lgtm Reviewed-by: Jon Derrick <jonathan.derr...@intel.com>
On Mon, 2019-08-19 at 20:49 +0800, Ming Lei wrote:
> 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, we still need to spread vectors among remained CPUs. The 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 remained nodes if 'numvecs' vectors
> have been handled already.
>
> Also, if the specified cpumask for one numa node is empty, simply not
> spread vectors on this node.
>
> Cc: Christoph Hellwig <h...@lst.de>
> Cc: Keith Busch <kbu...@kernel.org>
> Cc: linux-n...@lists.infradead.org,
> Cc: Jon Derrick <jonathan.derr...@intel.com>
> Cc: Jens Axboe <ax...@kernel.dk>
> Signed-off-by: Ming Lei <ming....@redhat.com>
> ---
> kernel/irq/affinity.c | 26 ++++++++++++++++++--------
> 1 file changed, 18 insertions(+), 8 deletions(-)
>
> diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
> index 6fef48033f96..c7cca942bd8a 100644
> --- a/kernel/irq/affinity.c
> +++ b/kernel/irq/affinity.c
> @@ -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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