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| author | Paul E. McKenney <paulmck@kernel.org> | 2022-05-24 18:19:17 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2022-06-20 09:22:27 -0700 |
| commit | 5d4c90d755d5703d5a74fac0870c0a697250ec33 (patch) | |
| tree | 3a91502456db2323b46c05f0ebe49a1fa06e38b4 | |
| parent | 897ba84dc5aa7a5518e19da180d2985790723d30 (diff) | |
| download | lwn-5d4c90d755d5703d5a74fac0870c0a697250ec33.tar.gz lwn-5d4c90d755d5703d5a74fac0870c0a697250ec33.zip | |
rcu-tasks: RCU Tasks Trace grace-period kthread has implicit QS
Because the task driving the grace-period kthread is in quiescent state
throughout, this commit excludes it from the list of tasks from which
a quiescent state is needed.
This does mean that attaching a sleepable BPF program to function in
kernel/rcu/tasks.h is a bad idea, by the way.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: KP Singh <kpsingh@kernel.org>
| -rw-r--r-- | kernel/rcu/tasks.h | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index 414861d65196..554b2e59a1d5 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -1433,8 +1433,9 @@ static void rcu_tasks_trace_pertask(struct task_struct *t, struct list_head *hop) { // During early boot when there is only the one boot CPU, there - // is no idle task for the other CPUs. Just return. - if (unlikely(t == NULL)) + // is no idle task for the other CPUs. Also, the grace-period + // kthread is always in a quiescent state. Either way, just return. + if (unlikely(t == NULL) || t == current) return; rcu_st_need_qs(t, 0); |