Linux-NVME Archive on lore.kernel.org
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* [PATCHv2 0/2] 
@ 2019-12-02 22:20 Keith Busch
  2019-12-02 22:20 ` [PATCHv2 1/2] PCI/MSI: Export __pci_msix_desc_mask_irq Keith Busch
  2019-12-02 22:20 ` [PATCHv2 2/2] nvme/pci: Mask device interrupts for threaded handlers Keith Busch
  0 siblings, 2 replies; 10+ messages in thread
From: Keith Busch @ 2019-12-02 22:20 UTC (permalink / raw)
  To: linux-nvme; +Cc: sagi, bigeasy, ming.lei, helgaas, Keith Busch, tglx, hch

NVMe devices had been able to continue sending interrupt messages while
the driver is handling the previous notification when threaded interrupts
are used. This can cause unnecessary CPU cycles spent in hard irq context,
and potentially triggers spurious interrupt detection if the threaded
handler runs sufficiently long: returning IRQ_WAKE_THREAD from the
primrary handler doesn't observe any changes to irq desc->thread_handled.

Use the appropriate masking for the interrupt type based on the NVMe
specification recommendations (see NVMe 1.4 section 7.5.1.1 for more
information) so that the primary handler does not get unnecessarily
triggered.

v1 -> v2:

  Don't split the nvme callbacks for MSI and MSI-x. Just check the type
  in the callback when selecting the masking method, and combine this
  in a single patch.

  Drop the more experiemental patches. That series will be posted
  separately.

Keith Busch (2):
  PCI/MSI: Export __pci_msix_desc_mask_irq
  nvme/pci: Mask device interrupts for threaded handlers

 drivers/nvme/host/pci.c | 28 ++++++++++++++++++++++++----
 drivers/pci/msi.c       |  1 +
 2 files changed, 25 insertions(+), 4 deletions(-)

-- 
2.21.0


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Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-12-02 22:20 [PATCHv2 0/2] Keith Busch
2019-12-02 22:20 ` [PATCHv2 1/2] PCI/MSI: Export __pci_msix_desc_mask_irq Keith Busch
2019-12-02 22:46   ` Christoph Hellwig
2019-12-03  9:04     ` Sebastian Andrzej Siewior
2019-12-06 21:18       ` Keith Busch
2019-12-02 22:20 ` [PATCHv2 2/2] nvme/pci: Mask device interrupts for threaded handlers Keith Busch
2019-12-03  7:47   ` Christoph Hellwig
2019-12-03 12:07     ` Keith Busch
2019-12-04 10:10   ` Sironi, Filippo
2019-12-04 13:58     ` hch

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