1 files changed, 288 insertions, 0 deletions
diff --git a/kernel/trace/trace_workqueue.c b/kernel/trace/trace_workqueue.c
new file mode 100644
index 00000000000..797201e4a13
--- /dev/null
+++ b/kernel/trace/trace_workqueue.c
@@ -0,0 +1,288 @@
+/*
+ * Workqueue statistical tracer.
+ *
+ * Copyright (C) 2008 Frederic Weisbecker <fweisbec@gmail.com>
+ *
+ */
+
+
+#include <trace/workqueue.h>
+#include <linux/list.h>
+#include <linux/percpu.h>
+#include "trace_stat.h"
+#include "trace.h"
+
+
+/* A cpu workqueue thread */
+struct cpu_workqueue_stats {
+	struct list_head            list;
+/* Useful to know if we print the cpu headers */
+	bool		            first_entry;
+	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))
+
+/* Insertion of a work */
+static void
+probe_workqueue_insertion(struct task_struct *wq_thread,
+			  struct work_struct *work)
+{
+	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) {
+			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 void
+probe_workqueue_execution(struct task_struct *wq_thread,
+			  struct work_struct *work)
+{
+	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) {
+			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);
+	cws->cpu = cpu;
+
+	cws->pid = wq_thread->pid;
+
+	spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
+	if (list_empty(&workqueue_cpu_stat(cpu)->list))
+		cws->first_entry = true;
+	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);
+			kfree(node);
+			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);
+
+	spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
+
+	return ret;
+}
+
+static void *workqueue_stat_start(void)
+{
+	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;
+	int cpu = prev_cws->cpu;
+	unsigned long flags;
+	void *ret = NULL;
+
+	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;
+	}
+	spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
+
+	return list_entry(prev_cws->list.next, struct cpu_workqueue_stats,
+			  list);
+}
+
+static int workqueue_stat_show(struct seq_file *s, void *p)
+{
+	struct cpu_workqueue_stats *cws = p;
+	unsigned long flags;
+	int cpu = cws->cpu;
+	struct pid *pid;
+	struct task_struct *tsk;
+
+	spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
+	if (&cws->list == workqueue_cpu_stat(cpu)->list.next)
+		seq_printf(s, "\n");
+	spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
+
+	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 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_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);