• Zach Brown's avatar
    [PATCH] aio: remove kioctx from mm_struct · 20dcae32
    Zach Brown authored
    Sync iocbs have a life cycle that don't need a kioctx.  Their retrying, if
    any, is done in the context of their owner who has allocated them on the
    stack.
    
    The sole user of a sync iocb's ctx reference was aio_complete() checking for
    an elevated iocb ref count that could never happen.  No path which grabs an
    iocb ref has access to sync iocbs.
    
    If we were to implement sync iocb cancelation it would be done by the owner of
    the iocb using its on-stack reference.
    
    Removing this chunk from aio_complete allows us to remove the entire kioctx
    instance from mm_struct, reducing its size by a third.  On a i386 testing box
    the slab size went from 768 to 504 bytes and from 5 to 8 per page.
    Signed-off-by: default avatarZach Brown <zach.brown@oracle.com>
    Acked-by: default avatarBenjamin LaHaise <bcrl@kvack.org>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    20dcae32
fork.c 32.1 KB