Re: [PATCH] Fix WARN_ON / WARN_ON_ONCE regression

Tim Chen
2006-10-05T21:50:53Z

On Thu, 2006-10-05 at 17:31 -0400, Andrew James Wade wrote:
> On Thursday 05 October 2006 04:36, Andrew Morton wrote:
> > On Thu, 5 Oct 2006 04:13:07 -0400
> > Andrew James Wade <andrew.j.wade@gmail.com> wrote:
> >
> > > (...)
> >
> >
> > That all looks OK (by sheer luck).
> >
> > Well. What's the cache line size on that machine? Every exit() will cause
> > a down_read() on task_exit_notifier's lock which might affect things. And
> > I think you snipped the above list a bit short (depending on that line
> > size).
> >
> >
> > But still, we know that moving those things into __read_mostly didn't fix
> > it, yes?
>
> No. To my knowledge Tim Chen hasn't tried __read_mostly, and I have not
> attempted to replicate the test case. (I only have a uniprocessor
> machine.) Core 2 machines have a cache line size of 64 bytes, but Tim
> Chen is likely using a different kernel/.config than I am so my objdump
> isn't definitive.
>
> Tim, perhaps you can try the __read_mostly marking as Andrew suggests?
>

I have run the workload with __read_mostly marking. But it didn't make
a difference. By the way, the cache line size of my machine is 64
bytes.

Thanks.

Tim