Re: [PATCH v6 0/3] genirq/vfio: Introduce irq_update_devid() and optimize VFIO irq ops

[Ben Luo]

A friendly reminder.


Thanks,

ÂÂÂ Ben

å 2019/9/2 äå12:01, Ben Luo åé:
> Currently, VFIO takes a free-then-request-irq way to do interrupt
> affinity setting and masking/unmasking for a VM with device passthru
> via VFIO. Sometimes it only changes the cookie data of irqaction or even
> changes 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 hang forever in waiting for IO completion
>
> This patchset solved the issue by:
> Patch 2 introduces irq_update_devid() to only update dev_id of irqaction
> Patch 3 make use of this function and optimize irq operations in VFIO
>
> changes from v5:
>   - Patch 3: remove an error log to avoid potential DDoS attacking
>   _ Patch 3: fix typo in comment
>
> changes from v4:
>   - Patch 3: follow the previous behavior to disable interrupt on error path
>   - Patch 3: do irqbypass registration before update or free the interrupt
>   - Patch 3: add more comments
>
> changes from v3:
>   - Patch 2: rename the new function to irq_update_devid()
>   - Patch 2: use disbale_irq() to avoid a twist for threaded interrupt
>   - ALL: amend commit messages and code comments
>
> 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 irq_update_devid
>   - use __must_check in external referencing of this function
>   - use EXPORT_SYMBOL_GPL for irq_update_devid
>   - reformat code of patch 3 for better readability
>
> Ben Luo (3):
>    genirq: enhance error recovery code in free irq
>    genirq: introduce irq_update_devid()
>    vfio/pci: make use of irq_update_devid() and optimize irq ops
>
>   drivers/vfio/pci/vfio_pci_intrs.c | 118 ++++++++++++++++++++++++++------------
>   include/linux/interrupt.h         |   3 +
>   kernel/irq/manage.c               | 105 +++++++++++++++++++++++++++++----
>   3 files changed, 177 insertions(+), 49 deletions(-)