Re: [patch 1/2] workqueue: mark init_workqueues() as early_initcall()

[Andrew Morton <akpm@linux-foundation.org>]

On Fri, 30 Jul 2010 14:57:37 -0700
Suresh Siddha <suresh.b.siddha@intel.com> wrote:

> Mark init_workqueues() as early_initcall() and thus it will be initialized
> before smp bringup. init_workqueues() registers for the hotcpu notifier
> and thus it should cope with the processors that are brought online after
> the workqueues are initialized.
> 
> x86 smp bringup code uses workqueues and uses a workaround for the
> cold boot process (as the workqueues are initialized post smp_init()).
> Marking init_workqueues() as early_initcall() will pave the way for
> cleaning up this code.
> 

I sure hope this has been tested against linux-next. 
kernel/workqueue.c has been vastly changed and -tip doesn't know about
that.  linux-next should include -tip and is hence a better tree to
develop and test against.

AFAICT the main thing which needs checking is that the new
init_workqueues() doesn't do anything which requires that
sched_init_smp() has been executed.

The patch otherwise looks OK and killing that hack in the x86 code was
most merciful.

for_each_gcwq_cpu(), for_each_online_gcwq_cpu() and for_each_cwq_cpu()
make me cry.