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-rw-r--r--kernel/posix-cpu-timers.c34
1 files changed, 34 insertions, 0 deletions
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index e5d7bfdfa7d4..2313a4cc14ea 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -261,6 +261,40 @@ out:
261 rcu_read_unlock(); 261 rcu_read_unlock();
262} 262}
263 263
264static void update_gt_cputime(struct task_cputime *a, struct task_cputime *b)
265{
266 if (cputime_gt(b->utime, a->utime))
267 a->utime = b->utime;
268
269 if (cputime_gt(b->stime, a->stime))
270 a->stime = b->stime;
271
272 if (b->sum_exec_runtime > a->sum_exec_runtime)
273 a->sum_exec_runtime = b->sum_exec_runtime;
274}
275
276void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
277{
278 struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
279 struct task_cputime sum;
280 unsigned long flags;
281
282 spin_lock_irqsave(&cputimer->lock, flags);
283 if (!cputimer->running) {
284 cputimer->running = 1;
285 /*
286 * The POSIX timer interface allows for absolute time expiry
287 * values through the TIMER_ABSTIME flag, therefore we have
288 * to synchronize the timer to the clock every time we start
289 * it.
290 */
291 thread_group_cputime(tsk, &sum);
292 update_gt_cputime(&cputimer->cputime, &sum);
293 }
294 *times = cputimer->cputime;
295 spin_unlock_irqrestore(&cputimer->lock, flags);
296}
297
264/* 298/*
265 * Sample a process (thread group) clock for the given group_leader task. 299 * Sample a process (thread group) clock for the given group_leader task.
266 * Must be called with tasklist_lock held for reading. 300 * Must be called with tasklist_lock held for reading.