Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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>
authored by
Oleg Nesterov
and committed by
Peter Zijlstra
488f48b3
cc39f387
+5
-15
+5
-15
kernel/sched/cputime.c
+5
-15
kernel/sched/cputime.c
···
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void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
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{
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struct signal_struct *sig = tsk->signal;
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-
u64 utime, stime;
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struct task_struct *t;
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unsigned int seq, nextseq;
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unsigned long flags;
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+
u64 utime, stime;
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/*
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* Update current task runtime to account pending time since last
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if (same_thread_group(current, tsk))
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(void) task_sched_runtime(current);
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rcu_read_lock();
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/* Attempt a lockless read on the first round. */
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nextseq = 0;
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do {
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seq = nextseq;
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flags = read_seqbegin_or_lock_irqsave(&sig->stats_lock, &seq);
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guard(rcu)();
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scoped_seqlock_read (&sig->stats_lock, ss_lock_irqsave) {
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times->utime = sig->utime;
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times->stime = sig->stime;
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times->sum_exec_runtime = sig->sum_sched_runtime;
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for_each_thread(tsk, t) {
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__for_each_thread(sig, t) {
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task_cputime(t, &utime, &stime);
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times->utime += utime;
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times->stime += stime;
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times->sum_exec_runtime += read_sum_exec_runtime(t);
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}
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/* If lockless access failed, take the lock. */
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nextseq = 1;
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} while (need_seqretry(&sig->stats_lock, seq));
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done_seqretry_irqrestore(&sig->stats_lock, seq, flags);
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rcu_read_unlock();
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}
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}
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#ifdef CONFIG_IRQ_TIME_ACCOUNTING