writeback: optimize periodic bdi thread wakeups

[deliverable/linux.git] / fs / fs-writeback.c

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 55f6e46e06f1cfb69db5048136ec3394117b4a82..bfa2df2c7ce27ed614f7c3a3297a527120706e73 100644 (file)
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -76,7 +76,7 @@ static void bdi_queue_work(struct backing_dev_info *bdi,
 {
        trace_writeback_queue(bdi, work);
 
-       spin_lock(&bdi->wb_lock);
+       spin_lock_bh(&bdi->wb_lock);
        list_add_tail(&work->list, &bdi->work_list);
        if (bdi->wb.task) {
                wake_up_process(bdi->wb.task);
@@ -88,7 +88,7 @@ static void bdi_queue_work(struct backing_dev_info *bdi,
                trace_writeback_nothread(bdi, work);
                wake_up_process(default_backing_dev_info.wb.task);
        }
-       spin_unlock(&bdi->wb_lock);
+       spin_unlock_bh(&bdi->wb_lock);
 }
 
 static void
@@ -704,13 +704,13 @@ get_next_work_item(struct backing_dev_info *bdi)
 {
        struct wb_writeback_work *work = NULL;
 
-       spin_lock(&bdi->wb_lock);
+       spin_lock_bh(&bdi->wb_lock);
        if (!list_empty(&bdi->work_list)) {
                work = list_entry(bdi->work_list.next,
                                  struct wb_writeback_work, list);
                list_del_init(&work->list);
        }
-       spin_unlock(&bdi->wb_lock);
+       spin_unlock_bh(&bdi->wb_lock);
        return work;
 }
 
@@ -810,6 +810,12 @@ int bdi_writeback_thread(void *data)
        trace_writeback_thread_start(bdi);
 
        while (!kthread_should_stop()) {
+               /*
+                * Remove own delayed wake-up timer, since we are already awake
+                * and we'll take care of the preriodic write-back.
+                */
+               del_timer(&wb->wakeup_timer);
+
                pages_written = wb_do_writeback(wb, 0);
 
                trace_writeback_pages_written(pages_written);
@@ -868,26 +874,6 @@ void wakeup_flusher_threads(long nr_pages)
        rcu_read_unlock();
 }
 
-/*
- * This function is used when the first inode for this bdi is marked dirty. It
- * wakes-up the corresponding bdi thread which should then take care of the
- * periodic background write-out of dirty inodes.
- */
-static void wakeup_bdi_thread(struct backing_dev_info *bdi)
-{
-       spin_lock(&bdi->wb_lock);
-       if (bdi->wb.task)
-               wake_up_process(bdi->wb.task);
-       else
-               /*
-                * When bdi tasks are inactive for long time, they are killed.
-                * In this case we have to wake-up the forker thread which
-                * should create and run the bdi thread.
-                */
-               wake_up_process(default_backing_dev_info.wb.task);
-       spin_unlock(&bdi->wb_lock);
-}
-
 static noinline void block_dump___mark_inode_dirty(struct inode *inode)
 {
        if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) {
@@ -1019,7 +1005,7 @@ out:
        spin_unlock(&inode_lock);
 
        if (wakeup_bdi)
-               wakeup_bdi_thread(bdi);
+               bdi_wakeup_thread_delayed(bdi);
 }
 EXPORT_SYMBOL(__mark_inode_dirty);