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![Anoob Soman](/assets/img/avatar_default.png)
A HVM domian booting generates around 200K (evtchn:qemu-dm xen-dyn) interrupts,in a short period of time. All these evtchn:qemu-dm are bound to VCPU 0, until irqbalance sees these IRQ and moves it to a different VCPU. In one configuration, irqbalance runs every 10 seconds, which means irqbalance doesn't get to see these burst of interrupts and doesn't re-balance interrupts most of the time, making all evtchn:qemu-dm to be processed by VCPU0. This cause VCPU0 to spend most of time processing hardirq and very little time on softirq. Moreover, if dom0 kernel PREEMPTION is disabled, VCPU0 never runs watchdog (process context), triggering a softlockup detection code to panic. Binding evtchn:qemu-dm to next online VCPU, will spread hardirq processing evenly across different CPU. Later, irqbalance will try to balance evtchn:qemu-dm, if required. Signed-off-by: Anoob Soman <anoob.soman@citrix.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com>
129 lines
4.2 KiB
C
129 lines
4.2 KiB
C
#ifndef _XEN_EVENTS_H
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#define _XEN_EVENTS_H
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#include <linux/interrupt.h>
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#ifdef CONFIG_PCI_MSI
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#include <linux/msi.h>
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#endif
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#include <xen/interface/event_channel.h>
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#include <asm/xen/hypercall.h>
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#include <asm/xen/events.h>
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unsigned xen_evtchn_nr_channels(void);
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int bind_evtchn_to_irq(unsigned int evtchn);
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int bind_evtchn_to_irqhandler(unsigned int evtchn,
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irq_handler_t handler,
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unsigned long irqflags, const char *devname,
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void *dev_id);
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int bind_virq_to_irq(unsigned int virq, unsigned int cpu, bool percpu);
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int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
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irq_handler_t handler,
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unsigned long irqflags, const char *devname,
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void *dev_id);
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int bind_ipi_to_irqhandler(enum ipi_vector ipi,
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unsigned int cpu,
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irq_handler_t handler,
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unsigned long irqflags,
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const char *devname,
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void *dev_id);
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int bind_interdomain_evtchn_to_irq(unsigned int remote_domain,
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unsigned int remote_port);
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int bind_interdomain_evtchn_to_irqhandler(unsigned int remote_domain,
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unsigned int remote_port,
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irq_handler_t handler,
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unsigned long irqflags,
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const char *devname,
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void *dev_id);
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/*
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* Common unbind function for all event sources. Takes IRQ to unbind from.
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* Automatically closes the underlying event channel (even for bindings
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* made with bind_evtchn_to_irqhandler()).
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*/
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void unbind_from_irqhandler(unsigned int irq, void *dev_id);
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#define XEN_IRQ_PRIORITY_MAX EVTCHN_FIFO_PRIORITY_MAX
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#define XEN_IRQ_PRIORITY_DEFAULT EVTCHN_FIFO_PRIORITY_DEFAULT
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#define XEN_IRQ_PRIORITY_MIN EVTCHN_FIFO_PRIORITY_MIN
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int xen_set_irq_priority(unsigned irq, unsigned priority);
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/*
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* Allow extra references to event channels exposed to userspace by evtchn
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*/
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int evtchn_make_refcounted(unsigned int evtchn);
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int evtchn_get(unsigned int evtchn);
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void evtchn_put(unsigned int evtchn);
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void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector);
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void rebind_evtchn_irq(int evtchn, int irq);
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int xen_rebind_evtchn_to_cpu(int evtchn, unsigned tcpu);
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static inline void notify_remote_via_evtchn(int port)
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{
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struct evtchn_send send = { .port = port };
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(void)HYPERVISOR_event_channel_op(EVTCHNOP_send, &send);
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}
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void notify_remote_via_irq(int irq);
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void xen_irq_resume(void);
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/* Clear an irq's pending state, in preparation for polling on it */
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void xen_clear_irq_pending(int irq);
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void xen_set_irq_pending(int irq);
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bool xen_test_irq_pending(int irq);
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/* Poll waiting for an irq to become pending. In the usual case, the
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irq will be disabled so it won't deliver an interrupt. */
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void xen_poll_irq(int irq);
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/* Poll waiting for an irq to become pending with a timeout. In the usual case,
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* the irq will be disabled so it won't deliver an interrupt. */
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void xen_poll_irq_timeout(int irq, u64 timeout);
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/* Determine the IRQ which is bound to an event channel */
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unsigned irq_from_evtchn(unsigned int evtchn);
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int irq_from_virq(unsigned int cpu, unsigned int virq);
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unsigned int evtchn_from_irq(unsigned irq);
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/* Xen HVM evtchn vector callback */
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void xen_hvm_callback_vector(void);
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#ifdef CONFIG_TRACING
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#define trace_xen_hvm_callback_vector xen_hvm_callback_vector
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#endif
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int xen_set_callback_via(uint64_t via);
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void xen_evtchn_do_upcall(struct pt_regs *regs);
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void xen_hvm_evtchn_do_upcall(void);
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/* Bind a pirq for a physical interrupt to an irq. */
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int xen_bind_pirq_gsi_to_irq(unsigned gsi,
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unsigned pirq, int shareable, char *name);
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#ifdef CONFIG_PCI_MSI
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/* Allocate a pirq for a MSI style physical interrupt. */
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int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc *msidesc);
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/* Bind an PSI pirq to an irq. */
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int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
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int pirq, int nvec, const char *name, domid_t domid);
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#endif
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/* De-allocates the above mentioned physical interrupt. */
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int xen_destroy_irq(int irq);
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/* Return irq from pirq */
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int xen_irq_from_pirq(unsigned pirq);
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/* Return the pirq allocated to the irq. */
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int xen_pirq_from_irq(unsigned irq);
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/* Return the irq allocated to the gsi */
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int xen_irq_from_gsi(unsigned gsi);
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/* Determine whether to ignore this IRQ if it is passed to a guest. */
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int xen_test_irq_shared(int irq);
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/* initialize Xen IRQ subsystem */
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void xen_init_IRQ(void);
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#endif /* _XEN_EVENTS_H */
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