• Ying Xue's avatar
    tipc: convert tipc reference table to use generic rhashtable · 07f6c4bc
    Ying Xue authored
    As tipc reference table is statically allocated, its memory size
    requested on stack initialization stage is quite big even if the
    maximum port number is just restricted to 8191 currently, however,
    the number already becomes insufficient in practice. But if the
    maximum ports is allowed to its theory value - 2^32, its consumed
    memory size will reach a ridiculously unacceptable value. Apart from
    this, heavy tipc users spend a considerable amount of time in
    tipc_sk_get() due to the read-lock on ref_table_lock.
    
    If tipc reference table is converted with generic rhashtable, above
    mentioned both disadvantages would be resolved respectively: making
    use of the new resizable hash table can avoid locking on the lookup;
    smaller memory size is required at initial stage, for example, 256
    hash bucket slots are requested at the beginning phase instead of
    allocating the entire 8191 slots in old mode. The hash table will
    grow if entries exceeds 75% of table size up to a total table size
    of 1M, and it will automatically shrink if usage falls below 30%,
    but the minimum table size is allowed down to 256.
    
    Also converts ref_table_lock to a separate mutex to protect hash table
    mutations on write side. Lastly defers the release of the socket
    reference using call_rcu() to allow using an RCU read-side protected
    call to rhashtable_lookup().
    Signed-off-by: default avatarYing Xue <ying.xue@windriver.com>
    Acked-by: default avatarJon Maloy <jon.maloy@ericsson.com>
    Acked-by: default avatarErik Hugne <erik.hugne@ericsson.com>
    Cc: Thomas Graf <tgraf@suug.ch>
    Acked-by: default avatarThomas Graf <tgraf@suug.ch>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    07f6c4bc
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