Re: [Qemu-devel] qemu_futex_wait() lockups in ARM64: 2 possible issues

[Jan Glauber]

On Fri, Oct 11, 2019 at 10:18:18AM +0200, Paolo Bonzini wrote:
> On 11/10/19 08:05, Jan Glauber wrote:
> > On Wed, Oct 09, 2019 at 11:15:04AM +0200, Paolo Bonzini wrote:
> >>> ...but if I bump notify_me size to uint64_t the issue goes away.
> >>
> >> Ouch. :)  Is this with or without my patch(es)?
> 
> You didn't answer this question.

Oh, sorry... I did but the mail probably didn't make it out.
I have both of your changes applied (as I think they make sense).

> >> Also, what if you just add a dummy uint32_t after notify_me?
> > 
> > With the dummy the testcase also runs fine for 500 iterations.
> 
> You might be lucky and causing list_lock to be in another cache line.
> What if you add __attribute__((aligned(16)) to notify_me (and keep the
> dummy)?

Good point. I'll try to force both into the same cacheline.

--Jan

> Paolo
> 
> > Dann, can you try if this works on the Hi1620 too?