| Message ID | 20231016062831.20630-2-jgross@suse.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 47d970204054f859f35a2237baa75c2d84fcf436 |
| Headers | show |
| Series | xen/events: do some cleanups in events_base.c | expand |
On 16.10.23 09:28, Juergen Gross wrote: Hello Juergen > When delaying eoi handling of events, the related elements are queued > into the percpu lateeoi list. In case the list isn't empty, the > elements should be sorted by the time when eoi handling is to happen. > > Unfortunately a new element will never be queued at the start of the > list, even if it has a handling time lower than all other list > elements. > > Fix that by handling that case the same way as for an empty list. > > Fixes: e99502f76271 ("xen/events: defer eoi in case of excessive number of events") > Reported-by: Jan Beulich <jbeulich@suse.com> > Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> > --- > drivers/xen/events/events_base.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c > index 1b2136fe0fa5..0e458b1c0c8c 100644 > --- a/drivers/xen/events/events_base.c > +++ b/drivers/xen/events/events_base.c > @@ -601,7 +601,9 @@ static void lateeoi_list_add(struct irq_info *info) > > spin_lock_irqsave(&eoi->eoi_list_lock, flags); > > - if (list_empty(&eoi->eoi_list)) { > + elem = list_first_entry_or_null(&eoi->eoi_list, struct irq_info, > + eoi_list); > + if (!elem || info->eoi_time < elem->eoi_time) { > list_add(&info->eoi_list, &eoi->eoi_list); > mod_delayed_work_on(info->eoi_cpu, system_wq, > &eoi->delayed, delay);
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c index 1b2136fe0fa5..0e458b1c0c8c 100644 --- a/drivers/xen/events/events_base.c +++ b/drivers/xen/events/events_base.c @@ -601,7 +601,9 @@ static void lateeoi_list_add(struct irq_info *info) spin_lock_irqsave(&eoi->eoi_list_lock, flags); - if (list_empty(&eoi->eoi_list)) { + elem = list_first_entry_or_null(&eoi->eoi_list, struct irq_info, + eoi_list); + if (!elem || info->eoi_time < elem->eoi_time) { list_add(&info->eoi_list, &eoi->eoi_list); mod_delayed_work_on(info->eoi_cpu, system_wq, &eoi->delayed, delay);
When delaying eoi handling of events, the related elements are queued into the percpu lateeoi list. In case the list isn't empty, the elements should be sorted by the time when eoi handling is to happen. Unfortunately a new element will never be queued at the start of the list, even if it has a handling time lower than all other list elements. Fix that by handling that case the same way as for an empty list. Fixes: e99502f76271 ("xen/events: defer eoi in case of excessive number of events") Reported-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com> --- drivers/xen/events/events_base.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)