These counters help determine how often the buffers had to be copied. Also
they help find out if packets are leaked, as if "sent != success + fail",
there are probably packets never freed up properly.
NOTE: if bisect brought you here, you should apply the series up until #9,
otherwise Windows guests can't work properly and malicious guests can block
other guests by not releasing their sent packets.
Signed-off-by: Zoltan Kiss <zoltan.k...@citrix.com>
---
drivers/net/xen-netback/common.h | 3 +++
drivers/net/xen-netback/interface.c | 15 +++++++++++++++
drivers/net/xen-netback/netback.c | 9 ++++++++-
3 files changed, 26 insertions(+), 1 deletion(-)
diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 79ba456..eac171e 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -167,6 +167,9 @@ struct xenvif {
/* Statistics */
unsigned long rx_gso_checksum_fixup;
+ unsigned long tx_zerocopy_sent;
+ unsigned long tx_zerocopy_success;
+ unsigned long tx_zerocopy_fail;
/* Miscellaneous private stuff. */
struct net_device *dev;
diff --git a/drivers/net/xen-netback/interface.c
b/drivers/net/xen-netback/interface.c
index 408ab57..adfed30 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -237,6 +237,21 @@ static const struct xenvif_stat {
"rx_gso_checksum_fixup",
offsetof(struct xenvif, rx_gso_checksum_fixup)
},
+ /* If (sent != success + fail), there are probably packets never
+ * freed up properly!
+ */
+ {
+ "tx_zerocopy_sent",
+ offsetof(struct xenvif, tx_zerocopy_sent),
+ },
+ {
+ "tx_zerocopy_success",
+ offsetof(struct xenvif, tx_zerocopy_success),
+ },
+ {
+ "tx_zerocopy_fail",
+ offsetof(struct xenvif, tx_zerocopy_fail)
+ },
};
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 bc91965..44e6988 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1554,8 +1554,10 @@ static int xenvif_tx_submit(struct xenvif *vif)
* do a skb_copy_ubufs while we are still in control of the
* skb. E.g. the __pskb_pull_tail earlier can do such thing.
*/
- if (skb_shinfo(skb)->destructor_arg)
+ if (skb_shinfo(skb)->destructor_arg) {
skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
+ vif->tx_zerocopy_sent++;
+ }
netif_receive_skb(skb);
}
@@ -1595,6 +1597,11 @@ void xenvif_zerocopy_callback(struct ubuf_info *ubuf,
bool zerocopy_success)
napi_schedule(&vif->napi);
local_bh_enable();
}
+
+ if (likely(zerocopy_success))
+ vif->tx_zerocopy_success++;
+ else
+ vif->tx_zerocopy_fail++;
}
static inline void xenvif_tx_dealloc_action(struct xenvif *vif)
--
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