_info.min_run_delay; d->cpu_delay_max_ts.tv_sec = tsk->sched_info.max_run_delay_ts.tv_sec; d->cpu_delay_max_ts.tv_nsec = tsk->sched_info.max_run_delay_ts.tv_nsec; 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;
if (!tsk->delays) return 0;
/* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */ raw_spin_lock_irqsave(&tsk->delays->lock, flags); UPDATE_DELAY(blkio); UPDATE_DELAY(swapin); UPDATE_DELAY(freepages); UPDATE_DELAY(thrashing); UPDATE_DELAY(compact); UPDATE_DELAY(wpcopy); UPDATE_DELAY(irq); 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); raw_spin_unlock_irqrestore(&tsk->delays->lock, flags); return ret;}
void __delayacct_freepages_start(void){ current->delays->freepages_start = local_clock();}
void __delayacct_freepages_end(void){ delayacct_end(¤t->delays->lock, ¤t->delays->freepages_start, ¤t->delays->freepages_delay, ¤t->delays->freepages_count, ¤t->delays->freepages_delay_max, ¤t->delays->freepages_delay_min, ¤t->delays->freepages_delay_max_ts);}
void __delayacct_thrashing_start(bool *in_thrashing){ *in_thrashing = !!current->in_thrashing; if (*in_thrashing) return;
current->in_thrashing = 1; current->delays->thrashing_start = local_clock();}
void __delayacct_thrashing_end(bool *in_thrashing){ if (*in_thrashing) return;
current->in_thrashing = 0; delayacct_end(¤t->delays->lock, ¤t->delays->thrashing_start, ¤t->delays->thrashing_delay, ¤t->delays->thrashing_count, ¤t->delays->thrashing_delay_max, ¤t->delays->thrashing_delay_min, ¤t->delays->thrashing_delay_max_ts);}
void __delayacct_swapin_start(void){ current->delays->swapin_start = local_clock();}
void __delayacct_swapin_end(void){ delayacct_end(¤t->delays->lock, ¤t->delays->swapin_start, ¤t->delays->swapin_delay, ¤t->delays->swapin_count, ¤t->delays->swapin_delay_max, ¤t->delays->swapin_delay_min, ¤t->delays->swapin_delay_max_ts);}
void __delayacct_compact_start(void){ current->delays->compact_start = local_clock();}
void __delayacct_compact_end(void){ delayacct_end(¤t->delays->lock, ¤t->delays->compact_start, ¤t->delays->compact_delay, ¤t->delays->compact_count, ¤t->delays->compact_delay_max, ¤t->delays->compact_delay_min, ¤t->delays->compact_delay_max_ts);}
void __delayacct_wpcopy_start(void){ current->delays->wpcopy_start = local_clock();}
void __delayacct_wpcopy_end(void){ delayacct_end(¤t->delays->lock, ¤t->delays->wpcopy_start, ¤t->delays->wpcopy_delay, ¤t->delays->wpcopy_count, ¤t->delays->wpcopy_delay_max, ¤t->delays->wpcopy_delay_min, ¤t->delays->wpcopy_delay_max_ts);}
void __delayacct_irq(struct task_struct *task, u32 delta){ unsigned long flags;
raw_spin_lock_irqsave(&task->delays->lock, flags); task->delays->irq_delay += delta; task->delays->irq_count++; if (delta > task->delays->irq_delay_max) { task->delays->irq_delay_max = delta; ktime_get_real_ts64(&task->delays->irq_delay_max_ts); } if (delta && (!task->delays->irq_delay_min || delta < task->delays->irq_delay_min)) task->delays->irq_delay_min = delta; raw_spin_unlock_irqrestore(&task->delays->lock, flags);}