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| author | Eric Dumazet <edumazet@google.com> | 2012-08-24 05:40:47 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-08-24 11:47:48 -0400 |
| commit | 78df76a065ae3b5dbcb9a29912adc02f697de498 (patch) | |
| tree | 5b9ab36790a2e0101a15d70bdf41b066ce0e55aa | |
| parent | a0dfb2634e5671770f598cda08002d8cda66ac77 (diff) | |
| download | linux-78df76a065ae3b5dbcb9a29912adc02f697de498.tar.gz linux-78df76a065ae3b5dbcb9a29912adc02f697de498.tar.bz2 linux-78df76a065ae3b5dbcb9a29912adc02f697de498.zip | |
ipv4: take rt_uncached_lock only if needed
Multicast traffic allocates dst with DST_NOCACHE, but dst is
not inserted into rt_uncached_list.
This slowdown multicast workloads on SMP because rt_uncached_lock is
contended.
Change the test before taking the lock to actually check the dst
was inserted into rt_uncached_list.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/route.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 8c8c748ebb28..24fd4c596643 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -1263,7 +1263,7 @@ static void ipv4_dst_destroy(struct dst_entry *dst) { struct rtable *rt = (struct rtable *) dst; - if (dst->flags & DST_NOCACHE) { + if (!list_empty(&rt->rt_uncached)) { spin_lock_bh(&rt_uncached_lock); list_del(&rt->rt_uncached); spin_unlock_bh(&rt_uncached_lock); |