static inline void task_group_account_field(struct task_struct *p, int index,
u64 tmp)
{
-#ifdef CONFIG_CGROUP_CPUACCT
- struct kernel_cpustat *kcpustat;
- struct cpuacct *ca;
-#endif
/*
* Since all updates are sure to touch the root cgroup, we
* get ourselves ahead and touch it first. If the root cgroup
*/
__get_cpu_var(kernel_cpustat).cpustat[index] += tmp;
-#ifdef CONFIG_CGROUP_CPUACCT
- if (unlikely(!cpuacct_subsys.active))
- return;
-
- rcu_read_lock();
- ca = task_ca(p);
- while (ca && (ca != &root_cpuacct)) {
- kcpustat = this_cpu_ptr(ca->cpustat);
- kcpustat->cpustat[index] += tmp;
- ca = parent_ca(ca);
- }
- rcu_read_unlock();
-#endif
+ cpuacct_account_field(p, index, tmp);
}
/*
struct rq *rq) {}
#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
-#ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
+/*
+ * Use precise platform statistics if available:
+ */
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+
+#ifndef __ARCH_HAS_VTIME_TASK_SWITCH
+void vtime_task_switch(struct task_struct *prev)
+{
+ if (!vtime_accounting_enabled())
+ return;
+
+ if (is_idle_task(prev))
+ vtime_account_idle(prev);
+ else
+ vtime_account_system(prev);
+
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
+ vtime_account_user(prev);
+#endif
+ arch_vtime_task_switch(prev);
+}
+#endif
+
+/*
+ * Archs that account the whole time spent in the idle task
+ * (outside irq) as idle time can rely on this and just implement
+ * vtime_account_system() and vtime_account_idle(). Archs that
+ * have other meaning of the idle time (s390 only includes the
+ * time spent by the CPU when it's in low power mode) must override
+ * vtime_account().
+ */
+#ifndef __ARCH_HAS_VTIME_ACCOUNT
+void vtime_account_irq_enter(struct task_struct *tsk)
+{
+ if (!vtime_accounting_enabled())
+ return;
+
+ if (!in_interrupt()) {
+ /*
+ * If we interrupted user, context_tracking_in_user()
+ * is 1 because the context tracking don't hook
+ * on irq entry/exit. This way we know if
+ * we need to flush user time on kernel entry.
+ */
+ if (context_tracking_in_user()) {
+ vtime_account_user(tsk);
+ return;
+ }
+
+ if (is_idle_task(tsk)) {
+ vtime_account_idle(tsk);
+ return;
+ }
+ }
+ vtime_account_system(tsk);
+}
+EXPORT_SYMBOL_GPL(vtime_account_irq_enter);
+#endif /* __ARCH_HAS_VTIME_ACCOUNT */
+#endif /* CONFIG_VIRT_CPU_ACCOUNTING */
+
+
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
+void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
+{
+ *ut = p->utime;
+ *st = p->stime;
+}
+
+void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
+{
+ struct task_cputime cputime;
+
+ thread_group_cputime(p, &cputime);
+
+ *ut = cputime.utime;
+ *st = cputime.stime;
+}
+#else /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
/*
* Account a single tick of cpu time.
* @p: the process that the cpu time gets accounted to
account_idle_time(jiffies_to_cputime(ticks));
}
-#endif /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
-
-/*
- * Use precise platform statistics if available:
- */
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
-void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
-{
- *ut = p->utime;
- *st = p->stime;
-}
-
-void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
-{
- struct task_cputime cputime;
-
- thread_group_cputime(p, &cputime);
-
- *ut = cputime.utime;
- *st = cputime.stime;
-}
-
-#ifndef __ARCH_HAS_VTIME_TASK_SWITCH
-void vtime_task_switch(struct task_struct *prev)
-{
- if (!vtime_accounting_enabled())
- return;
-
- if (is_idle_task(prev))
- vtime_account_idle(prev);
- else
- vtime_account_system(prev);
-
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
- vtime_account_user(prev);
-#endif
- arch_vtime_task_switch(prev);
-}
-#endif
/*
- * Archs that account the whole time spent in the idle task
- * (outside irq) as idle time can rely on this and just implement
- * vtime_account_system() and vtime_account_idle(). Archs that
- * have other meaning of the idle time (s390 only includes the
- * time spent by the CPU when it's in low power mode) must override
- * vtime_account().
