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Subject[PATCH 2/4] irq: move 2-stage irq spread into one helper
Date
No functional change, and prepare for the following patch to
support allocating (and affinitizing) sets of IRQs.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: Hannes Reinecke <hare@suse.com>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
kernel/irq/affinity.c | 92 +++++++++++++++++++++++++++++++--------------------
1 file changed, 56 insertions(+), 36 deletions(-)

diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
index f4f29b9d90ee..a16b601604aa 100644
--- a/kernel/irq/affinity.c
+++ b/kernel/irq/affinity.c
@@ -94,7 +94,7 @@ static int get_nodes_in_cpumask(cpumask_var_t *node_to_cpumask,
return nodes;
}

-static int irq_build_affinity_masks(const struct irq_affinity *affd,
+static int __irq_build_affinity_masks(const struct irq_affinity *affd,
int startvec, int numvecs,
cpumask_var_t *node_to_cpumask,
const struct cpumask *cpu_mask,
@@ -166,6 +166,58 @@ static int irq_build_affinity_masks(const struct irq_affinity *affd,
return done;
}

+/*
+ * build affinity in two stages:
+ * 1) spread present CPU on these vectors
+ * 2) spread other possible CPUs on these vectors
+ */
+static int irq_build_affinity_masks(const struct irq_affinity *affd,
+ int startvec, int numvecs,
+ cpumask_var_t *node_to_cpumask,
+ struct cpumask *masks)
+{
+ int curvec = startvec, usedvecs = -1;
+ cpumask_var_t nmsk, npresmsk;
+
+ if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL))
+ return usedvecs;
+
+ if (!zalloc_cpumask_var(&npresmsk, GFP_KERNEL))
+ goto fail;
+
+ /* 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,
+ node_to_cpumask, cpu_present_mask,
+ nmsk, masks);
+
+ /*
+ * Spread on non present CPUs starting from the next vector to be
+ * handled. If the spreading of present CPUs already exhausted the
+ * vector space, assign the non present CPUs to the already spread
+ * out vectors.
+ */
+ if (usedvecs >= numvecs)
+ curvec = affd->pre_vectors;
+ else
+ curvec = affd->pre_vectors + usedvecs;
+ cpumask_andnot(npresmsk, cpu_possible_mask, cpu_present_mask);
+ usedvecs += __irq_build_affinity_masks(affd, curvec, numvecs,
+ node_to_cpumask, npresmsk,
+ nmsk, masks);
+ put_online_cpus();
+
+ free_cpumask_var(npresmsk);
+
+ fail:
+ free_cpumask_var(nmsk);
+
+ return usedvecs;
+}
+
/**
* irq_create_affinity_masks - Create affinity masks for multiqueue spreading
* @nvecs: The total number of vectors
@@ -178,7 +230,7 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
{
int affvecs = nvecs - affd->pre_vectors - affd->post_vectors;
int curvec, usedvecs;
- cpumask_var_t nmsk, npresmsk, *node_to_cpumask;
+ cpumask_var_t *node_to_cpumask;
struct cpumask *masks = NULL;

/*
@@ -188,15 +240,9 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
if (nvecs == affd->pre_vectors + affd->post_vectors)
return NULL;

- if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL))
- return NULL;
-
- if (!zalloc_cpumask_var(&npresmsk, GFP_KERNEL))
- goto outcpumsk;
-
node_to_cpumask = alloc_node_to_cpumask();
if (!node_to_cpumask)
- goto outnpresmsk;
+ return NULL;

masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL);
if (!masks)
@@ -206,30 +252,8 @@ 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);

- /* 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, affvecs,
- node_to_cpumask, cpu_present_mask,
- nmsk, masks);
-
- /*
- * Spread on non present CPUs starting from the next vector to be
- * handled. If the spreading of present CPUs already exhausted the
- * vector space, assign the non present CPUs to the already spread
- * out vectors.
- */
- if (usedvecs >= affvecs)
- curvec = affd->pre_vectors;
- else
- curvec = affd->pre_vectors + usedvecs;
- cpumask_andnot(npresmsk, cpu_possible_mask, cpu_present_mask);
- usedvecs += irq_build_affinity_masks(affd, curvec, affvecs,
- node_to_cpumask, npresmsk,
- nmsk, masks);
- put_online_cpus();
+ node_to_cpumask, masks);

/* Fill out vectors at the end that don't need affinity */
if (usedvecs >= affvecs)
@@ -241,10 +265,6 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)

outnodemsk:
free_node_to_cpumask(node_to_cpumask);
-outnpresmsk:
- free_cpumask_var(npresmsk);
-outcpumsk:
- free_cpumask_var(nmsk);
return masks;
}

--
2.9.5
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