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xen-netback: Add stat counters for zerocopy

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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 <zoltan.kiss@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Zoltan Kiss 2014-03-06 21:48:28 +00:00 • committed by David S. Miller
commit 1bb332af4c
3 changed files with 26 additions and 1 deletions
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9
drivers/net/xen-netback/netback.c
View file

@ -1323,8 +1323,10 @@ 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);
}
@ -1364,6 +1366,11 @@ 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)