Re: Null scheduler and vwfi native problem

[Anders Törnqvist <anders.tornqvist@xxxxxxxxx>]

On 1/30/21 6:59 PM, Dario Faggioli wrote:
> On Fri, 2021-01-29 at 09:08 +0100, Anders Törnqvist wrote:
> > On 1/26/21 11:31 PM, Dario Faggioli wrote:
> > > Thanks again for letting us see these logs.
> > Thanks for the attention to this :-)
> >
> > Any ideas for how to solve it?
> So, you're up for testing patches, right?
>
> How about applying these two, and letting me know what happens? :-D
Great work guys!

Hi. Now I got the time to test the patches.

They was not possible to apply without fail on the code version I am 
using which is commit b64b8df622963accf85b227e468fe12b2d56c128 from 
https://source.codeaurora.org/external/imx/imx-xen.
I did some editing to get them into my code. I think I should have 
removed some sched_tick_suspend/sched_tick_resume calls also.
See the attached patches for what I have applied on the code.

Anyway, after applying the patches including the original 
rcu-quiesc-patch.patch the destroy of the domu seems to work.
I have rebooted, only destroyed-created and used Xen watchdog to reboot 
the domu in total about 20 times and so far it has nicely destroyed and 
the been able to start a new instance of the domu.
So it looks promising although my edited patches probably need some fixing.


> They are on top of current staging. I can try to rebase on something
> else, if it's easier for you to test.
>
> Besides being attached, they're also available here:
>
> https://gitlab.com/xen-project/people/dfaggioli/xen/-/tree/rcu-quiet-fix
>
> I could not test them properly on ARM, as I don't have an ARM system
> handy, so everything is possible really... just let me know.
>
> It should at least build fine, AFAICT from here:
>
> https://gitlab.com/xen-project/people/dfaggioli/xen/-/pipelines/249101213
>
> Julien, back in:
>
>   
> https://lore.kernel.org/xen-devel/315740e1-3591-0e11-923a-718e06c36445@xxxxxxx/
>
>
> you said I should hook in enter_hypervisor_head(),
> leave_hypervisor_tail(). Those functions are gone now and looking at
> how the code changed, this is where I figured I should put the calls
> (see the second patch). But feel free to educate me otherwise.
>
> For x86 people that are listening... Do we have, in our beloved arch,
> equally handy places (i.e., right before leaving Xen for a guest and
> right after entering Xen from one), preferrably in a C file, and for
> all guests... like it seems to be the case on ARM?
>
> Regards

Attachment: 1_1-xen-rcu-rename-idle-ignore.patch
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Attachment: 2_1-rcu-idle-guest.patch
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Attachment: 3_1-rcu-adaptations.patch
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Attachment: rcu-quiesc-patch.patch
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