[RFC PATCH 03/11] time,nohz: add cpu parameter to irqtime_account_process_tick

[riel@redhat.com]

From: Rik van Riel <riel@redhat.com>

Add a cpu parameter to irqtime_account_process_tick, to specify what
cpu to run the statistics for.

In order for this to actually work on a different cpu, all the functions
called by irqtime_account_process_tick need to be able to handle workng
for another CPU.

Signed-off-by: Rik van Riel <riel@redhat.com>
---
 kernel/sched/cputime.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 84b2d24a2238..7df761cd6dfc 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -336,12 +336,14 @@ void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
  * 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,
+static void irqtime_account_process_tick(struct task_struct *p, int cpu,
+					 int user_tick,
 					 struct rq *rq, int ticks)
 {
 	cputime_t scaled = cputime_to_scaled(cputime_one_jiffy);
+	struct kernel_cpustat *kstat = &kcpustat_cpu(cpu);
 	u64 cputime = (__force u64) cputime_one_jiffy;
-	u64 *cpustat = kcpustat_this_cpu->cpustat;
+	u64 *cpustat = kstat->cpustat;
 
 	if (steal_account_process_tick())
 		return;
@@ -374,12 +376,14 @@ static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
 static void irqtime_account_idle_ticks(int ticks)
 {
 	struct rq *rq = this_rq();
+	int cpu = smp_processor_id();
 
-	irqtime_account_process_tick(current, 0, rq, ticks);
+	irqtime_account_process_tick(current, cpu, 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,
+static inline void irqtime_account_process_tick(struct task_struct *p, int cpu,
+						int user_tick,
 						struct rq *rq, int nr_ticks) {}
 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
 
@@ -475,7 +479,7 @@ void account_process_tick(struct task_struct *p, int user_tick)
 		return;
 
 	if (sched_clock_irqtime) {
-		irqtime_account_process_tick(p, user_tick, rq, 1);
+		irqtime_account_process_tick(p, cpu, user_tick, rq, 1);
 		return;
 	}
 
-- 
2.1.0