diff options
| author | Daniel Wagner <wagi@kernel.org> | 2025-06-17 15:43:24 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2025-07-01 10:24:19 -0600 |
| commit | 3f27c1de5df265f9d8edf0cc5d75dc92e328484a (patch) | |
| tree | 3d46cc78f220bc7fdb2d2dedde5d9584b5e694d6 /block | |
| parent | b6139a6abf673029008f80d42abd3848d80a9108 (diff) | |
blk-mq: add number of queue calc helper
Add two variants of helper functions that calculate the correct number
of queues to use. Two variants are needed because some drivers base
their maximum number of queues on the possible CPU mask, while others
use the online CPU mask.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Daniel Wagner <wagi@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20250617-isolcpus-queue-counters-v1-2-13923686b54b@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-mq-cpumap.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/block/blk-mq-cpumap.c b/block/blk-mq-cpumap.c index 269161252add..705da074ad6c 100644 --- a/block/blk-mq-cpumap.c +++ b/block/blk-mq-cpumap.c @@ -12,10 +12,50 @@ #include <linux/cpu.h> #include <linux/group_cpus.h> #include <linux/device/bus.h> +#include <linux/sched/isolation.h> #include "blk.h" #include "blk-mq.h" +static unsigned int blk_mq_num_queues(const struct cpumask *mask, + unsigned int max_queues) +{ + unsigned int num; + + num = cpumask_weight(mask); + return min_not_zero(num, max_queues); +} + +/** + * blk_mq_num_possible_queues - Calc nr of queues for multiqueue devices + * @max_queues: The maximum number of queues the hardware/driver + * supports. If max_queues is 0, the argument is + * ignored. + * + * Calculates the number of queues to be used for a multiqueue + * device based on the number of possible CPUs. + */ +unsigned int blk_mq_num_possible_queues(unsigned int max_queues) +{ + return blk_mq_num_queues(cpu_possible_mask, max_queues); +} +EXPORT_SYMBOL_GPL(blk_mq_num_possible_queues); + +/** + * blk_mq_num_online_queues - Calc nr of queues for multiqueue devices + * @max_queues: The maximum number of queues the hardware/driver + * supports. If max_queues is 0, the argument is + * ignored. + * + * Calculates the number of queues to be used for a multiqueue + * device based on the number of online CPUs. + */ +unsigned int blk_mq_num_online_queues(unsigned int max_queues) +{ + return blk_mq_num_queues(cpu_online_mask, max_queues); +} +EXPORT_SYMBOL_GPL(blk_mq_num_online_queues); + void blk_mq_map_queues(struct blk_mq_queue_map *qmap) { const struct cpumask *masks; |