Re: [PATCH] move put_task_struct() reaping into a thread [Re: 2.6.18-rt1]

Bill Huey
2006-09-27T09:15:23Z

On Wed, Sep 27, 2006 at 10:57:12AM +0200, Ingo Molnar wrote:
> * Bill Huey <billh@gnuppy.monkey.org> wrote:
>
> > Because the conversion of memory allocation routines like kmalloc and
> > kfree aren't safely callable within a preempt_disable critical section
> > since they were incompletely converted in the -rt. [...]
>
> they were not 'incompletely converted' - they are /intentionally/ fully
> preemptible.

What I meant by "incompletely converted" is that the allocators could be
made more safe in non-preemptible scenarios under -rt. It's potentially
a valuable thing to have since GFP_ATOMIC semantics already exist in the
current allocators and a newer category could be added as a new feature of
that allocator for those scenarios. I'm happy dequeuing things off of my
own free list, but that's just me.

-rt semanatics created a couple of new locking scenarios that the previous
kernel didn't really have to address. That's all that I meant by that. :)

bill