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-rw-r--r--kernel/delayacct.c290
1 files changed, 290 insertions, 0 deletions
diff --git a/kernel/delayacct.c b/kernel/delayacct.c
new file mode 100644
index 0000000000..6f0c358e73
--- /dev/null
+++ b/kernel/delayacct.c
@@ -0,0 +1,290 @@
+// 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/sched/clock.h>
+#include <linux/slab.h>
+#include <linux/taskstats.h>
+#include <linux/sysctl.h>
+#include <linux/delayacct.h>
+#include <linux/module.h>
+
+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_SYSCTL
+static int sysctl_delayacct(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 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),
+ * accumalator (@total) and @count
+ */
+static void delayacct_end(raw_spinlock_t *lock, u64 *start, u64 *total, u32 *count)
+{
+ s64 ns = local_clock() - *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 = 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);
+}
+
+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;
+
+ if (!tsk->delays)
+ return 0;
+
+ /* 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;
+ tmp = d->compact_delay_total + tsk->delays->compact_delay;
+ d->compact_delay_total = (tmp < d->compact_delay_total) ? 0 : tmp;
+ tmp = d->wpcopy_delay_total + tsk->delays->wpcopy_delay;
+ d->wpcopy_delay_total = (tmp < d->wpcopy_delay_total) ? 0 : tmp;
+ tmp = d->irq_delay_total + tsk->delays->irq_delay;
+ d->irq_delay_total = (tmp < d->irq_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;
+ d->compact_count += tsk->delays->compact_count;
+ d->wpcopy_count += tsk->delays->wpcopy_count;
+ d->irq_count += tsk->delays->irq_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);
+ 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(&current->delays->lock,
+ &current->delays->freepages_start,
+ &current->delays->freepages_delay,
+ &current->delays->freepages_count);
+}
+
+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(&current->delays->lock,
+ &current->delays->thrashing_start,
+ &current->delays->thrashing_delay,
+ &current->delays->thrashing_count);
+}
+
+void __delayacct_swapin_start(void)
+{
+ current->delays->swapin_start = local_clock();
+}
+
+void __delayacct_swapin_end(void)
+{
+ delayacct_end(&current->delays->lock,
+ &current->delays->swapin_start,
+ &current->delays->swapin_delay,
+ &current->delays->swapin_count);
+}
+
+void __delayacct_compact_start(void)
+{
+ current->delays->compact_start = local_clock();
+}
+
+void __delayacct_compact_end(void)
+{
+ delayacct_end(&current->delays->lock,
+ &current->delays->compact_start,
+ &current->delays->compact_delay,
+ &current->delays->compact_count);
+}
+
+void __delayacct_wpcopy_start(void)
+{
+ current->delays->wpcopy_start = local_clock();
+}
+
+void __delayacct_wpcopy_end(void)
+{
+ delayacct_end(&current->delays->lock,
+ &current->delays->wpcopy_start,
+ &current->delays->wpcopy_delay,
+ &current->delays->wpcopy_count);
+}
+
+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++;
+ raw_spin_unlock_irqrestore(&task->delays->lock, flags);
+}
+