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Commit 1a2d0914 authored by Ming Lei's avatar Ming Lei Committed by Thomas Gleixner
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genirq/affinity: Allow irq spreading from a given starting point 



To support two stage irq vector spreading, it's required to add a starting
point to the spreading function. No functional change, just preparatory
work for the actual two stage change.

[ tglx: Renamed variables, tidied up the code and massaged changelog ]

Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Cc: Laurence Oberman <loberman@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Link: https://lkml.kernel.org/r/20180308105358.1506-4-ming.lei@redhat.com
parent b3e6aaa8

kernel/irq/affinity.c

+20 −15
Original line number Diff line number Diff line
@@ -94,17 +94,17 @@ static int get_nodes_in_cpumask(cpumask_var_t *node_to_cpumask, 
	return nodes;

}



static int irq_build_affinity_masks(int nvecs, 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,

				    struct cpumask *nmsk,

				    struct cpumask *masks)

{

	int affv = nvecs - affd->pre_vectors - affd->post_vectors;

	int last_affv = affv + affd->pre_vectors;

	int curvec = affd->pre_vectors;

	int n, nodes, cpus_per_vec, extra_vecs, done = 0;

	int last_affv = affd->pre_vectors + numvecs;

	int curvec = startvec;

	nodemask_t nodemsk = NODE_MASK_NONE;

	int n, nodes, cpus_per_vec, extra_vecs;



	nodes = get_nodes_in_cpumask(node_to_cpumask, cpu_mask, &nodemsk);
@@ -112,12 +112,13 @@ static int irq_build_affinity_masks(int nvecs, const struct irq_affinity *affd, 
	 * If the number of nodes in the mask is greater than or equal the

	 * number of vectors we just spread the vectors across the nodes.

	 */

	if (affv <= nodes) {

	if (numvecs <= nodes) {

		for_each_node_mask(n, nodemsk) {

			cpumask_copy(masks + curvec,

				     node_to_cpumask[n]);

			if (++curvec == last_affv)

			cpumask_copy(masks + curvec, node_to_cpumask[n]);

			if (++done == numvecs)

				break;

			if (++curvec == last_affv)

				curvec = affd->pre_vectors;

		}

		goto out;

	}
@@ -126,7 +127,7 @@ static int irq_build_affinity_masks(int nvecs, const struct irq_affinity *affd, 
		int ncpus, v, vecs_to_assign, vecs_per_node;



		/* Spread the vectors per node */

		vecs_per_node = (affv - (curvec - affd->pre_vectors)) / nodes;

		vecs_per_node = (numvecs - (curvec - affd->pre_vectors)) / nodes;



		/* Get the cpus on this node which are in the mask */

		cpumask_and(nmsk, cpu_mask, node_to_cpumask[n]);
@@ -150,13 +151,16 @@ static int irq_build_affinity_masks(int nvecs, const struct irq_affinity *affd, 
			irq_spread_init_one(masks + curvec, nmsk, cpus_per_vec);

		}



		if (curvec >= last_affv)

		done += v;

		if (done >= numvecs)

			break;

		if (curvec >= last_affv)

			curvec = affd->pre_vectors;

		--nodes;

	}



out:

	return curvec - affd->pre_vectors;

	return done;

}



/**
@@ -169,9 +173,9 @@ static int irq_build_affinity_masks(int nvecs, const struct irq_affinity *affd, 
struct cpumask *

irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)

{

	int curvec, affvecs = nvecs - affd->pre_vectors - affd->post_vectors;

	cpumask_var_t nmsk, *node_to_cpumask;

	struct cpumask *masks = NULL;

	int curvec;



	/*

	 * If there aren't any vectors left after applying the pre/post
@@ -198,8 +202,9 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd) 
	/* Stabilize the cpumasks */

	get_online_cpus();

	build_node_to_cpumask(node_to_cpumask);

	curvec += irq_build_affinity_masks(nvecs, affd, node_to_cpumask,

					   cpu_possible_mask, nmsk, masks);

	curvec += irq_build_affinity_masks(affd, curvec, affvecs,

					   node_to_cpumask, cpu_possible_mask,

					   nmsk, masks);

	put_online_cpus();



	/* Fill out vectors at the end that don't need affinity */