From 9cfef55bb57e7620c63087be18a76351628f8d0f Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Sat, 16 Feb 2019 18:13:08 +0100 Subject: [PATCH] genirq/affinity: Store interrupt sets size in struct irq_affinity The interrupt affinity spreading mechanism supports to spread out affinities for one or more interrupt sets. A interrupt set contains one or more interrupts. Each set is mapped to a specific functionality of a device, e.g. general I/O queues and read I/O queus of multiqueue block devices. The number of interrupts per set is defined by the driver. It depends on the total number of available interrupts for the device, which is determined by the PCI capabilites and the availability of underlying CPU resources, and the number of queues which the device provides and the driver wants to instantiate. The driver passes initial configuration for the interrupt allocation via a pointer to struct irq_affinity. Right now the allocation mechanism is complex as it requires to have a loop in the driver to determine the maximum number of interrupts which are provided by the PCI capabilities and the underlying CPU resources. This loop would have to be replicated in every driver which wants to utilize this mechanism. That's unwanted code duplication and error prone. In order to move this into generic facilities it is required to have a mechanism, which allows the recalculation of the interrupt sets and their size, in the core code. As the core code does not have any knowledge about the underlying device, a driver specific callback will be added to struct affinity_desc, which will be invoked by the core code. The callback will get the number of available interupts as an argument, so the driver can calculate the corresponding number and size of interrupt sets. To support this, two modifications for the handling of struct irq_affinity are required: 1) The (optional) interrupt sets size information is contained in a separate array of integers and struct irq_affinity contains a pointer to it. This is cumbersome and as the maximum number of interrupt sets is small, there is no reason to have separate storage. Moving the size array into struct affinity_desc avoids indirections and makes the code simpler. 2) At the moment the struct irq_affinity pointer which is handed in from the driver and passed through to several core functions is marked 'const'. With the upcoming callback to recalculate the number and size of interrupt sets, it's necessary to remove the 'const' qualifier. Otherwise the callback would not be able to update the data. Implement #1 and store the interrupt sets size in 'struct irq_affinity'. No functional change. [ tglx: Fixed the memcpy() size so it won't copy beyond the size of the source. Fixed the kernel doc comments for struct irq_affinity and de-'This patch'-ed the changelog ] Signed-off-by: Ming Lei Signed-off-by: Thomas Gleixner Acked-by: Marc Zyngier Cc: Christoph Hellwig Cc: Bjorn Helgaas Cc: Jens Axboe Cc: linux-block@vger.kernel.org Cc: Sagi Grimberg Cc: linux-nvme@lists.infradead.org Cc: linux-pci@vger.kernel.org Cc: Keith Busch Cc: Sumit Saxena Cc: Kashyap Desai Cc: Shivasharan Srikanteshwara Link: https://lkml.kernel.org/r/20190216172228.423723127@linutronix.de --- drivers/nvme/host/pci.c | 7 +++---- include/linux/interrupt.h | 9 ++++++--- kernel/irq/affinity.c | 16 ++++++++++++---- 3 files changed, 21 insertions(+), 11 deletions(-) diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index 9bc5854..21ffd67 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -2081,12 +2081,11 @@ static void nvme_calc_io_queues(struct nvme_dev *dev, unsigned int irq_queues) static int nvme_setup_irqs(struct nvme_dev *dev, unsigned int nr_io_queues) { struct pci_dev *pdev = to_pci_dev(dev->dev); - int irq_sets[2]; struct irq_affinity affd = { - .pre_vectors = 1, - .nr_sets = ARRAY_SIZE(irq_sets), - .sets = irq_sets, + .pre_vectors = 1, + .nr_sets = 2, }; + unsigned int *irq_sets = affd.set_size; int result = 0; unsigned int irq_queues, this_p_queues; diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index 35e7389..5afdfd5 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -241,20 +241,23 @@ struct irq_affinity_notify { void (*release)(struct kref *ref); }; +#define IRQ_AFFINITY_MAX_SETS 4 + /** * struct irq_affinity - Description for automatic irq affinity assignements * @pre_vectors: Don't apply affinity to @pre_vectors at beginning of * the MSI(-X) vector space * @post_vectors: Don't apply affinity to @post_vectors at end of * the MSI(-X) vector space - * @nr_sets: Length of passed in *sets array - * @sets: Number of affinitized sets + * @nr_sets: The number of interrupt sets for which affinity + * spreading is required + * @set_size: Array holding the size of each interrupt set */ struct irq_affinity { unsigned int pre_vectors; unsigned int post_vectors; unsigned int nr_sets; - unsigned int *sets; + unsigned int set_size[IRQ_AFFINITY_MAX_SETS]; }; /** diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c index 82e8799..278289c 100644 --- a/kernel/irq/affinity.c +++ b/kernel/irq/affinity.c @@ -238,9 +238,10 @@ static int irq_build_affinity_masks(const struct irq_affinity *affd, * Returns the irq_affinity_desc pointer or NULL if allocation failed. */ struct irq_affinity_desc * -irq_create_affinity_masks(unsigned int nvecs, const struct irq_affinity *affd) +irq_create_affinity_masks(unsigned int nvecs, struct irq_affinity *affd) { unsigned int affvecs, curvec, usedvecs, nr_sets, i; + unsigned int set_size[IRQ_AFFINITY_MAX_SETS]; struct irq_affinity_desc *masks = NULL; /* @@ -250,6 +251,9 @@ irq_create_affinity_masks(unsigned int nvecs, const struct irq_affinity *affd) if (nvecs == affd->pre_vectors + affd->post_vectors) return NULL; + if (WARN_ON_ONCE(affd->nr_sets > IRQ_AFFINITY_MAX_SETS)) + return NULL; + masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL); if (!masks) return NULL; @@ -263,11 +267,15 @@ irq_create_affinity_masks(unsigned int nvecs, const struct irq_affinity *affd) */ affvecs = nvecs - affd->pre_vectors - affd->post_vectors; nr_sets = affd->nr_sets; - if (!nr_sets) + if (!nr_sets) { nr_sets = 1; + set_size[0] = affvecs; + } else { + memcpy(set_size, affd->set_size, nr_sets * sizeof(unsigned int)); + } for (i = 0, usedvecs = 0; i < nr_sets; i++) { - unsigned int this_vecs = affd->sets ? affd->sets[i] : affvecs; + unsigned int this_vecs = set_size[i]; int ret; ret = irq_build_affinity_masks(affd, curvec, this_vecs, @@ -314,7 +322,7 @@ unsigned int irq_calc_affinity_vectors(unsigned int minvec, unsigned int maxvec, unsigned int i; for (i = 0, set_vecs = 0; i < affd->nr_sets; i++) - set_vecs += affd->sets[i]; + set_vecs += affd->set_size[i]; } else { get_online_cpus(); set_vecs = cpumask_weight(cpu_possible_mask); -- 2.7.4