+ * Perform (stime * rtime) / total, but avoid multiplication overflow by
+ * loosing precision when the numbers are big.
*/
-#ifndef __ARCH_HAS_VTIME_ACCOUNT
-void vtime_account_irq_enter(struct task_struct *tsk)
+static cputime_t scale_stime(u64 stime, u64 rtime, u64 total)
{
- if (!vtime_accounting_enabled())
- return;
+ u64 scaled;
- if (!in_interrupt()) {
- /*
- * If we interrupted user, context_tracking_in_user()
- * is 1 because the context tracking don't hook
- * on irq entry/exit. This way we know if
- * we need to flush user time on kernel entry.
- */
- if (context_tracking_in_user()) {
- vtime_account_user(tsk);
- return;
+ for (;;) {
+ /* Make sure "rtime" is the bigger of stime/rtime */
+ if (stime > rtime) {
+ u64 tmp = rtime; rtime = stime; stime = tmp;
}
- if (is_idle_task(tsk)) {
- vtime_account_idle(tsk);
- return;
- }
- }
- vtime_account_system(tsk);
-}
-EXPORT_SYMBOL_GPL(vtime_account_irq_enter);
-#endif /* __ARCH_HAS_VTIME_ACCOUNT */
+ /* Make sure 'total' fits in 32 bits */
+ if (total >> 32)
+ goto drop_precision;
-#else /* !CONFIG_VIRT_CPU_ACCOUNTING */
+ /* Does rtime (and thus stime) fit in 32 bits? */
+ if (!(rtime >> 32))
+ break;
-static cputime_t scale_stime(cputime_t stime, cputime_t rtime, cputime_t total)
-{
- u64 temp = (__force u64) rtime;
+ /* Can we just balance rtime/stime rather than dropping bits? */
+ if (stime >> 31)
+ goto drop_precision;
- temp *= (__force u64) stime;
+ /* We can grow stime and shrink rtime and try to make them both fit */
+ stime <<= 1;
+ rtime >>= 1;
+ continue;
- if (sizeof(cputime_t) == 4)
- temp = div_u64(temp, (__force u32) total);
- else
- temp = div64_u64(temp, (__force u64) total);
+drop_precision:
+ /* We drop from rtime, it has more bits than stime */
+ rtime >>= 1;
+ total >>= 1;
+ }
- return (__force cputime_t) temp;
+ /*
+ * Make sure gcc understands that this is a 32x32->64 multiply,
+ * followed by a 64/32->64 divide.
+ */
+ scaled = div_u64((u64) (u32) stime * (u64) (u32) rtime, (u32)total);
+ return (__force cputime_t) scaled;
}
/*
struct cputime *prev,
cputime_t *ut, cputime_t *st)
{
- cputime_t rtime, stime, total;
+ cputime_t rtime, stime, utime, total;
+
+ if (vtime_accounting_enabled()) {
+ *ut = curr->utime;
+ *st = curr->stime;
+ return;
+ }
stime = curr->stime;
total = stime + curr->utime;
*/
rtime = nsecs_to_cputime(curr->sum_exec_runtime);
- if (total)
- stime = scale_stime(stime, rtime, total);
- else
+ /*
+ * Update userspace visible utime/stime values only if actual execution
+ * time is bigger than already exported. Note that can happen, that we
+ * provided bigger values due to scaling inaccuracy on big numbers.
+ */
+ if (prev->stime + prev->utime >= rtime)
+ goto out;
+
+ if (total) {
+ stime = scale_stime((__force u64)stime,
+ (__force u64)rtime, (__force u64)total);
+ utime = rtime - stime;
+ } else {
stime = rtime;
+ utime = 0;
+ }
/*
* If the tick based count grows faster than the scheduler one,
* Let's enforce monotonicity.
*/
prev->stime = max(prev->stime, stime);
- prev->utime = max(prev->utime, rtime - prev->stime);
+ prev->utime = max(prev->utime, utime);
+out:
*ut = prev->utime;
*st = prev->stime;
}
thread_group_cputime(p, &cputime);
cputime_adjust(&cputime, &p->signal->prev_cputime, ut, st);
}
-#endif /* !CONFIG_VIRT_CPU_ACCOUNTING */
+#endif /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
static unsigned long long vtime_delta(struct task_struct *tsk)
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