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    SubjectRe: [PATCH] take 2 of the tr-based current
    Jakub Jelinek wrote:
    > On Thu, Nov 08, 2001 at 09:11:43PM -0500, Benjamin LaHaise wrote:
    > > -static unsigned get_TR(void) __attribute__ ((pure))
    > > +static unsigned get_TR(void) __attribute__ ((pure));
    > > +static unsigned get_TR(void)
    > > {
    > > unsigned tr;
    > > __asm__("str %w0" : "=g" (tr));
    > Why not
    > static inline unsigned __attribute__ ((const)) get_TR(void)
    > {
    > }
    > ?
    > If TR register only ever changes during cpu_init, I don't see why you
    > cannot use const.

    The task register is only pure, not const. It's true that it's only
    initialized during cpu_init(), but different cpus in the system have
    different task register values.
    must reload the task register.

    But the value of "current" can be considered as const: It never changes
    for a running thread. The exception are fork() and clone(), but both
    functions directly call asm code and run on a fresh stack after forking.

    > Using pure would mean if you do get_TR, then store
    > something into global memory and do get_TR again, it will be done twice.
    > Also, I wonder why you don't inline it.

    I think get_current should be inline, const. get_TR() and
    smp_processor_id would be inline, pure.

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