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Groups > linux.kernel > #1436342
| From | tip-bot for Christoph Hellwig <tipbot@zytor.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [tip:irq/core] genirq: Add a helper to spread an affinity mask for MSI/MSI-X vectors |
| Date | 2016-07-04 12:40 +0200 |
| Message-ID | <rR9sd-4tf-5@gated-at.bofh.it> (permalink) |
| References | <rR7JM-3ot-35@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
Commit-ID: 5e385a6ef31fbbf2acbda770aecc2bc2ff933d17
Gitweb: http://git.kernel.org/tip/5e385a6ef31fbbf2acbda770aecc2bc2ff933d17
Author: Christoph Hellwig <hch@lst.de>
AuthorDate: Mon, 4 Jul 2016 17:39:27 +0900
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Mon, 4 Jul 2016 12:25:14 +0200
genirq: Add a helper to spread an affinity mask for MSI/MSI-X vectors
This is lifted from the blk-mq code and adopted to use the affinity mask
concept just introduced in the irq handling code. It tries to keep the
algorithm the same as the one current used by blk-mq, but improvements
like assining vectors on a per-node basis instead of just per sibling
are possible with this simple move and refactoring.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: linux-block@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: linux-nvme@lists.infradead.org
Cc: axboe@fb.com
Cc: agordeev@redhat.com
Link: http://lkml.kernel.org/r/1467621574-8277-7-git-send-email-hch@lst.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
include/linux/interrupt.h | 8 +++++++
kernel/irq/Makefile | 1 +
kernel/irq/affinity.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 70 insertions(+)
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 9fcabeb..b6683f0 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -278,6 +278,8 @@ extern int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m);
extern int
irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify);
+struct cpumask *irq_create_affinity_mask(unsigned int *nr_vecs);
+
#else /* CONFIG_SMP */
static inline int irq_set_affinity(unsigned int irq, const struct cpumask *m)
@@ -308,6 +310,12 @@ irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
{
return 0;
}
+
+static inline struct cpumask *irq_create_affinity_mask(unsigned int *nr_vecs)
+{
+ *nr_vecs = 1;
+ return NULL;
+}
#endif /* CONFIG_SMP */
/*
diff --git a/kernel/irq/Makefile b/kernel/irq/Makefile
index 2ee42e9..1d3ee31 100644
--- a/kernel/irq/Makefile
+++ b/kernel/irq/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_GENERIC_IRQ_MIGRATION) += cpuhotplug.o
obj-$(CONFIG_PM_SLEEP) += pm.o
obj-$(CONFIG_GENERIC_MSI_IRQ) += msi.o
obj-$(CONFIG_GENERIC_IRQ_IPI) += ipi.o
+obj-$(CONFIG_SMP) += affinity.o
diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
new file mode 100644
index 0000000..f689593
--- /dev/null
+++ b/kernel/irq/affinity.c
@@ -0,0 +1,61 @@
+
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/cpu.h>
+
+static int get_first_sibling(unsigned int cpu)
+{
+ unsigned int ret;
+
+ ret = cpumask_first(topology_sibling_cpumask(cpu));
+ if (ret < nr_cpu_ids)
+ return ret;
+ return cpu;
+}
+
+/*
+ * Take a map of online CPUs and the number of available interrupt vectors
+ * and generate an output cpumask suitable for spreading MSI/MSI-X vectors
+ * so that they are distributed as good as possible around the CPUs. If
+ * more vectors than CPUs are available we'll map one to each CPU,
+ * otherwise we map one to the first sibling of each socket.
+ *
+ * If there are more vectors than CPUs we will still only have one bit
+ * set per CPU, but interrupt code will keep on assigning the vectors from
+ * the start of the bitmap until we run out of vectors.
