Messages in this thread | | | Subject | Re: [PATCH v3 0/3] genirq/vfio: Introduce update_irq_devid and optimize VFIO irq ops | From | luoben <> | Date | Tue, 20 Aug 2019 12:03:50 +0800 |
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在 2019/8/20 上午4:51, Alex Williamson 写道: > On Thu, 15 Aug 2019 21:02:58 +0800 > Ben Luo <luoben@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
By tracing centos5u8 on host, I found it keep masking and unmasking interrupt like this:
[1566032533709879] index:28 irte_hi:000000010004a601 irte_lo:adb54bc000b98001 [1566032533711242] index:28 irte_hi:0000000000000000 irte_lo:0000000000000000 [1566032533711258] index:28 irte_hi:000000000004a601 irte_lo:00003fff00ac002d [1566032533711269] index:28 irte_hi:000000000004a601 irte_lo:00003fff00ac002d [1566032533711291] index:28 irte_hi:000000000004a601 irte_lo:00003fff00ac002d [1566032533711321] index:28 irte_hi:0000000000000000 irte_lo:0000000000000000 [1566032533711340] index:28 irte_hi:000000000004a601 irte_lo:00003fff00ac002d [1566032533711361] index:28 irte_hi:000000000004a601 irte_lo:00003fff00ac002d [1566032533711376] index:28 irte_hi:000000010004a601 irte_lo:adb54bc000b98001 [1566032533713368] index:28 irte_hi:0000000000000000 irte_lo:0000000000000000 [1566032533713385] index:28 irte_hi:000000000004a601 irte_lo:00003fff00ac002d [1566032533713396] index:28 irte_hi:000000000004a601 irte_lo:00003fff00ac002d [1566032533713416] index:28 irte_hi:000000000004a601 irte_lo:00003fff00ac002d [1566032533713447] index:28 irte_hi:0000000000000000 irte_lo:0000000000000000 [1566032533713464] index:28 irte_hi:000000000004a601 irte_lo:00003fff00ac002d [1566032533713485] index:28 irte_hi:000000000004a601 irte_lo:00003fff00ac002d [1566032533713499] index:28 irte_hi:000000010004a601 irte_lo:adb54bc000b98001 [1566032533718855] index:28 irte_hi:0000000000000000 irte_lo:0000000000000000 [1566032533718871] index:28 irte_hi:000000000004a601 irte_lo:00003fff00ac002d [1566032533718882] index:28 irte_hi:000000000004a601 irte_lo:00003fff00ac002d [1566032533718902] index:28 irte_hi:000000000004a601 irte_lo:00003fff00ac002d [1566032533718932] index:28 irte_hi:0000000000000000 irte_lo:0000000000000000 [1566032533718949] index:28 irte_hi:000000000004a601 irte_lo:00003fff00ac002d [1566032533718969] index:28 irte_hi:000000000004a601 irte_lo:00003fff00ac002d [1566032533718984] index:28 irte_hi:000000010004a601 irte_lo:adb54bc000b98001 [1566032533719873] index:28 irte_hi:0000000000000000 irte_lo:0000000000000000 [1566032533719889] index:28 irte_hi:000000000004a601 irte_lo:00003fff00ac002d [1566032533719900] index:28 irte_hi:000000000004a601 irte_lo:00003fff00ac002d [1566032533719921] index:28 irte_hi:000000000004a601 irte_lo:00003fff00ac002d [1566032533719954] index:28 irte_hi:0000000000000000 irte_lo:0000000000000000 [1566032533719971] index:28 irte_hi:000000000004a601 irte_lo:00003fff00ac002d [1566032533719992] index:28 irte_hi:000000000004a601 irte_lo:00003fff00ac002d [1566032533720007] index:28 irte_hi:000000010004a601 irte_lo:adb54bc000b98001
"[1566032533720007]" is timestamp in μs, so centos5u8 tiggers 30+ irte modification within 10ms
Thanks,
Ben
>> 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(-) >>
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