On Thu, 01 Nov 2007 11:16:20 +0100 Eric Dumazet <[EMAIL PROTECTED]> wrote:
> 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) > > 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 NR_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 <[EMAIL PROTECTED]> > > include/net/inet_hashtables.h | 40 ++++++++++++++++++++++++++++---- > net/dccp/proto.c | 16 ++++++++++-- > net/ipv4/inet_diag.c | 9 ++++--- > net/ipv4/inet_hashtables.c | 7 +++-- > net/ipv4/inet_timewait_sock.c | 13 +++++----- > net/ipv4/tcp.c | 11 +++++++- > net/ipv4/tcp_ipv4.c | 11 ++++---- > net/ipv6/inet6_hashtables.c | 19 ++++++++------- > 8 files changed, 89 insertions(+), 37 deletions(-) > Longterm is there any chance of using rcu for this? Seems like it could be a big win. -- Stephen Hemminger <[EMAIL PROTECTED]> - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
