Thread (17 messages) 17 messages, 5 authors, 2013-09-30

Re: [PATCH net-next v3 2/3] bonding: modify the old and add new xmit hash policies

From: Eric Dumazet <hidden>
Date: 2013-09-26 16:02:34

On Thu, 2013-09-26 at 16:09 +0200, Nikolay Aleksandrov wrote:
This patch adds two new hash policy modes which use skb_flow_dissect:
3 - Encapsulated layer 2+3
4 - Encapsulated layer 3+4
There should be a good improvement for tunnel users in those modes.
It also changes the old hash functions to:
hash ^= (__force u32)flow.dst ^ (__force u32)flow.src;
hash ^= (hash >> 16);
hash ^= (hash >> 8);

Where hash will be initialized either to L2 hash, that is
SRCMAC[5] XOR DSTMAC[5], or to flow->ports which should be extracted
from the upper layer. Flow's dst and src are also extracted based on the
xmit policy either directly from the buffer or by using skb_flow_dissect,
but in both cases if the protocol is IPv6 then dst and src are obtained by
ipv6_addr_hash() on the real addresses. In case of a non-dissectable
packet, the algorithms fall back to L2 hashing.
The bond_set_mode_ops() function is now obsolete and thus deleted
because it was used only to set the proper hash policy. Also we trim a
pointer from struct bonding because we no longer need to keep the hash
function, now there's only a single hash function - bond_xmit_hash that
works based on bond->params.xmit_policy.

The hash function and skb_flow_dissect were suggested by Eric Dumazet.
The layer names were suggested by Andy Gospodarek, because I suck at
semantics.

Signed-off-by: Nikolay Aleksandrov <redacted>
---
v2: fix a bug in bond_flow_dissect which might've caused the use of
    uninitalized flow_keys and make use of skb_flow_get_ports
v3: no change
One line is intentionally left at 82 chars since it's the whole function
and IMO looks better that way.

 drivers/net/bonding/bond_3ad.c   |   2 +-
 drivers/net/bonding/bond_main.c  | 197 ++++++++++++++-------------------------
 drivers/net/bonding/bond_sysfs.c |   2 -
 drivers/net/bonding/bonding.h    |   3 +-
 include/uapi/linux/if_bonding.h  |   2 +
 5 files changed, 72 insertions(+), 134 deletions(-)

I love this patch, thanks for following up on this one.

Reviewed-by: Eric Dumazet <edumazet@google.com>
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