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authorIan Campbell <Ian.Campbell@citrix.com>2013-01-07 05:32:06 +0000
committerDavid S. Miller <davem@davemloft.net>2013-01-07 19:51:19 -0800
commitd9a58a782e396a0f04e8445b7ba3763c8a48c7fe (patch)
tree319af7e412885f2c7c9c7f45d5d7bfbc68d762cd
parent32fa10b24ef64b41e8ca17068fa9dc625427a05e (diff)
downloadconfigs-d9a58a782e396a0f04e8445b7ba3763c8a48c7fe.tar.gz
xen/netfront: improve truesize tracking
Using RX_COPY_THRESHOLD is incorrect if the SKB is actually smaller than that. We have already accounted for this in NETFRONT_SKB_CB(skb)->pull_to so use that instead. Fixes WARN_ON from skb_try_coalesce. Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Cc: Sander Eikelenboom <linux@eikelenboom.it> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: annie li <annie.li@oracle.com> Cc: xen-devel@lists.xen.org Cc: netdev@vger.kernel.org Cc: stable@kernel.org # 3.7.x only Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/xen-netfront.c27
1 files changed, 4 insertions, 23 deletions
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index c26e28b4bd9..7ffa43bd7cf 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -1015,29 +1015,10 @@ err:
i = xennet_fill_frags(np, skb, &tmpq);
/*
- * Truesize approximates the size of true data plus
- * any supervisor overheads. Adding hypervisor
- * overheads has been shown to significantly reduce
- * achievable bandwidth with the default receive
- * buffer size. It is therefore not wise to account
- * for it here.
- *
- * After alloc_skb(RX_COPY_THRESHOLD), truesize is set
- * to RX_COPY_THRESHOLD + the supervisor
- * overheads. Here, we add the size of the data pulled
- * in xennet_fill_frags().
- *
- * We also adjust for any unused space in the main
- * data area by subtracting (RX_COPY_THRESHOLD -
- * len). This is especially important with drivers
- * which split incoming packets into header and data,
- * using only 66 bytes of the main data area (see the
- * e1000 driver for example.) On such systems,
- * without this last adjustement, our achievable
- * receive throughout using the standard receive
- * buffer size was cut by 25%(!!!).
- */
- skb->truesize += skb->data_len - RX_COPY_THRESHOLD;
+ * Truesize is the actual allocation size, even if the
+ * allocation is only partially used.
+ */
+ skb->truesize += PAGE_SIZE * skb_shinfo(skb)->nr_frags;
skb->len += skb->data_len;
if (rx->flags & XEN_NETRXF_csum_blank)