linux-stable/kernel/irq
Jesse Brandeburg e2e64a9325 genirq: Set initial affinity in irq_set_affinity_hint()
Problem:
The default behavior of the kernel is somewhat undesirable as all
requested interrupts end up on CPU0 after registration.  A user can
run irqbalance daemon, or can manually configure smp_affinity via the
proc filesystem, but the default affinity of the interrupts for all
devices is always CPU zero, this can cause performance problems or
very heavy cpu use of only one core if not noticed and fixed by the
user.

Solution:
Enable the setting of the initial affinity directly when the driver
sets a hint.

This enabling means that kernel drivers can include an initial
affinity setting for the interrupt, instead of all interrupts starting
out life on CPU0. Of course if irqbalance is still running then the
interrupts will get moved as before.

This function is currently called by drivers in block, crypto,
infiniband, ethernet and scsi trees, but only a handful, so these will
be the devices affected by this change.

Tested on i40e, and default interrupts were spread across the CPUs
according to the hint.

drivers/block/mtip32xx/mtip32xx.c:3
drivers/block/nvme-core.c:2
drivers/crypto/qat/qat_dh895xcc/adf_isr.c:3
drivers/infiniband/hw/qib/qib_iba7322.c:2
drivers/net/ethernet/intel/i40e/i40e_main.c:3
drivers/net/ethernet/intel/i40evf/i40evf_main.c:3
drivers/net/ethernet/intel/ixgbe/ixgbe_main.c:3
drivers/net/ethernet/mellanox/mlx4/en_cq.c:2
drivers/scsi/hpsa.c:3
drivers/scsi/lpfc/lpfc_init.c:3
drivers/scsi/megaraid/megaraid_sas_base.c:8
drivers/soc/ti/knav_qmss_acc.c:1
drivers/soc/ti/knav_qmss_queue.c:2
drivers/virtio/virtio_pci_common.c:2

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20141219012206.4220.27491.stgit@jbrandeb-cp2.jf.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-01-23 11:38:25 +01:00
..
autoprobe.c genirq: Handle pending irqs in irq_startup() 2012-02-15 11:56:59 +01:00
chip.c genirq: Work around __irq_set_handler vs stacked domains ordering issues 2014-11-23 13:01:47 +01:00
debug.h irq: hide debug macros so they don't collide with others. 2012-04-23 12:30:03 -04:00
devres.c genirq: fix reference in devm_request_threaded_irq comment 2014-08-28 15:22:00 +02:00
dummychip.c genirq: Export dummy_irq_chip 2012-08-21 16:14:23 +02:00
generic-chip.c genirq: Generic chip: Add big endian I/O accessors 2014-11-09 04:02:00 +00:00
handle.c genirq: Export symbol no_action() 2014-03-22 11:33:09 +01:00
internals.h genirq: Prevent proc race against freeing of irq descriptors 2014-12-13 13:33:07 +01:00
irqdesc.c genirq: Prevent proc race against freeing of irq descriptors 2014-12-13 13:33:07 +01:00
irqdomain.c irqdomain: Introduce helper function irq_domain_add_hierarchy() 2014-11-23 13:01:46 +01:00
Kconfig genirq: Add generic msi irq domain support 2014-11-23 13:01:47 +01:00
Makefile genirq: Add generic msi irq domain support 2014-11-23 13:01:47 +01:00
manage.c genirq: Set initial affinity in irq_set_affinity_hint() 2015-01-23 11:38:25 +01:00
migration.c genirq: Introduce irq_do_set_affinity() to reduce duplicated code 2012-05-24 22:36:40 +02:00
msi.c genirq: Move irq_chip_write_msi_msg() helper to core 2014-12-07 21:49:45 +01:00
pm.c genirq: Simplify wakeup mechanism 2014-09-01 13:48:59 +02:00
proc.c genirq: Prevent proc race against freeing of irq descriptors 2014-12-13 13:33:07 +01:00
resend.c genirq: Provide means to retrigger parent 2012-11-01 12:11:31 +01:00
settings.h genirq: Prevent spurious detection for unconditionally polled interrupts 2013-11-13 16:03:02 +01:00
spurious.c genirq: Sanitize spurious interrupt detection of threaded irqs 2014-05-03 23:15:39 +02:00