On Mon, Oct 09, 2000 at 11:45:18PM +0100, Kenn Humborg wrote:
> Simple. Each interrupt stack is, say, 8 pages. You have an array
> of N interrupt stacks. Then you calculate
>
> cpu_id = (sp & ~(INT_STACK_SIZE-1)) >> (PAGE_SHIFT + 3);
>
> Actually, I'd put the interrupt stack and any other per-cpu data
> structures together in this region.
So your smp_processor_id() looks like:
#define smp_processor_id() \
(in_interrupt() ? (sp & ~(INT_STACK_SIZE-1)) >> (PAGE_SHIFT + 3) :
(struct task_struct *)(sp & -8192)->current_cpu)
?
There is just an ugly problem: in_interrupt already requires the CPU id
to look up the table of interrupt counters.
Now you could change the code to use interrupt_processor_id() and
usermode_processor_id(), but what would you do in code which can
be executed in both ?
-Andi
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Sun Oct 15 2000 - 21:00:14 EST