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Subject[PATCH 4/4] irq: add support for allocating (and affinitizing) sets of IRQs
Date
From: Jens Axboe <axboe@kernel.dk>

A driver may have a need to allocate multiple sets of MSI/MSI-X
interrupts, and have them appropriately affinitized. Add support for
defining a number of sets in the irq_affinity structure, of varying
sizes, and get each set affinitized correctly across the machine.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
drivers/pci/msi.c | 14 ++++++++++
include/linux/interrupt.h | 4 +++
kernel/irq/affinity.c | 71 ++++++++++++++++++++++++++++++++++-------------
3 files changed, 70 insertions(+), 19 deletions(-)

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index af24ed50a245..265ed3e4c920 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -1036,6 +1036,13 @@ static int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec,
if (maxvec < minvec)
return -ERANGE;

+ /*
+ * If the caller is passing in sets, we can't support a range of
+ * vectors. The caller needs to handle that.
+ */
+ if (affd && affd->nr_sets && minvec != maxvec)
+ return -EINVAL;
+
if (WARN_ON_ONCE(dev->msi_enabled))
return -EINVAL;

@@ -1087,6 +1094,13 @@ static int __pci_enable_msix_range(struct pci_dev *dev,
if (maxvec < minvec)
return -ERANGE;

+ /*
+ * If the caller is passing in sets, we can't support a range of
+ * supported vectors. The caller needs to handle that.
+ */
+ if (affd && affd->nr_sets && minvec != maxvec)
+ return -EINVAL;
+
if (WARN_ON_ONCE(dev->msix_enabled))
return -EINVAL;

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 1d6711c28271..ca397ff40836 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -247,10 +247,14 @@ struct irq_affinity_notify {
* 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
*/
struct irq_affinity {
int pre_vectors;
int post_vectors;
+ int nr_sets;
+ int *sets;
};

#if defined(CONFIG_SMP)
diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
index 9c74f21ab10e..d49d3bff702c 100644
--- a/kernel/irq/affinity.c
+++ b/kernel/irq/affinity.c
@@ -172,26 +172,28 @@ static int __irq_build_affinity_masks(const struct irq_affinity *affd,
* 2) spread other possible CPUs on these vectors
*/
static int irq_build_affinity_masks(const struct irq_affinity *affd,
- int startvec, int numvecs,
+ int startvec, int numvecs, int firstvec,
cpumask_var_t *node_to_cpumask,
struct cpumask *masks)
{
- int curvec = startvec, usedvecs = -1;
+ int curvec = startvec, nr_present, nr_others;
+ int ret = -ENOMEM;
cpumask_var_t nmsk, npresmsk;

if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL))
- return usedvecs;
+ return ret;

if (!zalloc_cpumask_var(&npresmsk, GFP_KERNEL))
goto fail;

+ ret = 0;
/* Stabilize the cpumasks */
get_online_cpus();
build_node_to_cpumask(node_to_cpumask);

/* Spread on present CPUs starting from affd->pre_vectors */
- usedvecs = __irq_build_affinity_masks(affd, curvec, numvecs,
- affd->pre_vectors, node_to_cpumask,
+ nr_present = __irq_build_affinity_masks(affd, curvec, numvecs,
+ firstvec, node_to_cpumask,
cpu_present_mask, nmsk, masks);

/*
@@ -200,22 +202,24 @@ static int irq_build_affinity_masks(const struct irq_affinity *affd,
* vector space, assign the non present CPUs to the already spread
* out vectors.
*/
- if (usedvecs >= numvecs)
- curvec = affd->pre_vectors;
+ if (nr_present >= numvecs)
+ curvec = firstvec;
else
- curvec = affd->pre_vectors + usedvecs;
+ curvec = firstvec + nr_present;
cpumask_andnot(npresmsk, cpu_possible_mask, cpu_present_mask);
- usedvecs += __irq_build_affinity_masks(affd, curvec, numvecs,
- affd->pre_vectors, node_to_cpumask, npresmsk,
+ nr_others = __irq_build_affinity_masks(affd, curvec, numvecs,
+ firstvec, node_to_cpumask, npresmsk,
nmsk, masks);
put_online_cpus();

+ if (nr_present < numvecs)
+ WARN_ON(nr_present + nr_others < numvecs);
+
free_cpumask_var(npresmsk);

fail:
free_cpumask_var(nmsk);
-
- return usedvecs;
+ return ret;
}

/**
@@ -232,6 +236,7 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
int curvec, usedvecs;
cpumask_var_t *node_to_cpumask;
struct cpumask *masks = NULL;
+ int i, nr_sets;

/*
* If there aren't any vectors left after applying the pre/post
@@ -252,8 +257,28 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
for (curvec = 0; curvec < affd->pre_vectors; curvec++)
cpumask_copy(masks + curvec, irq_default_affinity);

- usedvecs = irq_build_affinity_masks(affd, curvec, affvecs,
- node_to_cpumask, masks);
+ /*
+ * Spread on present CPUs starting from affd->pre_vectors. If we
+ * have multiple sets, build each sets affinity mask separately.
+ */
+ nr_sets = affd->nr_sets;
+ if (!nr_sets)
+ nr_sets = 1;
+
+ for (i = 0, usedvecs = 0; i < nr_sets; i++) {
+ int this_vecs = affd->sets ? affd->sets[i] : affvecs;
+ int ret;
+
+ ret = irq_build_affinity_masks(affd, curvec, this_vecs,
+ curvec, node_to_cpumask, masks);
+ if (ret) {
+ kfree(masks);
+ masks = NULL;
+ goto outnodemsk;
+ }
+ curvec += this_vecs;
+ usedvecs += this_vecs;
+ }

/* Fill out vectors at the end that don't need affinity */
if (usedvecs >= affvecs)
@@ -278,13 +303,21 @@ int irq_calc_affinity_vectors(int minvec, int maxvec, const struct irq_affinity
{
int resv = affd->pre_vectors + affd->post_vectors;
int vecs = maxvec - resv;
- int ret;
+ int set_vecs;

if (resv > minvec)
return 0;

- get_online_cpus();
- ret = min_t(int, cpumask_weight(cpu_possible_mask), vecs) + resv;
- put_online_cpus();
- return ret;
+ if (affd->nr_sets) {
+ int i;
+
+ for (i = 0, set_vecs = 0; i < affd->nr_sets; i++)
+ set_vecs += affd->sets[i];
+ } else {
+ get_online_cpus();
+ set_vecs = cpumask_weight(cpu_possible_mask);
+ put_online_cpus();
+ }
+
+ return resv + min(set_vecs, vecs);
}
--
2.9.5
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