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    hrtimer: removing all ur callback modes · ca109491
    Peter Zijlstra 提交于
    Impact: cleanup, move all hrtimer processing into hardirq context
    
    This is an attempt at removing some of the hrtimer complexity by
    reducing the number of callback modes to 1.
    
    This means that all hrtimer callback functions will be ran from HARD-irq
    context.
    
    I went through all the 30 odd hrtimer callback functions in the kernel
    and saw only one that I'm not quite sure of, which is the one in
    net/can/bcm.c - hence I'm CC-ing the folks responsible for that code.
    
    Furthermore, the hrtimer core now calls callbacks directly with IRQs
    disabled in case you try to enqueue an expired timer. If this timer is a
    periodic timer (which should use hrtimer_forward() to advance its time)
    then it might be possible to end up in an inf. recursive loop due to the
    fact that hrtimer_forward() doesn't round up to the next timer
    granularity, and therefore keeps on calling the callback - obviously
    this needs a fix.
    
    Aside from that, this seems to compile and actually boot on my dual core
    test box - although I'm sure there are some bugs in, me not hitting any
    makes me certain :-)
    Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
    Signed-off-by: NIngo Molnar <mingo@elte.hu>
    ca109491
hrtimer.h 13.4 KB