#include <linux/kthread.h>
#include <linux/freezer.h>
#include <linux/wait.h>
-#include <linux/proc_fs.h>
+#include <linux/debugfs.h>
#include "slow-work.h"
static void slow_work_cull_timeout(unsigned long);
ctl_table slow_work_sysctls[] = {
{
- .ctl_name = CTL_UNNUMBERED,
.procname = "min-threads",
.data = &slow_work_min_threads,
.maxlen = sizeof(unsigned),
.extra2 = &slow_work_max_threads,
},
{
- .ctl_name = CTL_UNNUMBERED,
.procname = "max-threads",
.data = &slow_work_max_threads,
.maxlen = sizeof(unsigned),
.extra2 = (void *) &slow_work_max_max_threads,
},
{
- .ctl_name = CTL_UNNUMBERED,
.procname = "vslow-percentage",
.data = &vslow_work_proportion,
.maxlen = sizeof(unsigned),
.mode = 0644,
- .proc_handler = &proc_dointvec_minmax,
+ .proc_handler = proc_dointvec_minmax,
.extra1 = (void *) &slow_work_min_vslow,
.extra2 = (void *) &slow_work_max_vslow,
},
- { .ctl_name = 0 }
+ {}
};
#endif
static struct slow_work *slow_work_unreg_work_item;
static DECLARE_WAIT_QUEUE_HEAD(slow_work_unreg_wq);
static DEFINE_MUTEX(slow_work_unreg_sync_lock);
+
+static void slow_work_set_thread_processing(int id, struct slow_work *work)
+{
+ if (work)
+ slow_work_thread_processing[id] = work->owner;
+}
+static void slow_work_done_thread_processing(int id, struct slow_work *work)
+{
+ struct module *module = slow_work_thread_processing[id];
+
+ slow_work_thread_processing[id] = NULL;
+ smp_mb();
+ if (slow_work_unreg_work_item == work ||
+ slow_work_unreg_module == module)
+ wake_up_all(&slow_work_unreg_wq);
+}
+static void slow_work_clear_thread_processing(int id)
+{
+ slow_work_thread_processing[id] = NULL;
+}
+#else
+static void slow_work_set_thread_processing(int id, struct slow_work *work) {}
+static void slow_work_done_thread_processing(int id, struct slow_work *work) {}
+static void slow_work_clear_thread_processing(int id) {}
#endif
/*
* Data for tracking currently executing items for indication through /proc
*/
-#ifdef CONFIG_SLOW_WORK_PROC
+#ifdef CONFIG_SLOW_WORK_DEBUG
struct slow_work *slow_work_execs[SLOW_WORK_THREAD_LIMIT];
pid_t slow_work_pids[SLOW_WORK_THREAD_LIMIT];
DEFINE_RWLOCK(slow_work_execs_lock);
DEFINE_SPINLOCK(slow_work_queue_lock);
/*
+ * The following are two wait queues that get pinged when a work item is placed
+ * on an empty queue. These allow work items that are hogging a thread by
+ * sleeping in a way that could be deferred to yield their thread and enqueue
+ * themselves.
+ */
+static DECLARE_WAIT_QUEUE_HEAD(slow_work_queue_waits_for_occupation);
+static DECLARE_WAIT_QUEUE_HEAD(vslow_work_queue_waits_for_occupation);
+
+/*
* The thread controls. A variable used to signal to the threads that they
* should exit when the queue is empty, a waitqueue used by the threads to wait
* for signals, and a completion set by the last thread to exit.
*/
static noinline bool slow_work_execute(int id)
{
-#ifdef CONFIG_MODULES
- struct module *module;
-#endif
struct slow_work *work = NULL;
unsigned vsmax;
bool very_slow;
very_slow = false; /* avoid the compiler warning */
}
-#ifdef CONFIG_MODULES
- if (work)
- slow_work_thread_processing[id] = work->owner;
-#endif
+ slow_work_set_thread_processing(id, work);
if (work) {
slow_work_mark_time(work);
slow_work_begin_exec(id, work);
/* sort out the race between module unloading and put_ref() */
slow_work_put_ref(work);
-
-#ifdef CONFIG_MODULES
- module = slow_work_thread_processing[id];
- slow_work_thread_processing[id] = NULL;
- smp_mb();
- if (slow_work_unreg_work_item == work ||
- slow_work_unreg_module == module)
- wake_up_all(&slow_work_unreg_wq);
-#endif
+ slow_work_done_thread_processing(id, work);
return true;
else
list_add_tail(&work->link, &slow_work_queue);
spin_unlock_irq(&slow_work_queue_lock);
- slow_work_thread_processing[id] = NULL;
+ slow_work_clear_thread_processing(id);
return true;
}
/**
+ * slow_work_sleep_till_thread_needed - Sleep till thread needed by other work
+ * work: The work item under execution that wants to sleep
+ * _timeout: Scheduler sleep timeout
+ *
+ * Allow a requeueable work item to sleep on a slow-work processor thread until
+ * that thread is needed to do some other work or the sleep is interrupted by
+ * some other event.
+ *
+ * The caller must set up a wake up event before calling this and must have set
+ * the appropriate sleep mode (such as TASK_UNINTERRUPTIBLE) and tested its own
+ * condition before calling this function as no test is made here.
