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    We are pleased to announce the next update to our new preempt-rt

    - fix the network live lock issue for real

    - disable preemption across iomap atomic section

    - indentify false positives in the softirq pending check
    in the nohz code.

    The network issue which I described in the -21 release still persists
    between net-rx and net-tx softirqs. The real fix is replacing the
    spin_trylock with spin_lock in the affected drivers.

    On -rt we had several unexplained reports of cpus going idle with a
    pending softirq. I got hands on a trace of such a situation. What
    happens is that a softirq is blocked on a lock which is held by a task
    which is either blocked itself or running on another CPU. When there
    is no other active task on the CPU then it goes idle but the softirq
    pending bit of the blocked softirq thread is still set. This leads to
    false positive warnings. To filter out those cases the blocked state
    of the softirq needs to be checked instead of printing the warning

    Download locations:

    Information on the RT patch can be found at:

    to build the tree, the following patches should be

    The broken out patches are also available at the same download

    Enjoy !


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      Last update: 2009-06-23 14:35    [W:0.041 / U:5.184 seconds]
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