[tip: timers/core] posix-cpu-timers: Provide array based sample functions

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the timers/core branch of tip:

Commit-ID:     b0d524f77956eec887b30732af1f5f98cbf62b9f
Gitweb:        https://git.kernel.org/tip/b0d524f77956eec887b30732af1f5f98cbf62b9f
Author:        Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate:    Wed, 21 Aug 2019 21:09:12 +02:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Wed, 28 Aug 2019 11:50:38 +02:00

posix-cpu-timers: Provide array based sample functions

Instead of using task_cputime and doing the addition of utime and stime at
all call sites, it's way simpler to have a sample array which allows
indexed based checks against the expiry cache array.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20190821192921.590362974@xxxxxxxxxxxxx

---
 kernel/time/posix-cpu-timers.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index 220e3c7..11c841c 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -202,6 +202,32 @@ static u64 cpu_clock_sample(const clockid_t clkid, struct task_struct *p)
 	return 0;
 }
 
+static inline void store_samples(u64 *samples, u64 stime, u64 utime, u64 rtime)
+{
+	samples[CPUCLOCK_PROF] = stime + utime;
+	samples[CPUCLOCK_VIRT] = utime;
+	samples[CPUCLOCK_SCHED] = rtime;
+}
+
+static void task_sample_cputime(struct task_struct *p, u64 *samples)
+{
+	u64 stime, utime;
+
+	task_cputime(p, &utime, &stime);
+	store_samples(samples, stime, utime, p->se.sum_exec_runtime);
+}
+
+static void proc_sample_cputime_atomic(struct task_cputime_atomic *at,
+				       u64 *samples)
+{
+	u64 stime, utime, rtime;
+
+	utime = atomic64_read(&at->utime);
+	stime = atomic64_read(&at->stime);
+	rtime = atomic64_read(&at->sum_exec_runtime);
+	store_samples(samples, stime, utime, rtime);
+}
+
 /*
  * Set cputime to sum_cputime if sum_cputime > cputime. Use cmpxchg
  * to avoid race conditions with concurrent updates to cputime.