The irqtime_account_process_tick path was introduced for precise ns irq
time account from commit abb74cefa9c6 ("sched: Export ns irqtimes
through /proc/stat") while account_process_tick still use jiffes. This
divide isn't necessary especially now both paths are ns precison.
Move out the irqtime_account_process_tick func from IRQ_TIME_ACCOUNTING.
and combine the code for both *account_process_tick funcs for 2 paths.
Then remove the useless irqtime_account_process_tick().
Signed-off-by: Alex Shi <alex....@linux.alibaba.com>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Frederic Weisbecker <fweis...@gmail.com>
Cc: Wanpeng Li <wanpeng...@hotmail.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: linux-kernel@vger.kernel.org
---
kernel/sched/cputime.c | 84 ++++++------------------------------------
1 file changed, 12 insertions(+), 72 deletions(-)
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 3bf94eb7b7c6..3cc581409252 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -332,68 +332,6 @@ void thread_group_cputime(struct task_struct *tsk, struct
task_cputime *times)
rcu_read_unlock();
}
-#ifdef CONFIG_IRQ_TIME_ACCOUNTING
-/*
- * Account a tick to a process and cpustat
- * @p: the process that the CPU time gets accounted to
- * @user_tick: is the tick from userspace
- * @rq: the pointer to rq
- *
- * Tick demultiplexing follows the order
- * - pending hardirq update
- * - pending softirq update
- * - user_time
- * - idle_time
- * - system time
- * - check for guest_time
- * - else account as system_time
- *
- * Check for hardirq is done both for system and user time as there is
- * no timer going off while we are on hardirq and hence we may never get an
- * opportunity to update it solely in system time.
- * p->stime and friends are only updated on system time and not on irq
- * softirq as those do not count in task exec_runtime any more.
- */
-static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
- struct rq *rq, int ticks)
-{
- u64 other, cputime = TICK_NSEC * ticks;
-
- /*
- * When returning from idle, many ticks can get accounted at
- * once, including some ticks of steal, irq, and softirq time.
- * Subtract those ticks from the amount of time accounted to
- * idle, or potentially user or system time. Due to rounding,
- * other time can exceed ticks occasionally.
- */
- other = account_other_time(ULONG_MAX);
- if (other >= cputime)
- return;
-
- cputime -= other;
-
- if (this_cpu_ksoftirqd() == p) {
- /*
- * ksoftirqd time do not get accounted in cpu_softirq_time.
- * So, we have to handle it separately here.
- * Also, p->stime needs to be updated for ksoftirqd.
- */
- account_system_index_time(p, cputime, CPUTIME_SYSTEM);
- } else if (user_tick) {
- account_user_time(p, cputime);
- } else if (p == rq->idle) {
- account_idle_time(cputime);
- } else if (p->flags & PF_VCPU) { /* System time or guest time */
- account_guest_time(p, cputime);
- } else {
- account_system_index_time(p, cputime, CPUTIME_SYSTEM);
- }
-}
-#else /* CONFIG_IRQ_TIME_ACCOUNTING */
-static inline void irqtime_account_process_tick(struct task_struct *p, int
user_tick,
- struct rq *rq, int nr_ticks) { }
-#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
-
/*
* Use precise platform statistics if available:
*/
@@ -466,26 +404,28 @@ void thread_group_cputime_adjusted(struct task_struct *p,
u64 *ut, u64 *st)
*/
void account_process_tick(struct task_struct *p, int user_tick)
{
- u64 cputime, steal;
+ u64 cputime, other;
struct rq *rq = this_rq();
if (vtime_accounting_cpu_enabled())
return;
- if (sched_clock_irqtime) {
- irqtime_account_process_tick(p, user_tick, rq, 1);
- return;
- }
-
cputime = TICK_NSEC;
- steal = steal_account_process_time(ULONG_MAX);
+ other = account_other_time(ULONG_MAX);
- if (steal >= cputime)
+ if (other >= cputime)
return;
- cputime -= steal;
+ cputime -= other;
- if (user_tick)
+ if (this_cpu_ksoftirqd() == p)
+ /*
+ * ksoftirqd time do not get accounted in cpu_softirq_time.
+ * So, we have to handle it separately here.
+ * Also, p->stime needs to be updated for ksoftirqd.
+ */
+ account_system_index_time(p, cputime, CPUTIME_SYSTEM);
+ else if (user_tick)
account_user_time(p, cputime);
else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET))
account_system_time(p, HARDIRQ_OFFSET, cputime);
--
2.19.1.856.g8858448bb
