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2014-08-05KVM: Move irq notifier implementation into eventfd.cPaul Mackerras
This moves the functions kvm_irq_has_notifier(), kvm_notify_acked_irq(), kvm_register_irq_ack_notifier() and kvm_unregister_irq_ack_notifier() from irqchip.c to eventfd.c. The reason for doing this is that those functions are used in connection with IRQFDs, which are implemented in eventfd.c. In future we will want to use IRQFDs on platforms that don't implement the GSI routing implemented in irqchip.c, so we won't be compiling in irqchip.c, but we still need the irq notifiers. The implementation is unchanged. Signed-off-by: Paul Mackerras <paulus@samba.org> Tested-by: Eric Auger <eric.auger@linaro.org> Tested-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-08-05KVM: Move all accesses to kvm::irq_routing into irqchip.cPaul Mackerras
Now that struct _irqfd does not keep a reference to storage pointed to by the irq_routing field of struct kvm, we can move the statement that updates it out from under the irqfds.lock and put it in kvm_set_irq_routing() instead. That means we then have to take a srcu_read_lock on kvm->irq_srcu around the irqfd_update call in kvm_irqfd_assign(), since holding the kvm->irqfds.lock no longer ensures that that the routing can't change. Combined with changing kvm_irq_map_gsi() and kvm_irq_map_chip_pin() to take a struct kvm * argument instead of the pointer to the routing table, this allows us to to move all references to kvm->irq_routing into irqchip.c. That in turn allows us to move the definition of the kvm_irq_routing_table struct into irqchip.c as well. Signed-off-by: Paul Mackerras <paulus@samba.org> Tested-by: Eric Auger <eric.auger@linaro.org> Tested-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-08-05KVM: irqchip: Provide and use accessors for irq routing tablePaul Mackerras
This provides accessor functions for the KVM interrupt mappings, in order to reduce the amount of code that accesses the fields of the kvm_irq_routing_table struct, and restrict that code to one file, virt/kvm/irqchip.c. The new functions are kvm_irq_map_gsi(), which maps from a global interrupt number to a set of IRQ routing entries, and kvm_irq_map_chip_pin, which maps from IRQ chip and pin numbers to a global interrupt number. This also moves the update of kvm_irq_routing_table::chip[][] into irqchip.c, out of the various kvm_set_routing_entry implementations. That means that none of the kvm_set_routing_entry implementations need the kvm_irq_routing_table argument anymore, so this removes it. This does not change any locking or data lifetime rules. Signed-off-by: Paul Mackerras <paulus@samba.org> Tested-by: Eric Auger <eric.auger@linaro.org> Tested-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-05kvm/irqchip: Speed up KVM_SET_GSI_ROUTINGChristian Borntraeger
When starting lots of dataplane devices the bootup takes very long on Christian's s390 with irqfd patches. With larger setups he is even able to trigger some timeouts in some components. Turns out that the KVM_SET_GSI_ROUTING ioctl takes very long (strace claims up to 0.1 sec) when having multiple CPUs. This is caused by the synchronize_rcu and the HZ=100 of s390. By changing the code to use a private srcu we can speed things up. This patch reduces the boot time till mounting root from 8 to 2 seconds on my s390 guest with 100 disks. Uses of hlist_for_each_entry_rcu, hlist_add_head_rcu, hlist_del_init_rcu are fine because they do not have lockdep checks (hlist_for_each_entry_rcu uses rcu_dereference_raw rather than rcu_dereference, and write-sides do not do rcu lockdep at all). Note that we're hardly relying on the "sleepable" part of srcu. We just want SRCU's faster detection of grace periods. Testing was done by Andrew Theurer using netperf tests STREAM, MAERTS and RR. The difference between results "before" and "after" the patch has mean -0.2% and standard deviation 0.6%. Using a paired t-test on the data points says that there is a 2.5% probability that the patch is the cause of the performance difference (rather than a random fluctuation). (Restricting the t-test to RR, which is the most likely to be affected, changes the numbers to respectively -0.3% mean, 0.7% stdev, and 8% probability that the numbers actually say something about the patch. The probability increases mostly because there are fewer data points). Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Michael S. Tsirkin <mst@redhat.com> Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> # s390 Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-04-26KVM: Move irq routing setup to irqchip.cAlexander Graf
Setting up IRQ routes is nothing IOAPIC specific. Extract everything that really is generic code into irqchip.c and only leave the ioapic specific bits to irq_comm.c. Signed-off-by: Alexander Graf <agraf@suse.de> Acked-by: Michael S. Tsirkin <mst@redhat.com>
2013-04-26KVM: Extract generic irqchip logic into irqchip.cAlexander Graf
The current irq_comm.c file contains pieces of code that are generic across different irqchip implementations, as well as code that is fully IOAPIC specific. Split the generic bits out into irqchip.c. Signed-off-by: Alexander Graf <agraf@suse.de> Acked-by: Michael S. Tsirkin <mst@redhat.com>