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@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192919.780348088@linutronix.de

diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index c22b6b604a95e7f00826c4eaa374d28048a40250..cb736787145bb4d315dd6b15babdd26760c5c401 100644 (file)
--- 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;