Re: [PATCH 2/2] IB/ipoib: fix GRO merge failure for IPoIB originated TCP streams
From: Or Gerlitz <hidden>
Date: 2012-02-02 14:01:47
Also in:
linux-rdma
Possibly related (same subject, not in this thread)
- 2012-02-06 · Re: [PATCH 2/2] IB/ipoib: fix GRO merge failure for IPoIB originated TCP streams · Or Gerlitz <hidden>
- 2012-02-06 · Re: [PATCH 2/2] IB/ipoib: fix GRO merge failure for IPoIB originated TCP streams · Eric Dumazet <hidden>
- 2012-02-06 · Re: [PATCH 2/2] IB/ipoib: fix GRO merge failure for IPoIB originated TCP streams · Or Gerlitz <hidden>
- 2012-02-03 · RE: [PATCH 2/2] IB/ipoib: fix GRO merge failure for IPoIB originated TCP streams · Hefty, Sean <hidden>
- 2012-02-03 · RE: [PATCH 2/2] IB/ipoib: fix GRO merge failure for IPoIB originated TCP streams · Eric Dumazet <hidden>
On 2/1/2012 4:07 PM, Eric Dumazet wrote:
quoted
quoted
If we just turn it into a memcmp with a variable length would that work for you?I think yes, FWIW we will compare the IPoIB header, Roland is that okay for you?A memcmp(xxx, yyy, variable_len) will be out of line and slow, its a bit sad ... Are skb_mac_header(p) / skb_gro_mac_header(skb) going to point to IPoIB header ?
yes, both skb_mac_header(p) / skb_gro_mac_header(skb) point to IPoIB header, however (see next)
Maybe we can keep a fastpath for ethernet case... (the "if (hlen == ETH_HLEN) being always predicted) Maybe need to introduce gro_hard_header_len as well)
today, IPoIB advertizes hard_header_len which is bigger than the IPoIB header len, this is done such that skbs sent by the network stack have enough headroom for a "pseudoheader" which for few flows (e.g unicast arp replies and multicast) is placed there by the ipoib hard_header function and later used by the xmit function. So we can either try and change that, such that hard_header_len will be equal to the ipoib header len or add gro_hard_header_len as you suggested, any preferences? Or. Or.
quoted hunk ↗ jump to hunk
diff --git a/net/core/dev.c b/net/core/dev.c index 115dee1..62abee4 100644 --- a/net/core/dev.c +++ b/net/core/dev.c@@ -3500,14 +3500,20 @@ static inline gro_result_t __napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb) { struct sk_buff *p; + unsigned int hlen = skb->dev->hard_header_len; for (p = napi->gro_list; p; p = p->next) { unsigned long diffs; diffs = (unsigned long)p->dev ^ (unsigned long)skb->dev; diffs |= p->vlan_tci ^ skb->vlan_tci; - diffs |= compare_ether_header(skb_mac_header(p), - skb_gro_mac_header(skb)); + if (hlen == ETH_HLEN) + diffs |= compare_ether_header(skb_mac_header(p), + skb_gro_mac_header(skb)); + else if (!diffs) + diffs = memcmp(skb_mac_header(p), + skb_gro_mac_header(skb), + skb->dev->hard_header_len); NAPI_GRO_CB(p)->same_flow = !diffs; NAPI_GRO_CB(p)->flush = 0; }
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