[PATCH net-next v3 7/9] xen-netback: Add stat counters for frag_list skbs

From: Zoltan Kiss
Date: Tue Jan 07 2014 - 19:15:36 EST


These counters help determine how often the guest sends a packet with more
than MAX_SKB_FRAGS frags.

Signed-off-by: Zoltan Kiss <zoltan.kiss@xxxxxxxxxx>
---
drivers/net/xen-netback/common.h | 1 +
drivers/net/xen-netback/interface.c | 7 +++++++
drivers/net/xen-netback/netback.c | 1 +
3 files changed, 9 insertions(+)

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index e3c28ff..c037efb 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -158,6 +158,7 @@ struct xenvif {
unsigned long tx_zerocopy_sent;
unsigned long tx_zerocopy_success;
unsigned long tx_zerocopy_fail;
+ unsigned long tx_frag_overflow;

/* Miscellaneous private stuff. */
struct net_device *dev;
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index ac27af3..b7daf8d 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -254,6 +254,13 @@ static const struct xenvif_stat {
"tx_zerocopy_fail",
offsetof(struct xenvif, tx_zerocopy_fail)
},
+ /* Number of packets exceeding MAX_SKB_FRAG slots. You should use
+ * a guest with the same MAX_SKB_FRAG
+ */
+ {
+ "tx_frag_overflow",
+ offsetof(struct xenvif, tx_frag_overflow)
+ },
};

static int xenvif_get_sset_count(struct net_device *dev, int string_set)
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 9841429..4305965 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1656,6 +1656,7 @@ static int xenvif_tx_submit(struct xenvif *vif, int budget)
skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
skb_shinfo(nskb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
vif->tx_zerocopy_sent += 2;
+ vif->tx_frag_overflow++;
nskb = skb;

skb = skb_copy_expand(skb, 0, 0, GFP_ATOMIC | __GFP_NOWARN);
--
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