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authorQin Chuanyu <qinchuanyu@huawei.com>2013-06-07 21:50:16 +0800
committerMichael S. Tsirkin <mst@redhat.com>2013-09-17 09:21:32 +0300
commitac9fde2474d04bd6574a037482e3de02b488a6c6 (patch)
treeb653c2581667d160a916f9680f9fd514360b5b54 /drivers/vhost
parent272b98c6455f00884f0350f775c5342358ebb73f (diff)
downloadlinux-ac9fde2474d04bd6574a037482e3de02b488a6c6.tar.gz
vhost: wake up worker outside spin_lock
the wake_up_process func is included by spin_lock/unlock in
vhost_work_queue,
but it could be done outside the spin_lock.
I have test it with kernel 3.0.27 and guest suse11-sp2 using iperf,
the num as below.
                  original                 modified
thread_num  tp(Gbps)   vhost(%)  |  tp(Gbps)     vhost(%)
1           9.59        28.82    |   9.59        27.49
8           9.61        32.92    |   9.62        26.77
64          9.58        46.48    |   9.55        38.99
256         9.6         63.7     |   9.6         52.59

Signed-off-by: Chuanyu Qin <qinchuanyu@huawei.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'drivers/vhost')
-rw-r--r--drivers/vhost/vhost.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 9a9502a4aa50..69068e0d8f31 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -161,9 +161,11 @@ void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work)
 	if (list_empty(&work->node)) {
 		list_add_tail(&work->node, &dev->work_list);
 		work->queue_seq++;
+		spin_unlock_irqrestore(&dev->work_lock, flags);
 		wake_up_process(dev->worker);
+	} else {
+		spin_unlock_irqrestore(&dev->work_lock, flags);
 	}
-	spin_unlock_irqrestore(&dev->work_lock, flags);
 }
 EXPORT_SYMBOL_GPL(vhost_work_queue);