[PATCH] btrfs/async-thread: introduce macro BTRFS_WORKERS_IDLE_THRESH to replace the magic number 32 used for btrfs_workers->idle_thresh

[Wang Sheng-Hui <shhuiw@gmail.com>]

Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>
---
 fs/btrfs/async-thread.c |    2 +-
 fs/btrfs/async-thread.h |    8 +++++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index 5a7d756..2491096 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -445,7 +445,7 @@ void btrfs_init_workers(struct btrfs_workers *workers, char *name, int max,
 	spin_lock_init(&workers->lock);
 	spin_lock_init(&workers->order_lock);
 	workers->max_workers = max;
-	workers->idle_thresh = 32;
+	workers->idle_thresh = BTRFS_WORKERS_IDLE_THRESH;
 	workers->name = name;
 	workers->ordered = 0;
 	workers->atomic_start_pending = 0;
diff --git a/fs/btrfs/async-thread.h b/fs/btrfs/async-thread.h
index f34cc31..9b9522e 100644
--- a/fs/btrfs/async-thread.h
+++ b/fs/btrfs/async-thread.h
@@ -60,6 +60,9 @@ struct btrfs_work {
 	struct list_head order_list;
 };
 
+/* default value for btrfs_workers->idle_thresh */
+#define BTRFS_WORKERS_IDLE_THRESH 32
+
 struct btrfs_workers {
 	/* current number of running workers */
 	int num_workers;
@@ -69,7 +72,10 @@ struct btrfs_workers {
 	/* max number of workers allowed.  changed by btrfs_start_workers */
 	int max_workers;
 
-	/* once a worker has this many requests or fewer, it is idle */
+	/*
+	 * once a worker has this many requests or fewer, it is idle.
+	 * default to BTRFS_WORKERS_IDLE_THRESH, which 32 is used currently.
+	 */
 	int idle_thresh;
 
 	/* force completions in the order they were queued */
-- 
1.7.1