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[v4,0/5] Support managed interrupts for platform devices

Message ID 1606757759-6076-1-git-send-email-john.garry@huawei.com
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Series Support managed interrupts for platform devices | expand

Message

John Garry Nov. 30, 2020, 5:35 p.m. UTC 
So far, managed interrupts are only used for PCI MSIs. This series adds
platform device support for managed interrupts. Initially this topic was
discussed at [0].

The method to enable managed interrupts is to allocate a group of IRQs for
the device, and then switch the interrupts to managed - this is done
through new function irq_update_affinity_desc().

Function devm_platform_get_irqs_affinity() is added as a helper to manage
this work, such that we don't need to export irq_update_affinity_desc() or
irq_create_affinity_masks().

In the devm_platform_get_irqs_affinity() release call a new platform
method is used to "put" an irq. The reason for this is that per-irq
mapping (and irq_desc) needs to be recreated anew for re-probing the LLDD,
such that we don't attempt to reconfigure the managed or any other flag
for an irq_desc.

For now, the HiSilicon SAS v2 hw driver is switched over. This is used
in the D05 dev board.

Performance gain observed for 6x SAS SSDs is ~357K -> 420K IOPs for fio read.

This series is tested based on Marc's "MSI: Track device proxying when
allocating MSIs" series, [1].

[0] https://lore.kernel.org/lkml/84a9411b-4ae3-1928-3d35-1666f2687ec8@huawei.com/
[1] https://lore.kernel.org/lkml/20201129135208.680293-1-maz@kernel.org/

Changes since v3:
- Fix genirq change to re-activate interrupt if we have deactivated it
- Remove standalone platform_put_irq(), and combine code into
  devm_platform_get_irqs_affinity_release()
- Add new inline function in ioport.h rather than making
  acpi_dev_irqresource_disabled() public

Changes since v2:
- Update genirq change as follows:
 - Handle when the irq is started, active, or already managed
 - Reject update when CONFIG_GENERIC_IRQ_RESERVATION_MODE is set
- Revamp platform.c API as follows:
 - Make it devm type
 - Add platform_put_irq() and associated change in ACPI code to allow irq
   resource to be reset
 - Unmap irqs for driver removal
 - Change API to accept min and max vectors

John Garry (5):
  genirq/affinity: Add irq_update_affinity_desc()
  resource: Add irqresource_disabled()
  ACPI: Drop acpi_dev_irqresource_disabled()
  Driver core: platform: Add devm_platform_get_irqs_affinity()
  scsi: hisi_sas: Expose HW queues for v2 hw

 drivers/acpi/resource.c                |  17 +---
 drivers/base/platform.c                | 121 +++++++++++++++++++++++++
 drivers/scsi/hisi_sas/hisi_sas.h       |   4 +
 drivers/scsi/hisi_sas/hisi_sas_main.c  |  11 +++
 drivers/scsi/hisi_sas/hisi_sas_v2_hw.c |  66 +++++++++++---
 include/linux/interrupt.h              |   8 ++
 include/linux/ioport.h                 |   7 ++
 include/linux/platform_device.h        |   6 ++
 kernel/irq/manage.c                    |  63 +++++++++++++
 9 files changed, 278 insertions(+), 25 deletions(-)

-- 
2.26.2

Comments

Thomas Gleixner Nov. 30, 2020, 11:19 p.m. UTC | #1 
On Tue, Dec 01 2020 at 01:35, John Garry wrote:

> Add a function to allow the affinity of an interrupt be switched to

> managed, such that interrupts allocated for platform devices may be

> managed.


Could you please add a paragraph which explains the limitations of that
interface?

> +/**

> + * irq_update_affinity_desc - Update affinity management for an interrupt

> + * @irq:	The interrupt number to update

> + * @affinity:	Pointer to the affinity descriptor

> + *

> + * This interface can be used to configure the affinity management of

> + * interrupts which have been allocated already.


Same here.

Thanks,

        tglx