linux-kernel - [RFC PATCH 2/3] cputime: unify account_idle

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Message-Id: <20190723060142.145747-2-alex.shi@linux.alibaba.com>
Date:   Tue, 23 Jul 2019 14:01:41 +0800
From:   Alex Shi <alex.shi@...ux.alibaba.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Alex Shi <alex.shi@...ux.alibaba.com>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Frederic Weisbecker <fweisbec@...il.com>,
        Wanpeng Li <wanpeng.li@...mail.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-kernel@...r.kernel.org
Subject: [RFC PATCH 2/3] cputime: unify account_idle_ticks

Check the 'current' task in account_idle_ticks is meaningless. So we
could remove irqtime_account_idle_ticks and unify this function.

Signed-off-by: Alex Shi <alex.shi@...ux.alibaba.com>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Frederic Weisbecker <fweisbec@...il.com>
Cc: Wanpeng Li <wanpeng.li@...mail.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: linux-kernel@...r.kernel.org
---
 kernel/sched/cputime.c | 21 ++++-----------------
 1 file changed, 4 insertions(+), 17 deletions(-)

diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index d78aee140957..3bf94eb7b7c6 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -389,15 +389,7 @@ static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
 		account_system_index_time(p, cputime, CPUTIME_SYSTEM);
 	}
 }
-
-static void irqtime_account_idle_ticks(int ticks)
-{
-	struct rq *rq = this_rq();
-
-	irqtime_account_process_tick(current, 0, rq, ticks);
-}
 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
-static inline void irqtime_account_idle_ticks(int ticks) { }
 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 */
@@ -507,20 +499,15 @@ void account_process_tick(struct task_struct *p, int user_tick)
  */
 void account_idle_ticks(unsigned long ticks)
 {
-	u64 cputime, steal;
-
-	if (sched_clock_irqtime) {
-		irqtime_account_idle_ticks(ticks);
-		return;
-	}
+	u64 cputime, other;
 
 	cputime = ticks * 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;
 	account_idle_time(cputime);
 }
 
-- 
2.19.1.856.g8858448bb