genirq/affinity: Improve __irq_build_affinity_masks() (53c1788b) · Commits · 戴 / test

One invariant of __irq_build_affinity_masks() is that all CPUs in the specified masks (cpu_mask AND node_to_cpumask for each node) should be covered during the spread. Even though all requested vectors have been reached, it's still required to spread vectors among remained CPUs. A similar policy has been taken in case of 'numvecs <= nodes' already. So remove the following check inside the loop: if (done >= numvecs) break; Meantime assign at least 1 vector for remaining nodes if 'numvecs' vectors have been handled already. Also, if the specified cpumask for one numa node is empty, simply do not spread vectors on this node. Signed-off-by:

Ming Lei <ming.lei@redhat.com> Signed-off-by:

Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20190816022849.14075-2-ming.lei@redhat.com

kernel/irq/affinity.c

+18 −8

Original line number	Diff line number	Diff line
		@@ -129,14 +129,26 @@ static int __irq_build_affinity_masks(unsigned int startvec,
		for_each_node_mask(n, nodemsk) {
		unsigned int ncpus, v, vecs_to_assign, vecs_per_node;

		/* Spread the vectors per node */
		vecs_per_node = (numvecs - (curvec - firstvec)) / nodes;

		/* Get the cpus on this node which are in the mask */
		cpumask_and(nmsk, cpu_mask, node_to_cpumask[n]);

		/* Calculate the number of cpus per vector */
		ncpus = cpumask_weight(nmsk);
		if (!ncpus)
		continue;

		/*
		* Calculate the number of cpus per vector
		*
		* Spread the vectors evenly per node. If the requested
		* vector number has been reached, simply allocate one
		* vector for each remaining node so that all nodes can
		* be covered
		*/
		if (numvecs > done)
		vecs_per_node = max_t(unsigned,
		(numvecs - done) / nodes, 1);
		else
		vecs_per_node = 1;

		vecs_to_assign = min(vecs_per_node, ncpus);

		/* Account for rounding errors */
		@@ -156,13 +168,11 @@ static int __irq_build_affinity_masks(unsigned int startvec,
		}

		done += v;
		if (done >= numvecs)
		break;
		if (curvec >= last_affv)
		curvec = firstvec;
		--nodes;
		}
		return done;
		return done < numvecs ? done : numvecs;
		}

		/*

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