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authorDavid S. Miller <davem@davemloft.net>2010-08-25 02:27:49 -0700
committerDavid S. Miller <davem@davemloft.net>2010-08-25 02:27:49 -0700
commitad1af0fedba14f82b240a03fe20eb9b2fdbd0357 (patch)
tree4d53aa8bc2d9df782aa792e52670ab55c7a44d5b /net/ipv4/tcp.c
parentb2bc85631e72485b984bcd202a104591874babba (diff)
downloadblackbird-op-linux-ad1af0fedba14f82b240a03fe20eb9b2fdbd0357.tar.gz
blackbird-op-linux-ad1af0fedba14f82b240a03fe20eb9b2fdbd0357.zip
tcp: Combat per-cpu skew in orphan tests.
As reported by Anton Blanchard when we use percpu_counter_read_positive() to make our orphan socket limit checks, the check can be off by up to num_cpus_online() * batch (which is 32 by default) which on a 128 cpu machine can be as large as the default orphan limit itself. Fix this by doing the full expensive sum check if the optimized check triggers. Reported-by: Anton Blanchard <anton@samba.org> Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Diffstat (limited to 'net/ipv4/tcp.c')
-rw-r--r--net/ipv4/tcp.c5
1 files changed, 1 insertions, 4 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 176e11aaea77..197b9b77fa3e 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2011,11 +2011,8 @@ adjudge_to_death:
}
}
if (sk->sk_state != TCP_CLOSE) {
- int orphan_count = percpu_counter_read_positive(
- sk->sk_prot->orphan_count);
-
sk_mem_reclaim(sk);
- if (tcp_too_many_orphans(sk, orphan_count)) {
+ if (tcp_too_many_orphans(sk, 0)) {
if (net_ratelimit())
printk(KERN_INFO "TCP: too many of orphaned "
"sockets\n");
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