On Tue, 20 Feb 2001, Keith Owens wrote:
> On Mon, 19 Feb 2001 06:15:22 -0600 (CST),
> Philipp Rumpf <[EMAIL PROTECTED]> wrote:
> No need for a callin routine, you can get this for free as part of
> normal scheduling. The sequence goes :-
>
> if (use_count == 0) {
> module_unregister();
> wait_for_at_least_one_schedule_on_every_cpu();
> if (use_count != 0) {
> module_register(); /* lost the unregister race */
> }
> else {
> /* nobody can enter the module now */
> module_release_resources();
> unlink_module_from_list();
> wait_for_at_least_one_schedule_on_every_cpu();
> free_module_storage();
> }
> }
>
> wait_for_at_least_one_schedule_on_every_cpu() prevents the next
wait_for_at_least_one_schedule_on_every_cpu() *is* callin_other_cpus().
I agree the name isn't optimal. (and yes, you could implement it by
hacking sched.c directly, but I don't think that's necessary).
> The beauty of this approach is that the rest of the cpus can do normal
> work. No need to bring everything to a dead stop.
Which nicely avoids potential deadlocks in modules that need to initialize
on all CPUs.
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