Re: [dpdk-dev] [PATCH v5 3/5] lib/mempool: allow page size aligned mempool

[Andrew Rybchenko <arybchenko@solarflare.com>]

On 3/25/19 9:03 AM, Xiaolong Ye wrote:
> Allow create a mempool with page size aligned base address.
>
> Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>
> Signed-off-by: Xiaolong Ye <xiaolong.ye@intel.com>
> ---
>   lib/librte_mempool/rte_mempool.c | 3 +++
>   lib/librte_mempool/rte_mempool.h | 1 +
>   2 files changed, 4 insertions(+)
>
> diff --git a/lib/librte_mempool/rte_mempool.c b/lib/librte_mempool/rte_mempool.c
> index 683b216f9..171ba1057 100644
> --- a/lib/librte_mempool/rte_mempool.c
> +++ b/lib/librte_mempool/rte_mempool.c
> @@ -543,6 +543,9 @@ rte_mempool_populate_default(struct rte_mempool *mp)
>   		if (try_contig)
>   			flags |= RTE_MEMZONE_IOVA_CONTIG;
>   
> +		if (mp->flags & MEMPOOL_F_PAGE_ALIGN)
> +			align = RTE_MAX(align, (size_t)getpagesize());
> +
>   		mz = rte_memzone_reserve_aligned(mz_name, mem_size,
>   				mp->socket_id, flags, align);
>   
> diff --git a/lib/librte_mempool/rte_mempool.h b/lib/librte_mempool/rte_mempool.h
> index 7c9cd9a2f..75553b36f 100644
> --- a/lib/librte_mempool/rte_mempool.h
> +++ b/lib/librte_mempool/rte_mempool.h
> @@ -264,6 +264,7 @@ struct rte_mempool {
>   #define MEMPOOL_F_POOL_CREATED   0x0010 /**< Internal: pool is created. */
>   #define MEMPOOL_F_NO_IOVA_CONTIG 0x0020 /**< Don't need IOVA contiguous objs. */
>   #define MEMPOOL_F_NO_PHYS_CONTIG MEMPOOL_F_NO_IOVA_CONTIG /* deprecated */
> +#define MEMPOOL_F_PAGE_ALIGN     0x0040 /**< Chunk's base address is page aligned */

For me it sounds like mempool objects should be page aligned since
MEMPOOL_F_NO_SPREAD, MEMPOOL_F_NO_CACHE_ALIGN and
MEMPOOL_F_NO_IOVA_CONTIG say about object properties, not chunk.

Personally I doubt that the final goal is just having chunk page aligned.

Andrew.