Re: [PATCH 2/3] work_on_cpu: Use our own workqueue.

[Rusty Russell <rusty@rustcorp.com.au>]

On Tuesday 10 February 2009 20:05:48 Andrew Morton wrote:
> On Tue, 10 Feb 2009 19:24:07 +1030 Rusty Russell <rusty@rustcorp.com.au> wrote:
> > How about we make work_on_cpu spawn a temp thread; if you care, use
> > something cleverer?  Spawning a thread just isn't that slow.
> 
> That's what
> work_on_cpu-rewrite-it-to-create-a-kernel-thread-on-demand.patch does?

Err, yeah.

> > Meanwhile, I'll prepare patches to convert all the non-controversial cases
> > (ie. smp_call_function-style ones).
> 
> arch-x86-kernel-acpi-cstatec-avoid-using-work_on_cpu.patch
> arch-x86-kernel-cpu-cpufreq-acpi-cpufreqc-avoid-using-work_on_cpu.patch
> arch-x86-kernel-cpu-mcheck-mce_amd_64c-avoid-using-work_on_cpu.patch
> 
> convert three work_on_cpu() callers.  The drivers/pci/pci-driver.c one
> is a bit problematic.

OK, I've pulled these in to play with them.  My main concern at the moment
is getting all cpumask_ts removed from core & x86 code for 2.6.30, which
usually means converting those save/restore to work_on_cpu or whatever.

> I guess as long as we don't find a high frequency set_cpus_allowed()
> callsite which can't be converted to smp_call_function_single() we'll
> be OK.

Yep.

Thanks,
Rusty.