[PATCH 6/6] Account ksoftirqd time as cpustat softirq -v1

[Venkatesh Pallipadi <venki@google.com>]

softirq time in ksoftirqd context is not accounted in ns granularity
per cpu softirq stats, as we want that to be a part of ksoftirqd
exec_runtime.

Accounting them as softirq on /proc/stat separately.

Tested-by: Shaun Ruffell <sruffell@digium.com>

Signed-off-by: Venkatesh Pallipadi <venki@google.com>
---
 kernel/sched.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/kernel/sched.c b/kernel/sched.c
index 49f6f61..0955050 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -3617,6 +3617,14 @@ static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
 		cpustat->irq = cputime64_add(cpustat->irq, tmp);
 	} else if (irqtime_account_si_update()) {
 		cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
+	} else 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_time(p, cputime_one_jiffy, one_jiffy_scaled,
+					&cpustat->softirq);
 	} else if (user_tick) {
 		account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
 	} else if (p == rq->idle) {
-- 
1.7.1