diff options
| author | Eric Dumazet <dada1@cosmosbay.com> | 2007-11-07 02:40:20 -0800 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2007-11-07 04:15:11 -0800 |
| commit | 230140cffa7feae90ad50bf259db1fa07674f3a7 (patch) | |
| tree | 815472add31606423a508a17806b7884f0ab3e2e /net/ipv4/tcp.c | |
| parent | efac52762b1e3fe3035d29e82d8ee1aebc45e4a7 (diff) | |
[INET]: Remove per bucket rwlock in tcp/dccp ehash table.
As done two years ago on IP route cache table (commit
22c047ccbc68fa8f3fa57f0e8f906479a062c426) , we can avoid using one
lock per hash bucket for the huge TCP/DCCP hash tables.
On a typical x86_64 platform, this saves about 2MB or 4MB of ram, for
litle performance differences. (we hit a different cache line for the
rwlock, but then the bucket cache line have a better sharing factor
among cpus, since we dirty it less often). For netstat or ss commands
that want a full scan of hash table, we perform fewer memory accesses.
Using a 'small' table of hashed rwlocks should be more than enough to
provide correct SMP concurrency between different buckets, without
using too much memory. Sizing of this table depends on
num_possible_cpus() and various CONFIG settings.
This patch provides some locking abstraction that may ease a future
work using a different model for TCP/DCCP table.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp.c')
| -rw-r--r-- | net/ipv4/tcp.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index c64072bb504b..8e65182f7af1 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2456,11 +2456,11 @@ void __init tcp_init(void) thash_entries ? 0 : 512 * 1024); tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size; for (i = 0; i < tcp_hashinfo.ehash_size; i++) { - rwlock_init(&tcp_hashinfo.ehash[i].lock); INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].chain); INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].twchain); } - + if (inet_ehash_locks_alloc(&tcp_hashinfo)) + panic("TCP: failed to alloc ehash_locks"); tcp_hashinfo.bhash = alloc_large_system_hash("TCP bind", sizeof(struct inet_bind_hashbucket), |