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    SubjectRe: [PATCH v3] softlockup: remove hung_task_check_count

    * Mandeep Baines <> wrote:

    > On Thu, Jan 22, 2009 at 11:55 AM, Mandeep Singh Baines <> wrote:
    > >
    > > The unlock and lock could be removed and only compiled in if PREEMPT.
    > > If the number of tasks isn't bound, the lock might be held too long.
    > >
    > This is incorrect. The adding the lock and unlock will not make the
    > system more pre-emptive. To be more pre-emptive you'd want to check
    > need_resched() as often as possible.
    > > It would be kinda funny if hung_task caused a softlockup.
    > >
    > Again. This is incorrect. Rescheduling if need_resched() will prevent
    > softlockup.
    > Not sure what I was thinking this morning;)
    > However, I am happy with the patch. To give writers a chance, the lock
    > should held for bounded time. Holding the lock in khungtask (which is
    > running at low scheduler priority) could potentially be delaying
    > important work. The longer the lock is held, the bigger the priority
    > inversion problem.

    not sure i like the whole idea of removing the max iterations check. In
    theory if there's a _ton_ of tasks, we could spend a lot of time looping
    there. So it always looked prudent to limit it somewhat.


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