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| author | Zhen Lei <thunder.leizhen@huawei.com> | 2023-07-12 23:15:56 +0800 |
|---|---|---|
| committer | Frederic Weisbecker <frederic@kernel.org> | 2023-09-11 21:45:29 +0200 |
| commit | b934b7ff5ea755473d9737d79ab303722ceba22e (patch) | |
| tree | d87392f51db884d7231da3cb3ec7f8d78bb58dff | |
| parent | 0bb80ecc33a8fb5a682236443c1e740d5c917d1d (diff) | |
rcu: Delete a redundant check in rcu_check_gp_kthread_starvation()
The rcu_check_gp_kthread_starvation() function uses task_cpu() to sample
the last CPU that the grace-period kthread ran on, and task_cpu() samples
the thread_info structure's ->cpu field. But this field will always
contain a number corresponding to a CPU that was online some time in
the past, thus never a negative number. This invariant is checked by
a WARN_ON_ONCE() in set_task_cpu().
This means that if the grace-period kthread exists, that is, if the "gpk"
local variable is non-NULL, the "cpu" local variable will be non-negative.
This in turn means that the existing check for non-negative "cpu" is
redundant with the enclosing check for non-NULL "gpk".
This commit threefore removes the redundant check of "cpu".
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
| -rw-r--r-- | kernel/rcu/tree_stall.h | 12 |
1 files changed, 5 insertions, 7 deletions
diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index 6f06dc12904a..b5ce0580074e 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -537,13 +537,11 @@ static void rcu_check_gp_kthread_starvation(void) pr_err("\tUnless %s kthread gets sufficient CPU time, OOM is now expected behavior.\n", rcu_state.name); pr_err("RCU grace-period kthread stack dump:\n"); sched_show_task(gpk); - if (cpu >= 0) { - if (cpu_is_offline(cpu)) { - pr_err("RCU GP kthread last ran on offline CPU %d.\n", cpu); - } else { - pr_err("Stack dump where RCU GP kthread last ran:\n"); - dump_cpu_task(cpu); - } + if (cpu_is_offline(cpu)) { + pr_err("RCU GP kthread last ran on offline CPU %d.\n", cpu); + } else { + pr_err("Stack dump where RCU GP kthread last ran:\n"); + dump_cpu_task(cpu); } wake_up_process(gpk); } |