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| 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/inet_diag.c | |
| parent | efac52762b1e3fe3035d29e82d8ee1aebc45e4a7 (diff) | |
| download | linux-230140cffa7feae90ad50bf259db1fa07674f3a7.tar.gz linux-230140cffa7feae90ad50bf259db1fa07674f3a7.tar.bz2 linux-230140cffa7feae90ad50bf259db1fa07674f3a7.zip | |
[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/inet_diag.c')
| -rw-r--r-- | net/ipv4/inet_diag.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c index dc429b6b0ba6..b0170732b5e9 100644 --- a/net/ipv4/inet_diag.c +++ b/net/ipv4/inet_diag.c @@ -747,13 +747,14 @@ skip_listen_ht: for (i = s_i; i < hashinfo->ehash_size; i++) { struct inet_ehash_bucket *head = &hashinfo->ehash[i]; + rwlock_t *lock = inet_ehash_lockp(hashinfo, i); struct sock *sk; struct hlist_node *node; if (i > s_i) s_num = 0; - read_lock_bh(&head->lock); + read_lock_bh(lock); num = 0; sk_for_each(sk, node, &head->chain) { struct inet_sock *inet = inet_sk(sk); @@ -769,7 +770,7 @@ skip_listen_ht: r->id.idiag_dport) goto next_normal; if (inet_csk_diag_dump(sk, skb, cb) < 0) { - read_unlock_bh(&head->lock); + read_unlock_bh(lock); goto done; } next_normal: @@ -791,14 +792,14 @@ next_normal: r->id.idiag_dport) goto next_dying; if (inet_twsk_diag_dump(tw, skb, cb) < 0) { - read_unlock_bh(&head->lock); + read_unlock_bh(lock); goto done; } next_dying: ++num; } } - read_unlock_bh(&head->lock); + read_unlock_bh(lock); } done: |