[PATCH 3/5] IB/hfi1: Add irq affinity notification handler

Dennis Dalessandro
2016-09-25T14:44:37Z

This patch adds an irq affinity notification handler.
When a user changes interrupt affinity settings for an sdma engine,
the driver needs to make changes to its internal sde structures and
also update the affinity_hint.

Reviewed-by: Dennis Dalessandro <dennis.dalessandro-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Reviewed-by: Sebastian Sanchez <sebastian.sanchez-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Reviewed-by: Jianxin Xiong <jianxin.xiong-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Tadeusz Struk <tadeusz.struk-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
drivers/infiniband/hw/hfi1/affinity.c | 112 ++++++++++++++++++++++++++++++---
drivers/infiniband/hw/hfi1/hfi.h | 1
2 files changed, 103 insertions(+), 10 deletions(-)

diff --git a/drivers/infiniband/hw/hfi1/affinity.c b/drivers/infiniband/hw/hfi1/affinity.c
index 17c805a..a26a9a0 100644
--- a/drivers/infiniband/hw/hfi1/affinity.c
+++ b/drivers/infiniband/hw/hfi1/affinity.c
@@ -47,6 +47,7 @@
#include <linux/topology.h>
#include <linux/cpumask.h>
#include <linux/module.h>
+#include <linux/interrupt.h>

#include "hfi.h"
#include "affinity.h"
@@ -309,6 +310,101 @@ int hfi1_dev_affinity_init(struct hfi1_devdata *dd)
}

/*
+ * Function updates the irq affinity hint for msix after it has been changed
+ * by the user using the /proc/irq interface. This function only accepts
+ * one cpu in the mask.
+ */
+static void hfi1_update_sdma_affinity(struct hfi1_msix_entry *msix, int cpu)
+{
+ struct sdma_engine *sde = msix->arg;
+ struct hfi1_devdata *dd = sde->dd;
+ struct hfi1_affinity_node *entry;
+ struct cpu_mask_set *set;
+ int i, old_cpu;
+
+ if (cpu > num_online_cpus() || cpu == sde->cpu)
+ return;
+
+ mutex_lock(&node_affinity.lock);
+ entry = node_affinity_lookup(dd->node);
+ if (!entry)
+ goto unlock;
+
+ old_cpu = sde->cpu;
+ sde->cpu = cpu;
+ cpumask_clear(&msix->mask);
+ cpumask_set_cpu(cpu, &msix->mask);
+ dd_dev_dbg(dd, "IRQ vector: %u, type %s engine %u -> cpu: %d\n",
+ msix->msix.vector, irq_type_names[msix->type],
+ sde->this_idx, cpu);
+ irq_set_affinity_hint(msix->msix.vector, &msix->mask);
+
+ /*
+ * Set the new cpu in the hfi1_affinity_node and clean
+ * the old cpu if it is not used by any other IRQ
+ */
+ set = &entry->def_intr;
+ cpumask_set_cpu(cpu, &set->mask);
+ cpumask_set_cpu(cpu, &set->used);
+ for (i = 0; i < dd->num_msix_entries; i++) {
+ struct hfi1_msix_entry *other_msix;
+
+ other_msix = &dd->msix_entries[i];
+ if (other_msix->type != IRQ_SDMA || other_msix == msix)
+ continue;
+
+ if (cpumask_test_cpu(old_cpu, &other_msix->mask))
+ goto unlock;
+ }
+ cpumask_clear_cpu(old_cpu, &set->mask);
+ cpumask_clear_cpu(old_cpu, &set->used);
+unlock:
+ mutex_unlock(&node_affinity.lock);
+}
+
+static void hfi1_irq_notifier_notify(struct irq_affinity_notify *notify,
+ const cpumask_t *mask)
+{
+ int cpu = cpumask_first(mask);
+ struct hfi1_msix_entry *msix = container_of(notify,
+ struct hfi1_msix_entry,
+ notify);
+
+ /* Only one CPU configuration supported currently */
+ hfi1_update_sdma_affinity(msix, cpu);
+}
+
+static void hfi1_irq_notifier_release(struct kref *ref)
+{
+ /*
+ * This is required by affinity notifier. We don't have anything to
+ * free here.
+ */
+}
+
+static void hfi1_setup_sdma_notifier(struct hfi1_msix_entry *msix)
+{
+ struct irq_affinity_notify *notify = &msix->notify;
+
+ notify->irq = msix->msix.vector;
+ notify->notify = hfi1_irq_notifier_notify;
+ notify->release = hfi1_irq_notifier_release;
+
+ if (irq_set_affinity_notifier(notify->irq, notify))
+ pr_err("Failed to register sdma irq affinity notifier for irq %d\n",
+ notify->irq);
+}
+
+static void hfi1_cleanup_sdma_notifier(struct hfi1_msix_entry *msix)
+{
+ struct irq_affinity_notify *notify = &msix->notify;
+
+ if (irq_set_affinity_notifier(notify->irq, NULL))
+ pr_err("Failed to cleanup sdma irq affinity notifier for irq %d\n",
+ notify->irq);
+}
+
+/*
* Function sets the irq affinity for msix.
* It *must* be called with node_affinity.lock held.
*/
@@ -374,22 +470,17 @@ static int get_irq_affinity(struct hfi1_devdata *dd,
cpumask_set_cpu(cpu, &set->used);
}

- switch (msix->type) {
- case IRQ_SDMA:
- sde->cpu = cpu;
- break;
- case IRQ_GENERAL:
- case IRQ_RCVCTXT:
- case IRQ_OTHER:
- break;
- }
-
cpumask_set_cpu(cpu, &msix->mask);
dd_dev_info(dd, "IRQ vector: %u, type %s %s -> cpu: %d\n",
msix->msix.vector, irq_type_names[msix->type],
extra, cpu);
irq_set_affinity_hint(msix->msix.vector, &msix->mask);

+ if (msix->type == IRQ_SDMA) {
+ sde->cpu = cpu;
+ hfi1_setup_sdma_notifier(msix);
+ }
+
free_cpumask_var(diff);
return 0;
}
@@ -417,6 +508,7 @@ void hfi1_put_irq_affinity(struct hfi1_devdata *dd,
switch (msix->type) {
case IRQ_SDMA:
set = &entry->def_intr;
+ hfi1_cleanup_sdma_notifier(msix);
break;
case IRQ_GENERAL:
/* Don't do accounting for general contexts */
diff --git a/drivers/infiniband/hw/hfi1/hfi.h b/drivers/infiniband/hw/hfi1/hfi.h
index 59f69fa..7eef11b 100644
--- a/drivers/infiniband/hw/hfi1/hfi.h
+++ b/drivers/infiniband/hw/hfi1/hfi.h
@@ -531,6 +531,7 @@ struct hfi1_msix_entry {
void *arg;
char name[MAX_NAME_SIZE];
cpumask_t mask;
+ struct irq_affinity_notify notify;
};

/* per-SL CCA information */