Revert "xen-netback: Aggregate TX unmap operations"

This reverts commit e9275f5e2df1b2098a8cc405d87b88b9affd73e6. This commit is the
last in the netback grant mapping series, and it tries to do more aggressive
aggreagtion of unmap operations. However practical use showed almost no
positive effect, whilst with certain frontends it causes significant performance
regression.

Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index bef37be402b869fde5012da20aed30017bbcac81..0355f8767e3bdf17b27c34669ac617554ddb154e 100644 (file)
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -137,8 +137,6 @@ struct xenvif {
        u16 dealloc_ring[MAX_PENDING_REQS];
        struct task_struct *dealloc_task;
        wait_queue_head_t dealloc_wq;
-       struct timer_list dealloc_delay;
-       bool dealloc_delay_timed_out;
 
        /* Use kthread for guest RX */
        struct task_struct *task;

diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index a6a8c1579eb97987a2bf8fea91fc646403817d9e..23bb2f4b18fe59e30b8268caefce4918db138195 100644 (file)
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -407,7 +407,6 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
                          .desc = i };
                vif->grant_tx_handle[i] = NETBACK_INVALID_HANDLE;
        }
-       init_timer(&vif->dealloc_delay);
 
        /*
         * Initialise a dummy MAC address. We choose the numerically
@@ -556,7 +555,6 @@ void xenvif_disconnect(struct xenvif *vif)
        }
 
        if (vif->dealloc_task) {
-               del_timer_sync(&vif->dealloc_delay);
                kthread_stop(vif->dealloc_task);
                vif->dealloc_task = NULL;
        }

diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 5a8c4a43c5227b4abd549c080530f0075b85ed3c..1f595e51791e83befb68f5c28a8092325771f24f 100644 (file)
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -133,11 +133,6 @@ static inline pending_ring_idx_t pending_index(unsigned i)
        return i & (MAX_PENDING_REQS-1);
 }
 
-static inline pending_ring_idx_t nr_free_slots(struct xen_netif_tx_back_ring *ring)
-{
-       return ring->nr_ents -  (ring->sring->req_prod - ring->rsp_prod_pvt);
-}
-
 bool xenvif_rx_ring_slots_available(struct xenvif *vif, int needed)
 {
        RING_IDX prod, cons;
@@ -1718,36 +1713,9 @@ static inline int tx_work_todo(struct xenvif *vif)
        return 0;
 }
 
-static void xenvif_dealloc_delay(unsigned long data)
-{
-       struct xenvif *vif = (struct xenvif *)data;
-
-       vif->dealloc_delay_timed_out = true;
-       wake_up(&vif->dealloc_wq);
-}
-
 static inline bool tx_dealloc_work_todo(struct xenvif *vif)
 {
-       if (vif->dealloc_cons != vif->dealloc_prod) {
-               if ((nr_free_slots(&vif->tx) > 2 * XEN_NETBK_LEGACY_SLOTS_MAX) &&
-                   (vif->dealloc_prod - vif->dealloc_cons < MAX_PENDING_REQS / 4) &&
-                   !vif->dealloc_delay_timed_out) {
-                       if (!timer_pending(&vif->dealloc_delay)) {
-                               vif->dealloc_delay.function =
-                                       xenvif_dealloc_delay;
-                               vif->dealloc_delay.data = (unsigned long)vif;
-                               mod_timer(&vif->dealloc_delay,
-                                         jiffies + msecs_to_jiffies(1));
-
-                       }
-                       return false;
-               }
-               del_timer_sync(&vif->dealloc_delay);
-               vif->dealloc_delay_timed_out = false;
-               return true;
-       }
-
-       return false;
+       return vif->dealloc_cons != vif->dealloc_prod;
 }
 
 void xenvif_unmap_frontend_rings(struct xenvif *vif)