diff options
Diffstat (limited to 'kernel/smp.c')
| -rw-r--r-- | kernel/smp.c | 56 |
1 files changed, 36 insertions, 20 deletions
diff --git a/kernel/smp.c b/kernel/smp.c index ab3e5dad6cfe..8455a53465af 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -27,6 +27,9 @@ #include <linux/jump_label.h> #include <trace/events/ipi.h> +#define CREATE_TRACE_POINTS +#include <trace/events/csd.h> +#undef CREATE_TRACE_POINTS #include "smpboot.h" #include "sched/smp.h" @@ -43,6 +46,8 @@ static DEFINE_PER_CPU_ALIGNED(struct call_function_data, cfd_data); static DEFINE_PER_CPU_SHARED_ALIGNED(struct llist_head, call_single_queue); +static DEFINE_PER_CPU(atomic_t, trigger_backtrace) = ATOMIC_INIT(1); + static void __flush_smp_call_function_queue(bool warn_cpu_offline); int smpcfd_prepare_cpu(unsigned int cpu) @@ -121,6 +126,14 @@ send_call_function_ipi_mask(struct cpumask *mask) arch_send_call_function_ipi_mask(mask); } +static __always_inline void +csd_do_func(smp_call_func_t func, void *info, struct __call_single_data *csd) +{ + trace_csd_function_entry(func, csd); + func(info); + trace_csd_function_exit(func, csd); +} + #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG static DEFINE_STATIC_KEY_MAYBE(CONFIG_CSD_LOCK_WAIT_DEBUG_DEFAULT, csdlock_debug_enabled); @@ -242,13 +255,15 @@ static bool csd_lock_wait_toolong(struct __call_single_data *csd, u64 ts0, u64 * *bug_id, !cpu_cur_csd ? "unresponsive" : "handling this request"); } if (cpu >= 0) { - dump_cpu_task(cpu); + if (atomic_cmpxchg_acquire(&per_cpu(trigger_backtrace, cpu), 1, 0)) + 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); } } - dump_stack(); + if (firsttime) + dump_stack(); *ts1 = ts2; return false; @@ -329,7 +344,7 @@ void __smp_call_single_queue(int cpu, struct llist_node *node) * even if we haven't sent the smp_call IPI yet (e.g. the stopper * executes migration_cpu_stop() on the remote CPU). */ - if (trace_ipi_send_cpu_enabled()) { + if (trace_csd_queue_cpu_enabled()) { call_single_data_t *csd; smp_call_func_t func; @@ -337,7 +352,7 @@ void __smp_call_single_queue(int cpu, struct llist_node *node) func = CSD_TYPE(csd) == CSD_TYPE_TTWU ? sched_ttwu_pending : csd->func; - trace_ipi_send_cpu(cpu, _RET_IP_, func); + trace_csd_queue_cpu(cpu, _RET_IP_, func, csd); } /* @@ -375,7 +390,7 @@ static int generic_exec_single(int cpu, struct __call_single_data *csd) csd_lock_record(csd); csd_unlock(csd); local_irq_save(flags); - func(info); + csd_do_func(func, info, NULL); csd_lock_record(NULL); local_irq_restore(flags); return 0; @@ -422,9 +437,14 @@ static void __flush_smp_call_function_queue(bool warn_cpu_offline) struct llist_node *entry, *prev; struct llist_head *head; static bool warned; + atomic_t *tbt; lockdep_assert_irqs_disabled(); + /* Allow waiters to send backtrace NMI from here onwards */ + tbt = this_cpu_ptr(&trigger_backtrace); + atomic_set_release(tbt, 1); + head = this_cpu_ptr(&call_single_queue); entry = llist_del_all(head); entry = llist_reverse_order(entry); @@ -477,7 +497,7 @@ static void __flush_smp_call_function_queue(bool warn_cpu_offline) } csd_lock_record(csd); - func(info); + csd_do_func(func, info, csd); csd_unlock(csd); csd_lock_record(NULL); } else { @@ -508,7 +528,7 @@ static void __flush_smp_call_function_queue(bool warn_cpu_offline) csd_lock_record(csd); csd_unlock(csd); - func(info); + csd_do_func(func, info, csd); csd_lock_record(NULL); } else if (type == CSD_TYPE_IRQ_WORK) { irq_work_single(csd); @@ -522,8 +542,10 @@ static void __flush_smp_call_function_queue(bool warn_cpu_offline) /* * Third; only CSD_TYPE_TTWU is left, issue those. */ - if (entry) - sched_ttwu_pending(entry); + if (entry) { + csd = llist_entry(entry, typeof(*csd), node.llist); + csd_do_func(sched_ttwu_pending, entry, csd); + } } @@ -728,7 +750,7 @@ static void smp_call_function_many_cond(const struct cpumask *mask, int cpu, last_cpu, this_cpu = smp_processor_id(); struct call_function_data *cfd; bool wait = scf_flags & SCF_WAIT; - int nr_cpus = 0, nr_queued = 0; + int nr_cpus = 0; bool run_remote = false; bool run_local = false; @@ -786,22 +808,16 @@ static void smp_call_function_many_cond(const struct cpumask *mask, csd->node.src = smp_processor_id(); csd->node.dst = cpu; #endif + trace_csd_queue_cpu(cpu, _RET_IP_, func, csd); + if (llist_add(&csd->node.llist, &per_cpu(call_single_queue, cpu))) { __cpumask_set_cpu(cpu, cfd->cpumask_ipi); nr_cpus++; last_cpu = cpu; } - nr_queued++; } /* - * Trace each smp_function_call_*() as an IPI, actual IPIs - * will be traced with func==generic_smp_call_function_single_ipi(). - */ - if (nr_queued) - trace_ipi_send_cpumask(cfd->cpumask, _RET_IP_, func); - - /* * Choose the most efficient way to send an IPI. Note that the * number of CPUs might be zero due to concurrent changes to the * provided mask. @@ -816,7 +832,7 @@ static void smp_call_function_many_cond(const struct cpumask *mask, unsigned long flags; local_irq_save(flags); - func(info); + csd_do_func(func, info, NULL); local_irq_restore(flags); } @@ -892,7 +908,7 @@ EXPORT_SYMBOL(setup_max_cpus); * SMP mode to <NUM>. */ -void __weak arch_disable_smp_support(void) { } +void __weak __init arch_disable_smp_support(void) { } static int __init nosmp(char *str) { |