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 adds more latency, but also increases the risk of losing interrupt, which may lead to a VM hung forever in waiting for IO completion
This patchset solved the issue by: Patch 2 introduces update_irq_devid to only update dev_id of irqaction Patch 3 make use of update_irq_devid and optimize irq operations in VFIO changes from v2: - reformat to avoid quoted string split across lines and etc. changes from v1: - add Patch 1 to enhance error recovery etc. in free irq per tglx's comments - enhance error recovery code and debugging info in update_irq_devid - use __must_check in external referencing of update_irq_devid - use EXPORT_SYMBOL_GPL for update_irq_devid - reformat code of patch 3 for better readability Ben Luo (3): genirq: enhance error recovery code in free irq genirq: introduce update_irq_devid() vfio_pci: make use of update_irq_devid and optimize irq ops drivers/vfio/pci/vfio_pci_intrs.c | 101 +++++++++++++++++++++------------- include/linux/interrupt.h | 3 ++ kernel/irq/manage.c | 110 +++++++++++++++++++++++++++++++++----- 3 files changed, 164 insertions(+), 50 deletions(-) -- 1.8.3.1
