Re: [PATCH v4 04/16] net/nbl: add Channel layer definitions and implementation

[Stephen Hemminger <stephen@networkplumber.org>]

On Tue, 12 Aug 2025 23:43:58 -0700
Dimon Zhao <dimon.zhao@nebula-matrix.com> wrote:

> +/**
> + * @brief: used to alloc continuous dma memory region for cmd buffer
> + * @mem: output, the memory object containing va, pa and size of memory
> + * @size: input, memory size in bytes
> + * @return: memory virtual address for cpu usage
> + */
> +void *nbl_alloc_dma_mem(struct nbl_dma_mem *mem, uint32_t size)
> +{
> +	const struct rte_memzone *mz = NULL;
> +	char z_name[RTE_MEMZONE_NAMESIZE];
> +
> +	if (!mem)
> +		return NULL;
> +
> +	snprintf(z_name, sizeof(z_name), "nbl_dma_%u",
> +		rte_atomic_fetch_add_explicit(&nbl_dma_memzone_id, 1, rte_memory_order_relaxed));
> +	mz = rte_memzone_reserve_bounded(z_name, size, SOCKET_ID_ANY, 0,
> +					 0, RTE_PGSIZE_2M);

Since this is setup during probe, and probe process is single threaded.
Using atomic here is overkill.