[dpdk-dev] Question about rte_hash ext flags on mulitithread read/write

[dpdk-dev] Question about rte_hash ext flags on mulitithread read/write

[Lilijun (Jerry)]

Hi All,
	There is some description about RTE hash's multi-thread support in Programmer's Guide. After reading that I still have some questions as follows:
    1)  There is a sentence " In all modes of operation lookups are thread-safe meaning lookups can be called from multiple threads concurrently.". 
        But if the extra_flag is only set RTE_HASH_EXTRA_FLAGS_EXT_TABLE, RTE hash will use a link list to store extend buckets due to excessive hash collisions.
        So how can we make sure the link list accesses are safe with reading/writing concurrently?
    2)  Can we support multithread writing with RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF being set?  Do we need add RTE_HASH_EXTRA_FLAGS_MULTI_WRITER_ADD flag?

    Any reply will be appreciated very much. Thanks.

Jerry