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    SubjectRe: [PATCH 00/11] nested sleeps, fixes and debug infrastructure
    On 10/27, Peter Zijlstra wrote:
    >
    > On Thu, Oct 02, 2014 at 02:15:53PM +0200, Peter Zijlstra wrote:
    > > On Thu, Oct 02, 2014 at 12:22:51PM +0200, Peter Zijlstra wrote:
    >
    > > > +#define __wait_event_freezable(wq, condition) \
    > > > + (void)___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0, \
    > > > + schedule(); try_to_freeze())
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

    see below.

    > > > +
    > > > +/**
    > > > + * wait_event - sleep until a condition gets true or freeze (for kthreads)
    > > > + * @wq: the waitqueue to wait on
    > > > + * @condition: a C expression for the event to wait for
    > > > + *
    > > > + * The process is put to sleep (TASK_INTERRUPTIBLE -- so as not to contribute
    > > > + * to system load) until the @condition evaluates to true. The
    > > > + * @condition is checked each time the waitqueue @wq is woken up.
    > > > + *
    > > > + * wake_up() has to be called after changing any variable that could
    > > > + * change the result of the wait condition.
    > > > + */
    > > > +#define wait_event_freezable(wq, condition) \
    > > > +do { \
    > > > + WARN_ON_ONCE(!(current->flags & PF_KTHREAD)); \
    > > > + might_sleep(); \
    > > > + if (condition) \
    > > > + break; \
    > > > + __wait_event_freezable(wq, condition); \
    > > > +} while (0)
    > > > +
    > > > #define __wait_event_timeout(wq, condition, timeout) \
    > > > ___wait_event(wq, ___wait_cond_timeout(condition), \
    > > > TASK_UNINTERRUPTIBLE, 0, timeout, \
    > >
    > > Bah, that doesn't compile, because there already appears to be one,
    > > hidden in freezer.h. Now I can't actually tell if it does the same thing
    > > or not.
    > >
    > > Rafael?
    >
    > Ping?

    I was going to say that wait_event_freezable() in kauditd_thread()
    is not friendly wrt kthread_should_stop() and thus we we need
    kthread_freezable_should_stop().

    But in fact we never stop this kauditd_task, so I think we should
    turn the main loop into "for (;;)" and change this code to use
    wait_event_freezable() like your patch does.

    Perhaps it also makes sense to redefine wait_event_freezable.*()
    via ___wait_event(cmd => freezable_schedule), but I think this needs
    another patch.

    Oleg.



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