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ublk: implement NUMA-aware memory allocation

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Implement NUMA-friendly memory allocation for ublk driver to improve
performance on multi-socket systems.

This commit includes the following changes:

1. Rename __queues to queues, dropping the __ prefix since the field is
   now accessed directly throughout the codebase rather than only through
   the ublk_get_queue() helper.

2. Remove the queue_size field from struct ublk_device as it is no longer
   needed.

3. Move queue allocation and deallocation into ublk_init_queue() and
   ublk_deinit_queue() respectively, improving encapsulation. This
   simplifies ublk_init_queues() and ublk_deinit_queues() to just
   iterate and call the per-queue functions.

4. Add ublk_get_queue_numa_node() helper function to determine the
   appropriate NUMA node for a queue by finding the first CPU mapped
   to that queue via tag_set.map[HCTX_TYPE_DEFAULT].mq_map[] and
   converting it to a NUMA node using cpu_to_node(). This function is
   called internally by ublk_init_queue() to determine the allocation
   node.

5. Allocate each queue structure on its local NUMA node using
   kvzalloc_node() in ublk_init_queue().

6. Allocate the I/O command buffer on the same NUMA node using
   alloc_pages_node().

This reduces memory access latency on multi-socket NUMA systems by
ensuring each queue's data structures are local to the CPUs that
access them.

Reviewed-by: Caleb Sander Mateos <csander@purestorage.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Ming Lei
2025-11-01 21:31:17 +08:00
committed by Jens Axboe
parent 011af85ccd
commit 529d4d6327
1 changed files with 53 additions and 31 deletions
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84
drivers/block/ublk_drv.c
View File

@@ -209,9 +209,6 @@ struct ublk_queue {
struct ublk_device {
struct gendisk *ub_disk;
char *__queues;
unsigned int queue_size;
struct ublksrv_ctrl_dev_info dev_info;
struct blk_mq_tag_set tag_set;
@@ -239,6 +236,8 @@ struct ublk_device {
bool canceling;
pid_t ublksrv_tgid;
struct delayed_work exit_work;
struct ublk_queue *queues[];
};
/* header of ublk_params */
@@ -781,7 +780,7 @@ static noinline void ublk_put_device(struct ublk_device *ub)
static inline struct ublk_queue *ublk_get_queue(struct ublk_device *dev,
int qid)
{
return (struct ublk_queue *)&(dev->__queues[qid * dev->queue_size]);
return dev->queues[qid];
}
static inline bool ublk_rq_has_data(const struct request *rq)
@@ -2662,9 +2661,13 @@ static const struct file_operations ublk_ch_fops = {
static void ublk_deinit_queue(struct ublk_device *ub, int q_id)
{
int size = ublk_queue_cmd_buf_size(ub);
struct ublk_queue *ubq = ublk_get_queue(ub, q_id);
int i;
struct ublk_queue *ubq = ub->queues[q_id];
int size, i;
if (!ubq)
return;
size = ublk_queue_cmd_buf_size(ub);
for (i = 0; i < ubq->q_depth; i++) {
struct ublk_io *io = &ubq->ios[i];
@@ -2676,57 +2679,76 @@ static void ublk_deinit_queue(struct ublk_device *ub, int q_id)
if (ubq->io_cmd_buf)
free_pages((unsigned long)ubq->io_cmd_buf, get_order(size));
kvfree(ubq);
ub->queues[q_id] = NULL;
}
static int ublk_get_queue_numa_node(struct ublk_device *ub, int q_id)
{
unsigned int cpu;
/* Find first CPU mapped to this queue */
for_each_possible_cpu(cpu) {
if (ub->tag_set.map[HCTX_TYPE_DEFAULT].mq_map[cpu] == q_id)
return cpu_to_node(cpu);
}
return NUMA_NO_NODE;
}
static int ublk_init_queue(struct ublk_device *ub, int q_id)
{
struct ublk_queue *ubq = ublk_get_queue(ub, q_id);
int depth = ub->dev_info.queue_depth;
int ubq_size = sizeof(struct ublk_queue) + depth * sizeof(struct ublk_io);
gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO;
void *ptr;
struct ublk_queue *ubq;
struct page *page;
int numa_node;
int size;
/* Determine NUMA node based on queue's CPU affinity */
numa_node = ublk_get_queue_numa_node(ub, q_id);
/* Allocate queue structure on local NUMA node */
ubq = kvzalloc_node(ubq_size, GFP_KERNEL, numa_node);
if (!ubq)
return -ENOMEM;
spin_lock_init(&ubq->cancel_lock);
ubq->flags = ub->dev_info.flags;
ubq->q_id = q_id;
ubq->q_depth = ub->dev_info.queue_depth;
ubq->q_depth = depth;
size = ublk_queue_cmd_buf_size(ub);
ptr = (void *) __get_free_pages(gfp_flags, get_order(size));
if (!ptr)
/* Allocate I/O command buffer on local NUMA node */
page = alloc_pages_node(numa_node, gfp_flags, get_order(size));
if (!page) {
kvfree(ubq);
return -ENOMEM;
}
ubq->io_cmd_buf = page_address(page);
ubq->io_cmd_buf = ptr;
ub->queues[q_id] = ubq;
ubq->dev = ub;
return 0;
}
static void ublk_deinit_queues(struct ublk_device *ub)
{
int nr_queues = ub->dev_info.nr_hw_queues;
int i;
if (!ub->__queues)
return;
for (i = 0; i < nr_queues; i++)
for (i = 0; i < ub->dev_info.nr_hw_queues; i++)
ublk_deinit_queue(ub, i);
kvfree(ub->__queues);
}
static int ublk_init_queues(struct ublk_device *ub)
{
int nr_queues = ub->dev_info.nr_hw_queues;
int depth = ub->dev_info.queue_depth;
int ubq_size = sizeof(struct ublk_queue) + depth * sizeof(struct ublk_io);
int i, ret = -ENOMEM;
int i, ret;
ub->queue_size = ubq_size;
ub->__queues = kvcalloc(nr_queues, ubq_size, GFP_KERNEL);
if (!ub->__queues)
return ret;
for (i = 0; i < nr_queues; i++) {
if (ublk_init_queue(ub, i))
for (i = 0; i < ub->dev_info.nr_hw_queues; i++) {
ret = ublk_init_queue(ub, i);
if (ret)
goto fail;
}
@@ -3128,7 +3150,7 @@ static int ublk_ctrl_add_dev(const struct ublksrv_ctrl_cmd *header)
goto out_unlock;
ret = -ENOMEM;
ub = kzalloc(sizeof(*ub), GFP_KERNEL);
ub = kzalloc(struct_size(ub, queues, info.nr_hw_queues), GFP_KERNEL);
if (!ub)
goto out_unlock;
mutex_init(&ub->mutex);