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/dccp | |
| parent | efac52762b1e3fe3035d29e82d8ee1aebc45e4a7 (diff) | |
| download | linux-230140cffa7feae90ad50bf259db1fa07674f3a7.tar.bz2 | |
[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/dccp')
| -rw-r--r-- | net/dccp/proto.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/net/dccp/proto.c b/net/dccp/proto.c index d84973928033..7a3bea9c28c1 100644 --- a/net/dccp/proto.c +++ b/net/dccp/proto.c @@ -1072,11 +1072,13 @@ static int __init dccp_init(void) } for (i = 0; i < dccp_hashinfo.ehash_size; i++) { - rwlock_init(&dccp_hashinfo.ehash[i].lock); INIT_HLIST_HEAD(&dccp_hashinfo.ehash[i].chain); INIT_HLIST_HEAD(&dccp_hashinfo.ehash[i].twchain); } + if (inet_ehash_locks_alloc(&dccp_hashinfo)) + goto out_free_dccp_ehash; + bhash_order = ehash_order; do { @@ -1091,7 +1093,7 @@ static int __init dccp_init(void) if (!dccp_hashinfo.bhash) { DCCP_CRIT("Failed to allocate DCCP bind hash table"); - goto out_free_dccp_ehash; + goto out_free_dccp_locks; } for (i = 0; i < dccp_hashinfo.bhash_size; i++) { @@ -1121,6 +1123,8 @@ out_free_dccp_mib: out_free_dccp_bhash: free_pages((unsigned long)dccp_hashinfo.bhash, bhash_order); dccp_hashinfo.bhash = NULL; +out_free_dccp_locks: + inet_ehash_locks_free(&dccp_hashinfo); out_free_dccp_ehash: free_pages((unsigned long)dccp_hashinfo.ehash, ehash_order); dccp_hashinfo.ehash = NULL; @@ -1139,6 +1143,7 @@ static void __exit dccp_fini(void) free_pages((unsigned long)dccp_hashinfo.ehash, get_order(dccp_hashinfo.ehash_size * sizeof(struct inet_ehash_bucket))); + inet_ehash_locks_free(&dccp_hashinfo); kmem_cache_destroy(dccp_hashinfo.bind_bucket_cachep); dccp_ackvec_exit(); dccp_sysctl_exit(); |