[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH v5 3/4] xen/console: remove max_init_domid dependency
On Wed, Jun 04, 2025 at 02:55:40PM +0200, Jan Beulich wrote: > On 31.05.2025 01:19, dmkhn@xxxxxxxxx wrote: > > --- a/xen/common/domain.c > > +++ b/xen/common/domain.c > > @@ -2461,6 +2461,39 @@ void domid_free(domid_t domid) > > spin_unlock(&domid_lock); > > } > > > > +/* > > + * Find the ID of the next possible console owner domain. > > + * > > + * @return Domain ID: DOMID_XEN or non-system domain IDs within > > + * the range of [0..DOMID_FIRST_RESERVED-1]. > > + */ > > +domid_t domid_find_with_input_allowed(domid_t hint) > > +{ > > + domid_t domid = DOMID_XEN; > > + > > + if ( hint < DOMID_FIRST_RESERVED ) > > + { > > + struct domain *d; > > + > > + rcu_read_lock(&domlist_read_lock); > > + > > + for ( d = domid_to_domain(hint); > > If the domain with ID "hint" went away, what is being switched to changes > compared to behavior prior to this patch, if I'm not mistaken. While this > _may_ be acceptable, not saying so in the description is imo a no-go. Will correct, thanks. > > > + d && get_domain(d) && d->domain_id < DOMID_FIRST_RESERVED; > > What's the DOMID_FIRST_RESERVED check for? And where's the put_domain() > for the get_domain() here? > > > + d = rcu_dereference(d->next_in_list) ) > > + { > > + if ( d->console.input_allowed ) > > + { > > + domid = d->domain_id; > > + break; > > + } > > + } > > + > > + rcu_read_unlock(&domlist_read_lock); > > + } > > + > > + return domid; > > +} > > My concern remains: With many domains, the loop here may take quite a few > iterations. That's even more concerning because it regresses right away in > environments where along with boot-time created domains (eligible for > console focus) later further domains are created (non of which are eligible > for console focus). That is, the step from last boot-time created back to > DOMID_XEN may now take excessively long. Julien in the other reply suggested to have a list of domains with console input permission only. Will rework. > > Jan
|
![]() |
Lists.xenproject.org is hosted with RackSpace, monitoring our |