linux/kernel/irq
Thomas Gleixner a0c9259dc4 irq/matrix: Spread interrupts on allocation
Keith reported an issue with vector space exhaustion on a server machine
which is caused by the i40e driver allocating 168 MSI interrupts when the
driver is initialized, even when most of these interrupts are not used at
all.

The x86 vector allocation code tries to avoid the immediate allocation with
the reservation mode, but the card uses MSI and does not support MSI entry
masking, which prevents reservation mode and requires immediate vector
allocation.

The matrix allocator is a bit naive and prefers the first CPU in the
cpumask which describes the possible target CPUs for an allocation. That
results in allocating all 168 vectors on CPU0 which later causes vector
space exhaustion when the NVMe driver tries to allocate managed interrupts
on each CPU for the per CPU queues.

Avoid this by finding the CPU which has the lowest vector allocation count
to spread out the non managed interrupt accross the possible target CPUs.

Fixes: 2f75d9e1c9 ("genirq: Implement bitmap matrix allocator")
Reported-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Keith Busch <keith.busch@intel.com>
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1801171557330.1777@nanos
2018-01-18 11:38:41 +01:00
..
affinity.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
autoprobe.c 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
chip.c 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
cpuhotplug.c genirq/cpuhotplug: Add sanity check for effective affinity mask 2017-10-09 13:26:48 +02:00
debug.h genirq: Guard handle_bad_irq log messages 2017-12-28 12:28:29 +01:00
debugfs.c genirq: Introduce IRQD_CAN_RESERVE flag 2017-12-29 21:13:04 +01:00
devres.c irq/generic-chip: Provide devm_irq_setup_generic_chip() 2017-06-21 15:53:11 +02:00
dummychip.c Merge branch 'linus' into irq/core 2015-06-05 22:25:01 +02:00
generic-chip.c kernel/irq: Extend lockdep class for request mutex 2017-12-28 12:26:35 +01:00
handle.c There has been a fair amount of activity in the docs tree this time 2017-07-03 21:13:25 -07:00
internals.h genirq/irqdomain: Rename early argument of irq_domain_activate_irq() 2017-12-29 21:13:04 +01:00
ipi.c genirq/ipi: Fixup checks against nr_cpu_ids 2017-08-20 10:49:05 +02:00
irq_sim.c genirq/irq_sim: Add a devres variant of irq_sim_init() 2017-08-16 16:40:02 +02:00
irqdesc.c arm64 updates for 4.15 2017-11-15 10:56:56 -08:00
irqdomain.c genirq/irqdomain: Rename early argument of irq_domain_activate_irq() 2017-12-29 21:13:04 +01:00
Kconfig genirq: Add config option for reservation mode 2017-10-18 15:38:30 +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 irqchip updates for 4.15, take #4 2017-11-14 11:23:05 +01:00
matrix.c irq/matrix: Spread interrupts on allocation 2018-01-18 11:38:41 +01:00
migration.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
msi.c genirq/msi, x86/vector: Prevent reservation mode for non maskable MSI 2017-12-29 21:13:05 +01:00
pm.c genirq/PM: Properly pretend disabled state when force resuming interrupts 2017-07-17 22:32:20 +02:00
proc.c 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
resend.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +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 treewide: Switch DEFINE_TIMER callbacks to struct timer_list * 2017-11-21 15:57:05 -08:00
timings.c irq/timings: Use lockdep to assert IRQs are disabled/enabled 2017-11-08 11:13:52 +01:00