| Message ID | 20250424-isolcpus-io-queues-v6-8-9a53a870ca1f@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | blk: honor isolcpus configuration | expand |
On Thu, Apr 24, 2025 at 08:19:47PM +0200, Daniel Wagner wrote: > When isolcpus=io_queue is enabled all hardware queues should run on > the housekeeping CPUs only. Thus ignore the affinity mask provided by > the driver. Also we can't use blk_mq_map_queues because it will map all > CPUs to first hctx unless, the CPU is the same as the hctx has the > affinity set to, e.g. 8 CPUs with isolcpus=io_queue,2-3,6-7 config > > queue mapping for /dev/nvme0n1 > hctx0: default 2 3 4 6 7 > hctx1: default 5 > hctx2: default 0 > hctx3: default 1 > > PCI name is 00:05.0: nvme0n1 > irq 57 affinity 0-1 effective 1 is_managed:0 nvme0q0 > irq 58 affinity 4 effective 4 is_managed:1 nvme0q1 > irq 59 affinity 5 effective 5 is_managed:1 nvme0q2 > irq 60 affinity 0 effective 0 is_managed:1 nvme0q3 > irq 61 affinity 1 effective 1 is_managed:1 nvme0q4 > > where as with blk_mq_hk_map_queues we get > > queue mapping for /dev/nvme0n1 > hctx0: default 2 4 > hctx1: default 3 5 > hctx2: default 0 6 > hctx3: default 1 7 > > PCI name is 00:05.0: nvme0n1 > irq 56 affinity 0-1 effective 1 is_managed:0 nvme0q0 > irq 61 affinity 4 effective 4 is_managed:1 nvme0q1 > irq 62 affinity 5 effective 5 is_managed:1 nvme0q2 > irq 63 affinity 0 effective 0 is_managed:1 nvme0q3 > irq 64 affinity 1 effective 1 is_managed:1 nvme0q4 > > Reviewed-by: Christoph Hellwig <hch@lst.de> > Reviewed-by: Hannes Reinecke <hare@suse.de> > Signed-off-by: Daniel Wagner <wagi@kernel.org> > --- > block/blk-mq-cpumap.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 67 insertions(+), 2 deletions(-) > > diff --git a/block/blk-mq-cpumap.c b/block/blk-mq-cpumap.c > index 6e6b3e989a5676186b5a31296a1b94b7602f1542..2d678d1db2b5196fc2b2ce5678fdb0cb6bad26e0 100644 > --- a/block/blk-mq-cpumap.c > +++ b/block/blk-mq-cpumap.c > @@ -22,8 +22,8 @@ static unsigned int blk_mq_num_queues(const struct cpumask *mask, > { > unsigned int num; > > - if (housekeeping_enabled(HK_TYPE_MANAGED_IRQ)) > - mask = housekeeping_cpumask(HK_TYPE_MANAGED_IRQ); > + if (housekeeping_enabled(HK_TYPE_IO_QUEUE)) > + mask = housekeeping_cpumask(HK_TYPE_IO_QUEUE); Here both two can be considered for figuring out nr_hw_queues: if (housekeeping_enabled(HK_TYPE_IO_QUEUE)) mask = housekeeping_cpumask(HK_TYPE_IO_QUEUE); else if (housekeeping_enabled(HK_TYPE_MANAGED_IRQ)) mask = housekeeping_cpumask(HK_TYPE_MANAGED_IRQ); > > num = cpumask_weight(mask); > return min_not_zero(num, max_queues); > @@ -61,11 +61,73 @@ unsigned int blk_mq_num_online_queues(unsigned int max_queues) > } > EXPORT_SYMBOL_GPL(blk_mq_num_online_queues); > > +/* > + * blk_mq_map_hk_queues - Create housekeeping CPU to hardware queue mapping > + * @qmap: CPU to hardware queue map > + * > + * Create a housekeeping CPU to hardware queue mapping in @qmap. If the > + * isolcpus feature is enabled and blk_mq_map_hk_queues returns true, > + * @qmap contains a valid configuration honoring the io_queue > + * configuration. If the isolcpus feature is disabled this function > + * returns false. > + */ > +static bool blk_mq_map_hk_queues(struct blk_mq_queue_map *qmap) > +{ > + struct cpumask *hk_masks; > + cpumask_var_t isol_mask; > + unsigned int queue, cpu, nr_masks; > + > + if (!housekeeping_enabled(HK_TYPE_IO_QUEUE)) > + return false; It could be more readable to move the above check to the caller. Thanks, Ming
On Fri, May 09, 2025 at 10:38:32AM +0800, Ming Lei wrote: > > +static bool blk_mq_map_hk_queues(struct blk_mq_queue_map *qmap) > > +{ > > + struct cpumask *hk_masks; > > + cpumask_var_t isol_mask; > > + unsigned int queue, cpu, nr_masks; > > + > > + if (!housekeeping_enabled(HK_TYPE_IO_QUEUE)) > > + return false; > > It could be more readable to move the above check to the caller. I wanted to avoid checking if housekeeping is enabled twice in a row. I'll post the next version with your suggestion and see if this approach is better.
