2 files changed, 46 insertions, 6 deletions

diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index f2e80f3768ec..c84ca1f5259a 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -19,7 +19,8 @@
 #include <linux/kthread.h>
 #include <linux/list.h>
 #include <linux/spinlock.h>
-# include <linux/freezer.h>
+#include <linux/freezer.h>
+#include <linux/ftrace.h>
 #include "async-thread.h"
 
 #define WORK_QUEUED_BIT 0
@@ -142,6 +143,7 @@ static int worker_loop(void *arg)
         struct btrfs_work *work;
         do {
                 spin_lock_irq(&worker->lock);
+again_locked:
                 while (!list_empty(&worker->pending)) {
                         cur = worker->pending.next;
                         work = list_entry(cur, struct btrfs_work, list);
@@ -164,14 +166,50 @@ static int worker_loop(void *arg)
                         check_idle_worker(worker);
 
                 }
-                worker->working = 0;
                 if (freezing(current)) {
+                        worker->working = 0;
+                        spin_unlock_irq(&worker->lock);
                         refrigerator();
                 } else {
-                        set_current_state(TASK_INTERRUPTIBLE);
                         spin_unlock_irq(&worker->lock);
-                        if (!kthread_should_stop())
+                        if (!kthread_should_stop()) {
+                                cpu_relax();
+                                /*
+                                 * we've dropped the lock, did someone else
+                                 * jump_in?
+                                 */
+                                smp_mb();
+                                if (!list_empty(&worker->pending))
+                                        continue;
+
+                                /*
+                                 * this short schedule allows more work to
+                                 * come in without the queue functions
+                                 * needing to go through wake_up_process()
+                                 *
+                                 * worker->working is still 1, so nobody
+                                 * is going to try and wake us up
+                                 */
+                                schedule_timeout(1);
+                                smp_mb();
+                                if (!list_empty(&worker->pending))
+                                        continue;
+
+                                /* still no more work?, sleep for real */
+                                spin_lock_irq(&worker->lock);
+                                set_current_state(TASK_INTERRUPTIBLE);
+                                if (!list_empty(&worker->pending))
+                                        goto again_locked;
+
+                                /*
+                                 * this makes sure we get a wakeup when someone
+                                 * adds something new to the queue
+                                 */
+                                worker->working = 0;
+                                spin_unlock_irq(&worker->lock);
+
                                 schedule();
+                        }
                         __set_current_state(TASK_RUNNING);
                 }
         } while (!kthread_should_stop());
@@ -355,8 +393,8 @@ int btrfs_requeue_work(struct btrfs_work *work)
                 goto out;
 
         spin_lock_irqsave(&worker->lock, flags);
-        atomic_inc(&worker->num_pending);
         list_add_tail(&work->list, &worker->pending);
+        atomic_inc(&worker->num_pending);
 
         /* by definition we're busy, take ourselves off the idle
          * list
@@ -405,9 +443,9 @@ int btrfs_queue_worker(struct btrfs_workers *workers, struct btrfs_work *work)
 
         spin_lock_irqsave(&worker->lock, flags);
 
+        list_add_tail(&work->list, &worker->pending);
         atomic_inc(&worker->num_pending);
         check_busy_worker(worker);
-        list_add_tail(&work->list, &worker->pending);
 
         /*
          * avoid calling into wake_up_process if this thread has already
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 7feac5a475e9..9c3810047976 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1679,6 +1679,8 @@ struct btrfs_root *open_ctree(struct super_block *sb,
          * low idle thresh
          */
         fs_info->endio_workers.idle_thresh = 4;
+        fs_info->endio_meta_workers.idle_thresh = 4;
+
         fs_info->endio_write_workers.idle_thresh = 64;
         fs_info->endio_meta_write_workers.idle_thresh = 64;