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| author | Zhen Lei <thunder.leizhen@huawei.com> | 2022-08-04 05:34:19 +0300 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2022-08-31 15:03:14 +0300 |
| commit | e73dfe30930b75c98746152e7a2f6a8ab6067b51 (patch) | |
| tree | eeee08b2da9d7dbb6cf0272012393eefb368dec2 | |
| parent | d8f3f5834febb74d18b5b2098f67d9db740f3e30 (diff) | |
| download | linux-e73dfe30930b75c98746152e7a2f6a8ab6067b51.tar.xz | |
sched/debug: Try trigger_single_cpu_backtrace(cpu) in dump_cpu_task()
The trigger_all_cpu_backtrace() function attempts to send an NMI to the
target CPU, which usually provides much better stack traces than the
dump_cpu_task() function's approach of dumping that stack from some other
CPU. So much so that most calls to dump_cpu_task() only happen after
a call to trigger_all_cpu_backtrace() has failed. And the exception to
this rule really should attempt to use trigger_all_cpu_backtrace() first.
Therefore, move the trigger_all_cpu_backtrace() invocation into
dump_cpu_task().
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Ben Segall <bsegall@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: Valentin Schneider <vschneid@redhat.com>
| -rw-r--r-- | kernel/rcu/tree_stall.h | 5 | ||||
| -rw-r--r-- | kernel/sched/core.c | 3 | ||||
| -rw-r--r-- | kernel/smp.c | 3 |
3 files changed, 6 insertions, 5 deletions
diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index c3fbbcc09327..5653560573e2 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -368,7 +368,7 @@ static void rcu_dump_cpu_stacks(void) if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu)) { if (cpu_is_offline(cpu)) pr_err("Offline CPU %d blocking current GP.\n", cpu); - else if (!trigger_single_cpu_backtrace(cpu)) + else dump_cpu_task(cpu); } raw_spin_unlock_irqrestore_rcu_node(rnp, flags); @@ -511,8 +511,7 @@ static void rcu_check_gp_kthread_starvation(void) 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"); - if (!trigger_single_cpu_backtrace(cpu)) - dump_cpu_task(cpu); + dump_cpu_task(cpu); } } wake_up_process(gpk); diff --git a/kernel/sched/core.c b/kernel/sched/core.c index ee28253c9ac0..e15b6a7f34f4 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -11183,6 +11183,9 @@ struct cgroup_subsys cpu_cgrp_subsys = { void dump_cpu_task(int cpu) { + if (trigger_single_cpu_backtrace(cpu)) + return; + pr_info("Task dump for CPU %d:\n", cpu); sched_show_task(cpu_curr(cpu)); } diff --git a/kernel/smp.c b/kernel/smp.c index 650810a6f29b..e8cdc025a046 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -370,8 +370,7 @@ static bool csd_lock_wait_toolong(struct __call_single_data *csd, u64 ts0, u64 * if (cpu >= 0) { if (static_branch_unlikely(&csdlock_debug_extended)) csd_lock_print_extended(csd, cpu); - if (!trigger_single_cpu_backtrace(cpu)) - dump_cpu_task(cpu); + dump_cpu_task(cpu); if (!cpu_cur_csd) { pr_alert("csd: Re-sending CSD lock (#%d) IPI from CPU#%02d to CPU#%02d\n", *bug_id, raw_smp_processor_id(), cpu); arch_send_call_function_single_ipi(cpu); |