Re: [PATCH] rwsem-spinlock: let rwsem write lock stealable

Yuanhan Liu
2013-01-31T14:35:42Z

On Thu, Jan 31, 2013 at 02:12:28PM +0100, Ingo Molnar wrote:
>
> * Yuanhan Liu <yuanhan.liu@linux.intel.com> wrote:
>
> > BTW, mind to tell a nice test case for mmap_sem?
>
> this one was write-hitting on mmap_sem pretty hard, last I
> checked:
>
> http://people.redhat.com/mingo/threaded-mmap-stresstest/

Thanks!

Is there any pass condition? I tested a while, at least I found no oops
or any noisy from dmesg output. Is that OK?

Well, sometimes, it will quit peacefully. Sometimes it will not.
ps -eo 'pid, state,wchan,comm' shows that it is sleeping at
futex_wait_queue_me().

NOTE: this happens both with or w/o this patch. Thus it may not an issue
introduced by this patch?

Thanks.

--yliu