+ */
+struct cpumask *irq_create_affinity_mask(unsigned int *nr_vecs)
+{
+ struct cpumask *affinity_mask;
+ unsigned int max_vecs = *nr_vecs;
+
+ if (max_vecs == 1)
+ return NULL;
+
+ affinity_mask = kzalloc(cpumask_size(), GFP_KERNEL);
+ if (!affinity_mask) {
+ *nr_vecs = 1;
+ return NULL;
+ }
+
+ if (max_vecs >= num_online_cpus()) {
+ cpumask_copy(affinity_mask, cpu_online_mask);
+ *nr_vecs = num_online_cpus();
+ } else {
+ unsigned int vecs = 0, cpu;
+
+ for_each_online_cpu(cpu) {
+ if (cpu == get_first_sibling(cpu)) {
+ cpumask_set_cpu(cpu, affinity_mask);
+ vecs++;
+ }
+
+ if (--max_vecs == 0)
+ break;
+ }
+ *nr_vecs = vecs;
+ }
+
+ return affinity_mask;
+}
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
automatic interrupt affinity for MSI/MSI-X capable devices V3 Christoph Hellwig <hch@lst.de> - 2016-07-04 10:40 +0200
[PATCH 04/13] irq: Use affinity hint in irqdesc allocation Christoph Hellwig <hch@lst.de> - 2016-07-04 10:50 +0200
[tip:irq/core] genirq: Use affinity hint in irqdesc allocation tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-07-04 12:40 +0200
[PATCH 02/13] irq: Introduce IRQD_AFFINITY_MANAGED flag Christoph Hellwig <hch@lst.de> - 2016-07-04 10:50 +0200
[tip:irq/core] genirq: Introduce IRQD_AFFINITY_MANAGED flag tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-07-04 12:40 +0200
[PATCH 05/13] irq/msi: Make use of affinity aware allocations Christoph Hellwig <hch@lst.de> - 2016-07-04 10:50 +0200
[tip:irq/core] genirq/msi: Make use of affinity aware allocations tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-07-04 12:40 +0200
[PATCH 11/13] blk-mq: allow the driver to pass in an affinity mask Christoph Hellwig <hch@lst.de> - 2016-07-04 10:50 +0200
[PATCH 13/13] nvme: remove the post_scan callout Christoph Hellwig <hch@lst.de> - 2016-07-04 10:50 +0200
[PATCH 08/13] pci: spread interrupt vectors in pci_alloc_irq_vectors Christoph Hellwig <hch@lst.de> - 2016-07-04 10:50 +0200
Re: [PATCH 08/13] pci: spread interrupt vectors in pci_alloc_irq_vectors Alexander Gordeev <agordeev@redhat.com> - 2016-07-07 13:10 +0200
[PATCH 01/13] irq/msi: Remove unused MSI_FLAG_IDENTITY_MAP Christoph Hellwig <hch@lst.de> - 2016-07-04 10:50 +0200
[tip:irq/core] genirq/msi: Remove unused MSI_FLAG_IDENTITY_MAP tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-07-04 12:40 +0200
[PATCH 12/13] nvme: switch to use pci_alloc_irq_vectors Christoph Hellwig <hch@lst.de> - 2016-07-04 10:50 +0200
Re: [PATCH 12/13] nvme: switch to use pci_alloc_irq_vectors Alexander Gordeev <agordeev@redhat.com> - 2016-07-07 21:40 +0200
[PATCH 10/13] blk-mq: only allocate a single mq_map per tag_set Christoph Hellwig <hch@lst.de> - 2016-07-04 10:50 +0200
[PATCH 09/13] blk-mq: don't redistribute hardware queues on a CPU hotplug event Christoph Hellwig <hch@lst.de> - 2016-07-04 10:50 +0200
[PATCH 06/13] irq: add a helper spread an affinity mask for MSI/MSI-X vectors Christoph Hellwig <hch@lst.de> - 2016-07-04 10:50 +0200
[tip:irq/core] genirq: Add a helper to spread an affinity mask for MSI/MSI-X vectors tip-bot for Christoph Hellwig <tipbot@zytor.com> - 2016-07-04 12:40 +0200
[PATCH 07/13] pci: Provide sensible irq vector alloc/free routines Christoph Hellwig <hch@lst.de> - 2016-07-04 10:50 +0200
Re: [PATCH 07/13] pci: Provide sensible irq vector alloc/free routines Alexander Gordeev <agordeev@redhat.com> - 2016-07-06 10:10 +0200
[PATCH 03/13] irq: Add affinity hint to irq allocation Christoph Hellwig <hch@lst.de> - 2016-07-04 10:50 +0200
[tip:irq/core] genirq: Add affinity hint to irq allocation tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2016-07-04 12:40 +0200
Re: automatic interrupt affinity for MSI/MSI-X capable devices V3 Thomas Gleixner <tglx@linutronix.de> - 2016-07-04 12:40 +0200
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