[Xen-devel] [PATCH 2/4] xen/netback: Split one page pool into two(tx/rx) page pool.

[Annie Li <annie.li@xxxxxxxxxx>]

For tx path, this implementation simplifies the work of searching out
grant page from page pool based on grant reference.

Signed-off-by: Annie Li <annie.li@xxxxxxxxxx>
---
 drivers/net/xen-netback/common.h    |   14 ++++++++++----
 drivers/net/xen-netback/interface.c |   12 ++++++++----
 drivers/net/xen-netback/netback.c   |   15 +++++++++------
 3 files changed, 27 insertions(+), 14 deletions(-)

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index a85cac6..02c8573 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -47,8 +47,6 @@
 
 #define XEN_NETIF_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
 #define XEN_NETIF_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
-#define MAXIMUM_OUTSTANDING_BLOCK_REQS \
-                       (XEN_NETIF_TX_RING_SIZE + XEN_NETIF_RX_RING_SIZE)
 
 struct xen_netbk;
 
@@ -111,8 +109,16 @@ struct xenvif {
 
        wait_queue_head_t waiting_to_free;
 
-       struct persistent_entry *persistent_gnt[MAXIMUM_OUTSTANDING_BLOCK_REQS];
-       unsigned int persistent_gntcnt;
+       struct persistent_entry *persistent_tx_gnt[XEN_NETIF_TX_RING_SIZE];
+
+       /*
+        * 2*XEN_NETIF_RX_RING_SIZE is for the case of each head/fragment page
+        * using 2 copy operations.
+        */
+       struct persistent_entry *persistent_rx_gnt[2*XEN_NETIF_RX_RING_SIZE];
+
+       unsigned int persistent_tx_gntcnt;
+       unsigned int persistent_rx_gntcnt;
 };
 
 static inline struct xenbus_device *xenvif_to_xenbus_device(struct xenvif *vif)
diff --git a/drivers/net/xen-netback/interface.c 
b/drivers/net/xen-netback/interface.c
index 226d159..ecbe116 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -300,7 +300,8 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t 
domid,
                return ERR_PTR(err);
        }
 
-       vif->persistent_gntcnt = 0;
+       vif->persistent_tx_gntcnt = 0;
+       vif->persistent_rx_gntcnt = 0;
 
        netdev_dbg(dev, "Successfully created xenvif\n");
        return vif;
@@ -385,9 +386,12 @@ void xenvif_disconnect(struct xenvif *vif)
        unregister_netdev(vif->dev);
 
        xen_netbk_unmap_frontend_rings(vif);
-       if (vif->persistent_grant)
-               xenvif_free_grants(vif->persistent_gnt,
-                                  vif->persistent_gntcnt);
+       if (vif->persistent_grant) {
+               xenvif_free_grants(vif->persistent_tx_gnt,
+                                  vif->persistent_tx_gntcnt);
+               xenvif_free_grants(vif->persistent_rx_gnt,
+                                  vif->persistent_rx_gntcnt);
+       }
 
        free_netdev(vif->dev);
 }
diff --git a/drivers/net/xen-netback/netback.c 
b/drivers/net/xen-netback/netback.c
index a26d3fc..ec59c73 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -208,14 +208,17 @@ grant_memory_copy_op(unsigned int cmd, void *vuop, 
unsigned int count,
 
        BUG_ON(cmd != GNTTABOP_copy);
        for (i = 0; i < count; i++) {
-               if (tx_pool)
+               if (tx_pool) {
                        vif = netbk->gnttab_tx_vif[i];
-               else
+                       gnt_count = &vif->persistent_tx_gntcnt;
+                       gnt_total = XEN_NETIF_TX_RING_SIZE;
+                       pers_entry = vif->persistent_tx_gnt;
+               } else {
                        vif = netbk->gnttab_rx_vif[i];
-
-               pers_entry = vif->persistent_gnt;
-               gnt_count = &vif->persistent_gntcnt;
-               gnt_total = MAXIMUM_OUTSTANDING_BLOCK_REQS;
+                       gnt_count = &vif->persistent_rx_gntcnt;
+                       gnt_total = 2*XEN_NETIF_RX_RING_SIZE;
+                       pers_entry = vif->persistent_rx_gnt;
+               }
 
                if (vif->persistent_grant) {
                        void *saddr, *daddr;
-- 
1.7.3.4


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