Currently, VFIO takes a lot of free-then-request-irq actions whenever a VM (with device passthru via VFIO) sets irq affinity or mask/unmask irq. Those actions only change the cookie data of irqaction or even change nothing. The free-then-request-irq not only add more latency, but also increases the risk of losing interrupt, this may lead to a VM hung forever in waiting IO completion
This patchset solved this issue by: patch 1 introduces update_irq_devid to only update dev_id of irqaction patch 2 make use of update_irq_devid and optimize irq operations in VFIO Ben Luo (2): genirq: introduce update_irq_devid() vfio_pci: make use of update_irq_devid and optimize irq ops drivers/vfio/pci/vfio_pci_intrs.c | 100 +++++++++++++++++++++++--------------- include/linux/interrupt.h | 3 ++ kernel/irq/manage.c | 74 ++++++++++++++++++++++++++++ 3 files changed, 139 insertions(+), 38 deletions(-) -- 1.8.3.1
