Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux-2.6-omap-h63xx.git] / kernel / workqueue.c

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 2f445833ae371a58d35c56907e2eeb638e75a453..b6b966ce1451adf7c71fffd38524e68587f7504e 100644 (file)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -33,6 +33,7 @@
 #include <linux/kallsyms.h>
 #include <linux/debug_locks.h>
 #include <linux/lockdep.h>
+#include <trace/workqueue.h>
 
 /*
  * The per-CPU workqueue (if single thread, we always use the first
@@ -48,8 +49,6 @@ struct cpu_workqueue_struct {
 
        struct workqueue_struct *wq;
        struct task_struct *thread;
-
-       int run_depth;          /* Detect run_workqueue() recursion depth */
 } ____cacheline_aligned;
 
 /*
@@ -125,9 +124,13 @@ struct cpu_workqueue_struct *get_wq_data(struct work_struct *work)
        return (void *) (atomic_long_read(&work->data) & WORK_STRUCT_WQ_DATA_MASK);
 }
 
+DEFINE_TRACE(workqueue_insertion);
+
 static void insert_work(struct cpu_workqueue_struct *cwq,
                        struct work_struct *work, struct list_head *head)
 {
+       trace_workqueue_insertion(cwq->thread, work);
+
        set_wq_data(work, cwq);
        /*
         * Ensure that we get the right work->data if we see the
@@ -259,16 +262,11 @@ int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
 }
 EXPORT_SYMBOL_GPL(queue_delayed_work_on);
 
+DEFINE_TRACE(workqueue_execution);
+
 static void run_workqueue(struct cpu_workqueue_struct *cwq)
 {
        spin_lock_irq(&cwq->lock);
-       cwq->run_depth++;
-       if (cwq->run_depth > 3) {
-               /* morton gets to eat his hat */
-               printk("%s: recursion depth exceeded: %d\n",
-                       __func__, cwq->run_depth);
-               dump_stack();
-       }
        while (!list_empty(&cwq->worklist)) {
                struct work_struct *work = list_entry(cwq->worklist.next,
                                                struct work_struct, entry);
@@ -284,7 +282,7 @@ static void run_workqueue(struct cpu_workqueue_struct *cwq)
                 */
                struct lockdep_map lockdep_map = work->lockdep_map;
 #endif
-
+               trace_workqueue_execution(cwq->thread, work);
                cwq->current_work = work;
                list_del_init(cwq->worklist.next);
                spin_unlock_irq(&cwq->lock);
@@ -311,7 +309,6 @@ static void run_workqueue(struct cpu_workqueue_struct *cwq)
                spin_lock_irq(&cwq->lock);
                cwq->current_work = NULL;
        }
-       cwq->run_depth--;
        spin_unlock_irq(&cwq->lock);
 }
 
@@ -368,29 +365,20 @@ static void insert_wq_barrier(struct cpu_workqueue_struct *cwq,
 
 static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq)
 {
-       int active;
-
-       if (cwq->thread == current) {
-               /*
-                * Probably keventd trying to flush its own queue. So simply run
-                * it by hand rather than deadlocking.
-                */
-               run_workqueue(cwq);
-               active = 1;
-       } else {
-               struct wq_barrier barr;
+       int active = 0;
+       struct wq_barrier barr;
 
-               active = 0;
-               spin_lock_irq(&cwq->lock);
-               if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) {
-                       insert_wq_barrier(cwq, &barr, &cwq->worklist);
-                       active = 1;
-               }
-               spin_unlock_irq(&cwq->lock);
+       WARN_ON(cwq->thread == current);
 
