linux/kernel/irq
Long Li b825921990 genirq/affinity: Spread IRQs to all available NUMA nodes
If the number of NUMA nodes exceeds the number of MSI/MSI-X interrupts
which are allocated for a device, the interrupt affinity spreading code
fails to spread them across all nodes.

The reason is, that the spreading code starts from node 0 and continues up
to the number of interrupts requested for allocation. This leaves the nodes
past the last interrupt unused.

This results in interrupt concentration on the first nodes which violates
the assumption of the block layer that all nodes are covered evenly. As a
consequence the NUMA nodes above the number of interrupts are all assigned
to hardware queue 0 and therefore NUMA node 0, which results in bad
performance and has CPU hotplug implications, because queue 0 gets shut
down when the last CPU of node 0 is offlined.

Go over all NUMA nodes and assign them round-robin to all requested
interrupts to solve this.

[ tglx: Massaged changelog ]

Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Link: https://lkml.kernel.org/r/20181102180248.13583-1-longli@linuxonhyperv.com
2018-11-05 12:16:26 +01:00
..
affinity.c genirq/affinity: Spread IRQs to all available NUMA nodes 2018-11-05 12:16:26 +01:00
autoprobe.c genirq: Cleanup top of file comments 2018-03-20 14:23:27 +01:00
chip.c genirq: Add missing SPDX identifiers 2018-03-20 14:23:28 +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: Add missing SPDX identifiers 2018-03-20 14:23:28 +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: Add missing SPDX identifiers 2018-03-20 14:23:28 +01:00
irq_sim.c genirq/irq_sim: Remove the license boilerplate 2018-04-26 22:26:39 +02:00
irqdesc.c genirq: Use rcu in kstat_irqs_usr() 2018-06-19 09:19:40 +02:00
irqdomain.c genirq: Fix grammar s/an /a / 2018-10-09 07:50:41 +02:00
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 race on spurious interrupt detection 2018-10-19 17:31:00 +02:00
matrix.c irq/matrix: Fix memory overallocation 2018-11-01 10:00:38 +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/msi: Allow level-triggered MSIs to be exposed by MSI providers 2018-05-13 15:58:59 +02:00
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: Cleanup top of file comments 2018-03-20 14:23:27 +01:00
timings.c genirq: Remove license boilerplate/references 2018-03-20 14:23:28 +01:00