[PATCH net-next v7 6/9] xen-netback: Add stat counters for zerocopy
From: Zoltan Kiss <hidden>
Date: 2014-03-06 21:51:27
Also in:
lkml, xen-devel
Subsystem:
networking drivers, the rest, xen network backend driver · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Wei Liu, Paul Durrant
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 "xen-netback: Timeout packets in RX path", 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 <redacted> ---
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)