Messages in this thread Patch in this message | | | Date | Sat, 12 Dec 2020 12:58:35 -0000 | From | "tip-bot2 for Thomas Gleixner" <> | Subject | [tip: irq/core] xen/events: Use immediate affinity setting |
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The following commit has been merged into the irq/core branch of tip:
Commit-ID: 9b23ffcbfa15f2d4959eaa42faae11e3e39d027a Gitweb: https://git.kernel.org/tip/9b23ffcbfa15f2d4959eaa42faae11e3e39d027a Author: Thomas Gleixner <tglx@linutronix.de> AuthorDate: Thu, 10 Dec 2020 20:26:02 +01:00 Committer: Thomas Gleixner <tglx@linutronix.de> CommitterDate: Sat, 12 Dec 2020 12:59:06 +01:00
xen/events: Use immediate affinity setting
There is absolutely no reason to mimic the x86 deferred affinity setting. This mechanism is required to handle the hardware induced issues of IO/APIC and MSI and is not in use when the interrupts are remapped.
XEN does not need this and can simply change the affinity from the calling context. The core code invokes this with the interrupt descriptor lock held so it is fully serialized against any other operation.
Mark the interrupts with IRQ_MOVE_PCNTXT to disable the deferred affinity setting. The conditional mask/unmask operation is already handled in xen_rebind_evtchn_to_cpu().
This makes XEN on x86 use the same mechanics as on e.g. ARM64 where deferred affinity setting is not required and not implemented and the code path in the ack functions is compiled out.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Juergen Gross <jgross@suse.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Link: https://lore.kernel.org/r/20201210194045.157601122@linutronix.de
--- drivers/xen/events/events_base.c | 35 +++++++------------------------ 1 file changed, 9 insertions(+), 26 deletions(-)
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c index 9cade19..eaba42a 100644 --- a/drivers/xen/events/events_base.c +++ b/drivers/xen/events/events_base.c @@ -628,6 +628,11 @@ static void xen_irq_init(unsigned irq) info->refcnt = -1; set_info_for_irq(irq, info); + /* + * Interrupt affinity setting can be immediate. No point + * in delaying it until an interrupt is handled. + */ + irq_set_status_flags(irq, IRQ_MOVE_PCNTXT); INIT_LIST_HEAD(&info->eoi_list); list_add_tail(&info->list, &xen_irq_list_head); @@ -739,18 +744,7 @@ static void eoi_pirq(struct irq_data *data) if (!VALID_EVTCHN(evtchn)) return; - if (unlikely(irqd_is_setaffinity_pending(data)) && - likely(!irqd_irq_disabled(data))) { - int masked = test_and_set_mask(evtchn); - - clear_evtchn(evtchn); - - irq_move_masked_irq(data); - - if (!masked) - unmask_evtchn(evtchn); - } else - clear_evtchn(evtchn); + clear_evtchn(evtchn); if (pirq_needs_eoi(data->irq)) { rc = HYPERVISOR_physdev_op(PHYSDEVOP_eoi, &eoi); @@ -1641,7 +1635,6 @@ void rebind_evtchn_irq(evtchn_port_t evtchn, int irq) mutex_unlock(&irq_mapping_update_lock); bind_evtchn_to_cpu(evtchn, info->cpu); - /* This will be deferred until interrupt is processed */ irq_set_affinity(irq, cpumask_of(info->cpu)); /* Unmask the event channel. */ @@ -1688,8 +1681,9 @@ static int set_affinity_irq(struct irq_data *data, const struct cpumask *dest, bool force) { unsigned tcpu = cpumask_first_and(dest, cpu_online_mask); - int ret = xen_rebind_evtchn_to_cpu(evtchn_from_irq(data->irq), tcpu); + int ret; + ret = xen_rebind_evtchn_to_cpu(evtchn_from_irq(data->irq), tcpu); if (!ret) irq_data_update_effective_affinity(data, cpumask_of(tcpu)); @@ -1719,18 +1713,7 @@ static void ack_dynirq(struct irq_data *data) if (!VALID_EVTCHN(evtchn)) return; - if (unlikely(irqd_is_setaffinity_pending(data)) && - likely(!irqd_irq_disabled(data))) { - int masked = test_and_set_mask(evtchn); - - clear_evtchn(evtchn); - - irq_move_masked_irq(data); - - if (!masked) - unmask_evtchn(evtchn); - } else - clear_evtchn(evtchn); + clear_evtchn(evtchn); } static void mask_ack_dynirq(struct irq_data *data)
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