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    SubjectRe: prev->has_cpu

    On Fri, 13 Nov 1998, Andrea Arcangeli wrote:
    > >one. That always works - even if next == prev, in which case it doesn't
    > If next == prev we don' t switch_to() another task. But the other task
    > (not going to be scheduled yet) will just have next->has_cpu == 1 even if
    > will not run soon. I think _only_ running (currents) tasks should have
    > ->has_cpu == 1.

    If "next == prev", then there _is_ no other task.

    > >actually do anything. I don't see the problem: schedule() is always
    > >guaranteed to be entered with "current->has_cpu == 1" (because otherwise
    > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    > Where? I can' t find such piece of code. I think instead that if `prev ==
    > next', we' ll exit from the scheule() without changing the current process
    > and with current->has_cpu == 0.

    No, "current->has_cpu" is _always_ 1 (except inside the scheduler itself,
    when it can temporarily drop down to zero while we hold the scheduler
    lock). The only case "next == prev" happens is when "current == next ==

    "has_cpu" essentially means that it is actually physcially running on some


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