path: root/kernel/irq/devres.c
diff options
authorDou Liyang <douliyangs@gmail.com>2018-12-04 23:51:20 +0800
committerThomas Gleixner <tglx@linutronix.de>2018-12-19 11:32:08 +0100
commitbec04037e4e484f41ee4d9409e40616874169d20 (patch)
tree5fde4bc9e597250dbdac3a4c0741b13766da8d4e /kernel/irq/devres.c
parentc2899c3470de04823870b28646981695c0046efe (diff)
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
Diffstat (limited to 'kernel/irq/devres.c')
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/irq/devres.c b/kernel/irq/devres.c
index 6a682c229e10..5d5378ea0afe 100644
--- a/kernel/irq/devres.c
+++ b/kernel/irq/devres.c
@@ -169,7 +169,7 @@ static void devm_irq_desc_release(struct device *dev, void *res)
* @cnt: Number of consecutive irqs to allocate
* @node: Preferred node on which the irq descriptor should be allocated
* @owner: Owning module (can be NULL)
- * @affinity: Optional pointer to an affinity mask array of size @cnt
+ * @affinity: Optional pointer to an irq_affinity_desc array of size @cnt
* which hints where the irq descriptors should be allocated
* and which default affinities to use
@@ -179,7 +179,7 @@ static void devm_irq_desc_release(struct device *dev, void *res)
int __devm_irq_alloc_descs(struct device *dev, int irq, unsigned int from,
unsigned int cnt, int node, struct module *owner,
- const struct cpumask *affinity)
+ const struct irq_affinity_desc *affinity)
struct irq_desc_devres *dr;
int base;