RE: [PATCH] SN2 user-MMIO CPU migration

Brent Casavant
2006-01-25T17:45:04Z

On Wed, 25 Jan 2006, Chen, Kenneth W wrote:

> Thought everyone agreed to call the sync function with the new task context,
> (after ia64_switch_to). Something changed which made you changed your mind?

Yeah. I mentioned this in my other message, but I kept running into
invalid accesses (and migration/swapper threads dying) in sn_migrate()
when the sync was done after ia64_switch_to(). Any idea what I might
be doing wrong? Perhaps I need to call barrier() first?

> diff --git a/include/asm-ia64/thread_info.h b/include/asm-ia64/thread_info.h
> > @@ -46,6 +47,7 @@ struct thread_info {
> > .exec_domain = &default_exec_domain, \
> > .flags = 0, \
> > .cpu = 0, \
> > + .last_cpu = 0, \
> > .addr_limit = KERNEL_DS, \
> > .preempt_count = 0, \
> > .restart_block = { \
>
> Looked spurious, init_task has static initializer, which will have zero
> initial value automatically.

I was just following the existing mechanism in the code (obviously
I'm not the only one to add "= 0" in here.

I can submit a separate cleanup patch for this and quite a bit of other
code if you'd like. I've run into all sorts of 80-column/etc issues
while working on this, but didn't want to mix cleanup with meatier
changes.

Brent

--
Brent Casavant All music is folk music. I ain't
bcasavan@sgi.com never heard a horse sing a song.
Silicon Graphics, Inc. -- Louis Armstrong