On Thu, 15 Aug 2019 21:02:58 +0800 Ben Luo <luo...@linux.alibaba.com> wrote:
> 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 What guest environment is generating this? Typically I don't see that Windows or Linux guests bounce the interrupt configuration much. Thanks, Alex > > 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(-) >
