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    SubjectRe: [v2 PATCH 1/4] timers: framework to identify pinned timers.
    * Oleg Nesterov <oleg@redhat.com> [2009-03-05 17:53:40]:

    > On 03/04, Arun R Bharadwaj wrote:
    > >
    > > +static inline unsigned long tbase_get_flag_bits(struct timer_list *timer)
    > > +{
    > > + return tbase_get_deferrable(timer->base) |
    > > + tbase_get_pinned(timer->base);
    > > +}
    >
    > I'd say this looks a bit strange. Hopefully compiler can optimize this code
    > to return (unsigned long)base & (TBASE_DEFERRABLE_FLAG | TBASE_PINNED_FLAG).
    >

    Yes, it does.

    > > @@ -736,6 +759,7 @@ void add_timer_on(struct timer_list *tim
    > > struct tvec_base *base = per_cpu(tvec_bases, cpu);
    > > unsigned long flags;
    > >
    > > + timer_set_pinned(timer);
    >
    > But we never clear TBASE_PINNED_FLAG?
    >
    > If we use mod_timer() next time, the timer remains "pinned". I do not say
    > this is really wrong, but a bit strange imho.
    >
    > Oleg.
    >

    The pinned timer would expect to continue firing on the same CPU
    although it does a mod_timer() the next time, right?
    Thats why I have not cleared the TBASE_PINNED_FLAG.

    --arun


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