diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2025-10-08 14:30:52 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2025-10-21 12:31:57 +0200 |
| commit | 488f48b32654dc6be04d9cc12f75ce030c9cb21b (patch) | |
| tree | 55cd83c21d8fe197ad358c7455d4ef5b09042b0c | |
| parent | cc39f3872c0865bef992b713338df369554fa9e0 (diff) | |
seqlock: Change thread_group_cputime() to use scoped_seqlock_read()
To simplify the code and make it more readable.
While at it, change thread_group_cputime() to use __for_each_thread(sig).
[peterz: update to new interface]
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
| -rw-r--r-- | kernel/sched/cputime.c | 20 |
1 files changed, 5 insertions, 15 deletions
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c index 7097de2c8cda..4f97896887ec 100644 --- a/kernel/sched/cputime.c +++ b/kernel/sched/cputime.c @@ -313,10 +313,8 @@ static u64 read_sum_exec_runtime(struct task_struct *t) void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times) { struct signal_struct *sig = tsk->signal; - u64 utime, stime; struct task_struct *t; - unsigned int seq, nextseq; - unsigned long flags; + u64 utime, stime; /* * Update current task runtime to account pending time since last @@ -329,27 +327,19 @@ void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times) if (same_thread_group(current, tsk)) (void) task_sched_runtime(current); - rcu_read_lock(); - /* Attempt a lockless read on the first round. */ - nextseq = 0; - do { - seq = nextseq; - flags = read_seqbegin_or_lock_irqsave(&sig->stats_lock, &seq); + guard(rcu)(); + scoped_seqlock_read (&sig->stats_lock, ss_lock_irqsave) { times->utime = sig->utime; times->stime = sig->stime; times->sum_exec_runtime = sig->sum_sched_runtime; - for_each_thread(tsk, t) { + __for_each_thread(sig, t) { task_cputime(t, &utime, &stime); times->utime += utime; times->stime += stime; times->sum_exec_runtime += read_sum_exec_runtime(t); } - /* If lockless access failed, take the lock. */ - nextseq = 1; - } while (need_seqretry(&sig->stats_lock, seq)); - done_seqretry_irqrestore(&sig->stats_lock, seq, flags); - rcu_read_unlock(); + } } #ifdef CONFIG_IRQ_TIME_ACCOUNTING |