With mega flow implementation ovs flow can be shared between
multiple CPUs which makes stats updates highly contended
operation. This patch uses per-CPU stats in cases where a flow
is likely to be shared (if there is a wildcard in the 5-tuple
and therefore likely to be spread by RSS). In other situations,
it uses the current strategy, saving memory and allocation time.
Signed-off-by: NPravin B Shelar <pshelar@nicira.com>
Signed-off-by: NJesse Gross <jesse@nicira.com>

Flow lookup can happen either in packet processing context or userspace
context but it was annotated as requiring RCU read lock to be held. This
also allows OVS mutex to be held without causing warnings.
Reported-by: NJustin Pettit <jpettit@nicira.com>
Signed-off-by: NJesse Gross <jesse@nicira.com>
Reviewed-by: NThomas Graf <tgraf@redhat.com>

API changes only for code readability. No functional chnages.

This patch removes the underscored version. Added a new API
ovs_flow_tbl_lookup_stats() that returns the n_mask_hits.

Reported by: Ben Pfaff <blp@nicira.com>
Reviewed-by: NThomas Graf <tgraf@redhat.com>
Signed-off-by: NAndy Zhou <azhou@nicira.com>
Signed-off-by: NJesse Gross <jesse@nicira.com>

Signed-off-by: NBen Pfaff <blp@nicira.com>
Signed-off-by: NJesse Gross <jesse@nicira.com>

Flow->hash can be used to detect hash collisions and avoid flow key
compare in flow lookup.
Signed-off-by: NPravin B Shelar <pshelar@nicira.com>
Signed-off-by: NJesse Gross <jesse@nicira.com>

Collect mega flow mask stats. ovs-dpctl show command can be used to
display them for debugging and performance tuning.
Signed-off-by: NAndy Zhou <azhou@nicira.com>
Signed-off-by: NJesse Gross <jesse@nicira.com>

Hides mega-flow implementation in flow_table.c rather than
datapath.c.
Signed-off-by: NPravin B Shelar <pshelar@nicira.com>
Signed-off-by: NJesse Gross <jesse@nicira.com>

ovs-flow rehash does not touch mega flow list. Following patch
moves it dp struct datapath.  Avoid one extra indirection for
accessing mega-flow list head on every packet receive.
Signed-off-by: NPravin B Shelar <pshelar@nicira.com>
Signed-off-by: NJesse Gross <jesse@nicira.com>

Over the time datapath.c and flow.c has became pretty large files.
Following patch restructures functionality of component into three
different components:

flow.c: contains flow extract.
flow_netlink.c: netlink flow api.
flow_table.c: flow table api.

This patch restructures code without changing logic.
Signed-off-by: NPravin B Shelar <pshelar@nicira.com>
Signed-off-by: NJesse Gross <jesse@nicira.com>