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| author | Ryo Takakura <takakura@valinux.co.jp> | 2024-06-28 06:18:26 +0200 |
|---|---|---|
| committer | Neeraj Upadhyay <neeraj.upadhyay@kernel.org> | 2024-08-14 20:40:50 +0200 |
| commit | 51b739990cc81316768b85db519eac3999ba92a9 (patch) | |
| tree | 7c23bbaf926a049a908d023da48d539590b710b0 | |
| parent | rcu: Summarize expedited RCU CPU stall warnings during CSD-lock stalls (diff) | |
| download | linux-51b739990cc81316768b85db519eac3999ba92a9.tar.xz linux-51b739990cc81316768b85db519eac3999ba92a9.zip | |
rcu: Let dump_cpu_task() be used without preemption disabled
The commit 2d7f00b2f0130 ("rcu: Suppress smp_processor_id() complaint
in synchronize_rcu_expedited_wait()") disabled preemption around
dump_cpu_task() to suppress warning on its usage within preemtible context.
Calling dump_cpu_task() doesn't required to be in non-preemptible context
except for suppressing the smp_processor_id() warning.
As the smp_processor_id() is evaluated along with in_hardirq()
to check if it's in interrupt context, this patch removes the need
for its preemtion disablement by reordering the condition so that
smp_processor_id() only gets evaluated when it's in interrupt context.
Signed-off-by: Ryo Takakura <takakura@valinux.co.jp>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
| -rw-r--r-- | kernel/rcu/tree_exp.h | 2 | ||||
| -rw-r--r-- | kernel/sched/core.c | 2 |
2 files changed, 1 insertions, 3 deletions
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h index d4be644afb50..c5d9a7eb0803 100644 --- a/kernel/rcu/tree_exp.h +++ b/kernel/rcu/tree_exp.h @@ -597,9 +597,7 @@ static void synchronize_rcu_expedited_stall(unsigned long jiffies_start, unsigne mask = leaf_node_cpu_bit(rnp, cpu); if (!(READ_ONCE(rnp->expmask) & mask)) continue; - preempt_disable(); // For smp_processor_id() in dump_cpu_task(). dump_cpu_task(cpu); - preempt_enable(); } rcu_exp_print_detail_task_stall_rnp(rnp); } diff --git a/kernel/sched/core.c b/kernel/sched/core.c index a9f655025607..78ae888a1fa2 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -9726,7 +9726,7 @@ struct cgroup_subsys cpu_cgrp_subsys = { void dump_cpu_task(int cpu) { - if (cpu == smp_processor_id() && in_hardirq()) { + if (in_hardirq() && cpu == smp_processor_id()) { struct pt_regs *regs; regs = get_irq_regs(); |