ipv4: speedup ip_idents_reserve()
authorEric Dumazet <edumazet@google.com>
Fri, 1 May 2015 17:37:49 +0000 (10:37 -0700)
committerDavid S. Miller <davem@davemloft.net>
Fri, 1 May 2015 23:44:00 +0000 (19:44 -0400)
commit355b590ca24a53f5e2f6999218b5321eaf730a7e
treee6a48af10ed15aca0c6d6a34533aef5636714c1c
parent9dd3c797496affd699805c8a9d8429ad318c892f
ipv4: speedup ip_idents_reserve()

Under stress, ip_idents_reserve() is accessing a contended
cache line twice, with non optimal MESI transactions.

If we place timestamps in separate location, we reduce this
pressure by ~50% and allow atomic_add_return() to issue
a Request for Ownership.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/ipv4/route.c