+ *
+ * False is returned if there is nothing on the queue; true is returned if the
+ * work item should be requeued
+ */
+bool slow_work_sleep_till_thread_needed(struct slow_work *work,
+ signed long *_timeout)
+{
+ wait_queue_head_t *wfo_wq;
+ struct list_head *queue;
+
+ DEFINE_WAIT(wait);
+
+ if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags)) {
+ wfo_wq = &vslow_work_queue_waits_for_occupation;
+ queue = &vslow_work_queue;
+ } else {
+ wfo_wq = &slow_work_queue_waits_for_occupation;
+ queue = &slow_work_queue;
+ }
+
+ if (!list_empty(queue))
+ return true;
+
+ add_wait_queue_exclusive(wfo_wq, &wait);
+ if (list_empty(queue))
+ *_timeout = schedule_timeout(*_timeout);
+ finish_wait(wfo_wq, &wait);
+
+ return !list_empty(queue);
+}
+EXPORT_SYMBOL(slow_work_sleep_till_thread_needed);
+
+/**
* slow_work_enqueue - Schedule a slow work item for processing
* @work: The work item to queue
*
*/
int slow_work_enqueue(struct slow_work *work)
{
+ wait_queue_head_t *wfo_wq;
+ struct list_head *queue;
unsigned long flags;
int ret;
* maintaining our promise
*/
if (!test_and_set_bit_lock(SLOW_WORK_PENDING, &work->flags)) {
+ if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags)) {
+ wfo_wq = &vslow_work_queue_waits_for_occupation;
+ queue = &vslow_work_queue;
+ } else {
+ wfo_wq = &slow_work_queue_waits_for_occupation;
+ queue = &slow_work_queue;
+ }
+
spin_lock_irqsave(&slow_work_queue_lock, flags);
if (unlikely(test_bit(SLOW_WORK_CANCELLING, &work->flags)))
if (ret < 0)
goto failed;
slow_work_mark_time(work);
- if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags))
- list_add_tail(&work->link, &vslow_work_queue);
- else
- list_add_tail(&work->link, &slow_work_queue);
+ list_add_tail(&work->link, queue);
wake_up(&slow_work_thread_wq);
+
+ /* if someone who could be requeued is sleeping on a
+ * thread, then ask them to yield their thread */
+ if (work->link.prev == queue)
+ wake_up(wfo_wq);
}
spin_unlock_irqrestore(&slow_work_queue_lock, flags);
*/
static void delayed_slow_work_timer(unsigned long data)
{
+ wait_queue_head_t *wfo_wq;
+ struct list_head *queue;
struct slow_work *work = (struct slow_work *) data;
unsigned long flags;
- bool queued = false, put = false;
+ bool queued = false, put = false, first = false;
+
+ if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags)) {
+ wfo_wq = &vslow_work_queue_waits_for_occupation;
+ queue = &vslow_work_queue;
+ } else {
+ wfo_wq = &slow_work_queue_waits_for_occupation;
+ queue = &slow_work_queue;
+ }
spin_lock_irqsave(&slow_work_queue_lock, flags);
if (likely(!test_bit(SLOW_WORK_CANCELLING, &work->flags))) {
put = true;
} else {
slow_work_mark_time(work);
- if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags))
- list_add_tail(&work->link, &vslow_work_queue);
- else
- list_add_tail(&work->link, &slow_work_queue);
+ list_add_tail(&work->link, queue);
queued = true;
+ if (work->link.prev == queue)
+ first = true;
}
}
spin_unlock_irqrestore(&slow_work_queue_lock, flags);
if (put)
slow_work_put_ref(work);
+ if (first)
+ wake_up(wfo_wq);
if (queued)
wake_up(&slow_work_thread_wq);
}
goto cancelled;
/* the timer holds a reference whilst it is pending */
- ret = work->ops->get_ref(work);
+ ret = slow_work_get_ref(work);
if (ret < 0)
goto cant_get_ref;
static const struct slow_work_ops slow_work_new_thread_ops = {
.owner = THIS_MODULE,
.execute = slow_work_new_thread_execute,
-#ifdef CONFIG_SLOW_WORK_PROC
+#ifdef CONFIG_SLOW_WORK_DEBUG
.desc = slow_work_new_thread_desc,
#endif
};
*/
static void slow_work_wait_for_items(struct module *module)
{
+#ifdef CONFIG_MODULES
DECLARE_WAITQUEUE(myself, current);
struct slow_work *work;
int loop;
remove_wait_queue(&slow_work_unreg_wq, &myself);
mutex_unlock(&slow_work_unreg_sync_lock);
+#endif /* CONFIG_MODULES */
}
/**
if (slow_work_max_max_threads < nr_cpus * 2)
slow_work_max_max_threads = nr_cpus * 2;
#endif
-#ifdef CONFIG_SLOW_WORK_PROC
- proc_create("slow_work_rq", S_IFREG | 0400, NULL,
- &slow_work_runqueue_fops);
+#ifdef CONFIG_SLOW_WORK_DEBUG
+ {
+ struct dentry *dbdir;
+
+ dbdir = debugfs_create_dir("slow_work", NULL);
+ if (dbdir && !IS_ERR(dbdir))
+ debugfs_create_file("runqueue", S_IFREG | 0400, dbdir,
+ NULL, &slow_work_runqueue_fops);
+ }
#endif
return 0;
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff