Doug / smarc-fsl-linux-kernel

10 Sep, 2010

1 commit

  • a73f8844e   lglock: make lg_lock_global() actually lock globally ... Browse Code »

    lg_lock_global() currently only acquires spinlocks for online CPUs, but
    it's meant to lock all possible CPUs. Lglock-protected resources may be
    associated with removed CPUs - and, indeed, that could happen with the
    per-superblock open files lists.

    At Nick's suggestion, change for_each_online_cpu() to
    for_each_possible_cpu() to protect accesses to those resources.

    Cc: Al Viro
    Acked-by: Nick Piggin
    Signed-off-by: Jonathan Corbet
    Signed-off-by: Linus Torvalds

    Jonathan Corbet
     

18 Aug, 2010

1 commit

  • 2dc91abe0   lglock: introduce special lglock and brlock spin locks ... Browse Code »

    lglock: introduce special lglock and brlock spin locks

    This patch introduces "local-global" locks (lglocks). These can be used to:

    - Provide fast exclusive access to per-CPU data, with exclusive access to
    another CPU's data allowed but possibly subject to contention, and to provide
    very slow exclusive access to all per-CPU data.
    - Or to provide very fast and scalable read serialisation, and to provide
    very slow exclusive serialisation of data (not necessarily per-CPU data).

    Brlocks are also implemented as a short-hand notation for the latter use
    case.

    Thanks to Paul for local/global naming convention.

    Cc: linux-kernel@vger.kernel.org
    Cc: Al Viro
    Cc: "Paul E. McKenney"
    Signed-off-by: Nick Piggin
    Signed-off-by: Al Viro

    Nick Piggin