Commit 529d4d63 authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

ublk: implement NUMA-aware memory allocation 



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: default avatarCaleb Sander Mateos <csander@purestorage.com>
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 011af85c

drivers/block/ublk_drv.c

+53 −31
Original line number Diff line number Diff line
@@ -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);