diff --git a/block/blk-mq-cpumap.c b/block/blk-mq-cpumap.c index 6e6b3e989a5676186b5a31296a1b94b7602f1542..2d678d1db2b5196fc2b2ce5678fdb0cb6bad26e0 100644 --- a/block/blk-mq-cpumap.c +++ b/block/blk-mq-cpumap.c @@ -22,8 +22,8 @@ static unsigned int blk_mq_num_queues(const struct cpumask *mask, { unsigned int num; - if (housekeeping_enabled(HK_TYPE_MANAGED_IRQ)) - mask = housekeeping_cpumask(HK_TYPE_MANAGED_IRQ); + if (housekeeping_enabled(HK_TYPE_IO_QUEUE)) + mask = housekeeping_cpumask(HK_TYPE_IO_QUEUE); num = cpumask_weight(mask); return min_not_zero(num, max_queues); @@ -61,11 +61,73 @@ unsigned int blk_mq_num_online_queues(unsigned int max_queues) } EXPORT_SYMBOL_GPL(blk_mq_num_online_queues); +/* + * blk_mq_map_hk_queues - Create housekeeping CPU to hardware queue mapping + * @qmap: CPU to hardware queue map + * + * Create a housekeeping CPU to hardware queue mapping in @qmap. If the + * isolcpus feature is enabled and blk_mq_map_hk_queues returns true, + * @qmap contains a valid configuration honoring the io_queue + * configuration. If the isolcpus feature is disabled this function + * returns false. + */ +static bool blk_mq_map_hk_queues(struct blk_mq_queue_map *qmap) +{ + struct cpumask *hk_masks; + cpumask_var_t isol_mask; + unsigned int queue, cpu, nr_masks; + + if (!housekeeping_enabled(HK_TYPE_IO_QUEUE)) + return false; + + /* map housekeeping cpus to matching hardware context */ + hk_masks = group_cpus_evenly(qmap->nr_queues, &nr_masks); + if (!hk_masks) + goto fallback; + + for (queue = 0; queue < qmap->nr_queues; queue++) { + for_each_cpu(cpu, &hk_masks[queue % nr_masks]) + qmap->mq_map[cpu] = qmap->queue_offset + queue; + } + + kfree(hk_masks); + + /* map isolcpus to hardware context */ + if (!alloc_cpumask_var(&isol_mask, GFP_KERNEL)) + goto fallback; + + queue = 0; + cpumask_andnot(isol_mask, + cpu_possible_mask, + housekeeping_cpumask(HK_TYPE_IO_QUEUE)); + + for_each_cpu(cpu, isol_mask) { + qmap->mq_map[cpu] = qmap->queue_offset + queue; + queue = (queue + 1) % qmap->nr_queues; + } + + free_cpumask_var(isol_mask); + + return true; + +fallback: + /* map all cpus to hardware context ignoring any affinity */ + queue = 0; + for_each_possible_cpu(cpu) { + qmap->mq_map[cpu] = qmap->queue_offset + queue; + queue = (queue + 1) % qmap->nr_queues; + } + return true; +} + void blk_mq_map_queues(struct blk_mq_queue_map *qmap) { const struct cpumask *masks; unsigned int queue, cpu, nr_masks; + if (blk_mq_map_hk_queues(qmap)) + return; + masks = group_cpus_evenly(qmap->nr_queues, &nr_masks); if (!masks) { for_each_possible_cpu(cpu) @@ -120,6 +182,9 @@ void blk_mq_map_hw_queues(struct blk_mq_queue_map *qmap, if (!dev->bus->irq_get_affinity) goto fallback; + if (blk_mq_map_hk_queues(qmap)) + return; + for (queue = 0; queue < qmap->nr_queues; queue++) { mask = dev->bus->irq_get_affinity(dev, queue + offset); if (!mask)
When isolcpus=io_queue is enabled all hardware queues should run on the housekeeping CPUs only. Thus ignore the affinity mask provided by the driver. Also we can't use blk_mq_map_queues because it will map all CPUs to first hctx unless, the CPU is the same as the hctx has the affinity set to, e.g. 8 CPUs with isolcpus=io_queue,2-3,6-7 config queue mapping for /dev/nvme0n1 hctx0: default 2 3 4 6 7 hctx1: default 5 hctx2: default 0 hctx3: default 1 PCI name is 00:05.0: nvme0n1 irq 57 affinity 0-1 effective 1 is_managed:0 nvme0q0 irq 58 affinity 4 effective 4 is_managed:1 nvme0q1 irq 59 affinity 5 effective 5 is_managed:1 nvme0q2 irq 60 affinity 0 effective 0 is_managed:1 nvme0q3 irq 61 affinity 1 effective 1 is_managed:1 nvme0q4 where as with blk_mq_hk_map_queues we get queue mapping for /dev/nvme0n1 hctx0: default 2 4 hctx1: default 3 5 hctx2: default 0 6 hctx3: default 1 7 PCI name is 00:05.0: nvme0n1 irq 56 affinity 0-1 effective 1 is_managed:0 nvme0q0 irq 61 affinity 4 effective 4 is_managed:1 nvme0q1 irq 62 affinity 5 effective 5 is_managed:1 nvme0q2 irq 63 affinity 0 effective 0 is_managed:1 nvme0q3 irq 64 affinity 1 effective 1 is_managed:1 nvme0q4 Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Daniel Wagner <wagi@kernel.org> --- block/blk-mq-cpumap.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 67 insertions(+), 2 deletions(-)