From: Eric Dumazet <edumazet@google.com> mainline inclusion from mainline-v6.15-rc1 commit 9544d60a2605d1500cf5c3e331a76b9eaf4538c9 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/ICA4Z5 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- In order to speedup __inet_hash_connect(), we want to ensure hash values for <source address, port X, destination address, destination port> are not randomly spread, but monotonically increasing. Goal is to allow __inet_hash_connect() to derive the hash value of a candidate 4-tuple with a single addition in the following patch in the series. Given : hash_0 = inet_ehashfn(saddr, 0, daddr, dport) hash_sport = inet_ehashfn(saddr, sport, daddr, dport) Then (hash_sport == hash_0 + sport) for all sport values. As far as I know, there is no security implication with this change. After this patch, when __inet_hash_connect() has to try XXXX candidates, the hash table buckets are contiguous and packed, allowing a better use of cpu caches and hardware prefetchers. Tested: Server: ulimit -n 40000; neper/tcp_crr -T 200 -F 30000 -6 --nolog Client: ulimit -n 40000; neper/tcp_crr -T 200 -F 30000 -6 --nolog -c -H server Before this patch: utime_start=0.271607 utime_end=3.847111 stime_start=18.407684 stime_end=1997.485557 num_transactions=1350742 latency_min=0.014131929 latency_max=17.895073144 latency_mean=0.505675853 latency_stddev=2.125164772 num_samples=307884 throughput=139866.80 perf top on client: 56.86% [kernel] [k] __inet6_check_established 17.96% [kernel] [k] __inet_hash_connect 13.88% [kernel] [k] inet6_ehashfn 2.52% [kernel] [k] rcu_all_qs 2.01% [kernel] [k] __cond_resched 0.41% [kernel] [k] _raw_spin_lock After this patch: utime_start=0.286131 utime_end=4.378886 stime_start=11.952556 stime_end=1991.655533 num_transactions=1446830 latency_min=0.001061085 latency_max=12.075275028 latency_mean=0.376375302 latency_stddev=1.361969596 num_samples=306383 throughput=151866.56 perf top: 50.01% [kernel] [k] __inet6_check_established 20.65% [kernel] [k] __inet_hash_connect 15.81% [kernel] [k] inet6_ehashfn 2.92% [kernel] [k] rcu_all_qs 2.34% [kernel] [k] __cond_resched 0.50% [kernel] [k] _raw_spin_lock 0.34% [kernel] [k] sched_balance_trigger 0.24% [kernel] [k] queued_spin_lock_slowpath There is indeed an increase of throughput and reduction of latency. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Tested-by: Jason Xing <kerneljasonxing@gmail.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Link: https://patch.msgid.link/20250305034550.879255-2-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Conflicts: net/ipv4/inet_hashtables.c net/ipv6/inet6_hashtables.c [commit 6e0735723ab4 and df51b8456415 are not backport] Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com> --- net/ipv4/inet_hashtables.c | 4 ++-- net/ipv6/inet6_hashtables.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index ca0f9097a53b..a3621a056f31 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -38,8 +38,8 @@ u32 inet_ehashfn(const struct net *net, const __be32 laddr, net_get_random_once(&inet_ehash_secret, sizeof(inet_ehash_secret)); - return __inet_ehashfn(laddr, lport, faddr, fport, - inet_ehash_secret + net_hash_mix(net)); + return lport + __inet_ehashfn(laddr, 0, faddr, fport, + inet_ehash_secret + net_hash_mix(net)); } EXPORT_SYMBOL_GPL(inet_ehashfn); diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c index b72ebbd65f8d..e5e6cb26a432 100644 --- a/net/ipv6/inet6_hashtables.c +++ b/net/ipv6/inet6_hashtables.c @@ -36,8 +36,8 @@ u32 inet6_ehashfn(const struct net *net, lhash = (__force u32)laddr->s6_addr32[3]; fhash = __ipv6_addr_jhash(faddr, ipv6_hash_secret); - return __inet6_ehashfn(lhash, lport, fhash, fport, - inet6_ehash_secret + net_hash_mix(net)); + return lport + __inet6_ehashfn(lhash, 0, fhash, fport, + inet6_ehash_secret + net_hash_mix(net)); } EXPORT_SYMBOL_GPL(inet6_ehashfn); -- 2.25.1