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  1. 01 2月, 2008 1 次提交
  3. 29 1月, 2008 4 次提交
  5. 07 11月, 2007 1 次提交
    • E
      [INET]: Remove per bucket rwlock in tcp/dccp ehash table. · 230140cf
      由 Eric Dumazet 提交于 
      As done two years ago on IP route cache table (commit
22c047cc) , 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: NEric Dumazet <dada1@cosmosbay.com>
Acked-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      230140cf
  7. 19 10月, 2007 1 次提交
  9. 11 10月, 2007 1 次提交
  11. 11 2月, 2007 1 次提交
  13. 09 2月, 2007 1 次提交
    • E
      [NET]: change layout of ehash table · dbca9b27
      由 Eric Dumazet 提交于 
      ehash table layout is currently this one :

First half of this table is used by sockets not in TIME_WAIT state
Second half of it is used by sockets in TIME_WAIT state.

This is non optimal because of for a given hash or socket, the two chain heads 
are located in separate cache lines.
Moreover the locks of the second half are never used.

If instead of this halving, we use two list heads in inet_ehash_bucket instead 
of only one, we probably can avoid one cache miss, and reduce ram usage, 
particularly if sizeof(rwlock_t) is big (various CONFIG_DEBUG_SPINLOCK, 
CONFIG_DEBUG_LOCK_ALLOC settings). So we still halves the table but we keep 
together related chains to speedup lookups and socket state change.

In this patch I did not try to align struct inet_ehash_bucket, but a future 
patch could try to make this structure have a convenient size (a power of two 
or a multiple of L1_CACHE_SIZE).
I guess rwlock will just vanish as soon as RCU is plugged into ehash :) , so 
maybe we dont need to scratch our heads to align the bucket...

Note : In case struct inet_ehash_bucket is not a power of two, we could 
probably change alloc_large_system_hash() (in case it use __get_free_pages()) 
to free the unused space. It currently allocates a big zone, but the last 
quarter of it could be freed. Again, this should be a temporary 'problem'.

Patch tested on ipv4 tcp only, but should be OK for IPV6 and DCCP.
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      dbca9b27
  15. 08 12月, 2006 2 次提交
  17. 29 9月, 2006 2 次提交
  19. 23 9月, 2006 2 次提交
  21. 01 7月, 2006 1 次提交
  23. 15 4月, 2006 1 次提交
    • A
      [IPV4]: Possible cleanups. · 6c97e72a
      由 Adrian Bunk 提交于 
      This patch contains the following possible cleanups:
- make the following needlessly global function static:
  - arp.c: arp_rcv()
- remove the following unused EXPORT_SYMBOL's:
  - devinet.c: devinet_ioctl
  - fib_frontend.c: ip_rt_ioctl
  - inet_hashtables.c: inet_bind_bucket_create
  - inet_hashtables.c: inet_bind_hash
  - tcp_input.c: sysctl_tcp_abc
  - tcp_ipv4.c: sysctl_tcp_tw_reuse
  - tcp_output.c: sysctl_tcp_mtu_probing
  - tcp_output.c: sysctl_tcp_base_mss
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      6c97e72a
  25. 24 3月, 2006 1 次提交
  27. 04 1月, 2006 1 次提交
  29. 30 8月, 2005 6 次提交