/* * Workqueue statistical tracer. * * Copyright (C) 2008 Frederic Weisbecker <fweisbec@gmail.com> * */  #include <trace/events/workqueue.h>#include <linux/list.h>#include <linux/percpu.h>#include <linux/slab.h>#include <linux/kref.h>#include "trace_stat.h"#include "trace.h"  /* A cpu workqueue thread */struct cpu_workqueue_stats {	struct list_head            list;	struct kref                 kref;	int		            cpu;	pid_t			    pid;/* Can be inserted from interrupt or user context, need to be atomic */	atomic_t	            inserted;/* *  Don't need to be atomic, works are serialized in a single workqueue thread *  on a single CPU. */	unsigned int		    executed;}; /* List of workqueue threads on one cpu */struct workqueue_global_stats {	struct list_head	list;	spinlock_t		lock;}; /* Don't need a global lock because allocated before the workqueues, and * never freed. */static DEFINE_PER_CPU(struct workqueue_global_stats, all_workqueue_stat);#define workqueue_cpu_stat(cpu) (&per_cpu(all_workqueue_stat, cpu)) static void cpu_workqueue_stat_free(struct kref *kref){	kfree(container_of(kref, struct cpu_workqueue_stats, kref));} /* Insertion of a work */static voidprobe_workqueue_insertion(struct task_struct *wq_thread,			  struct work_struct *work){	int cpu = cpumask_first(&wq_thread->cpus_allowed);	struct cpu_workqueue_stats *node;	unsigned long flags; 	spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);	list_for_each_entry(node, &workqueue_cpu_stat(cpu)->list, list) {		if (node->pid == wq_thread->pid) {			atomic_inc(&node->inserted);			goto found;		}	}	pr_debug("trace_workqueue: entry not found\n");found:	spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);} /* Execution of a work */static voidprobe_workqueue_execution(struct task_struct *wq_thread,			  struct work_struct *work){	int cpu = cpumask_first(&wq_thread->cpus_allowed);	struct cpu_workqueue_stats *node;	unsigned long flags; 	spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);	list_for_each_entry(node, &workqueue_cpu_stat(cpu)->list, list) {		if (node->pid == wq_thread->pid) {			node->executed++;			goto found;		}	}	pr_debug("trace_workqueue: entry not found\n");found:	spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);} /* Creation of a cpu workqueue thread */static void probe_workqueue_creation(struct task_struct *wq_thread, int cpu){	struct cpu_workqueue_stats *cws;	unsigned long flags; 	WARN_ON(cpu < 0); 	/* Workqueues are sometimes created in atomic context */	cws = kzalloc(sizeof(struct cpu_workqueue_stats), GFP_ATOMIC);	if (!cws) {		pr_warning("trace_workqueue: not enough memory\n");		return;	}	INIT_LIST_HEAD(&cws->list);	kref_init(&cws->kref);	cws->cpu = cpu;	cws->pid = wq_thread->pid; 	spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);	list_add_tail(&cws->list, &workqueue_cpu_stat(cpu)->list);	spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);} /* Destruction of a cpu workqueue thread */static void probe_workqueue_destruction(struct task_struct *wq_thread){	/* Workqueue only execute on one cpu */	int cpu = cpumask_first(&wq_thread->cpus_allowed);	struct cpu_workqueue_stats *node, *next;	unsigned long flags; 	spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);	list_for_each_entry_safe(node, next, &workqueue_cpu_stat(cpu)->list,							list) {		if (node->pid == wq_thread->pid) {			list_del(&node->list);			kref_put(&node->kref, cpu_workqueue_stat_free);			goto found;		}	} 	pr_debug("trace_workqueue: don't find workqueue to destroy\n");found:	spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags); } static struct