btrfs: Add high priority workqueue support for btrfs_workqueue_struct

Add high priority function to btrfs_workqueue.

This is implemented by embedding a btrfs_workqueue into a
btrfs_workqueue and use some helper functions to differ the normal
priority wq and high priority wq.
So the high priority wq is completely independent from the normal
workqueue.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fb.com>

diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index 905de02e4386d8b03dd66b62029faac2218f2721..193c84964db9b04965faf197979f47342000351e 100644 (file)
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -730,7 +730,7 @@ void btrfs_queue_worker(struct btrfs_workers *workers, struct btrfs_work *work)
        spin_unlock_irqrestore(&worker->lock, flags);
 }
 
-struct btrfs_workqueue_struct {
+struct __btrfs_workqueue_struct {
        struct workqueue_struct *normal_wq;
        /* List head pointing to ordered work list */
        struct list_head ordered_list;
@@ -739,6 +739,38 @@ struct btrfs_workqueue_struct {
        spinlock_t list_lock;
 };
 
+struct btrfs_workqueue_struct {
+       struct __btrfs_workqueue_struct *normal;
+       struct __btrfs_workqueue_struct *high;
+};
+
+static inline struct __btrfs_workqueue_struct
+*__btrfs_alloc_workqueue(char *name, int flags, int max_active)
+{
+       struct __btrfs_workqueue_struct *ret = kzalloc(sizeof(*ret), GFP_NOFS);
+
+       if (unlikely(!ret))
+               return NULL;
+
+       if (flags & WQ_HIGHPRI)
+               ret->normal_wq = alloc_workqueue("%s-%s-high", flags,
+                                                max_active, "btrfs", name);
+       else
+               ret->normal_wq = alloc_workqueue("%s-%s", flags,
+                                                max_active, "btrfs", name);
+       if (unlikely(!ret->normal_wq)) {
+               kfree(ret);
+               return NULL;
+       }
+
+       INIT_LIST_HEAD(&ret->ordered_list);
+       spin_lock_init(&ret->list_lock);
+       return ret;
+}
+
+static inline void
+__btrfs_destroy_workqueue(struct __btrfs_workqueue_struct *wq);
+
 struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
                                                     int flags,
                                                     int max_active)
@@ -748,19 +780,25 @@ struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char *name,
        if (unlikely(!ret))
                return NULL;
 
-       ret->normal_wq = alloc_workqueue("%s-%s", flags, max_active,
-                                        "btrfs", name);
-       if (unlikely(!ret->normal_wq)) {
+       ret->normal = __btrfs_alloc_workqueue(name, flags & ~WQ_HIGHPRI,
+                                             max_active);
+       if (unlikely(!ret->normal)) {
                kfree(ret);
                return NULL;
        }
 
-       INIT_LIST_HEAD(&ret->ordered_list);
-       spin_lock_init(&ret->list_lock);
+       if (flags & WQ_HIGHPRI) {
+               ret->high = __btrfs_alloc_workqueue(name, flags, max_active);
+               if (unlikely(!ret->high)) {
+                       __btrfs_destroy_workqueue(ret->normal);
+                       kfree(ret);
+                       return NULL;
+               }
+       }
        return ret;
 }
 
-static void run_ordered_work(struct btrfs_workqueue_struct *wq)
+static void run_ordered_work(struct __btrfs_workqueue_struct *wq)
 {
        struct list_head *list = &wq->ordered_list;
        struct btrfs_work_struct *work;
@@ -804,7 +842,7 @@ static void run_ordered_work(struct btrfs_workqueue_struct *wq)
 static void normal_work_helper(struct work_struct *arg)
 {
        struct btrfs_work_struct *work;
-       struct btrfs_workqueue_struct *wq;
+       struct __btrfs_workqueue_struct *wq;
        int need_order = 0;
 
        work = container_of(arg, struct btrfs_work_struct, normal_work);
@@ -840,8 +878,8 @@ void btrfs_init_work(struct btrfs_work_struct *work,
        work->flags = 0;
 }
 
-void btrfs_queue_work(struct btrfs_workqueue_struct *wq,
-                     struct btrfs_work_struct *work)
+static inline void __btrfs_queue_work(struct __btrfs_workqueue_struct *wq,
+                                     struct btrfs_work_struct *work)
 {
        unsigned long flags;
 
@@ -854,13 +892,42 @@ void btrfs_queue_work(struct btrfs_workqueue_struct *wq,
        queue_work(wq->normal_wq, &work->normal_work);
 }
 
-void btrfs_destroy_workqueue(struct btrfs_workqueue_struct *wq)
+void btrfs_queue_work(struct btrfs_workqueue_struct *wq,
+                     struct btrfs_work_struct *work)
+{
+       struct __btrfs_workqueue_struct *dest_wq;
+
+       if (test_bit(WORK_HIGH_PRIO_BIT, &work->flags) && wq->high)
+               dest_wq = wq->high;
+       else
+               dest_wq = wq->normal;
+       __btrfs_queue_work(dest_wq, work);
+}
+
+static inline void
+__btrfs_destroy_workqueue(struct __btrfs_workqueue_struct *wq)
 {
        destroy_workqueue(wq->normal_wq);
        kfree(wq);
 }
 
+void btrfs_destroy_workqueue(struct btrfs_workqueue_struct *wq)
+{
+       if (!wq)
+               return;
+       if (wq->high)
+               __btrfs_destroy_workqueue(wq->high);
+       __btrfs_destroy_workqueue(wq->normal);
+}
+
 void btrfs_workqueue_set_max(struct btrfs_workqueue_struct *wq, int max)
 {
-       workqueue_set_max_active(wq->normal_wq, max);
+       workqueue_set_max_active(wq->normal->normal_wq, max);
+       if (wq->high)
+               workqueue_set_max_active(wq->high->normal_wq, max);
+}
+
+void btrfs_set_work_high_priority(struct btrfs_work_struct *work)
+{
+       set_bit(WORK_HIGH_PRIO_BIT, &work->flags);
 }

diff --git a/fs/btrfs/async-thread.h b/fs/btrfs/async-thread.h
index 9d8da53f6dd9fe616927a97ceedb906ca4ec9448..fce623cfe3dad03adf6f808760dfb118bac117ac 100644 (file)
--- a/fs/btrfs/async-thread.h
+++ b/fs/btrfs/async-thread.h
@@ -121,6 +121,8 @@ void btrfs_requeue_work(struct btrfs_work *work);
 void btrfs_set_work_high_prio(struct btrfs_work *work);
 
 struct btrfs_workqueue_struct;
+/* Internal use only */
+struct __btrfs_workqueue_struct;
 
 struct btrfs_work_struct {
        void (*func)(struct btrfs_work_struct *arg);
@@ -130,7 +132,7 @@ struct btrfs_work_struct {
        /* Don't touch things below */
        struct work_struct normal_work;
        struct list_head ordered_list;
-       struct btrfs_workqueue_struct *wq;
+       struct __btrfs_workqueue_struct *wq;
        unsigned long flags;
 };
 
@@ -145,4 +147,5 @@ void btrfs_queue_work(struct btrfs_workqueue_struct *wq,
                      struct btrfs_work_struct *work);
 void btrfs_destroy_workqueue(struct btrfs_workqueue_struct *wq);
 void btrfs_workqueue_set_max(struct btrfs_workqueue_struct *wq, int max);
+void btrfs_set_work_high_priority(struct btrfs_work_struct *work);
 #endif