Re: [PATCH] migration thread fix

Robert Love
2002-04-18T21:41:07Z

On Thu, 2002-04-18 at 17:28, William Lee Irwin III wrote:
> I have a patch to fix #2 as well. Did you see it? Did you try it?

Eric, I am interested in your opinion of wli's patch, too. I really
liked his approach.

You seem to remove a lot of code since, after starting the first thread,
you rely on set_cpus_allowed and the existing migration_thread to push
the task to the correct place. I suppose this will work .. but it may
depend implicitly on behavior of the migration_threads and load_balance
(not that the current code doesn't rely on load_balance - it does).

What happens if a migration_thread comes up on a CPU without a migration
thread and then you call set_cpus_allowed?

I am also curious what causes #1 you mention. Do you see it in the
_normal_ code or just with your patch? I cannot see what we race
against wrt interrupts ... disabling interrupts, however, would disable
load_balance and that is a potential pitfall with using
migration_threads to migrate migration_threads as noted above.

Robert Love