Messages in this thread | | | Date | Thu, 22 Aug 2019 10:03:12 -0600 | From | Keith Busch <> | Subject | Re: [PATCH V6 1/2] genirq/affinity: Improve __irq_build_affinity_masks() |
| |
On Mon, Aug 19, 2019 at 05:49:36AM -0700, 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 <hch@lst.de> > Cc: Keith Busch <kbusch@kernel.org> > Cc: linux-nvme@lists.infradead.org, > Cc: Jon Derrick <jonathan.derrick@intel.com> > Cc: Jens Axboe <axboe@kernel.dk> > Signed-off-by: Ming Lei <ming.lei@redhat.com>
Looks good to me
Reviewed-by: Keith Busch <kbusch@kernel.org>
> --- > 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; > } > > /* > --
| |