Re: [PATCH v3] xen/balloon: add late_initcall_sync() for initial ballooning done

[Juergen Gross]

On 29.10.21 23:46, Boris Ostrovsky wrote:
> On 10/29/21 10:20 AM, Juergen Gross wrote:
> > --- a/Documentation/ABI/stable/sysfs-devices-system-xen_memory
> > +++ b/Documentation/ABI/stable/sysfs-devices-system-xen_memory
> > @@ -84,3 +84,13 @@ Description:
> >           Control scrubbing pages before returning them to Xen for 
> > others domains
> >           use. Can be set with xen_scrub_pages cmdline
> >           parameter. Default value controlled with 
> > CONFIG_XEN_SCRUB_PAGES_DEFAULT.
> > +
> > +What:        /sys/devices/system/xen_memory/xen_memory0/boot_timeout
> > +Date:        November 2021
> > +KernelVersion:    5.16
> > +Contact:    xen-devel@xxxxxxxxxxxxxxxxxxxx
> > +Description:
> > +        The time (in seconds) to wait before giving up to boot in case
> > +        initial ballooning fails to free enough memory. Applies only
> > +        when running as HVM or PVH guest and started with less memory
> > +        configured than allowed at max.
>
>
> How is this going to be used? We only need this during boot.

Of course. Will switch to module_param().

> > -        state = update_schedule(state);
> > +        balloon_state = update_schedule(balloon_state);
>
>
> Now that balloon_state has whole file scope it can probably be updated 
> inside update_schedule().

I can do that.

> > +    while ((credit = current_credit()) < 0) {
> > +        if (credit != last_credit) {
> > +            last_changed = jiffies;
> > +            last_credit = credit;
> > +        }
> > +        if (balloon_state == BP_ECANCELED) {
>
>
> What about other states? We are really waiting for BP_DONE, aren't we?

Nearly. We are waiting for credit not being negative.

And in case of cancelled we know this won't happen without Xen admin
intervention.


Juergen

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