Re: [Patch] jbd commit code deadloop when installing Linux

Ingo Molnar
2006-06-28T09:34:14Z

* Andrew Morton <akpm@osdl.org> wrote:

> > However I still have some concern on cond_resched_lock(), on an UP
> > kernel it will return 1 if schedule happen, but actually it does not
> > drop any lock, that semantic seems to be different to SMP kernel.
>
> That's OK (I think - I don't have a good track record in this thread).
>
> If the kernel is non-preemptible and UP, we want to return true from
> cond_resched_foo() if we called schedule(). Because schedule() might
> allow a different thread into the kernel which might modify the locked
> data.
>
> And if the kernel is preemptible and UP, we want to return true from
> cond_resched_foo() if we dropped the lock, because that internally
> does a preempt_enable().
>
> And the patch (hopefully) satisfies those requirements. Does that all
> sound solid?

it looks solid to me ... but this is subtle stuff and i dont seem to
have a good track record for these details today. I guess if it's
inadequate Zou ought to see them in practice?

Ingo