linux/kernel/irq
Dou Liyang bec04037e4 genirq/core: Introduce struct irq_affinity_desc
The interrupt affinity management uses straight cpumask pointers to convey
the automatically assigned affinity masks for managed interrupts. The core
interrupt descriptor allocation also decides based on the pointer being non
NULL whether an interrupt is managed or not.

Devices which use managed interrupts usually have two classes of
interrupts:

  - Interrupts for multiple device queues
  - Interrupts for general device management

Currently both classes are treated the same way, i.e. as managed
interrupts. The general interrupts get the default affinity mask assigned
while the device queue interrupts are spread out over the possible CPUs.

Treating the general interrupts as managed is both a limitation and under
certain circumstances a bug. Assume the following situation:

 default_irq_affinity = 4..7

So if CPUs 4-7 are offlined, then the core code will shut down the device
management interrupts because the last CPU in their affinity mask went
offline.

It's also a limitation because it's desired to allow manual placement of
the general device interrupts for various reasons. If they are marked
managed then the interrupt affinity setting from both user and kernel space
is disabled.

To remedy that situation it's required to convey more information than the
cpumasks through various interfaces related to interrupt descriptor
allocation.

Instead of adding yet another argument, create a new data structure
'irq_affinity_desc' which for now just contains the cpumask. This struct
can be expanded to convey auxilliary information in the next step.

No functional change, just preparatory work.

[ tglx: Simplified logic and clarified changelog ]

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Dou Liyang <douliyangs@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-pci@vger.kernel.org
Cc: kashyap.desai@broadcom.com
Cc: shivasharan.srikanteshwara@broadcom.com
Cc: sumit.saxena@broadcom.com
Cc: ming.lei@redhat.com
Cc: hch@lst.de
Cc: douliyang1@huawei.com
Link: https://lkml.kernel.org/r/20181204155122.6327-2-douliyangs@gmail.com
2018-12-19 11:32:08 +01:00
..
affinity.c genirq/core: Introduce struct irq_affinity_desc 2018-12-19 11:32:08 +01:00
autoprobe.c genirq: Cleanup top of file comments 2018-03-20 14:23:27 +01:00
chip.c genirq: Fix various typos in comments 2018-12-18 14:22:28 +01:00
cpuhotplug.c genirq: Add missing SPDX identifiers 2018-03-20 14:23:28 +01:00
debug.h Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk 2018-02-01 13:36:15 -08:00
debugfs.c genirq/debugfs: Add missing IRQCHIP_SUPPORTS_LEVEL_MSI debug 2018-06-22 14:22:00 +02:00
devres.c genirq/core: Introduce struct irq_affinity_desc 2018-12-19 11:32:08 +01:00
dummychip.c genirq: Add missing SPDX identifiers 2018-03-20 14:23:28 +01:00
generic-chip.c genirq: Add missing SPDX identifiers 2018-03-20 14:23:28 +01:00
handle.c genirq: Add missing SPDX identifiers 2018-03-20 14:23:28 +01:00
internals.h genirq: Make legacy autoprobing work again 2018-02-01 11:09:40 +01:00
ipi.c genirq: Fix various typos in comments 2018-12-18 14:22:28 +01:00
irq_sim.c irq/irq_sim: Store multiple interrupt offsets in a bitmap 2018-12-13 09:35:31 +00:00
irqdesc.c genirq/core: Introduce struct irq_affinity_desc 2018-12-19 11:32:08 +01:00
irqdomain.c genirq/core: Introduce struct irq_affinity_desc 2018-12-19 11:32:08 +01:00
Kconfig genirq/irqchip: Remove MULTI_IRQ_HANDLER as it's now obselete 2018-08-03 12:14:10 +02:00
Makefile Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-11-13 17:33:11 -08:00
manage.c genirq: Fix various typos in comments 2018-12-18 14:22:28 +01:00
matrix.c genirq/matrix: Improve target CPU selection for managed interrupts. 2018-11-06 23:20:13 +01:00
migration.c genirq/migration: Avoid out of line call if pending is not set 2018-06-06 15:18:20 +02:00
msi.c genirq/core: Introduce struct irq_affinity_desc 2018-12-19 11:32:08 +01:00
pm.c genirq: Add missing SPDX identifiers 2018-03-20 14:23:28 +01:00
proc.c genirq: Speedup show_interrupts() 2018-06-22 14:22:58 +02:00
resend.c genirq: Cleanup top of file comments 2018-03-20 14:23:27 +01:00
settings.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
spurious.c genirq: Fix various typos in comments 2018-12-18 14:22:28 +01:00
timings.c genirq: Remove license boilerplate/references 2018-03-20 14:23:28 +01:00