[tip: timers/core] posix-cpu-timers: Sample directly in timer check

[tip-bot2 for Thomas Gleixner]

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

Commit-ID:     a324956fae05d863386c682830e917f6685f1d4f
Gitweb:        https://git.kernel.org/tip/a324956fae05d863386c682830e917f6685f1d4f
Author:        Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate:    Wed, 21 Aug 2019 21:08:53 +02:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Wed, 28 Aug 2019 11:50:27 +02:00

posix-cpu-timers: Sample directly in timer check

The thread group accounting is active, otherwise the expiry function would
not be running. Sample the thread group time directly.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20190821192919.780348088@xxxxxxxxxxxxx

---
 kernel/time/posix-cpu-timers.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index c22b6b6..cb73678 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -914,16 +914,17 @@ static void check_process_timers(struct task_struct *tsk,
 	if (!READ_ONCE(tsk->signal->cputimer.running))
 		return;
 
-        /*
+       /*
 	 * Signify that a thread is checking for process timers.
 	 * Write access to this field is protected by the sighand lock.
 	 */
 	sig->cputimer.checking_timer = true;
 
 	/*
-	 * Collect the current process totals.
+	 * Collect the current process totals. Group accounting is active
+	 * so the sample can be taken directly.
 	 */
-	thread_group_cputimer(tsk, &cputime);
+	sample_cputime_atomic(&cputime, &sig->cputimer.cputime_atomic);
 	utime = cputime.utime;
 	ptime = utime + cputime.stime;
 	sum_sched_runtime = cputime.sum_exec_runtime;