• Roland Dreier's avatar
    nvme-fabrics: Convert nvmf_transports_mutex to an rwsem · 489beb91
    Roland Dreier authored
    The mutex protects against the list of transports changing while a
    controller is being created, but using a plain old mutex means that it
    also serializes controller creation.  This unnecessarily slows down
    creating multiple controllers - for example for the RDMA transport,
    creating a controller involves establishing one connection for every IO
    queue, which involves even more network/software round trips, so the
    delay can become significant.
    
    The simplest way to fix this is to change the mutex to an rwsem and only
    hold it for writing when the list is being mutated.  Since we can take
    the rwsem for reading while creating a controller, we can create multiple
    controllers in parallel.
    Signed-off-by: default avatarRoland Dreier <roland@purestorage.com>
    Reviewed-by: default avatarSagi Grimberg <sagi@grimberg.me>
    Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
    489beb91
fabrics.c 25.9 KB