cpu_workqueue_stats *workqueue_stat_start_cpu(int cpu){	unsigned long flags;	struct cpu_workqueue_stats *ret = NULL;  	spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags); 	if (!list_empty(&workqueue_cpu_stat(cpu)->list)) {		ret = list_entry(workqueue_cpu_stat(cpu)->list.next,				 struct cpu_workqueue_stats, list);		kref_get(&ret->kref);	} 	spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags); 	return ret;} static void *workqueue_stat_start(struct tracer_stat *trace){	int cpu;	void *ret = NULL; 	for_each_possible_cpu(cpu) {		ret = workqueue_stat_start_cpu(cpu);		if (ret)			return ret;	}	return NULL;} static void *workqueue_stat_next(void *prev, int idx){	struct cpu_workqueue_stats *prev_cws = prev;	struct cpu_workqueue_stats *ret;	int cpu = prev_cws->cpu;	unsigned long flags; 	spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);	if (list_is_last(&prev_cws->list, &workqueue_cpu_stat(cpu)->list)) {		spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);		do {			cpu = cpumask_next(cpu, cpu_possible_mask);			if (cpu >= nr_cpu_ids)				return NULL;		} while (!(ret = workqueue_stat_start_cpu(cpu)));		return ret;	} else {		ret = list_entry(prev_cws->list.next,				 struct cpu_workqueue_stats, list);		kref_get(&ret->kref);	}	spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags); 	return ret;} static int workqueue_stat_show(struct seq_file *s, void *p){	struct cpu_workqueue_stats *cws = p;	struct pid *pid;	struct task_struct *tsk; 	pid = find_get_pid(cws->pid);	if (pid) {		tsk = get_pid_task(pid, PIDTYPE_PID);		if (tsk) {			seq_printf(s, "%3d %6d     %6u       %s\n", cws->cpu,				   atomic_read(&cws->inserted), cws->executed,				   tsk->comm);			put_task_struct(tsk);		}		put_pid(pid);	} 	return 0;} static void workqueue_stat_release(void *stat){	struct cpu_workqueue_stats *node = stat; 	kref_put(&node->kref, cpu_workqueue_stat_free);} static int workqueue_stat_headers(struct seq_file *s){	seq_printf(s, "# CPU  INSERTED  EXECUTED   NAME\n");	seq_printf(s, "# |      |         |          |\n");	return 0;} struct tracer_stat workqueue_stats __read_mostly = {	.name = "workqueues",	.stat_start = workqueue_stat_start,	.stat_next = workqueue_stat_next,	.stat_show = workqueue_stat_show,	.stat_release = workqueue_stat_release,	.stat_headers = workqueue_stat_headers};  int __init stat_workqueue_init(void){	if (register_stat_tracer(&workqueue_stats)) {		pr_warning("Unable to register workqueue stat tracer\n");		return 1;	} 	return 0;}fs_initcall(stat_workqueue_init); /* * Workqueues are created very early, just after pre-smp initcalls. * So we must register our tracepoints at this stage. */int __init trace_workqueue_early_init(void){	int ret, cpu; 	ret = register_trace_workqueue_insertion(probe_workqueue_insertion);	if (ret)		goto out; 	ret = register_trace_workqueue_execution(probe_workqueue_execution);	if (ret)		goto no_insertion; 	ret = register_trace_workqueue_creation(probe_workqueue_creation);	if (ret)		goto no_execution; 	ret = register_trace_workqueue_destruction(probe_workqueue_destruction);	if (ret)		goto no_creation; 	for_each_possible_cpu(cpu) {		spin_lock_init(&workqueue_cpu_stat(cpu)->lock);		INIT_LIST_HEAD(&workqueue_cpu_stat(cpu)->list);	} 	return 0; no_creation:	unregister_trace_workqueue_creation(probe_workqueue_creation);no_execution:	unregister_trace_workqueue_execution(probe_workqueue_execution);no_insertion:	unregister_trace_workqueue_insertion(probe_workqueue_insertion);out:	pr_warning("trace_workqueue: unable to trace workqueues\n"); 	return 1;}early_initcall(trace_workqueue_early_init);