Hello.
On 09/29/2016 05:04 PM, Paolo Abeni wrote:
The commit 879c7220e828 ("net: pktgen: Observe needed_headroom
of the device") increased the 'pkt_overhead' field value by
LL_RESERVED_SPACE.
As a side effect the generated packet size, computed as:
/* Eth + IPh + UDPh + mpls */
datalen = pkt_dev->cur_pkt_size - 14 - 20 - 8 -
pkt_dev->pkt_overhead;
is decreased by the same value.
The above changed slightly the behavior of existing pktgen users,
and made the interface somewhat inconsistent.
Fix it by restoring the previous pkt_overhead value and using
LL_RESERVED_SPACE as extralen in skb allocation.
Also, change pktgen_alloc_skb() to only partially reserve
the headroom to allow the caller to prefetch from ll header
start.
Fixes: 879c7220e828 ("net: pktgen: Observe needed_headroom of the device")
Suggested-by: Ben Greear <gree...@candelatech.com>
Signed-off-by: Paolo Abeni <pab...@redhat.com>
---
net/core/pktgen.c | 21 ++++++++++-----------
1 file changed, 10 insertions(+), 11 deletions(-)
diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index bbd118b..5c9b397 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
[...]
@@ -2796,8 +2796,9 @@ static struct sk_buff *pktgen_alloc_skb(struct net_device
*dev,
skb = __netdev_alloc_skb(dev, size, GFP_NOWAIT);
}
+ /* the caller prefetch from skb->data and reserve for the mac hdr */
Pre-fetches and reserves?
[...]
MBR, Sergei