-               if (active)
-                       wait_for_completion(&barr.done);
+       spin_lock_irq(&cwq->lock);
+       if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) {
+               insert_wq_barrier(cwq, &barr, &cwq->worklist);
+               active = 1;
        }
+       spin_unlock_irq(&cwq->lock);
+
+       if (active)
+               wait_for_completion(&barr.done);
 
        return active;
 }
@@ -416,7 +404,7 @@ void flush_workqueue(struct workqueue_struct *wq)
        might_sleep();
        lock_map_acquire(&wq->lockdep_map);
        lock_map_release(&wq->lockdep_map);
-       for_each_cpu_mask_nr(cpu, *cpu_map)
+       for_each_cpu(cpu, cpu_map)
                flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu));
 }
 EXPORT_SYMBOL_GPL(flush_workqueue);
@@ -547,7 +535,7 @@ static void wait_on_work(struct work_struct *work)
        wq = cwq->wq;
        cpu_map = wq_cpu_map(wq);
 
-       for_each_cpu_mask_nr(cpu, *cpu_map)
+       for_each_cpu(cpu, cpu_map)
                wait_on_cpu_work(per_cpu_ptr(wq->cpu_wq, cpu), work);
 }
 
@@ -765,6 +753,8 @@ init_cpu_workqueue(struct workqueue_struct *wq, int cpu)
        return cwq;
 }
 
+DEFINE_TRACE(workqueue_creation);
+
 static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
 {
        struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
@@ -787,6 +777,8 @@ static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
                sched_setscheduler_nocheck(p, SCHED_FIFO, &param);
        cwq->thread = p;
 
+       trace_workqueue_creation(cwq->thread, cpu);
+
        return 0;
 }
 
@@ -868,6 +860,8 @@ struct workqueue_struct *__create_workqueue_key(const char *name,
 }
 EXPORT_SYMBOL_GPL(__create_workqueue_key);
 
+DEFINE_TRACE(workqueue_destruction);
+
 static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq)
 {
        /*
@@ -891,6 +885,7 @@ static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq)
         * checks list_empty(), and a "normal" queue_work() can't use
         * a dead CPU.
         */
+       trace_workqueue_destruction(cwq->thread);
        kthread_stop(cwq->thread);
        cwq->thread = NULL;
 }
@@ -911,7 +906,7 @@ void destroy_workqueue(struct workqueue_struct *wq)
        list_del(&wq->list);
        spin_unlock(&workqueue_lock);
 
-       for_each_cpu_mask_nr(cpu, *cpu_map)
+       for_each_cpu(cpu, cpu_map)
                cleanup_workqueue_thread(per_cpu_ptr(wq->cpu_wq, cpu));
        cpu_maps_update_done();
 
@@ -971,6 +966,8 @@ undo:
 }
 
 #ifdef CONFIG_SMP
+static struct workqueue_struct *work_on_cpu_wq __read_mostly;
+
 struct work_for_cpu {
        struct work_struct work;
        long (*fn)(void *);
@@ -991,8 +988,8 @@ static void do_work_for_cpu(struct work_struct *w)
  * @fn: the function to run
  * @arg: the function arg
  *
- * This will return -EINVAL in the cpu is not online, or the return value
- * of @fn otherwise.
+ * This will return the value @fn returns.
+ * It is up to the caller to ensure that the cpu doesn't go offline.
  */
 long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg)
 {
@@ -1001,14 +998,8 @@ long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg)
        INIT_WORK(&wfc.work, do_work_for_cpu);
        wfc.fn = fn;
        wfc.arg = arg;
-       get_online_cpus();
-       if (unlikely(!cpu_online(cpu)))
-               wfc.ret = -EINVAL;
-       else {
-               schedule_work_on(cpu, &wfc.work);
-               flush_work(&wfc.work);
-       }
-       put_online_cpus();
+       queue_work_on(cpu, work_on_cpu_wq, &wfc.work);
+       flush_work(&wfc.work);
 
        return wfc.ret;
 }
@@ -1025,4 +1016,8 @@ void __init init_workqueues(void)
        hotcpu_notifier(workqueue_cpu_callback, 0);
        keventd_wq = create_workqueue("events");
        BUG_ON(!keventd_wq);
+#ifdef CONFIG_SMP
+       work_on_cpu_wq = create_workqueue("work_on_cpu");
+       BUG_ON(!work_on_cpu_wq);
+#endif
 }